Crystal clear with no pressure?

[Gonzowerke]

Hey All,

Looking to get into casting, mostly for lighting parts. I have read that you need to use pressure to get crystal clear parts. I'm looking to make light guides at first, so crystal is what I want. I found thisat Michael's(a craft store here in the US) and it does not require pressure. At least the label makes no mention of it.

What do you think?

Gonzo out

[modelnutz]

If the mix ratio is one to one..it's probably urethane.
If the mix ratio is 10 to 1 it's probably epoxy.
If the ratio is "a few drops per ounce" it's polyester.

If it's polyester, you want to use the smallest amount of catlyst required for a cure...any extra and it will fog up.

Mix and pour slowly to prevent bubbles.

Hope this helps.


Ooops...just opened your link.....this stuff is polyester resin....see note above.

[Joseph Osborn]

Look around at Michaels or Hobby Lobby for Castin' Craft "Easycast" clear epoxy. Here's the manufacturer's website:
http://eti-usa.com/consum/easycast/easycast.html

Like always, epoxy is more expensive than polyester, but is way easier to work with. 1:1 mix and no stinky smell.

As for bubbles, very careful mixing is critical if you don't have a pressure pot. Try to use a round rod to stir the mixture and go slow. You will have time to pour or work with the stuff before it gels, so resist the urge to stir really fast. It's been my experience that a flat wooden stick is more apt to pull air into a thick mixture (like epoxy) than a round stick.

[Scott Hasty]

Hey All,

Looking to get into casting, mostly for lighting parts. I have read that you need to use pressure to get crystal clear parts. I'm looking to make light guides at first, so crystal is what I want. I found thisat Michael's(a coraft store here in the US) and it does not require pressure. At least the label makes no mention of it.

What do you think?

Gonzo out

I've used gallons of the stuff for propmaking. It is polyester and requires trial and error to mix the resin and catalyst (usually MEK). I don't recommend it for clear parts; it is great for strong parts when used with glass cloth. Oh, and use outside with rubber or nitrate gloves as the fumes will kill many brain cells and it can be a sensitizer to bare skin...

The Castin' Craft "Easycast" is available at Micheals as well. It degasses well, but is softer than most resins.

Scottiei

[jgoldader]

I've used gallons of the stuff for propmaking. It is polyester and requires trial and error to mix the resin and catalyst (usually MEK). I don't recommend it for clear parts; it is great for strong parts when used with glass cloth. Oh, and use outside with rubber or nitrate gloves as the fumes will kill many brain cells and it can be a sensitizer to bare skin...

The Castin' Craft "Easycast" is available at Micheals as well. It degasses well, but is softer than most resins.

Scottiei

You aren't kidding--I used it for the first time a couple of weeks ago, and the fumes nearly knocked me over. I poured it inside my basement and ran the thing outside as soon as the cup was empty.

A little Future airbrushed onto the completed casting will seal the surface.

Jeff

[Gonzowerke]

Ooops! Instead of putting the whole link in my post, I made the word "This"
the link. I was asking about The Castin' Craft "Easycast" polyester at Michael's. Thanks for all the info though! When I get into it, I will be in my garage where I have an exhaust fan from an old paint shop set up as a ventilator for my cardboard box spray booth. It vents outside so fumes will not be a problem. When I graduate to actually making exterior clear parts, what's the best stuff to use, and what psi and time do I leave it for?





http://www.michaels.com/art/online/disp ... Num=gc0509

[Umi_Ryuzuki]

I had issues with polyester resin not playing well with silicone molds, shrinking too much. The silicone was somehow inhibiting the cure, when the part shrank, it would hang sticky threads on the mold as it shrunk, and these would drop on the part and make a horrible mess.