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tyggerjai... was "Early day today lads, finish at 3". As opposed to 3.30, granted, btu hey. It's all good time to ... clean up my own workshop at home. *sigh*
But the best thing my boss said today, as we were shaping styrofoam blocks to make the twiddly bits for the capitals of some lovel corinthian columns, was "We're trying to get into more of this fabrication, especially in styrofoam " ....
Mmmm, fabrication. Metalwork is good, but styrofoam is so, so versatile, especially as a base for fibreglass/resin work.
Yum. Gonna be a good year.
sol.
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But the best thing my boss said today, as we were shaping styrofoam blocks to make the twiddly bits for the capitals of some lovel corinthian columns, was "We're trying to get into more of this fabrication, especially in styrofoam " ....
Mmmm, fabrication. Metalwork is good, but styrofoam is so, so versatile, especially as a base for fibreglass/resin work.
Yum. Gonna be a good year.
sol.
.
(no subject)
Date: 2006-01-23 08:25 am (UTC)You make a mold in styrofoam, and pour the resin in? Or make a model in styrofoam and use that as a base for fibreglass?
What kind of resin do you use? I've tried a few times with a crystal clear resin, but either my measurements of the hardener were off, or the jelly-based mold-making stuff I used was too wet...
(no subject)
Date: 2006-01-23 09:36 am (UTC)You can make the negative in styrofoam, seal it, and then use resin, or you can make the positive in styrofoam, then make negatives in plaster and then cast positives again in resin. The plaster is a little more rugged than the foam if you're doing a big run, but overkill perhaps for a one off.
I've read about (but not yet tried) a technique of making "forms" in styrofoam, using *epoxy* resin to cover it, and then eating the styrofoam out with acetone. Which in theory doen't attack the epoxy. In theory. Or, as you say, just leave the foam in, if that's appropriate.
Epoxy doesn't eat foam the way Polyurethane does, so if you're working directly on foam, use epoxy. Otherwise, you can use an acrylic undercoat and lacquer to seal the foam (or even a thin coat of epoxy), and then use Polyurethane with a mold release agent (pva!).
I use Polyurethane, generally, because it's less touchy about catalyst proportion and temperature. If it's cold, or you get too little catalyst, wait a week instead of a day. Epoxy is more foam friendly, but it's much, much fussier - you have to get the catalyst proportion spot on, and you *must* keep the temperature above 25 degrees celcius while it cures. Latex also should work fine for molds - I've heard very good things about dental alginate, but not tried it yet.
I have at least one project on the boil for resin casting - I'll borrow a *decent* camera and post a log, shall I?
sol.
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(no subject)
Date: 2006-01-23 05:01 pm (UTC)Yes. Yes, you shall!
(no subject)
Date: 2006-01-23 09:37 am (UTC)sol.
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