Introduction: Cooking Hood Design
This is my first ever instructable here although I have been a member for about two years now.
What informed my project:
I have been running all the light points in my home on 12 volts DC supply for about 2 years now. This is provided solely by solar panel set up. All the lights are LEDs which run very efficiently and have lasted the two years without needing a single replacement yet. The security lights are hooked to a photodiode sensor that detects light and darkness to control the on-off cycle. The home security alarm system runs on 12 volts DC direct, so also is the satellite decoder that works on 12 volt DC direct (I simply jettisoned the 220VAC-12VDC 2amp power pack that comes with both). However, other heavier gadgets like the refrigerator and big screen TV instead of 12 volt supply, all have 24volt solar supply bumped up to 240VAC before it's fed into 'em.
I realized that all the kitchen hoods in the market run on AC supply. I initially considered getting an AC powered model and mod it into direct DC supply, but I figured out the best I can do is to change the AC fan and possibly the AC lights to DC, but tinkering with the circuits, especially in my favoured touchscreen models will pose a formidable challenge. I therefore needed to come up with my own model, built from scratch, handcrafted to look original and designed to run on both 12volt DC or AC (240VAC~12VDC external power pack) for user preference.
There are not much treated 'ibles to get on DIY kitchen hood on the internet as well as on this site. So I had to come up with most dimensions on my own. I got several pictures of different sizes and shapes of cooking hoods and I decided to stick with one high end hood that caught my fancy. It stands out to be beautiful for having front glass as part of the component and is also a touch screen model.
I went with the 30 inch by 19.5 inch dimension variant of hoods. This will be appropriate since my cooker is the typical 4- burners. Others include 45 inches and 90 inches lenght variants for the 6-burner and other larger cookers. For no special reason, I made my own length 29.5 inches instead of 30 inches.
My choice of material is aluminium for the following reasons:
- Easy workability and pliability compared to steel and wood.
- Easy to source in my area
- Fairly inexpensive
- Easy to paint and it takes paint well.
- Unpainted aluminium has a characteristic natural colour that resembles dull stainless steel. If you can lay your hands on this, it means that you at not have to do much spray painting to achieve the stainless steel appearance that the factory hoods have. However in my area, this colour is very rare and hard to come by. The available ones are already factory painted. While this may be undesirable with the profile frames, it is of little consequence with the aluminium sheets because the unpainted side can be used.
On the flip side, coloured aluminium profiles can provide you with a finished hood that provides an exotic taste of colour rendering that is never before seen with factory hoods.
- Aluminium glues easily to itself and will glue easily with other materials that I will use in the project (glass, acrylic, plastic)
- Unlike with steel, the aluminium profiles are designed with grips for screws at strategic places (Check the pictures). The grip holes extend the entire lenght of the aluminium profile so at whatever point you saw it across, you still get your screw grip holes. You can also easily drill new holes to create recess where and when you don't want screw heads showing outside. This provides more finesse and aesthetics close to originality.
- Less fire hazard than wood. This consideration is important since it will overhang a fireplace.
Step 1: Tools and Requirements
1. Cordless drill and various drill bit sizes.
2. Circular saws of various sizes
4. Screwdriver set.
7. Razor blade.
8. Bradawl or a hole punching tool
9. Hacksaw (for cutting aluminum profile into required sizes)
10. Scraper and sandpaper (tiny grit)
11. Angle ruler
12. Transparent ruler
13. Glass cutter (To trim or cut the already cut-to-size glasses for adequate flush and finishing and aesthetics.
14. Transparent cellotape and insulating electrical tape.
15. Mini clamp.
16. Tape measure.
17. Soldering iron (I have a 4.5volt battery operated one that I modded to run on 5 volt portable power bank.
18. Wire clips.
19. Acrylic glue - this is a 4 minute drying glue - (get enough on stand-by as you'll use lots of it)
20. Super glue - this dries in a minute but nothing close to the strength of acrylic glue.
21. Gasket gum - available colours are transparent, white and black. The white or black may cause stains from unintended smears on my project, so I went with the transparent silicone. Silicone takes 12hours to cure/dry.
22. Lenght of copper wires
I had the plan of doing some intricate works with glass so I ordered various glass drills, circular diamond cutters of various diameters and diamond sanders. I later found out that working with glass is not easy as I had many breakages. Painstaking patience is needed in the process but I wanted to finish the version 1 of my hood in record time. The easier alternative was to go with acrylic to replace the points that require machining, significant cutting and intricate sanding. That was where the acrylic came in to the components.
1. Aluminium profile frames (50mm width)
2. Aluminum profile frames (80mm width)
3. Aluminium profile frames (30mm width)
4. Aluminum sheets (0.45mm or more thickness, and preferably chrome coloured)
5. Aluminium profile 90 degree angle plate
6. Aluminium profile screws. Any type of screws will suffice anyways. Get different sizes on standby.
7. Rubber stripes (don't know the technical name but it is normally used to anchor nets to aluminium Windows and it serves similar purpose for the grease filter in my project)
8. Right angle plastic angle for 30mm profile (8pcs). You might require more depending on the number of filters you want to have. I settled for two filters.
9. 6" plastic pipe
10. 6" angle plastic pipe.
11. Blue or Green reflective glass cut to the width of Aluminium profile frame (50mm width)
12. Transparent Acrylic glass cut to the width of Aluminium profile frame (50mm width)
13. Screws to hold aluminium frames together. More screws of different sizes will be required also for other parts. The sizes range from between 0.5mm to 2mm.
14. Spray paints (Transparent - Mandatory, Chrome or Aluminum - depending on preference, Gold colour. I started with and maintained use of Aluminium colour because I couldn't get Chrome which was a preferred choice)
15. Metal nets (2 sizes)
16. A small solar 12 volt AC/DC fan with 10 inches blade diameter. I have two of this that was included in one of the 12v solar packs that I purchased. So I guess I can sacrifice one.
STUFFS PURCHASED ONLINE
17. LED Downlights. My choice of this downlight is informed by the fact that it is small size (just 50mm) and it has an adjustable angle which helps you to easily adjust the light direction and illumination over the burners.
