Introduction: Tea Light Mug Warmer
This build idea came from an old Instructable by HHarry back in 2011. So thanks HHarry for the build idea.
I built this mug heater for my Dad who likes his hot drinks to stay hot for ages while he works. This build started off relatively easy then I just kept modifying the original design to be almost completely metal. Now it can accommodate larger mugs and small tea pots.
Most of the materials I had laying around from past projects and I only had to source the thick aluminum plate and solid round bar.
Step 1: Materials & Tools
- 6.3mm solid aluminum round bar (if you needed to know it was Alloy 6063/Temper T5 tho that isn't important for this build)
- 12mm x 12mm x 1.4mm Aluminum Equal Angle (think it was Alloy 6060 T5)
- 0.5mm Aluminum Sheeting
- 10mm Aluminum Sheet Plate (Alloy 5083)
- 25mm x 25mm x 1.4mm Aluminum Equal Angle (not shore on the Alloy)
- 12mm Thick Plywood (but you can use any type of wood as I just ended up laminating it)
- 140mm wide and 12mm thick pine board cut to size
- M3 screws and nuts (length isn't that important as I cut them down to size)
Tools Used & Stuff:
- Hack saw
- Drill (with 2.5mm, 3mm and 6.5mm drill bits)
- 40mm hole saw drill bit
- M3 screw tap
- Rotary cutting power tool/Dremel
- Hole Punch
- Orbital Sander
- Sand paper
- Bench Vice
- Tin Snips/Aviation snips
- 2 Part Epoxy glue
- Wood Glue
- Dust Mask
- Safety specs
Step 2: Cutting Metal to Size
All but the 10mm aluminum sheet plate was cut by hand. The plate was sourced and cut to size at a local aluminum fabrication business.
Note: Some businesses only sell by minimum length so I had to shop around. Depending where you are your local hardware store may even stock the 10mm thick plate.
The aluminum was cut to these sizes (Using these tools):
- 10mm thick sheet plate was cut to a 100mm x 100mm square (Very Helpful Fabricator) to become the heating plate
12mm x 12mm x 1.4mm Aluminum Equal Angle was cut to 70mm lengths, x4 to make the legs for the heating plate (Hacksaw & Bench vice).
0.5mm Aluminum Sheeting was cut to match the size of the heating plate (Tin snips) 100mm square x2.
- 8x M3 Screws cut down to 5mm lengths (Dremel with a cutting blade & Bench vice). To protect the threading while being cut I added 2 nuts to each screw. The 2 nuts covered 5mm of threading, the rest was cut away
- 6.3mm solid rod was left uncut for the moment since it is easier to bend if left uncut
- 25mm x 25mm x 1.4mm Aluminum Equal Angle, cut as close as I could to 79mm (Hacksaw & Bench vice). These also formed part of the base.
The 25mm x25mm sections also needed to have the bottom corners cut off as well. This is so they would not overlap when placed in a square with spacing left for the legs. (shown in the Sketchup (3D) pictures)
To cut the corners off:
- Measured a 13mm x 13mm square on the base corners of the 79mm length sections
- Draw a diagonal line across the square then cut off (Hacksaw and Vice).
Once all the corners have been cut off you should have something like the last Sketchup image.
Step 3: Cutting Wood to Size
The base is made out of a scrap piece of 12mm thick plywood I had lying around.
This was cut to:
- 100mm x 100mm square (hacksaw). As this wood is being laminated the wood type isn't important.
The carrying stand is made of standard 140mm wide x 12mm thick pine board.
- Cut to 160mm length (hacksaw).
Note: To make routing the pine board easier I did not cut it until after I had routed it, (see seventh step).
Step 4: Laminating and Preparing Base
As I wanted to go for the full aluminum look without using another plate I decided to to just laminate the base with 0.5 thick sheets.
- Give one of the aluminum sheets a very rough sand around the edges, this is to give the glue something to stick to. As I needed to make a hole for the tea light candle I didn't sand the center of the sheet.
- Apply a thin layer of wood glue to one side of the plywood and place the sanded sheet onto it
- Sandwich the aluminum plate against the sheet and clamp.
When clamping use a damp cloth to wipe away all the wood glue that comes out the sides when clamping.
Leave to dry for a couple of days, just to be sure.
Note: If this surface was any larger or structural then I would of used epoxy resin to glue it down. Tho feel free to use epoxy for this part as it may save on re glue/clamping later on.
Once completely dry clamp it down and (carefully) drill a 40mm hole in the center of the laminated side.Lightly sand to remove sharp edges on the new hole.
Repeat the laminating process for the other side of the plywood and try to keep the candle hole clean of glue.
One extra step I took once the plywood was laminated was to clean the sides up.
- Using a Dremal sander bit and the orbital sander sand the sides smooth.
- Use clamps during this process so you don't accidentally lift the laminate off the wood. (I re positioned the clamps when I needed to sand the other sides)
Step 5: Metalwork
Since I don't have a drill press I started with the legs so I could transfer the holes to the heating plate once drilled through.
