empire247 Posted July 31, 2007 Report Share Posted July 31, 2007 Hi guys has anyone made any 2 piece resin molds? and if so how are they for detail compared to POP or RTV? im thinking of making a 2 piece mold out of the castin craft clear resin that you can buy from from hobby stores. also what would be a good mold release for the resin other than the stuff that castin craft sells? thanks brett Quote Link to comment Share on other sites More sharing options...
Gloomisman Posted July 31, 2007 Report Share Posted July 31, 2007 glad you asked this question. I'd like to know too but on bondo if its possible. Quote Link to comment Share on other sites More sharing options...
Vodkaman Posted August 1, 2007 Report Share Posted August 1, 2007 I have not tried either. But what I have done is a latex splash of my thumb and cast it in resin (for a keyring). The resin thumb picked up every single mark, including the finger print. So my guess is that it would work well. There is a significant shrinkage problem, but this can be eliminated by having the master at the bottom of the pour, the resin will shrink down from the top. Confused? Husky covered the mould thing very well. After pouring, the resin is a bit tacky, it is best to let it cure for a couple of days at least before putting it to work. I would be interested to hear if it can be used for casting foam instead of RTV. I cannot source RTV in Malaysia and the resin is very cheap. Quote Link to comment Share on other sites More sharing options...
MDC Posted August 1, 2007 Report Share Posted August 1, 2007 Gman I've made a few out of Bondo. Mix 2/3 Bondo with 1/3 Resin to make it more pourable and give a longer work time. They have to be coated same as POP though Quote Link to comment Share on other sites More sharing options...
GB GONE Posted August 1, 2007 Report Share Posted August 1, 2007 I have made a few for fun and they came out pretty nice. I have used only bondo though. For a release between the halves, I used WD-40. Spray it on a rag and then coat the mold half after it dries. Be sure to coat it well and in all the spots or you will have a time seperating the halves. Shrinkage was minimal and definition is high. No coating of the surface is needed once the mold is complete. Baits will be shiny and clear. All that said, POP and Durham's are much easier to work with and cost considerably less. I have over 50 POP 2 piece molds that I use regularly. Just be sure not to drop your mold!!!! Quote Link to comment Share on other sites More sharing options...
windal Posted August 2, 2007 Report Share Posted August 2, 2007 I have some wood blanks that I want to make two piece resin molds out of. What do you guys use to coat you blank with and will the casting destroy the blank? Quote Link to comment Share on other sites More sharing options...
Vodkaman Posted August 2, 2007 Report Share Posted August 2, 2007 As long as the pattern is not die locked and it is sealed to prevent the resin soaking in, it should be OK. I would apply a light smear of petrolium gelly, just to be safe. Quote Link to comment Share on other sites More sharing options...
windal Posted August 2, 2007 Report Share Posted August 2, 2007 This is probably a stupid question but what do you mean by die loked? Aslo, what is the best way to seal a master? Quote Link to comment Share on other sites More sharing options...
Vodkaman Posted August 2, 2007 Report Share Posted August 2, 2007 Sorry about that, it's engineering talk. The pattern has to be a shape that can be withdrawn from the mould without 'hanging up' or 'catching' on the mould. For example, if you sank your pattern into the resin passed half way, the 'die locked' condition would be present as you could not remove the pattern from the mould. If the mould material was soft plastic, this would not be a problem, as the mould would deform over the die locked casting, allowing it to be withdrawn. Resin is a hard material and die lock has to be considered. Not so easy to explain as I thought it would be, not my best skill. Quote Link to comment Share on other sites More sharing options...
windal Posted August 2, 2007 Report Share Posted August 2, 2007 Vodkaman, Perfect explination. I understand completely. Would sealing the master with a quality laquer work ( brush or spray?). Would an epoxy live Devcon be better? Quote Link to comment Share on other sites More sharing options...
Vodkaman Posted August 3, 2007 Report Share Posted August 3, 2007 Like I said, I haven't tried it. If you already have the materials, try it on a test piece first. But from my very limited experience of resin, I would guess that it would be no problem. Remove it after about half an hour. The stuff I used, the instructions were 15 drops per 25grm and it hardened after about 20 mins. After 30 mins I removed it from the latex mould. The surface was kind of greasy, like the surface layer had not gone off, but the definition was first class. This greasy layer leads me to the conclusion that the master will not bond to the resin and give you 'withdrawal symptoms'. Also, the stuff does not smell too healthy, I would wear kitchen gloves as it tends to get everywhere. Please try it and report back. Quote Link to comment Share on other sites More sharing options...
GB GONE Posted August 3, 2007 Report Share Posted August 3, 2007 The masters I make from wood I seal with Devcon 2 ton epoxy. Anything that seals the wood pours should work fine. If the wood is not sealed adequately, the bondo will penetrate and bond to your master ruining the master and the mold. Jim Quote Link to comment Share on other sites More sharing options...
windal Posted August 3, 2007 Report Share Posted August 3, 2007 Thanks guys, I will post some picts as soon as I get the molds done. One more question though. Do you need to thin the resin with anything or will it form to and pick up detail well with out thinning? I'll try to make that my last question. Quote Link to comment Share on other sites More sharing options...
Vodkaman Posted August 3, 2007 Report Share Posted August 3, 2007 Ask as many questions as you like, probably many people out there thinking the same questions. No thinning required. Tap the mould container to release any air bubbles as for any moulding process. Quote Link to comment Share on other sites More sharing options...
jigmeister Posted August 4, 2007 Report Share Posted August 4, 2007 My first attempta 2 piece resin mold was a disaster with the master trapped inside of the two halves fused together . I tried using petrolium jelly as a release agent and it did'nt work .Next attempt I used a paste type release agent from TAP plastics with a two piece resin mold again with polyester casting resin . Detail is excellent as with any resin mold as long as you dislodge any bubbles trapped on the bait . A release agent is definately needed when pouring the second half in an effort to keep both halves from bonding together . I was'nt sure if they would come apart easy even with the release agent so I put some soft strips of plastic around the outer edges of the mating surfaces of the mold making an indentation . As it turned out this is the only thing that made it possible to get the thing apart as even with the paste type release agent it took some severe prying so finally get the two halves separated and many times I thought for sure I was going to shatter the mold before I got it apart. It is possible but not easy . Good luck -jigmeister Quote Link to comment Share on other sites More sharing options...