18. Touch type LED controller. This sensor is touch-on, touch-off and sustained touch-dimmer. It also has this always-on, stand-by beautiful faint blue indicator circumferential light which stays on as long as there is current in it and irrespective of the on or off status. Another plus is that this stand-by state consumes very negligible current.
19. 6 volts - 24 volts DC motor speed PWM controller with digital display. https://www.aliexpress.com/item/Hot-Selling-DC-6-28V-2A-DC-Motor-Stepless-Speed-Controller-Switch-PWM-With-2-Bit/32651859195.html
20. 12 volts digital temperature controller. I intend to have it "always-on" because it will give me an instant, on-the-spot ambience temperature of the kitchen. But I have had second thoughts about that decision and also a reservation for the controller because of the high current (120mA) it consumes on stand-by. It rises to around 140mA when it switches relay. But I used it anyways.
21. NTC thermistor temperature sensor 3 meters length. The one that came with the digital temp controller is just few centimeters in length. I needed something much longer so I had to purchase a longer probe differently. I intend to course the probe to another point in the kitchen far away from the hood and the burners so that it measures the approximate ambience temperature of the kitchen at any point in time.
Suffice it to say that up till the time I'm writing this 'ible, the item has not arrived and it cannot be tracked. So I had to make do with the 50 cm length I have for now.
22. Large 12 volt computer case fan with red LED fancy light. This will serve as the accessory exhaust fan which will be mounted on the outside. As a computer case fan, it is originally designed for exhaust function so I need not reverse the blade or reverse the wiring. Its on-of cycle is controlled by the relay of the thermostat. It does not consume much current therefore it runs most time of the afternoon. The CFM is very small, so there is no fear of creating a negative pressure in the kitchen. But to a small extent, especially when there is no cooking going on, it keeps the kitchen air fresh and circulating much like a toilet exhaust fan.
23. Self sticking PVC wallpaper.
24. Acrylic mirror stickers.
25. 120 ohms resistor (4 pcs). I have these lying around in my collection.
NOTE: That some of the components I purchased have wide voltage ratings between 5volts to as high as 24volts. This was intentional. I plan to run the hood off of 5 volt power bank supply at some point in the future. I have a 5 volt power-bank powered portable fan on stand-by for that. Other components that can't run on 5 volts and have no 5 volt alternatives with at par performance in the market will have their supply voltage bumped up to 12 volts by a DC-DC boost converter before it is fed into them. I am awaiting receipt of converters I ordered online from the following links:
Step 2: ALUMINIUM PROFILE CUT AND PARTIALLY ASSEMBLED
The assembled profiles consist of the following:
A. The 50mm width aluminium profile cut into four parts viz:
1. A front facing horizontal profile panel - A1- (29.5 inches in lenght) which houses the displays and touch button for the light, the temperature controller and the PWM motor speed controller. Also it will later house the temp controller buttons and the PWM rotating knob. I have cut and drilled the necessary holes on this panel to accommodate those various components and buttons. Initially I fabricated this front panel in such a way that it can be unscrewed from the other two side frames to make it kind of "hot-swappable" so that I can have the choice to put in any other front panel design of my choice and liking. However as I later found out, I had to glue it with silicone adhesive to the top aluminium sheet covering. So my "hot-swappable" concept is somehow defeated.
2. A right side horizontal frame (19.5 inches length) A2.
3. Another horizontal frame for the left side (19.5 inches length) A3.
4. A rear horizontal frame (25 inches) A4. This rear frame will later form the base of and hold the two vertical frames (D1, D2) which will anchor the hood exhaust pipe. D1 and D2 also hold the hook/anchor to mount/screw the hood to the wall.
All four frames were cut at each end in a 45 degrees angle to ensure the 90 degrees right angle meeting point when they are screwed end-to-end. This forms a perfect rectangular shape measuring 29.6 inches by 19.6 inches). I think the 0.1 inch unexpected increase arose from the joints between the cut aluminium frames. This forms what I call the BASE HORIZONTAL FRAME.
B. The 80 mm width aluminum profile cut into three dimensions -
1. 1 piece (11.4 inches)
2. 1 piece (11.4 inches)
3. 1 piece (12.7 inches)
I screwed all these together to form a three- side rectangle 11.5" by 12.8" dimension, with the 4th side absent. All angles are 90 degrees. This SMALLER HORIZONTAL FRAME will go on top of the BASE HORIZONTAL FRAME. It functions as follows:
- To anchor the remaining top of the hood (the 6" pipe and its COLLECTOR) to the base horizontal frame.
- It holds the frame that will house the motor for the MAIN HOOD FAN. The motor frame attaches to B1 and B2.
- At the rear, it also partially screws onto the TWO VERTICAL FRAMES - i.e. B1 to D1 and B2 to D2 (that holds the wall mounts) at the back.
- They are screwed onto the top of A4, each at 8.4 inches away from each end of A4, i.e. D1 to A4 and D2 to A4.
Note that I did not bother myself with the stress of cutting all three B frames at 45 degrees simply because it will be finally covered by the hood exhaust pipe aluminium sheet covering.
C. Another 80mm profile cut into a single 29.6 inches length (C1). C1 functions as follows:
- This will be a center girdle to the main horizontal base frame.
- It will also form the base of the smaller horizontal frame (formed by the B profiles), i.e. the furthest edge of B3 is flush with the furthest edge of C1.
- It will serve as anchor point (glued and screwed) for the inner edge of the aluminium sheet cover that will form the top of the hood base.
The position of both edges of C1 along B2 and B3 must be equal. The exact point will be determined by your preferred point of rest of B3 frame on it (C1). I preferred the furthest edge of B3 to rest on the furthest edge of C1. This is so that it will not occlude any part of the 12.7" by 11.4" inlet of the smaller B frame and by extension the AIR COLLECTOR inlet.
D. Yet another 80mm aluminium frame cut into two pieces each 32 inches in length
1. 1 piece (32 inches) D1
2. 1 piece (32 inches) D2
These function as follows:
- They hold the horizontal mounting bar (for the wall mount installation). This probably is their most important function.
- They complete the height of the hood
- They screw flush to the top of A4.
- On either side, they act as anchor frames for the exhaust pipe aluminium sheet covering at the rear.