- Measure and mark a line 5mm from the edge of a leg. Then mark one 5mm from the top.
- Line the hole punch up with the center of the cross just made and tap it with a mallet or hammer
- Repeat for the other top side
- Once all the tops of the legs are marked/punched drill these out with a 3mm drill bit
Note: As my holes were hand drilled a few of them were less than a millimeter out so it is a good idea to number the inside of the angled pieces. This is so once the heating plate is completed you know which leg attaches where.
- Using a sharpie or other marker transfer the holes to the heating plate. Do this on a smooth surface applying pressure to the leg to press it against the heating plate while marking
- Number all the holes on the plate
- Clamp the heating plate in the vice and punch the center of all the marked points
In the vice I am using some scrap aluminum angle so the metal isn't marked by the vice calipers.
- Using the 2.5mm drill bit, drill out all the marked plate holes to a depth of 6mm (or slightly deeper)
- Use the M3 tapping tool to tap all the holes in the plate.
- Test fit the legs and screws
From past projects using aluminum I didn't like the way bare aluminum would age and easily show dents and scratches over the years. So for this project prior to assembly I added some texture to all the exposed surfaces using the orbital sander.
All exposed surfaces were only lightly sanded then wiped clean with a damp cloth.
Once the texturing is completed attach the legs and measure out the spacing of the aluminum base pieces. I marked the location on the underside of the laminated base to make sure I had room for the legs.
- Mix up some epoxy and finely coat the inside of the base pieces (25mm x 25mm x 1.4mm Aluminum Equal Angle). I only put adhesive on one of the inside edges, the area that had corners cut off.
- Press into its marked position and clamp till dry
- Finished, time for some testing
Step 6: Testing
As I wanted to make shore this would work before giving it as a present to my Dad I did some basic testing with a cooking (candy) thermometer and two identical mugs.
One mug was on the heater, the other was not. Both were filled with boiled water.
- After the first 15 minutes there was about a 10 degree (celsius) difference
- This trend continued for a while
- Over an hour later the unheated mug was room temperature/cold and the heated mug was holding steady at 50 degrees celsius
During testing one issue became very apparent. I had completely forgotten about thermal energy transfer and the aluminum was conducting heat very well.
This meant that the whole thing was way too hot to touch, let a lone move when hot. In the bottom of the last image you can see that it is sitting on a tile so I could actually move it.
Bit of a whoops moment....
So to rectify this I built a base for the whole unit that included some carrying handles.
Step 7: Carrer Base
As noted earlier I did not cut this board yet to make routing it easier.
- Measure out a 140mm length of the pine and mark a line with a pencil
- Measure a square in the center of the marked 160mm x 140mm pine board to match the base of the heater. Mine was around 105mm x 105mm square.
- Clamp the wood down ready to route
- Set Router with cutting bit to a depth of 5mm then cut out the center square section. Be careful not to run it all the way to the corners as you can use a chisel to remove the remaining material.
- Use the chisel to remove the rounded corner edges to form neat straight corners
- Cut pine board down to pre marked 140mm length
After cutting the 140mm length I sanded the surface and edges to smooth it out.
To make the handles I used a bench vice and gentile force to bend the handles to the required shape.
- Mark a line around the rod 30mm from one of the ends
- Mark another line around 100mm up from the last line
- Place the marked 30mm part of the rod into a vice with the rest of the rod sticking out.
- Gently bend the rod down until a 90 degree angle is achieved
- Move the bent part down into the vice and secure at the 100mm mark.
- Gently bend the rod again until the 90 degree angle is achieved (see pictures)
- Cut rod at second 30mm mark to create a handle
- Repeat process for second handle
Note: I had forgotten to use my scrap aluminum angles for this process and as you can see the vice calipers had marked the rods.
As the handles are bent by hand you might find they are not uniform in shape. As such you may want to free hand drill the hole locations. Which is what I did in the images above.
- Mark out the handle hole locations
- Using the 6.5mm drill bit, drill out the marked spots to a depth of 5mm
- Test fit the handles.
If everything fits well use the orbital sander to finish the surface.
I only had some clear spray paint around to finish it so I gave it a couple of coats and left it to dry (outside) for a few days to get rid of the paint smell. I probably would of gone with a linseed oil finish if I had any left.
Once the base is completely dry it is time to fit the handles.
- Give the bottom 4mm on each rod handle a rough sanding or shallow cuts to give the glue something to grip onto
- Mix up a small amount of epoxy and apply to the inside of the holes using a bit of scrap material or earbud.
- Place the handles into the mounting holes and tap into position
- Clean up excess Epoxy if needed
- Leave to dry
Step 8: Finished
While the build needed some changes at last minute it turned out pretty good and works very well to keep hot drinks hot for hours.
I hope this gives you some interesting build ideas.
Thanks for reading and good luck!