Casting semi clear parts

[my5thmopar]

It was suggested I post this over here with you model making folks. I'm using Alumalite Performance 65D and Amazing Clear cast. I'm working on to reproduce some plastic parts. These are thin 1/16 inch translucent parts. I'm helping to make a custom dome light lens. I've already created the mold and attempted to cast 15 or so parts. I'm either using the wrong chemicals or something in my process is wrong. The chemicals aren't cheap. I'm using a vacuum chamber for my chemicals, I'm hoping someone here is a hobbyist doing some of this stuff. If you're actively into this stuff and can help me out, please PM me. I'll send you my number and we can talk. Thanks Craig

 

[RedFish]

Not enough info.
You trying to pour cast a closed cavity mold ?
Can't get all the bubbles out ?

 

[67 Power Wagon]

I agree, I need more info on how your going about this....CLEAR plastic is NEVER an easy pour...I do a lot of mold work myself BUT model parts and all so, I may have a remedy to help you.....

 

[my5thmopar]

This is silicone 2 piece mold. Fill bottom, put on top and room temp cure. I have tried oven cure also. Bubbles are not an issue, Ive got that figured out. Problem is lens is too flexable and not ridgid like a lens should be. It is translucent like an old dome lens would be but, almost white.

 

[RedFish]

One 2 part epoxy will cure a bit more rigid than another but... it is what it is.
I get fairly good results from Easy Cast 2 part acrylic. I'm thinking the 1/16th thickness is your biggest problem. Either increase the thickness of the part or incorporate ribs or a more substantial rim at perimeter, something to reinforce it.

 

[67 Power Wagon]

I cast relatively thin parts, and I think its merely due to the denseness of the cured material used, AS WELL as the size making it flimsy....

You can remedy this in a multitude of ways, one would be to score in some "ribs" as mentioned, OR use a different medium to make the part, AKA for GLASS clear lens I'd use top coating epoxy, this is then 2 part liquid used on counter tops and or bar tops, it looks over wood applied that its 1/2 thick.....you know? I've used this same stuff for things that are less then 1/16th inch thick, but have a pretty good size of circumference. NOW, to make them even better, add the ribs, and THEN use the 2 part epoxy coating....It dries clear, and will make a perfect part BUT, you must ALLOW itto totally cure 24 to 36 hours, the stuff your currently using I would BET, it cures A LOT faster then this, which is part of the problem the faster the cure, the less dense the material is when cured. The slower it is to cure, the more dense it is, AND the slow cure stuff, will be much more clear...

PM me for info on what materials you need, I can help!