- On either side, they hold and support the 6 inches bend pipe at the exit point at the top.
- They also screw to the rear end of the B frames, i.e.B1 to D1 and B2 to D2
E. 50mm aluminium profile cut into two equal lengths of 20 inches each.
1. 20 inches (1 pieces) E1
2. 20 inches (1 pieces) E2
They function as follows:
- Brace the B frames to the D frames.
F. An 80mm aluminium profile cut along the long axis to get a width of 52mm (F1). This will have the holes to house the two LED downlights of the hood. It also hides the wirings of components housed in A1 away from direct view and away from heat and steam that will get into the hood.
F1 is 27.5 inches in length and is anchored by A2 and A3 on either side and along its long axis in the front by lower 1/4 of the width of A1.
G. A short 12.4 inches length of 50mm aluminium profile was cut (G1). This will serve as a horizontal brace somewhere along the length of D1 and D2. It also helps to maintain the 12.7 inches separation of D1 and D2 thru their entire 32 inches length.
H. 12 inches length of the 80mm aluminium profile (H1). This will house the DC motor and screwed onto it. G1 will be anchored by frames B1 and B2 on either side midway along their length.
G1 will also be easily removable to provide easy access to the components housed inside A1.
This set up is to ensure a rigid frame.
Step 3: BRACING THE D1 and D2 PILLARS
As seen in the picture, the pillars D1 and D2 both taper upward and therefore become narrower on the top than below. D1 and D2 need to be equidistant above as they are below.
Also D1 and D2 will bear most weight of the hood as it carries the mount that hangs it on the wall. The joint that D1 and D2 makes with A4 therefore needs adequate strenghtening. The solutions are as follows:
E1 and E2 solve the second problem.
G1, as we will see later, will solve the first problem.
Step 4: CUTTING THE TOP ALUMINIUM COVER SHEET
The aluminium cover is cut out from a 0.55mm thickness aluminium sheet. You may use more thickness if affordable, but anything less than 0.45 will not give an ideal tension resistant covering. You will need the shiny unpainted surface of the sheet to face the exterior, therefore that will be the part facing up when marking out your dimensions on the sheet.
The dimensions on the sheet follows that of the rectangular dimensions of the HORIZONTAL BASE A FRAME (i.e 29.6 inch by 19.6 inch) but with an overshoot of 10mm on all sides. This overshoot is to guard against any errors that may cause the sheets not to completely cover the tops of the base A frame on all sides. After the gluing and screws are appropriately applied, all overshoots beyond the extent of the base A frame will be cut off with knife to give a fine flush.
After cutting out the rectangular dimension, another rectangular shape corresponding to the space for the smaller B frame (12.7" x 11.4") will still have to be cut out of the bigger rectangular shape of 25.6" x 19.6". However when cutting this, an allowance/overshoot of 4mm should be allowed on all the three sides (refer to picture). This overshoot forms part of the cover sheet that slides into the narrow grooves between frame C1 under and B1, B2 and B3 above. The overshoots will later be glued and screwed tightly to the underside of the B frame.
Refer to the picture for the outline and the calculations to arrive at the dimensions.
Step 5: SLIDE AND GLUE THE SHEET TO THE FRAMES.
After the sheet has been cut to the proper size, it is carefully SLID into the frame from the front. This way ensures that the 4mm overshoot of the 12.7" x 11.4" rectangle cut slides right under the B1 and B2 frames and finally into the narrow groove between B3 and C1. This may not be as easy as said, requiring some fondling or at worst, minor cutting off, at some point. But you should soon be able to slide it cleanly in to position. Ensure there are no wrinkles or undulations on the sheet. It must be cleanly smooth in all places on the top of the hood, failure of which the hood will appear irregular and rough when viewed from the side and from above.
The next step is to glue the sheets in place on the frames below excluding A1 (i.e. A2, A3, A4 and C1. Gluing A1 will be saved for the final last steps. This stage of gluing is not a one off process or stage but it requires a step by step approach. Start preferably from the A4 frame behind on both sides. Holding the sheet on opposite ends of the posterior edge (i.e. the edge that lines with A4, pull the sheet tightly backwards towards yourself and use a clamp to hold it firmly in place. Then begin the process of gluing.
- Identify the short area you want to work on.
- Slightly seperate the area and the sheet covering it.
- Carefully apply the glue to the surface of the A4 frame where you want to work on.
- Return the sheet and firmly press it together using a clamp.
Except you have a clamp with a very wide surface or you have many clamps to spare, you can only do the gluing a small area at a time.
I have a very small clamp with a small surface but I achieved a larger work area by placing a flat hard metal on the whole set up and clamping all three together. Along with clamping, I held it together with my hands in some other points (I know, but it's just for four minutes, right?). Do this for three of the four sides of the A frame. Also do it for the C1 frame. Leave the A1 frame for the last.
After they are strongly glued and dried, using a sharp knife, begin to cut off the overshoots on all glued sides. The glue is strong enough that it holds firmly to withstand the stress from the cutting. A1 is yet to be glued, so it is left out of the cutting.
Step 6: ASSEMBLING THE FAN AND ITS FRAME
The fan is fixed onto its frame H1. The fan blade is centripetal rather han centrifugal which is commoner in the models of hoods I've come across. The good thing is that this fan performs creditably well. While I can't be sure of its CFM, I'll estimate something in the range of 450cfm.
I needed to turn the blade in the opposite direction since the curve of the blades is already fixed to be a blower rather than an extractor. This means that the motor connection also has to be reversed in polarity to make the fan turn in the opposite direction - it turns right to blow air, hence it needs to turn left to extract air.
H1 has screw grip holes already manufactured with the aluminium profile. The grip holes extend the entire lenght of the aluminium profile so at whatever point you saw it across, you still get your screw grip holes. Two grip holes on each end (blue circle in the picture). Drill the corresponding screw holes on B1 and B2.
Drilling holes, especially with small power tools can be time consuming and I suspect it will be worse with manual drills. So since the rotor assembly is lightweight (not heavier than the weight of two of my Lumia 1520 cellphone), I decided that one hole rather than two holes on each of B1 and B2 will suffice. So I drilled one hole on B1, and an alternating hole on B2 corresponding to the second screw grip hole of H1.
