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Epoxy Composite Body


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I have a crazy idea to make a guitar body out of a mixture of epoxy and (other stuff), mainly using the epoxy to fill in the pore space between the (other stuff).

If I make a 1-1/2" thick body like this, is it too thick to allow the epoxy to cure properly? Anyone out there have any experience with thick layers of epoxy curing?

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I would do it in a silicone mould or a fibreglass mould or somthing like that. The problem with acrylics and epoxies is that theyre brittle and if they get hit theyll flake chunks off. Kinda looking like a split piece of flint stone. Thats why fibreglass weave is added to fibreglass parts.

There are some hi impact resins available but im skeptical wether you would find a clear version.

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Let me start by saying my experience is with structural composites so not all of this might apply to the sorts of materials you'll be using.

With epoxies you're catalyzing a chemical reaction. There are reaction products (the stuff that evaporates off) and heat. What limits the thickness of structural composites is a runaway exothermic reaction. You put to much epoxy in one place, it generates more heat that it can dissipate and... spontaneous combustion.

Just to mix enough epoxy, mix with your aggregate, and fill the mold, you'll probably use retarders to give you more working time. That might keep you from starting a fire. You still might have problems from the heat.

Things expand when they're hot and contract when they're cool. The outside cools (and solidifies) before the inside does. As the inside cools and contracts, restrained by the cool, rigid outside, a few things can happen. There can be "sinks", where the outer surfaces gets sucked in by the shrinking center. The part can warp, when it balances the opposing forces from an outside that's too big and an inside that's too small. If the outside is rigid enough to resist either of those two effects, the part might have internal voids. These can be bubbles or cracks and fissures.

Get some of the materials you want to use. Cast a test specimen in a plastic tub in the thickness you want, to see how it behaves.

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I think if you're to use acrylic, it's not a crazy idea at all (the ibanez js2000? i believe is made of acrylic/clear)

Here's a PRS style example.

Just looking at these things give me the goosebumps.. cuz of their instability..

Like GuitarGuy said, I would do it in a mould too although I dont have much experience I like unique stuffs, and this is just one of them.

Also, i think even if you do moulds, you would need some function to compensate for its instability. (thinner body 1 1/2 sounds ok I think, color white would help, dunno.. some holes trough the body? to stabilize temp?)

Also, wouldn't pressuring the epoxy help alot? In mould, during cure, probably.?

-IR

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Thanks for the info so far....pretty interesting.

Yeah, acrylic is more transparent than epoxy, but man....it doesn't look like one of those materials you could obtain in liquid form and mold it up in your garage.....does it?

That's why I was thinking epoxy...I've got a fair bit of experience using stuff that takes 24 hours to set. But tirapop nailed my main concerns with using it, the fact that it will cure outside before it cures inside when thick.

Anyone mold their own acrylic?

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I worked as a bowling pro shop guy for years and used an epoxy to fill the hole for redrilling.

It's refered to as "ball plug", really nice to work with, cures in large amounts with no problem.

It has a slow cure time, 10+ hours and is very clear.

I use to mix it with cork, saw dust, all kinds of stuff with no problems.

You just need to mix it carefully to avoid bubbles.

You could ask at a Pro-Shop if they could order you some.

Good Luck,

d ward

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I don't know why you would want to do it like that since you can purchase Lucite and just cut it with a router like you would a piece of wood... as a matter of fact it's probably easier on your router bits. You just have to make sure you precut your body within an 1/8" of it's final size.... when you are done completely routing it, you will need to sand everything you routed to at least 600 grit, then you will need to polish it... this means you will either need a bench polisher (resembles a bench grinder) or, if you have a compressor, you can get a straight die grinder and put a polishing wheel on the end of it and do it by hand... You don't want to run it full bore (like 20000 rpm), you will want to run it more like 5000 rpm. You will need polishing rouge also. They have 2 different types (white which is fine, and blue for very fine) start with the white and finish with the blue.... it will be as clear as glass when you are finished... it will also be a whole lot cheaper than making a silicone mold, and filling it with liquid acrylic... (That's about 200 bucks just for the materials to make the mold and fill it.)

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I don't know why you would want to do it like that since you can purchase Lucite and just cut it with a router like you would a piece of wood... as a matter of fact it's probably easier on your router bits. You just have to make sure you precut your body within an 1/8" of it's final size.... when you are done completely routing it, you will need to sand everything you routed to at least 600 grit, then you will need to polish it... this means you will either need a bench polisher (resembles a bench grinder) or, if you have a compressor, you can get a straight die grinder and put a polishing wheel on the end of it and do it by hand... You don't want to run it full bore (like 20000 rpm), you will want to run it more like 5000 rpm. You will need polishing rouge also. They have 2 different types (white which is fine, and blue for very fine) start with the white and finish with the blue.... it will be as clear as glass when you are finished... it will also be a whole lot cheaper than making a silicone mold, and filling it with liquid acrylic... (That's about 200 bucks just for the materials to make the mold and fill it.)

How much would a piece of lucite large enough to make a body... at 1 1/2" thickness cost?

That's what has to be compared to the cost of molding one.

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The reason I can't just use an acrylic or leucite blank (as stated in the *ahem* first post) is because I want to mix in an aggregate of interesting things. And it should be low-enough viscosity that the interesting things won't crush or break.

I don't care too much how it will sound...this is purely for visual.

This looks pretty promising: http://www.alumilite.com/default.cfm

This too (scroll down to Crystal Clear 200-series): http://www.smooth-on.com/liqplas.htm

They put off some noxious vapors, but look like they might do the trick!

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so... what are you trying to add in?

you can start with a 1/2' piece of acrylic and cut it to your template, then you can mix in whatever you want to mix into your clear acrylic casting resin. Run some green painters tape (2 inch variety) and tape around the sides making a template on top of the clear acrylic. Pour the casting resin into the form and let it cure. When it is cured, you can rout it like normal, since essentially it will be acrylic. A tip would be to make a mark with black marker on the outside of the tape where you want the acrylic to come up to so you don't have a ton of sanding to do.

You can pick up casting resin at US Composites. Just look for the Simlar 41 casting resin. It's about 28 bucks a gallon.

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