Calling all plastic molders...

[Zhangliqun]

I'm interested in plastic P90-like covers in black and cream, but for humbucker slot P90's, like the Duncan Phat Cat or Gibson P94. Anyone with this molding capability (or knows someone who has it), let me know.

[cbarrow7625]

Rapid Prototype Injection Molders?

Why not try a rapid prototype injection molder?

They can make limited quantities of any part you can draw as a 3D model and sell them to you at a reasonable price.

Try someone like Protomold:

http://www.protomold.com/

-Chris Barrow

[Dave Kerr]

...

prices Start At $1795!

[cbarrow7625]

What? Are you cheap or something??

OK, bad idea....

[David Schwab]

Some of the rapid prototyping systems don't leave the smoothest finish either. So they need to be filled and primed and painted.

This photo is out of focus, but you can clearly see the pattern on the surface. The new machine I have access to does a smoother finish.

Zhangliqun, I'm sending you a PM....

[cbarrow7625]

David,

What machine do you have access to that provides smoother finishes. I am actually looking to buy a 3D ABS printer right now and I thought I had to live with the lines. What brand works best for you?

Chris

[David Schwab]

Chris, I don't know as much about these machines as my partner... but the machine in question is a Dimension BST 1200. It's a fairly low end ($19k!) machine. John says you have to do some work to get the parts smooth. The machines that do really smooth finishes are the ones that use lasers firing into a vat of resin.

But from what I've seen it does flat surfaces pretty smooth.

Also apparently the cover I'm holding was printed with the front face down, which didn't help the finish situation. We had that done somewhere else as a sample. Printing a hollow box with the face up results in a better finish, but the shell is filled with filler material which needs to be removed.

Our plan is to print a cover, clean it up, and make a rubber mold for casting the pickups in epoxy.

I'd love to get parts injection molded, but the set up cost is too high.

[Spence]

Thinglab

If only I had the space I'd be speculating on one of these :


http://www.youtube.com/watch?v=g0m1cVqNsRA


Still, I can get a much faster result by vacuum forming from a mould.

[David Schwab]

If only I had the space I'd be speculating on one of these...

Yeah and $53,030!!!

It's nice how it prints color... but that's a lot more expensive than the Dimension printer.

It's interesting how it uses an ink jet printer. The Dimension uses a hot melt nozzle like a glue gun.

For $53K we could have all the injection molded parts we could want.

[R.G.]

Casting plastics does not have to require a multiton injection press, because cast plastics don't have to be thermoplastics.

You can do much the same thing with castable urethane, epoxy and polyester if you're willing to have a suitable two piece mold made.

You can make a two-piece urethane mold by adding a parting surface to the original, spraying with release and casting one side at a time. The resulting two part mold can then be used to cast replicas, or used to make a number of intermediate masters for making up a multiple mold for, say, 25 at at time.

You can probably hire someone who's a model railroad or amateur jewelry fanatic to make the two part mold.

I make custom cast knobs a lot. It's just not that hard. Check out Micro-Mark for materials and ideas.

[Zhangliqun]

Thanks for everyone's contributions here and those who PM'd me. I stepped away for a while so sorry I didn't return the PM's sooner.

A lot to ponder, and it may well be worth learning to do it myself -- if I can get a finish just like a typical P90 cover. Just figured I'd throw some business somebody's way if they're already handy with this sort of thing.

[David Schwab]

Making a rubber mold and casting the covers is the way to go. Someone over at MIMF did a photo essay on making plastic parts, and it included some P-90 covers in cream.

This is my intention with the 3D printing. You can either hand make a model from wood or what ever, or do it this way. Then I have to clean up the model from the 3D printer... prime it and paint it, depending on the surface finish I want, and then make the molds. In my case I don't really need a two part mold, since I'm molding the whole pickup in epoxy.

So the cover I have printed is not what I will use as a cover, just a model for the mold.

Some people vacuform their covers. Dingwall is doing that, but he said the detail isn't as good as he wanted so he's going to a rubber mold.

The Animal Magnetism for Musicians book has some good info on casting pickups in molds.

[Spence]

You can achieve great detail with a vacuum former if you get the plastic to sag just right. In fact it will pickup the slightest flaws in the former. The key thing is to polish the finished article with glass polish.

[Zhangliqun]

Dave, I PM'd you back. Did you get it?

[David Schwab]

I just saw that.. and answered it.