Crazyju Posted January 12, 2012 Report Share Posted January 12, 2012 I have a cnc that can machine pvc but not aluminum. Would pvc hold up to the heat? If not what plastic are the commerical molds made from? Thanks Quote Link to comment Share on other sites More sharing options...
nova Posted January 12, 2012 Report Share Posted January 12, 2012 It is going to have to hold at least 450 F. without breaking down We pour at about 350 F. www.novalures.com Quote Link to comment Share on other sites More sharing options...
Crazyju Posted January 12, 2012 Author Report Share Posted January 12, 2012 The frame is pvc (zen cnc) spindel runs around 28,000. 1/8 or 1/4 bits. What bit would you recommend and what kind of feed/depth rates? Quote Link to comment Share on other sites More sharing options...
FuzzyGrub Posted January 12, 2012 Report Share Posted January 12, 2012 I think this guy is cnc machining hard plastic molds: http://linmarfishing.com/ I first saw his molds on ebay, and thought they were POP. I bought a 3.5" beaver from his website, just to try. I am wondering how it will hold up to the heat, as well. Quote Link to comment Share on other sites More sharing options...
Crazyju Posted January 12, 2012 Author Report Share Posted January 12, 2012 One of his sure looks like pvc. Quote Link to comment Share on other sites More sharing options...
Crazyju Posted January 12, 2012 Author Report Share Posted January 12, 2012 He replied "They are high temperature resistant plastic (PVC). Thank you for your question" Quote Link to comment Share on other sites More sharing options...
SHK Posted January 12, 2012 Report Share Posted January 12, 2012 i would be worried about our soft plastic (liquid PVC) bonding with the hard PVC mold. Quote Link to comment Share on other sites More sharing options...
Crazyju Posted January 12, 2012 Author Report Share Posted January 12, 2012 I guess ill just melt some tonight and find out Quote Link to comment Share on other sites More sharing options...
mangeboy79 Posted January 13, 2012 Report Share Posted January 13, 2012 I have a cnc that can machine pvc but not aluminum. Would pvc hold up to the heat? If not what plastic are the commerical molds made from? Thanks if you whant to machine moulds out off plastic , why dont you cast blocks off bondo or polyester and machine your moulds out of them? Quote Link to comment Share on other sites More sharing options...
Crazyju Posted January 13, 2012 Author Report Share Posted January 13, 2012 Thanks Bob! Yeah my estimates on cut times for aluminum are way too long. Maching the pvc is easy thats why i asked in the first place. Well it turns out the pvc is not affected by the heat at all. I even burned a few batches and the pvc held up fine. Now with no sealer or release agent the plastic stuck to the pvc. It would come off so it did not bond just not very practical. Just spraying it with pam worked pretty good. Little sticking in edges.My last attempt i put a lure/jig sealer on it, let it dry for about 30 minutes and sprayed with pam. I turned it upside down and the plastic fell out. I have an injector on the way does anyone have a closeup of how a two piece injected mold is set up. Quote Link to comment Share on other sites More sharing options...
Crazyju Posted January 13, 2012 Author Report Share Posted January 13, 2012 Quote Link to comment Share on other sites More sharing options...
SHK Posted January 13, 2012 Report Share Posted January 13, 2012 I think this guy is cnc machining hard plastic molds: http://linmarfishing.com/ I first saw his molds on ebay, and thought they were POP. I bought a 3.5" beaver from his website, just to try. I am wondering how it will hold up to the heat, as well. looking around at the molds on that site they arent machined, if you look at the craw molds on one of the claws you can see where it lifted at the tips of one claw, you cant machine an undercut like that. my guess is he is pouring a liquid PVC casting resin. Quote Link to comment Share on other sites More sharing options...
FuzzyGrub Posted January 13, 2012 Report Share Posted January 13, 2012 looking around at the molds on that site they arent machined, if you look at the craw molds on one of the claws you can see where it lifted at the tips of one claw, you cant machine an undercut like that. my guess is he is pouring a liquid PVC casting resin. Could be, I'm not any cnc expert, but was going by the sharpness of the details. The detail is better than any of the resin molds I've done, and the two cavities look identicle. If he was using soft masters, expect to see some diff in the details. Hard masters would make undercuts a problem, too. On the other hand, at that price, doubt it could pay for the cnc time. Quote Link to comment Share on other sites More sharing options...
Crazyju Posted January 13, 2012 Author Report Share Posted January 13, 2012 Looks like it time for me to upgrade my machine. So how much you think a 5 axis machine will run? Quote Link to comment Share on other sites More sharing options...
FuzzyGrub Posted January 13, 2012 Report Share Posted January 13, 2012 (edited) Those machines are a little on the pricey side, but they would sure be fun to play with. Bob, your toys embarress me! :0 I can't compete! I did a test pour on that mold. No issue with releasing. I did use a light spray of veg oil. The instructions do say to use a release spray. Edited January 13, 2012 by FuzzyGrub Quote Link to comment Share on other sites More sharing options...
Crazyju Posted January 16, 2012 Author Report Share Posted January 16, 2012 Well, sealing with epoxy seems to work good. The plastic will just fall out. Now to just get the designs cad. Bob you have any paticular brand of bits you would recommend for aluminum? Quote Link to comment Share on other sites More sharing options...
Crazyju Posted January 16, 2012 Author Report Share Posted January 16, 2012 Thanks Bob! Quote Link to comment Share on other sites More sharing options...
Crazyju Posted January 22, 2012 Author Report Share Posted January 22, 2012 Here is my first go at it. These are two piece hand poured. Ive never seen a commercial mold, but these seem to be working pretty well. Quote Link to comment Share on other sites More sharing options...
Crazyju Posted January 23, 2012 Author Report Share Posted January 23, 2012 Thanks Bob. How small does the vent need to be? Quote Link to comment Share on other sites More sharing options...
mark poulson Posted January 24, 2012 Report Share Posted January 24, 2012 I wonder... would the Elmers and water work on the PVC molds like they do with POP? Bob, PVC is totally waterproof, so any water-based sealer would probably just lie on the surface. If it's rough enough to bond, the Elmers could fill in the roughness a little, but I'm thinking it would peel out sooner or later. Thinned epoxy would probably bond, and hold up better. Quote Link to comment Share on other sites More sharing options...
Crazyju Posted January 26, 2012 Author Report Share Posted January 26, 2012 Here is another go at it. Need to add a little venting to this one. Quote Link to comment Share on other sites More sharing options...