The B1, B2 and B3 frames will subsequently host the aluminium sheet that houses the air collector, exhaust pipe, the two pillars D1 D2, the horizontal brace G1 and the braces E1 E2. The B frame will attach to the base of the aluminum sheet. So it needs to be smooth on all its 80mm wide flat surfaces. Therefore the screws that will hold B1 to one end of H1 and B2 to the other end of H1 will need to have their heads recessed.
THIS IS HOW TO RECESS SCREW HOLES ON THE ALUMINIUM PROFILES.
On the outside surface of B1 and B2, drill the outer holes larger than the head of whatever screw you will use. The inner holes on the inner surface will be the size of the screw proper. This way, when turning the screw, the head goes right past the outer surface and continues inside to do the job of gripping the B frame with H1. If more aesthetics is desired, the defect created by the outside hole can be covered by some sort of filler, sanded smooth and painted as the colour of the aluminum.
PS. Ensure the rotor, fan and H1 holder are
installed before the next step. Check that the rotor works and the fan is installed in the right direction (i.e. It draws/blows air UPWARDS and NOT DOWNWARDS)
Step 7: AIR COLLECTOR
This is something I call the air collector ( I don't know the technical term to qualify it). But it is the short portion between the flat part of the hood that overhangs the fireplace and the point at which the 6 inches exhaust pipe begins. This place should be wide enough to house the 10 inches diameter fan. This practicability can be achieved with the aluminium sheet.
- First is to make paper templates of what shapes the aluminium sheets will be cut into. Note that the paper templates all have a 10mm overshoot all round. These overshoots are to ensure that there is a place for each shape to be glued together.
- Next is to cut out the respective shapes from the aluminium sheets using the paper templates.
- Then bend the sheets at the respective overshoots and align then properly. DO NOT BEND THE 40mm overshoot of the rear sheet. The 40mm overshoot does not interact with other sheets that form the air collector but it's only business is with the 50mm breadth of A4, the front of which it lies. So it slides inside and straight down instead. It is later glued to the front facing part of A4 to form part of the anchorage for the air collector we construct.
- The overshoots at the base of the air collector (excluding the rear plate overshoot) bend to the outside and enables it to comfortably sit atop the partial rectangle formed by B1, B2 and B3.
- The overshoots are glued (using acrylic glue) and later screwed firmly onto B1, B2, B3. This double reinforcement is needed because the air collector will carry the 6" exhaust pipe at its origin. The pipe is the thick variant and therefore it's a little heavy.
- Ensure that there are no leaks around the corners and edges of the air collector and at its junction with the B frame. Any potential leaks will reduce efficiency as the air from the fan will escape thru such places. Plug any leaks by using silicone gasket gum from the inside surface.
- Allow for the set-up to strengten and the silicone to fully cure (24 hours)
Step 8: ADDING THE 6 INCHES EXHAUST PIPE
After the air collector is ready and all glued points are well dried and hardened (the silicone can take up to 24hours for complete cure), next is to add the exhaust pipe.
The entire height of the hood is 34". Approximately 2" (50mm) outta it is taken by the BASE HORIZONTAL A FRAME. Another 8" is taken up by the AIR COLLECTOR. This makes a total of about 10" already occupied. This leaves like 22" of the height remaining. So I figured that the exhaust pipe alone (without the bend/shoulder) should take up around 12". So I added 2" more to care for errors. If this is correct, it will leave around 8" to be taken by the 6" bend/shoulder and the little space (around 1.5" that will be between the top of the bend and the entire height of the hood.
However, keep in mind that this 6" exhaust pipe will slide a few centimeters into the 6" bend superiorly and a few more centimeters into the air collector inferiorly. So at the end, the 2" error check may work out or may even be an excess.
Cut out 14" length of the 6" pipe. A part of its lower end (around 0.7") goes into the air collector. Remember that the top dimension of the paper template (of the air collector) was a 7" by 6" rectangle so at the end of the day, there will be some allowances around the pipe. The excess length above that will inevitably occur from the air collector is scissored out and released as flanges to encircle the 6" pipe (as seen in the picture). These flanges to the entire extent of their reach superiorly and laterally, are glued (using acrylic glue) to the pipe. This creates a solid joint between the air collector and the exhaust pipe.
Check out points of loose connection and apply more acrylic glue to such points. The top of the air collector will most likely not form a airtight wrap-around for the pipe. The narrow spaces created can be escape routes for air from the fan and this will impair function and efficiency of the hood. Locate such spaces and seal shut with generous amount of silicone. Silicone has the added advantage of high heat tolerance, so it is perfectly suitable as a filler and sealer at this spaces.
Step 9: ADDING THE 6 INCH BEND / SHOULDER PIPE
This pipe will form the upward continuation of the exhaust pipe that originates from the air collector below. The bend allows the vent to be installed on the side of the outside wall rather than through the roof.
I have the alternative of using a flexible bend, but I went with the rigid bend because it will also contribute to the wall support of the hood. It projects out by as much as 3 inch, so it acts as a "hanger" on its hole/vent in the wall.
I later realized that the exhaust pipe is much longer than is required. The 2" extra turned out to give an excess of 3" that need to be sawed off. Using a handsaw will create sudden and wide movements that can dislodge the joint between the exhaust pipe and air collector, even though its a strong bond. Besides, the space is too occluded to allow for the wide range of movement a hand saw requires. So I had it cleanly sawed off using a circular saw mounted on power drill.
The bend fits perfectly around the 6" pipe.
The distal end of the bend has to pass thru the D1 and D2 pillars. The bend is 6.3" wide but the pillars are only 5.7" apart. This means that a hole wide enough to accommodate the circumference of the bend will have to be created on both D1 and D2.
This is achieved by creating a 6.6" template on a cardboard paper. This is placed against D1 and D2 ensuring that the centre of the circle aligns with the centre of the lenght of a straight horizontal line joining the two lateral ends of D1 D2.
Also create an allowance of about 1.5" between the highest point formed by the D1 and D2 pillars superiorly and the highest point that will be formed by the bend.
The circle is them traced out on both pillars and it is cut out.
