tylerd1994 Posted August 21, 2009 Author Report Share Posted August 21, 2009 i think his molds did not warp because he used the 'rebar" idea, maybe u can do this with fiberglass resin? Quote Link to comment Share on other sites More sharing options...
96dak Posted August 23, 2009 Report Share Posted August 23, 2009 The resin warps due to exotherm (heat). Depends on the depth, volume, size of container you're building the mold in. Polyester is the worst for this. Manufacturers specs say it shrinks between 2 and 5% depending on the conditions. the crap resin most of these guys are using is worse than that, figure 7% - 10% shinkage. to solve most of this issue, mix a bit (upwards of 50%) body filler to cut down on the shrinkage. remember as well to slightly reduce the amount of catalyst as body filler reacts alot faster with liquid hardener. Quote Link to comment Share on other sites More sharing options...
tauruck Posted August 23, 2009 Report Share Posted August 23, 2009 the crap resin most of these guys are using is worse than that, figure 7% - 10% shinkage. to solve most of this issue, mix a bit (upwards of 50%) body filler to cut down on the shrinkage. remember as well to slightly reduce the amount of catalyst as body filler reacts alot faster with liquid hardener. 96dak is 100% correct. Quote Link to comment Share on other sites More sharing options...
Bugpac Posted September 1, 2009 Report Share Posted September 1, 2009 Bondo and fiberglass resing are the same, Except bondo has microbaloons in it to give it fill, Fiberglass is only stable to the temp it has seen, if it hasnt ever seen 100 it will move when subjected to it... Bake a fiberglass mold at 350 degrees for a while after it cures, It will never move until it gets to 351 degrees again... and so on... Quote Link to comment Share on other sites More sharing options...
96dak Posted September 3, 2009 Report Share Posted September 3, 2009 Bondo and fiberglass resing are the same, Except bondo has microbaloons in it to give it fill, UMMMMMMM, sorry, straight polyester resin doesnt contain microbaloons unless you add them. "Bondo" resin is the worst quality your going to find as well. Quote Link to comment Share on other sites More sharing options...
HAWGHUNNA Posted September 3, 2009 Report Share Posted September 3, 2009 UMMMMMMM, sorry, straight polyester resin doesnt contain microbaloons unless you add them. "Bondo" resin is the worst quality your going to find as well. 96dak,What resin would you recommend? Quote Link to comment Share on other sites More sharing options...
96dak Posted September 4, 2009 Report Share Posted September 4, 2009 i was just making a point. the "Bondo" brand resin is fine and the most cost effective for what it is being used for here. I would cut it with a body filler to reduce shrinking though. myself i use a much better quality (more expensive) resin because i have it on hand for another use where the cheap stuff can actually cost more in the long run. Quote Link to comment Share on other sites More sharing options...
Bugpac Posted September 5, 2009 Report Share Posted September 5, 2009 UMMMMMMM, sorry, straight polyester resin doesnt contain microbaloons unless you add them. "Bondo" resin is the worst quality your going to find as well. Isnt that what i said? Bondo is polyester resin with micro baloons for fill... Quote Link to comment Share on other sites More sharing options...
96dak Posted September 6, 2009 Report Share Posted September 6, 2009 (edited) Bondo is a brand, not a product. Body filler does not contain micro baloons. it is a thermal-set plastic. it does contain Talc (as in talcum powder) Edited September 6, 2009 by 96dak Quote Link to comment Share on other sites More sharing options...
Bugpac Posted September 7, 2009 Report Share Posted September 7, 2009 Bondo is a brand, not a product. Body filler does not contain micro baloons. it is a thermal-set plastic. it does contain Talc (as in talcum powder) Bondo is a very common generic name for body filler, It is indeed polyester resin regardless, we can argue back and forth for 10 yrs, but why? many types of body filler on the market, with tons of ingredients, I do agree the main ingredient is talk... There is plenty of additives than can be added to polyester resin to make a very very strong part, without using bondo "Mud"... Quote Link to comment Share on other sites More sharing options...
