Making pickguards

Setup, repair and restoration of Rickenbacker Instruments

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sloop_john_b
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Making pickguards

Post by sloop_john_b »

Hey Paul, I was wondering what tools/machinery you use to make pickguards? Are the methods different if you're doing back-painted clear vs. the typical white stuff?

Any idea how they do it at the factory?

I've made a couple using a jeweler's saw and a Dremel (with sandpaper & micromesh pads to finish the edges off), but I've had several experiences with the plexi cracking before I finished the job.
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winston
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Re: Making pickguards

Post by winston »

Working with Plexi, is hard work John. Even re-shaping a pickguard is a work out. :wink:
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teb
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Re: Making pickguards

Post by teb »

You may want to read up on annealing plexiglass. I believe it's mostly magic, but the word is that working the stuff builds up stresses in it, which are just waiting for an excuse to crack it at the slightest provocation (including exposure to solvents, paint, etc.). I cut mine with a band saw, shape them with an oscillating spindle drum and finish/polish the edges wetsanding with micromesh all the way up to 12,000 grit, followed by Finesse-It or similar on a rag (I don't own a buffer). Having had problems with drill bits splitting them, I usually drill the pot and screw holes as a first step, before even cutting them out. Sometimes I'll even grind a tiny pilot hole with the Dremel through the piece before drilling the big holes, as they tend to break just as a drill bit makes it through the far side.

Once the cutting, drilling and sanding is done, I put them on a cookie sheet, stick it in the oven and bake them at about 200 degrees for a couple of hours. Then you turn the oven off, leave them in there and let it slowly cool to room temperature (may take 3-4 hours). Once that's done, they're annealed and pretty tough. I haven't had any splits and they don't seem to react at all to paint.

As to how the pros do these things, I have no clue and PW will certainly know and have some pointers, but this is how I do the out in the driveway.

Edges beveled and polished then back-painted.
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Wiker
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Re: Making pickguards

Post by Wiker »

Maybe there is a difference between extruded and cast acrylic (plexiglass). I’ve made several out of cast acrylic (using a hand saw, Dremel etc.) without any problems with cracking. Only problem I had working with cast acrylic was when I tried to drill out holes for pots with an ordinary metal drill.
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Hotzenplotz
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Re: Making pickguards

Post by Hotzenplotz »

I took polycarbonate. - Undestroyable and no problems with cracks at all!
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doctorwho
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Re: Making pickguards

Post by doctorwho »

Hotzenplotz wrote:I took polycarbonate. - Undestroyable and no problems with cracks at all!
Polycarbonate is very resistant to cracking.
Wiker wrote:Maybe there is a difference between extruded and cast acrylic (plexiglass). I’ve made several out of cast acrylic (using a hand saw, Dremel etc.) without any problems with cracking. Only problem I had working with cast acrylic was when I tried to drill out holes for pots with an ordinary metal drill.

There is probably a difference with regard to what additives are used, being that extrusion (IIRC) is done as a melt (hot plastic), whereas casting is done at room temperature.

IIRC from my days working at a plastics warehouse, for acrylic (Plexiglas) sheets, we made straight cuts using a plastic blade (lots of fine teeth) on the table saw, then curved the edge(s) with a router with a plastics blade. We may have also used the same tools (band saw, drum sander, etc.) as detailed by Ted above ... it was 40 years ago and the memory is a bit fuzzy ... :roll:

Also IIRC, we used a special set of drill bits for drilling holes in acrylic, and I think that we had to use slow speeds to prevent heat-stress cracking.
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collin
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Re: Making pickguards

Post by collin »

John, if you're looking for good Plexi material (or acrylic) try TAP plastics (www.tapplastics.com) their stuff is good quality and cheap.

One good tip is to keep the paper cover attached that covers the Plexi stock from new. Cut the Plexi with this covering on it, do your sanding, then remove it for final detail work.

It's also advisable to stay away from your shape line and hand sand it down t meet the line you want.
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teb
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Re: Making pickguards

Post by teb »

I leave the paper on until all the cutting, sanding, and drilling is done and then remove it right before baking them. Cut-outs and notches are the hardest part for me. You have to determine what corner radius you need, drill holes that size and then connect them with straight lines. If you try it, do it early in the process. If it doesn't work and you have to start over, then you haven't wasted too much time.
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Hotzenplotz
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Re: Making pickguards

Post by Hotzenplotz »

O.K., I hope I do not tell too much, the trick do two hours at 70°C (160°F) - maybe in your regular coocker.

While working with the plexiglass You change the structure and the forces of the material. When You paint it now, the solvents in the paint do the rest for cracking.

A temperature of the above mentioned degree helps the plexiglass to wind down. This does not avoid 100% of cracking but it is a much closer to zero. Btw.: less paint, less danger! Do thin coats.
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kiramdear
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Re: Making pickguards

Post by kiramdear »

I use a hard block for sanding outside curves and straight bits, and a dowel for inside curves. This helps to remove waviness from my line. :idea:
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doctorwho
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Re: Making pickguards

Post by doctorwho »

Hotzenplotz wrote:O.K., I hope I do not tell too much, the trick do two hours at 70°C (160°F) - maybe in your regular coocker.

While working with the plexiglass You change the structure and the forces of the material. When You paint it now, the solvents in the paint do the rest for cracking.

A temperature of the above mentioned degree helps the plexiglass to wind down. This does not avoid 100% of cracking but it is a much closer to zero. Btw.: less paint, less danger! Do thin coats.
There are some additional details on annealing cut/machined acrylic at Wikipedia:

http://en.wikipedia.org/wiki/Poly%28met ... crylate%29

For the record, we never annealed any cut/machined acrylic at the plastics warehouse I worked at, but it is probably a good idea. :)
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kiramdear
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Re: Making pickguards

Post by kiramdear »

I've never done that either, but it does make sense. Thanks for the tip! :)
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