Clear Resin - What do you use? What must you do to use it?

[OdysseySlipways]

I have spoken to one of the Tech's at Smooth-on and they tell me i need a resperator, a vaccum chamber, a pressure pot.

what they tell me, it's a bit of work just to use and it seems to be on the harsh side of resins.


I am just wondering, what clear resins do any of you use. How does it tuen out? what do you have to do to use it?

I am considering clear resin parts for a kit that I hope to have by sometime mid next year (if all goes well).

[macfrank]

I have spoken to one of the Tech's at Smooth-on and they tell me i need a resperator, a vaccum chamber, a pressure pot.

what they tell me, it's a bit of work just to use and it seems to be on the harsh side of resins.

I've used a couple of clear resins.

Envirotex makes a fairly simple to use clear resin. It hardens within a few hours and it's very clear. It can also remain slightly tacky and softer than your typical resin, though. The type of mold material and its preparation make all the difference between success and failure.Read my warnings and Shinnentai's suggestion for a workaround when using RTV molds. Even with a fully baked mold, I was still getting slightly yellowed Envirotex casts.

Alumilite also makes a clear resin, and it's much like the regular Alumilite resin (quick setting and hard when set). It works well in RTV molds, but the molds have to be pretty hot (120F or hotter) for the resin to set correctly. I got it from Hobby Engineering. The quick setting time also makes it difficult (but not impossible) to get all the air bubbles out.

Frank

[OdysseySlipways]

I think i had Polytek (I think) clear resin before, but you need to use a blue rtv rubber with it. i had someone do a few sample casts, but the rest was tossed out (the resin) as it only sat for the next few years.

my problem is, heating up the molds and tanks, i have one tank, but it won't go above 95' I have two heating blankets rapped around it plus fiberglass insulation, but still can't get no heat.

[DasPhule]

I use SmoothOn's 220 or 202 clears, so I can help some. First off, make sure you mix it correctly, it's a 90-100 mix, not 100-100. If it isn't mixed as close as possible to 90-100, it'll come out sticky and useless. It has the ratios right on the cans, ask me and Blap how we know....

Don't wrap electric anything around your pots, that's a good way to get dead. The heat issue isn't a problem unless it's freezing where you cast. What you SHOULD do though is post cure the parts in an oven set as low as it'll go, or set to the indicated temp in the instructions. Pull the parts BEFORE you bake them.

As for the respirator, YES, wear one. You can pour it without, but you'll be tasting the resin for the next day or so and it'll cause coughing and a sore feeling in your chest. Geting it on your skin aint so bad, but wear gloves and cover up just to be safe. Sucks to wear the mask, but if it pays....

Other than that, the stuff is pretty much like any other resin except it's thicker. Pressure cast it at 40-65psi and let it sit in pressure the complete time period that the instructions say it'll take to set up. Then post bake. Tint it with SmoothOn's tint line, use sparingly for translucence.

"Clear" enough fer ya?

Erin
<*>

It's not completely necessary to deair it in a vac tank, I've pourd it without doing it and it came out ok. I DO vac all my clear though.

[Kun2112]

I picked up some "castin'craft" brand clear casting resin at the railroad shop across the river. It dries cyrstal clear, but it is very thick, so a vac chamber is a must have. The mixing directions are also kind of vauge as they apply to the thickness of the prototype.

[OdysseySlipways]

is that resin used for water effects? or is it a real resin for casting?

[Umi_Ryuzuki]

I want to say, BJB-800, a 60-100 mix, and the Polytek PolyOptic-1411

The bjb had to be heat cured, at the time I was doing some single sided spires. After subjecting the mixed material to a vacuum, I would pour the piece, and stick it in a box with a light bulb. The box would get upto 95-105 degrees with just a 100 watt light bulb stuck in the end.

The PolyOptic was a nice 1-1 mix, and makes nice flood lights, and marking lights.

I tried the Tap Plastics Clear casting resin, but it is an,"air inhibited cure".
Apparently silicone molds are "porous" enough to keep the polyester clear cast resin from properly curing. The parts remain sticky and tacky.
Then the resin shrinks up to 20 percent. So as the sticky tacky piece shrinks, it pulls strands of resin across the space created between the RTV and the piece. These then drop onto your part and make an absolutely horribly sticky stringy mess. And the part stays that way for days. If nothing else avoid the Tap plastics polyester clear casting resin.

[OdysseySlipways]

sounds like i may have to pay polytek a visit.

did you have to use there blue colored rubber for the casting? what about heating the casting durring curring? don't think i can put a lightbulb into my pressure tank while curring - don't think the tank will want to seal to well

[Umi_Ryuzuki]

sounds like i may have to pay polytek a visit.

did you have to use there blue colored rubber for the casting? what about heating the casting durring curring? don't think i can put a lightbulb into my pressure tank while curring - don't think the tank will want to seal to well

Blue, green,... I may try the pink

I actually prefer to leave these out when they cure.
No pressure, no heat. The polytek's cure time allows the bubbles to float up and out. When I pressure cast, the bubbles shrank, and hung in the part.

So, all i have done is put the material in a vacuum, de aired it, and then pour or inject slowly.

For the BJB I did the same thing, an open air cure, but I placed the mold under a four sided fomecore box and placed a light bulb across one end.