An item for our wish list for our fledgling parts makers...

[Zhangliqun]

I'm looking at putting out a line of humbucker-spaced P90's soon and it would be really cool to have a plastic cover that has the same glossy finish and the same rounded corners as a real P90. I think P90 fiends would dig a look that's closer to the real thing for their 'bucker guitars.

(But for now, it's metal covers, a la Phat Cat.)

[Spence]

That's a good idea. why don't you make your own covers. you should aquire a vacuum former, make a mould from epoxy and use PVC for the covers or ABS.

Here's the kind of thing I use.



It's suitable for one cover at a time but hey, it's cheaper and a damned sight quicker than getting them from elsewhere.

It's a dental vacu former.

next I'll be off looking for an autoclave.....

[Zhangliqun]

Wouldn't know the first thing about using one of those. You got some info on Plastic molding 101? And what does one of those cost? Then there's making the dyes (I assume) for molding...

I'm up for giving it a try -- you never know, I could end up being a 'boutique parts supplier' in here. I never thought I'd ever be winding pickups for my next door neighbor, never mind folks all over the world. (I still catch myself wondering "who said that?" when I tell folks I wind pickups.) Home-made parts does look to be more and more the way to go.

[David King]

Here's some links to vacuum thermo-forming kits and info.
I know a couple of pickup guys who use one of these to make their shells:
http://www.build-stuff.com/1001plans_hobby_vac.htm

Heres an overview;
http://en.wikipedia.org/wiki/Thermoforming

Here's a tutorial;
http://www.studiocreations.com/howto/vacuumforming/

[David Schwab]

What about getting some plastic covers with no holes, and drilling some holes for the poles?

[Zhangliqun]

That would be great but I don't know of any with the P90 gloss and rounded corners in humbucker size. I take it you have a bead on some?

[Zhangliqun]

Thanks for the links, Mr. King. Am absorbing it...looks like it's not such a crazy out-of-reaching thing. I guess the only tricky part is getting the molds/dyes made. I've got a Phat Cat cover that I suppose I could give to a mold/dye maker as a template for specs.

EDIT: And thanks to Spence and Mr. Schwab too for your present and future input...

[Spence]

I bought my dental vacu former on Ebay. i think i paid $60 or something like that. I get sheets of styrene and ABS in 0.06 and 0.08" from modeller's shops. Still trying to get PVC.
The moulds are easy. Get an existing cover, smear a vaseline/turps release agent inside and fill with Epoxy. Use the type that has aluminium in it. It will release quite easily when set. Add a couple of pieces of VFB to the base of the newly made former, (glue it on) drill the screw holes right through the former and tidy up any flaws.

Then you put a sheet of plastic in the clamp and heat until it really sags. Then move the frame down onto the former and apply the vacuum.

Piece of piss. I'm suprised we're not all doing it.

[Zhangliqun]

What's VFB?

And can you get styrene in a decent cream color?

One other thing -- would it make sense to leave some rods in the mould screw holes so the holes form in the cover automatically during the process to avoid messy post-mould drilling?

[David Schwab]

What's VFB?

Vulcanized fiberboard?

[Spence]

Careful now, hasn't DiMarzipan patented the color cream? I don't know if you can get it in cream but why not? I use white for '54 Strat covers and black currently for soapbar covers. ABS is better for durability, strength and shine. PVC is very good stuff. You can get it in cream too.

Yes Dave; Vulcanized fibre Board ( VBF ) .... couldn't be bothered to type all that out at the time.

Please don't be afraid to do vacuum forming. It's really pleasurable to see it happen. For sure I screwed up the first half dozen but it really is worth the effort.

Warning! Don't buy the Matel vacu-former. It will work but it's a toy. The dental vacu former is small but industrial quality and will require no modification.

Drilling the screwpole or magnet holes isn't as hard as you may think. Where you've drilled holes in the former will allow the hot plastic to sink in. that's a good starting point for drilling. For strat covers, I put a top flatwork inside the cover as a drilling guide. tidy up with a reamer.

[DoctorX]

some tidbits

the ABS brand of plastic used for injection molding covers, some bobbins, etc is Cycolac, and the Nylon sometimes used is Capron.

An interesting source of vacuum molding machines is found here:

http://www.iasco-tesco.com/

a great source of books on how to make punches and dies is:

www.industrialpress.com -- and one book in particular is detailed here:

http://www.industrialpress.com/en/Bo...3/Default.aspx

[DoctorX]

more tidbits

iasco-tesco also has small injection molders. More for the educational market, but interesting.

A good part of the work involved in mold making is the polishing of the cavity. The better the finish in the cavity, the better the result. Use of diamond paste and a die profiler make the process easier.

You have to get rid of the tool marks and finish the mold to the right size so the plastic will shrink to the desired dimensions. You also have to take into account the expansion of the mold once it is heated and size the mold accordingly. Also, the plastic is held under pressure once the mold is packed and until it cools to control the rate of shrinkage, which adds another variable to the equation. And you wonder why an injection mold costs about 10 grand?

[Zhangliqun]

Drilling the screwpole or magnet holes isn't as hard as you may think. Where you've drilled holes in the former will allow the hot plastic to sink in. that's a good starting point for drilling. For strat covers, I put a top flatwork inside the cover as a drilling guide. tidy up with a reamer.

I've just had major problems with wandering drill bits making holes with nasty burrs and in a crooked line with each other because a plastic cover is hard to clamp with enough pressure to hold it steady without marring or breaking it.

Yes, I have a drill press and yes I do drill pilot holes first.

[Joe Gwinn]

I've just had major problems with wandering drill bits making holes with nasty burrs and in a crooked line with each other because a plastic cover is hard to clamp with enough pressure to hold it steady without marring or breaking it.

Yes, I have a drill press and yes I do drill pilot holes first.

Use a spire-point (brad-point) drill bit, and cool with tap water while drilling. Sharp helps too.

http://www.mcfeelys.com/product.asp?pid=BRD-0305&ref=F

Click on individual drill sizes for more info, and specific prices.

As for clamping, you may need to build a fixture that fills the cover with wood or metal, so there is something solid to clamp against.