Next is to fix the bend in position. The bend fits perfectly and very tightly around the 6" pipe. This is an airtight fit, so no need for any gluing of the joint. Another reason not to glue the joint is that you will need some extent of flexibility at the joint when mounting the hood on the wall.
In case the bend is already too high for the holes cut on D1 D2, the 6" exhaust pipe below may require further sawing off to correct the error and achieve the desired allowance. This correction is another reason not to have glued the joint.
Step 10: MAKING THE FINAL HOUSING
This housing covers the bare bone height of the hood. The bare bone height is made up of everything above the hood wing - B frame, air collector, exhaust pipe, lower 3/4 of the 6" bend, D1, D2, E1, E2 and G1. This will be formed by aluminium sheet. It is cuboidal in shape measuring about 11.5" x 12.8" x 32" (WxLxH)
Also have it in mind that the shiny unpainted surface of the aluminium sheet will need to face outside.
The total length of the width and length together is 11.5"+12.8"+11.5"+12.8" = 48.6"
The total height will be the height of the vertical D pillars = 32"
- Spread out a full length of aluminium sheet with the shiny surface facing upwards.
- Measure out 48.6" by 32" rectangle, ensuring that the 4 right angles are correct using the angle rule. Give an overshoot of 50mm on 2 adjacent sides (this is the same as giving overshoots of 25mm on all sides.
- Mark out the dimensions using a sharp object.
- Also mark out the 3 points at which the sheet will be bent. Rule them straight from top to bottom. This will make three rectangles side by side within the largest rectangle. This marks made inside the bigger rectangle is to serve as guides when the sheet is being flexed to right angles to form all four corners and four faces of the housing. DO NOT CUT AT THESE MARKS.
- Cut out the big rectangle using a scissors.
- Bend the sheet accordingly using the three marks as guides. This will require some skills but it is not difficult either.
- Test the housing by lightly wrapping it around the B frame inferiorly and the D1 and D2 frames superiorly. This should fit snugly.
- At the top, cut out the space to accommodate the 6 inch bend.
- Remove it and keep it away safely to be installed later.
Step 11: THE FRONT PANEL - SELECT THE CONTROLLERS TO BE INSTALLED
The front panel is formed by A1 frame. This is what will carry the electrical controllers and house majority of the wirings. Three major electrical controllers will be fixed onto the front panel viz:
- The touch switch controller for the LED lights.
- The digital thermostat/temperature meter and controller.
- The digital PWM motor speed controller (this switches on the fan and controls the fan speed)
The arrangement will be from left to right as outlined above.
- You must first ensure that these controllers have heights that do not exceed the inner height (47mm) of the A1 frame. I was lucky that two out of the three components are less than 48mm in their heights so they easily fit into the A1 frame.
- The temperature controller however is a rectangular shape that measures 50mm(H) by 72mm(L). So it will not easily fit into A1.
- I examined the thermostat and realized that the most lateral of its components are the relay switch and terminals (below) and the LED screen (above). These are the most extended to the edges. There is still an overshoot of about 0.5mm of the PCB beyond these components above and below. This portion of PCB also upon critical examination appears to be bare(i.e. free of circuit lines). This means that removing this portion will be of no consequence.
- So using a metal file, I carefully sanded off this 0.5mm edge above and below.
- Having in mind that there may be one or two circuit lines that I had missed seeing in these sanded-off edges, I tested the thermostat again to ensure it is still working. It works! Yay!
- I again checked to see if it will go into the 50mm A1 aluminium profile. Sadly, it still would not fit into the 47mm internal height.
- I need 2mm more to be sawed- off the controller.
- So I reasoned what more could be done. On the top of the thermostat is the LED display with its plastic housing. The plastic housing is just 0.15mm thick and filing it off could be destructive to the display. Besides, 0.15mm will amount to nothing.
- Below the thermostat are two components that are just ordinary screw terminals for the power supply and the output relay switch. In between these two lies the relay switch. I also found out that some circuit lines run directly below these three. The lowest of these circuit lines is off the lower edge by as much as 2.5mm. I figured I can saw off around 2.2mm of the terminals and relay switch and the PCB under them without much damage to the controller. That is what I did using a hand saw.
- After sawing off, I immediately again tested the controller and it works. Yay again!
Step 12: CREATE a CARDBOARD PAPER TEMPLATE FOR CONTROLLERS
You must then create a paper template for the components and how you want them arranged into the A1 frame. This template is what you will need to mark out your cuts on the front of the A1 frame, the self-adhesive aluminium sticker, the blue reflective glass/acrylic plexiglass.
I chose my arrangement from left to right to be:
- LED switch
- Digital temperature regulator
- PWM motor controller
You may use your own preferred arrangement.
Make a dummy arrangement of the controllers into the paper template to check that they align well and arranged properly. This will give a rough idea of how the front panel will look with the controllers in place. If you're not satisfied, you may have to cut a new template. If you are okay with what you get, proceed to the next step.
Step 13: TRACE ON AND CUT OUT TRACINGS ON THE A1 FRAME
The A1 frame is still not glued to the aluminium sheet at this point, so it can still be unscrewed from the rest of the A frame to ease working on it. You first unscrew the C1 frame attached to it behind, then unscrew the A1 itself. You get to screw both back on when you are done.
- On the A1 frame, mark out the centre of its entire length 29.6" divided by 2 gives 14.8 inches. This must also align with the midpoint of your template.
- Using a sharp object, trace out your template onto the front of A1 frame.
- Drill, cut and dremel as necessary.
My own cut out was a rough one, but that does not matter since the aluminium sticker, the glass and spray paint will still cover it. I will be more careful and patient with cutting and doing those.
You will also need to mark and cut out a rectangular space on the back of the A1 panel. This space, cut directly opposite the holes created with the template, is to create access when fixing the components and wrong them. Without this space, you cannot do those.
I sawed out this rectangle using circular saws mounted on the power drill.
Step 14: MAKING THE FILTER FRAMES
Before starting this, you will need to measure the internal dimensions formed by the A frame.
The external dimensions are 29.6" by 19.6". The base of the aluminum A frame measures about 25mm , which is the dimension it takes from each side of the A frame. That makes a total of 50mm (1.96 inch) along the length of A frame and 60mm along the breadth.
