Today I'm going to show you how to make a(n) (almost) flat packed toaster.
I'm saying almost because this is still a CONCEPT. for example the space between the cells isn't big enough, and somewhere the electronic circuit isn't closed. So there is need for improvement.
What will you need for this project:
- mica plates (you can find this in a magnetron, toaster or online)
- aluminium plate. for example a plate 80cm x 10 cm. my triangles are 10 high.
- electrilicy cable
- glowthread (nichrome). If you take an old toaster apart, make sure not to break those.
- M3 screws and washer.
- M3 rivets
- cutter to cut alumium and mica plates.
- Rivet pincer
- drilling machine
- sanding machine
Step 1: Concepts
As this is a school assignment I've made a lot more prototypes, but I'll only share my final choise.
I first started with a 3-leged prototype but found it to instable.
So after that I changed to a 4-leged prototype.
If you use a 3-leged toaster, make the toasting square also triangular and not square like it is now.
Also, you can chose the seize. In prototyping version the 'grill' is 10 cm by 10 cm. In my final version it is 20 cm x 20 cm + space inbeteen the cells.
Step 2: Making the Legs
I tried two manners for that.
About the length of the sticks: I took about 35cm, because that's the dept in my mom's kabinet in the kitchen.
The first way:
Take some square long sticks and sand one side away.
Your stick will change into a pentagonal shape. Make sure that it doesn't become a triangle since you need the sides to glue everyting together.
When you think that you've sanded enough, try to stick both of your electricity cables through the hole. Using elastics can come in handy here, so you don't have to glue it all together yet if something doesn't fit.
When you are sure that your cables fit, you can start glueing it all toghether. Use some clamps to set pressure to your structure.
Once this is dry and sollid you can start shaping the square stick into a cilinder, with a hole inside. If you sanded to far before, you'll have some spaces inbetween the parts. You can simply fill them with glue and put pressure on them again.
During my whole work, I've kept elastics around this leg for security.
The second way
Here we'll use a milling machine. We take a rectangle formed piece of wood and mill the cable path in it. Make sure you mill a little bit deeper than needed so all you cables fit good.
Then you glue everything back together and you can sand this into a cilinder form.
Step 3: Making the Electronic Circuit.
1. Start drawing possible plans for the nichrome thread on paper.
Because the toaster needs to be foldable, I deceided to have as little as possible crossings in between the cells.
But you can also work circular or have all the cells as a little circuit on their own.
Just make sure that, if you take the nichrome thread out of an original toaster, you keep the length and are sure of the circuit that was used to you don't blow your nichrome like I did.
2. When I had my plan on paper I started drawing on the mica-plate. I drew triangles with legs that are both 10 cm, and a corner of 90°.
I ordered a plate online, 30 cm x 30 cm (microwave oven seize) and I had enough to have 2 layers of mica in my toaster.
3. After cutting the mica plate in triangles I drew lines on it. These lines represent where the nichrome thread would come. At the end of the plates I always made a small inscion so that the nichrome thread would be able to get stuck there.
I used a stick of wood to turn the nichrome around before putting it on the mica plate, so there would be no twists in it (and no cats playing with the nichrome).
4. The next step is to get the nichrome on the mica plate. Start with holding (or taping) your startpoint to the mica plate and always make S-turns around the inscions that you made. Remember that the nichrome only comes to one side of the mica plate!
5. Do this for all 8 cells. Tape the end and the beginning of the nichrome to the mica place as it would start unwinding.
Step 4: Connecting the Mica Plates to the Aluminium
1. Cut your aluminium the same seize as your mica triangles.
I was able to put 3 layers of aluminium. So make sure you have 3 x 8 pieces.
2. Take 8 of these aluminium pieces and keep them close.
3. Clamp your mica plates ( one with nichrome, one without) carefully to the table with an aluminium plate under it.
I took two mica plates because of isolation. A toaster gets pretty hot, so does aluminium. So to have an extra layer of isolation I put two mica layers (my plate was big enough anyway)
4. Drill holes for the rivets where you know that you won't need the space for the other pannels!
So not the most upper and lower places on the plate, but between the first and second nichrome threads.
