First you will need a card template of the pick-guard to cut around. Once you have this your ready to cut, you can if you have one cut the Perspex with a band-saw, a scroll saw or a coping saw.
TIP - Take your time cutting the plastic as it does shatter and snap very easily.
Once you have the shape cut out you will need to cut the pickup holes out, I do this with a router and follow the card template. Some people do make jigs to cut these holes. If you are hand cutting, make a hole in the pickup area, detach the blade from your coping saw / scroll saw and put it through the hole and re-attach the blade and proceed with the cutting, again take your time, do this for all three pickup holes.
After you may need to file the holes with a round and a Flat File so the edges aren't to messy.
The next part I do is the switch selector holes, I always have problems in this area but now happy with the method I found and happy with the results I'm going to share how to do this.
People can try saws, routers ect..... But what I found easier is this, get your switch measure how big the plastic selector part is which should be around 6 - 6.5 mm, drill close not to close to each end of the switch hole, which should just leave a small piece in the middle which you can file away.
Now that most of the material is clear, it then become easy to file the holes in to small rectangles. Again take your time, too much filed you will have a big gap and the hole isn't straight, not enough then the switch could get stuck.
The type of files you use are needle files, I use a square file and a flat fine file to finish off the holes.
This Is the part where finally you can start your control plate. You can make this plate out of aluminium, or plastic.
The way you get the shape of the chamber to fit your control plate in to is easy, simple and anyone can do it. Take a piece of paper hold it down with one hand but keep it thought, with you right hand take a pencil, and with the side of your pencil rub along the edges of the chamber soon you should be able to see the outline of the cavity.
Now there are various methods of control plates, one is just to have one plate supported by small legs on the chamber walls, or 2 shelves one for the pots and and switches, the pot shelf is supported by a piece of wood with one screw attaching it, the switch shelf is supported by legs again, but has a leg which is bent over and secured down with 2 screws.
For this tutorial I have decided to show you as its easier the one plate system to see how it all happens. After the rubbing of the chamber, cut it out and transfer it to the aluminium plate. You can cut round this using a coping saw again as its quite soft, or if you have a band-saw use that. Give it a quick file to take off the sharp edges, you may need to play around with it to get it to fit but this is what it should look like.
You can now drill the holes for small screws to attach the plate to the body by the wood legs that support the control plate.
After this the Pick-guard then goes on again over the plate to mark out where the switch holes go on the plate, I always do it first on the pick-guard, so you don't spend ages faffing around screwing pick-guard's up by trying to get the holes in the right place.
What I then do is also mark out where the screws go on the pick-guard. I then drilled the holes with a 3.5 mm drill bit. After that, you need to countersink the holes for the pick-guard screws.
After this part I then attach the pick-guard with screws to hold it in position for the switch holes. Again I do the same as before, I use a drill to make 2 holes at either end of the switch hole, this time I use a 6 mm drill as not to damage the neatly filed hole from be for.
After I again use the same needle files as before, and finish off the holes, the plate should look like this:
Next part of the operation is the Pot holes. Depending on how you mount the pot depends on how big the hole has to be.
If you mount the pot and a lower shelf to the switch shelf you will need a 6mm hole, if your mounting the pot to the pick-guard you will need a 10mm hole.
Again same method as before with the pick-guard in place I drilled 10mm holes through the pick-guard in to the aluminium so the pots will line up as well as the switches.
The pots used on brains guitar are 220k Log pots, the switches are 2 way double pole switches. Suppliers will be listed at the end.
When your have drilled the 2 holes, time to finish the edges, as most of you would notice its got a small slant on the edge, pick-guards have a bevelled or chamfered edge, you can do this by filing the edge, or you can attach the pick-guard to a piece of wood, cut round the pick-guard again, so the wood is the same shape as the pick-guard,. Then if you have a router you can use a chamfer cutter with a ball bearing guide on the base of it to follow the wood guide around the pick-guard.
After this the Pick-guard is pretty much finished, the finishing touches you need to do, is scrape the edges with a Stanley blade / knife, removing the cutting marks and wet and dry sand the edges.
After doing this the edges will be quite dull. Use an old cloth, and some Brasso and rub the edges, this will polish up the edges making it look very smart.