29.6" - 1.96" = 27.64"
19.6" - 1.96" = 17.64"
This is the expected dimensions. However this may be slightly different from what you have lying on the workbench in front of you. So I proceeded to measure.
I measured the internal dimensions of the A frame to be 27.5" by 18.4". Check the measurements from opposite sides to ensure the dimensions are equal on each of the two opposite sides.
DECIDE ON THE NUMBER OF FILTER FRAMES YOU WANT.
From pictures of factory hoods online, the filters range from 1 to 4. The very largest sizes I've seen (120") length hoods have 4 filters. Three filters are very common with the 30" and 90" size hoods. My project is in the 30" range but I decided to go with two filters instead because of simplicity, ease of fabrication and I think it will provide a neater appearance.
The measured internal dimension of the A frame is 27.5" by 18.5". Therefore two filter frames will give you:
27.5" divided by 2 = 13.75"
Two filter frames will be side by side, so you will need to create an allowance to ensure they fit perfectly into the A frame. I removed 0.05 inch from the width of 13.75".
Therefore finally, each filter frame will measure 13.7" by 18.5".
Please note that my filter frame dimensions may vary from project to project, so it is wise that you do not take the filter dimensions as sacrosanct. You will need to carefully work out what your filter lenght, breadth and allowances will be.
To make the frame, you will need the 50mm aluminium profile. This frame is used for aluminum window nets. It has grooves that hold the window nets in place.
- Cut out the dimensions making sure you create the 45 degrees angle on each side as you did with the A frame. For two filter frames, you will cut out 8 pieces.
18.5" (4 pieces)
13.7" (4 pieces)
- Assemble them accordingly using the rubber angles to hold them in place at the corners. You will require 8 plastic angles.
- If there are any adjustments or cuts to be made on the filter frame, now is the time to do that by doing the following:
- Try to arrange the frames as they will be (i.e. side by side) into the A frame. These should fit snugly. If they won't slide in freely or if they are too tight, mark out the adjustments with an indelible marker.
- Then bring out the frames, disassemble and saw out the marks as necessary.
- Assemble the filter frames again and arrange into the A frame to check that your adjustments are effective and accurate.
- If satisfied, GENTLY bring out the two frames and place them gently on the workbench. Do not disassemble this time.
- From your set up, locate the inner side (the side that will face the inside of the hood). With that side facing you, use a nail to punch holes in the aluminium thru into the plastic angle. About 4 punches on each end will do. This ensures a very firm grip at the angles.
Measure out what dimensions your frames finally produce. There may be slight variations between the two frames. Not to worry. This is a hand fabrication and not a computer aided, computer generated or laser cut process, so absolute top notch precision is a luxury here.
CUTTING THE NET
PS. You will need a strong hand glove to protect from punctures. Handling it requires extreme care.
Note the dimensions of your frames. This is what you will cut out from the metal net. I got two different sizes of the net. These are sold on per feet basis and come in rolls. One is so thick that it was hard to work so I had to ditch it. Fortunately, the other size that was easier to work had desired holes sizes and I could cut it with an ordinary scissors.
- This part is preferably done on the floor with a wide clear space. You will need a hand glove, pair of tall boots and also be in your trousers and a long sleeve shirt. Perhaps the only protective gears you won't be using are face masks, earmuffs and maybe a pair of googles. Of course I did it bare and I have the scars to tell the story (Lol).
- With extreme care, unroll the net and spread it out, placing heavy objects (hammers, power drills, pliers) on the four corners and at other points to hold it down and prevent it from rolling back in place, of which it may roll to your legs and puncture or cut your skin in the process.
- Using the indelible marker, trace out the dimensions of the filter frame on the net.
- Because I needed to spend as little time as possible with this "barbed" object, I chose the marking from one side and also marked out the two filter frame sizes in one length.
- With the scissors, cut out the dimensions.
- Carefully roll back that devil and take it far away from your work space and away from the reach of the kids. Phew!
AFFIX THE NET ON THE FRAMES
- With the inner side of the frame facing you, place the net on the filter frame.
- Take a wide flat Phillips screwdriver and work the edges of the net into the groove of the aluminium profile. It is a hard net unlike the nylon net the frame is originally designed for, but it is still workable with some perseverance.
- Some parts of the perimeter may have recalcitrant nets that will still struggle out of the groove. You may need to apply glue or gasket gum to these points and hold them down with a clamp until dried.
- After working in the net on the perimeter of the frame, ensure the net and the inner flat surface of the frame is flush by scissoring off any extra edges of the net that shoot out anywhere along the perimeter.
- Repeat the procedure for the second frame.
SPAY THE FRAME.
As I said earlier, my choice of aluminium colour was the unpainted aluminium but that was unavailable. I got could only get profiles with various colour offerings. So I had to spray paint this to my desired colour. But I will only paint the exterior and the edges of the frame. I won't bother myself with the side facing inside the hood.
- From experience, small nets hold the paints in the spaces and holes in them giving an undesired appearance. In addition, I love the original color of the net, so I covered it with nylon and taped it at the edges.
- Clean the surfaces to be sprayed to ensure it is free of debris and metal filings.
- Spray paint evenly.
- Allow to dry in the sun (5 hours), as much as 12 hours on cloudy days.
Step 15: AFFIXING THE GREASE FILTER
I ordered the filter online, two of 'em.
Each (LxW) measures about 60cm (23.6") by 45cm (17.7"). I ended up using one cos the length cut in equal halves provided enough cover for the filter frame. You only need to stretch the filter a little.
Also there is about 4 installation stickers that came with each grease filter. I won't be needing those since I have the rubber strip to do the job.
- Arrange the grease filter directly on the filter frame.
- From one edge of the filter frame, use a flat plastic and begin to push the rubber strip into the aluminium groove and over grease filter and the net in the groove.
- Work the rubber all the way making sure that there are no stick-outs or bulges along its path. You may need to stretch the grease filter some in order to for it to properly cover the frame. Work it to your starting edge.
- There will be excess grease filter along on edge of the breadth of the frame. Do not scissor it off. Rather gently fold it over. It will form part of the filtering process.
- Do this for the other filter frame.
