casting with fiberglass resin?

[Master_Shake]

Man am I happy registration finally opened up. I've been a daily observer on rpf for several years now and all i have to say is you guys do amazing work. Although I've been a fan of replica prop building for sometime i have finally decided to try it myself. So my question is, is it possible to cast using the bondo brand of fiberglass resin available from automotive stores? I ask because I'm on a budget ($75 for a few ounces from smooth-on is a little pricey for me) and i have a quart of it lying around. And if so what type of mold would I use? Liquid latex? What about a release agent? :confused

 

[exoray]

So my question is, is it possible to cast using the bondo brand of fiberglass resin available from automotive stores?

Possible, yeah a good idea no... The casting will be extremely brittle, and you will probably have surface issues and huge shrinking and pulling from the mold...

I ask because I'm on a budget ($75 for a few ounces from smooth-on is a little pricey for me) and i have a quart of it lying around.

Proper casting resin can be had for much less then $75, in fact it's not much more expensive the fiberglassing resin...

And if so what type of mold would I use? Liquid latex? What about a release agent? :confused

Again save your money and wasted time and get some decent molding silicone...

Truth is with molding and casting you get what you pay for, trying to do it ghetto and save $20 is almost always a waste of time and money...

Check out Alumilite

http://www.alumilite.com/Category.cfm?Category=Starter Kits

For $30 you can get a complete small starter kit or for $70 get a decent starter kit, trust me it's money well worth spending...

 

[Master_Shake]

thanks for the help

 

[Master_Shake]

Another question. are all epoxy resins the same? I have a local manufacturer of epoxy resin Gougeon Brothers, but its mostly geared towards boat building. do you think this would be suitable? http://www.westsystem.com/

 

[exoray]

Another question. are all epoxy resins the same? I have a local manufacturer of epoxy resin Gougeon Brothers, but its mostly geared towards boat building. do you think this would be suitable? http://www.westsystem.com/

That is a glue, layup or finishing coat, not a casting resin...

Again stick to urethane based casting resins... The right stuff for the right job...

 

[clonesix]

A (Polyester) laminating resin should not be used for casting. I will generate too much heat if poured thicker than 1/2"

 

[vaderman1701]

If you are going to use epoxy resins, you may want to use a platinum base silicone. Epoxy resin tends to eat up molds much quicker. You may want to try polyester resin (check UScomposites.com). But, like Exoray said, save your money to buy the right materials. Smooth-on is probably the best brand out there for silicone and casting resins.

 

[Master_Shake]

thanks guys

 

[Studio Stasis]

Smooth-on is crap
The last shop I worked at refused to use it

 

[Great_Bizarro]

I never had any problem with Smooth-on, probably depends on which type you use and what you are trying to do. I know that too much humidity can cause alot of problems.
If you are building boats, go with epoxy resins they are great to work with and don't smell too bad, otherwise poly to cast parts.

 

[Big_Water99]

well to me it depends on what your casting if you casting a solid oblect like 1 / 4 th scale firgure for example in the past I have used resin from the store and mixed it with Bondo then kicked them with both clear and cream kickers and have had great results but as for plain resin would I not go that route but thats just my experiences with it

 

[JtotheP]

well to me it depends on what your casting if you casting a solid oblect like 1 / 4 th scale firgure for example in the past I have used resin from the store and mixed it with Bondo then kicked them with both clear and cream kickers and have had great results but as for plain resin would I not go that route but thats just my experiences with it

Bondo mixed with resin is a good idea to keep the resin from cracking and shrinking too much. The heat could be an issue though depending on how many pulls from the mold you're doing.

When mixing bondo with resin it's important to mix the mekP first then the bondo catalyst next.

 

[RussellSculpts]

I've made parts with all kinds of resins, building parts and props in the theme park industry, and my favorite weapon of choice is smooth cast-roto. epoxie resin IS the strongest but only when backed with fiberglass. You can't really cast with regular polyester resin. If it's an open mold you can hand lay it but first put down a layer of gel coat. Check out Reynolds Advanced Materials in Orlando, For all you molding and casting needs, they are really helpful. Oh, and spend the money, You won't be happy with molds that don't work or bad castings.

 

[weaselflinger]

When mixing bondo with resin it's important to mix the mekP first then the bondo catalyst next.

Yes, you need to use the catalysts from both the bondo and resin.