Guitar Hero Hacks: Key Molding

Step 5 Casting the plastic keys

The Polyester resin I used was clear. For the translucent frosted look I was going for, it had to be modified a little before casting. For a frosted look, you can apply a crystal clear spray into the mold in a thick coat before molding. When the parts come out of the mold you can wipe the spray off of them with acetone. For a super smooth look, you can spray PVA mold sealant into the mold using a Preval Sprayer. It will form a super shiny water soluble layer in the mold. When your parts come out, rinse them in water to reveal a remarkable shine.

To begin, I measured about an ounce and a half of resin on a digital scale. I marked how much resin was in the cup with a marker and measured its height. Then I transcribed that line onto another cup and cut it in half vertically. Now I could put this half cup over each cup I'd use to mix and just draw the line on it, meaning that I didn't have to weigh out my resin each time.

To color the resin, I used red, yellow, and blue dyes made especially for it. I also made the resin slightly more opaque by adding a pea sized daub of Bondo to it before mixing. Make sure you mix your resin thoroughly before adding your catalyst. Each of my 1.5oz servings of resin would need six drops of MEKP. Be careful when using MEKP, as it burns when it contacts the skin, and is very bad for your health. Make sure to work in a well ventilated area or use a NIOSH rated respirator.

After you've mixed your resin and catalyst, you can pour your keys using the same high pour method described before. Make sure to go slowly, and to take out all the bubbles you can with a stirring stick or other small instrument.

Comments

[armored bore]

I managed to make a mold just fine, but the resin came out funny on me again. Even after letting it sit for a day, it was still very tacky. Does that mean I'm not adding enough of the catalyst?

[{$EoF}Elite]

For the crystal clear spray, can you offer any recommendations on what I should use?

[kagenin]

Is it possible to set the LEDs in the cast during this step instead of drilling out cavities for them later? Or at the very least, maybe using another mold to prepare a cavity for them later?

[Slagr]

It's possible to mold the cavities during casting, but it'd be more trouble than it's worth and it would be more difficult to ensure a uniform location for each hole. If you were make a new mold with the cavity already in place, you would have to make a two-part mold.

[Slagr]

was you decision to make the keys translucent just a personal choice, or does it improve the effect or have some other positive effect on the overall outcome?

[Bazzatron]

theres another instructable on putting LED's into the keys for awesome play effects - you could make the keys look however you like - its your guitar lol

[Slagr]

I thought my intent to add LEDs was implied. I asked because I wondered if translucency would make the light more visible within the key or improve it in some other way. I'd just as soon cast transparent buttons and sand them for light reflection, but I figured I'd ask first.

I do have experience btw: http://www.scorehero.com/forum/viewtopic.php?t=72498&start=135

I will be putting the LEDs in a different guitar though.

[clamoring]

By the way, I found that blue + yellow doesn't make a very good green when it comes to resin dyes. They actually make a green dye though!