Step 16: BACK TO THE FRONT PANEL
Here we consider the things that form part of the front panel. Things that overlay the A1 frame to give the aesthetic appearance.
I chose to go with glass, the reflective type. I was torn between the green reflective and the blue reflective but I bought the two anyways.
- Using the glass cutter and a ruler, I was able to cut out the dimensions of the front panel (29.6" by 50mm). Next is the most daunting part of the cutting.
In one of the pictures you'll see my glass cutting arsenal.
So next is to cut the template out on the glass. I first traced it on the glass using an indelible marker. I tried to cut, out the big circle (for the touch switch) first but I broke the glass.
I took a second glass and tried again. It broke. This is hopeless. I guess that I may need to consult with professional glass cutters to handle this part. Sadly, I do not have that luxury as no one in that capacity is known. It's not even available in a directory.
So I eventually settled for less: The acrylic.
But I still loved to use that glass because of the premium look it gives. So I decided the acrylic will be only for the middle of the A1 frame, that is, the place where the trace out is. So I proceeded to cut out an 8 inched length of acrylic with a width of 50mm.
- Using a sharp object, I traced out the outline on the template.
- Next I dremelled, drilled, punched sawed and sanded as appropriate.
- Place it against the cut out tracings already made on the A1 frame and ensure that they align well. Keep it safely away.
- Take the self adhesive acrylic sticker and cut out the same tracings on it. The tracings can be cut out by ordinary razor blade and scissors. Since this material is softer, the cut out should be cleaner than that on the A1 frame.
-Stick this adhesive on the A1 frame where the controls are, with the reflective side facing outwards.
- Take the acrylic that you've earlier cut and place it on the sticker.
- Hold in place with acrylic glue.
- Take the self-adhesive flowered wallpaper and cut out a width of 50mm and a length of about 25 inches long.
- Stick this adhesive wallpaper on the remaining surfaces of the A1 frame that lies on either ide of the acrylic centre.
- The idea is to make this flowered wallpaper serve as a background for the reflective glass that will later come on it.
- Then take the glass that is already in the 50mm dimension and use it to complete the acrylic (i.e. the same area occupied by the flowered wallpaper on both sides of the acrylic. I was able to salvage enough length from the broken glass to cover one side of the A1 frame.
- Ensure proper alignment of all these layers.
- Glue it in in place.
- Remember that at this point, the free overshoot of the aluminium sheet cover over the A1 frame is still not glued into place. Now is the time to do that.
Step 17: COMPLETE THE GLUING OF THE ALUMINIUM SHEET ONTO A1 FRAME.
The free A1 end of the aluminium sheet is now from left to right glued to the top of A1 and the glass and acrylic parts overlying it. This in addition ensures a proper grip of the whole A1 frame apparatus and layers (formed by the A1 frame itself, the acrylic and the glass) tightly altogether.
The A1 frame is glued to this sheet. This is why I said my plan to make the front panel "hot swappable" got defeated.
A quick look at the 80% finished front panel shows a reflective glass with a beautiful flower-patterned background. The centre of the front panel occupied by the controls is not so beautiful yet, at least not to my taste.
Next is to cut off the overshoot of the aluminium sheet on A1 frame, using a sharp knife, the same way it was done for the A2, A3 and A4 frames.
Step 18: THE CONTROLLERS AND SENSORS
Suffice it to mention here that I ended up burning the PWM fan speed controller due to a short circuit.
I had installed all components (LED lights and LED switch, Thermostat and motor speed controller) into the A1 frame and wired all to one lead supply from a 12 volt source. The moment I switched on the 12volt source, the two wires supply from the source simply melted.
Afraid that I may have damaged the components, I decided to try them out singly. The LED lights and LED controller worked fine, so also is the thermostat. The problem was the motor controller which has broken already.
I initially though it was my negligence of the manufacturer's instruction to have the motor controller fused with about 6Amps that caused this. I later discovered that the aluminum A1 frame housing had caused a short circuit (I annoyingly forgot that aluminium is a good conductor) of the +ve and -ve terminals of the controller. That was what caused the wires from the 12 volt supply to melt.
Subsequently I had the short circuit points on the controller covered with an insulating tape. For double protection, I also have the bare surface on A1 frame where the short-circuit occurred pressed back and also covered with a nylon insulator which I glued on it.
Had to purchase a new motor controller but this time I ordered for two sets just in case. This set me back by another 3 weeks of waiting for delivery.
I couldn't bear the six weeks waiting for the LED drivers I ordered, so I constructed a cheap one from the 100 ohms resistors I have lying around. I need 50 ohms per LED, so these will be connected in parallel to get 50ohms. Check the diagram for calculations.
- Having learnt my lesson with the motor controller short circuit, I used an insulating tape to ensure the proper insulation of the PCB board before screwing it on the C1 frame.
- Instead of being soldered permanently on, the LED lights will be connected to the driver via JST connectors. This makes it easy to disconnect the LED from, the driver in case of replacement.
The LED driver comes with a 2.5mm x 3.1mm male female DC plugs. I simply soldered the appropriate junction on the LED driver input.
The relay switch on the thermostat has a long wire that runs the entire height (34 inches) of the hood and with extra 15cm length to spare. This relay and wire controls external fan that will be installed on the exhaust outlet outside the kitchen.
The 12 volt power supply wire also run the entire height with about 20cm extra to spare.
Another wire that will run the entire height and extend further is the 3 meters NTC thermometer probe. Alas I've been awaiting its delivery for 6 weeks now.
For the time being, I used the 50cm probe that comes stock with the thermostat. The probe lies directly on CI not far from the LED driver. Expectedly, the display will likely show a temperature higher than the kitchen temperature.
Step 19: FIX THE THERMOSTAT BUTTONS
Couldn't get factory buttons so I improvised using pen covers. I used blue and black covers (woulda preferred red and blue but couldn't get the red colour on time.
- If the button holes in the acrylic front panel covering is not large enough to accommodate the pen covers, use a tool to enlarge them. Do not enlarge too much that the buttons become loose when fixed.
- The buttons do well to fix firmly on the projecting heads of the tactile buttons.
- Arranged as two blues and two blacks for the cold and hot buttons respectively.