5. Use the rivets to put everything together (3 layers).
Do this for all 8 of the cells. The nichrome will be loose at the bridges, but we'll fix this later.
In the third picture I checked for the seize of the grill. What I didn't bring into account, nor when I was spinning the nichrome around the mica, was the thickness of the whole plate. So both the mica and the silicone are a bit to small to be able to fully bend.
And yes, I used the clothpins of my mom to keep them in place, because: I was moving it around... and cats.
Next up was the connection of the nichrome to the electronics cable.
Logically you'll say, I'll solder it together, but that doen't work in this case, since the temperatures of the grill will get the soldering melting. So I had to come up with my own invention. See the last picture.
- The stand alone hole was for the nichrome. That together with a rivet made a good connction, as I tested it before on a piece of useless mica. And the same technique is used in a real toaster.
- The electronics cable is attatched at the side of the 3 holes (M3 holes). The first and last are for the rivets, the middle one to stick the cable through.
I've mad the little plates out of a rest of aluminium. Bending it over the corner of the table or cutting in it with a cutter will make you able to have these pieces. After that I drilled 4 M3 holes in it.
Step 5: Connecting the Two Layers of Cells
As this step is kinda the same af before, I don't have pictures of it.
1. Take your silicone. (I used a silicon placemat because the silcicone backing mold was to small)
2. Cut it into the right seize. See picture.
Since my place mat was big enough, I could have two layers of it. The silicon makes the whole grill flexible. And the reason why I took silicone was because it can stand the heath (at least the backing form)
3. Put your silicone on the table, with on that 2 plates of aluminium (remember these 2x 8 that you've put appart?), now put the nichrome-mica-aluminium cells on top of that. Make sure that you put the last cells with the mica upwards so you can see where you will be drilling. So in the end you'll get an sandwich of (starting from top to bottom):
- nichrome (1x)
- mica (2x)
- silicone (2x)
Now you can drill with an M3 drill through everything. Make sure that you've used clamps as it can shift and then it won't fit anymore. I've put the silicone under everything because the with the second cell the most down aluminium plate shifted and I didn't see it until assembly because of the silicone.
To assemble everything you need the following order:
- M3 nut
- 1x M3 washer
- nichrome (1x)
- mica (2x)
-aluminium (1x) (but the first three layers are already assembled and pinned together)
- put 5 M3 washers in between (5 for every bolt)
- aluminium again
- your layers of silicone
- aluminium again
Now make a small hole in the middle of your sicilone to put the electricity cables through.
- Use rubber washers! (these one are giving through the electricity!)
- use electronics tape around the bold so that one isn't giving through electricity to!
After this you should have all the cells lined up and flexible.
Step 6: Making the Top
So we have 4 sticks and nothing to hold them.
My inspiration for this part came from a parasol. In the top it also has a fixed piece and some pieces that can move.
My first idead was to 3D print it. But since both of the printers were broken, I made it by hand, or at least tried it.
There also is another mistake, I made it for 3 legs instead of 4.
My second idea was to make a square to fit the legs through.
In the top I made a 6mm hole for my cables, and an 13 mm x 20 hole for the legs.
The with is 13 mm because of the stick, but since they aren't in it straight you need the length a bit longer.
As extra security I drilled through 3 of the 4 sticks, remember the 4th one is hollow and has cables, where I could put some cord as anchor so they can't move to much.
Step 7: Connecting the Legs to the Grill
In my prototype I could use a perforator and the straws fitted perfectly.
Sadly, this wasn't the case here.
So I deceided to punt a small hole in the silicone at the end of a corner.
Drill a hole at the right height in a leg and put a cord through it.
This also secures the legs, so that they don't stand to wide and keeps the grill in form and from swinging.
Step 8: Connecting It to the Electricity Network.
I've connected the + and the - cord from the grill (I don't have a ground so you can chose which one is wich), to a switch. After that an extention cable with fuse and then into the electricity network of the garage. And since there was danger of 'this might go wrong' we did it outside.
The sad news is: it said 'poef'
The good news is, non of the fuses said 'kllik'.
So, learn from my mistakes and put a transformator (you know, the little spool that you also find in an original toaster?) in between the 220V and your toaster. And isolate the bolts so you don't get a short circuit.