- Check that the appearance is okay and well aligned, then remove the buttons again and keep them safely away.
The appearance of the front panel where the glass is (on either side of the console area) appears perfect. However the centre console itself is not looking good enough for me. I think I need to give it a spray paint finish.
Step 20: SPRAY PAINT CONSOLE
The console will be painted. Therefore every other parts of the front panel including the glass areas need to be left out.
- These areas are covered with nylon and taped firmly.
- The holes for the LED touch sensor and the thermostat tactile buttons are covered too to prevent paints clogging them.
- The parts of the acrylic glass that show the digital displays will also have to be covered. This include the thermostat display, the hot (red LED) and cold (green LED) thermostat indicator and the fan controller digital indicators.
- Carefully fix the tape (preferably a transparent tape so that you can see what goes on behind the covered area).
- Spray paint with the aluminium colour. I didn't think chrome or gold colour will be good for this place.
- Don't remove the nylon protectors yet.
- Allow to dry well.
- Them spray paint over with transparent paint. This is to protect the aluminium paint under it from scratches and the likes.
Step 21: FABRICATE THE WALL MOUNT
The wall mount/hanger will be screwed on the D1 pillars.
- Cut out a flat metal measuring about 50mm by 18 inches. This metal must be a non pliable one that will not bend easily or break under the weight of the hood it will carry.
- Locate the site on the back of D1 and D2 pillars to screw it on. I chose midway between the height (i.e. 16 inches)
- Place the mount on this position and drill screw holes thru the two (metal and D1/D2 pillars) together. The metal hole may be harder to drill but once you are past it, the aluminum is bread and butter.
- Use a large screw to secure the metal to the D pillars, but not all the way because you will still unscrew it. This is to test if it is well placed and tight.
- Unscrew the hanger/mount and set aside.
Step 22: SPRAY PAINT THE B FRAME AND F1 FRAME
What will be painted are:
The underside of A1 frame
The undersides and outsides of A2, A3 and A4 frames
- Cover the whole front B frame with protective tape or nylon to protect them from the paint.
- If the LED downlights are on the F1 frame, pull 'em out.
- Ensure the surfaces to be sprayed are clean and free of dust particles.
- Spray evenly.
- Allow to dry.
- Note that the sides of A2 and A3 frames will still be covered with the acrylic self-adhesive stickers which gives a reflective chrome appearance. This is despite the painting and this is because there are holes for recessed screws (for A1, F1 and C1) present on the B1 and B2 frames. These holes if made visible will be serious flaws and eyesores om the finishing.
An alternative would be to fill the holes with primers, sand them smooth and spray paint along with the frame evenly. But ding that will mean losing easy access to the recessed screws I talked about. I need easy disassembling in case of one in the future and all I need to do is to just pull back the stickers to reveal the screws and stick them back on when I'm done.
Step 23: FIX ON THE ALUMINIUM HOUSING
- Take the aluminum housing that you have earlier constructed and wrap it around the whole height of the hood.
- Ensure it rests well on the aluminum hood wing cover that it lies on. There should be minimal if any slits at all between the junction of the two. I could have applied glue at the junction but I figured out that I need easy disassembling in case of one in the future.
- The exhaust bend hole you have earlier created in the cover should also align well with the exhaust bend.
- Once all the above are ensured, punch small screw holes thru the aluminium covering on each side of B1 and B2 frame, and bigger screw holes on the back of D1 and D2 above and below. Note that the screws that go in these holes cannot be recessed. So I purposely left out B3 frame because that side faces outside directly and I don't want a screw sticking out to spoil the show.
NB: Remember your fabricated hood mount/hanger. There was a hole for its screws drilled on D1 D2. Remember? Yeah right.
So what you need to do is punch the corresponding holes in the aluminium cover.
Step 24: FIX BACK THE HANGER / MOUNT
Take the hanger that you earlier fabricated and screw it back on the D1 D2 pillars.
Step 25: FIX ON THE STICKERS
The stickers are self-adhesive and come in 15cm squares. They have a blue protective film that you remove once you are done with sticking them on the wall. They are very sticky and with a reflective chrome effect. It is applied in a similar manner as the self-adhesive wallpaper earlier used as the reflective glass background.
- Mark the stickers to the 50mm width dimensions on the paper covering them. Draw the lines.
- Cut these stickers following the drawn lines. You can achieve a clean cut using a pair of scissors.
- Carefully stick them onto the outside of the A2 and A3 frames.
- The sticker holds quite well on the A frame, but in case there are recalcitrant areas that won't stick well, augment with super glue or acrylic glue.
- Don't remove the protective blue film yet. Leave that for last.
Step 26: INSTALL AND CONNECT THE EXTERIOR FAN
The computer cooling fan goes on the outside as an accessory exhaust fan. It has very little working current. It will be connected to the wire from inside with a JST connector. I have already created the hole on the wall where the exhaust bend goes in.
Because of the JST connector, it is very easy to first install the fan without the need to mount the hood first.
- the scaffold for the exhaust hole in the wall is formed by a short 6 inch pipe. The idea is that this pipe receives the 6 inch bend from inside and holds the exterior fan outside.
- To keep away pests and flies (my region falls within the malaria belt, so mosquitoes are a major problem), I covered the scaffold pipe with metal net.
- I then passed the computer fan lead supply to the inside by taping it to the exterior of the pipe scaffold.
- I placed the fan on the pipe and screwed on tightly.
- Ensure the metal net is not wrinkled otherwise it will jut out awkwardly to obstruct the free rotation of the fan blades.
Step 27: MOUNT THE HOOD
Mount your hood on the wall. Connect the 12 volt DC supply and connect the exterior fan.
I have not removed the protective film in the stickers yet (Lol).
Step 28: COMPARATIVE ADVANTAGE
Factory hoods in the stores I have visited range from 210 usd to around 350 usd. What finished this project is in the range of 60 usd.
In addition, this design works well with my 12 volts solar home DC supply. So I don't have to worry about grid electricity or at least a 220 VAC source before the hood functions.
I may make more versions in the future or try to construct more advanced functions on another A1 frame to hot-swap with the present A1 frame.
Ideas are welcome. Thanks for reading.