andy1976 Posted August 31, 2016 Report Share Posted August 31, 2016 Any of you cnc guys ever try any other materials like high temp plastic for making two piece cnc molds? Quote Link to comment Share on other sites More sharing options...
edgecrusher Posted August 31, 2016 Report Share Posted August 31, 2016 There appears to be a heap of Eastern European makers using artificial stone. Quote Link to comment Share on other sites More sharing options...
Baitjunkys Posted August 31, 2016 Report Share Posted August 31, 2016 From what I found. Plastic are 2x as much as aluminum. You just gotta buy some quantity in aluminum. Quote Link to comment Share on other sites More sharing options...
andy1976 Posted August 31, 2016 Author Report Share Posted August 31, 2016 Yes I was thinking the additional cost could be off set by the ease of machining. Just curious. I was thinking phenolic bar stock might be good. Quote Link to comment Share on other sites More sharing options...
Baitjunkys Posted August 31, 2016 Report Share Posted August 31, 2016 (edited) Plastic is not gonna machine much easier if at all. Some will be even harder on your tooling. Edited September 1, 2016 by Baitjunkys Quote Link to comment Share on other sites More sharing options...
andy1976 Posted September 1, 2016 Author Report Share Posted September 1, 2016 Thanks for the answer. If I find something I'll be sure and update everyone. Quote Link to comment Share on other sites More sharing options...
CNC Molds N Stuff Posted September 1, 2016 Report Share Posted September 1, 2016 (edited) I do some plastics for things like circuit board mounts, and it does machine quite fast if you get things figured just right, but it can turn into a melted mess quick if you get something out of kilter. I machine HDPE all the time for misc stuff. I also keep a small supply of acetal, polycarbonate, and peek on hand. At one time I was making so many circuit board mounts I was bulk ordering HDPE cutting boars from one of the restaurant supply companies because it was cheaper than ordering HDPE sheets by the time I paid the truck freight on it. One of my associates machines PVC foam board by the 4x8 sheet everyday. He has a plastics vendor down the street from him though. Plastics can be expensive. The working temperatures are not all that much higher than plastisol, etc etc... If I recall the guy from the Ukraine who does the plastic molds gets his materials for free from the cabinet and counter shop he works for. Every time they cut out a sink there is a block he can take home and machine. If I recall he is using a functional equivalent to Corian . There are some issues with plastics. You absolutely have to have fresh sharp cutters. You can't take it easy to test an operation. It will just melt. The maximum chip size a cutter can remove doesn't change with the materials you are cutting, so a lot of the detail work still takes a long time. Anyway, I don't think the savings in time justifies it unless you are getting your plastic for free. Almost forgot. Mark sent me a couple pieces of PVC board to try a few years ago. I melted some of it trying to cut it to slow, made a couple simple open pour molds with if, and found if I oiled it up everytime before every pour it worked fine, but when I forgot for a couple pours the plastisol sort of welded itself into the PVC board. Not a big surprise though since they are very similar materials. Both PVC based if I recall. I also did some experiments with wood. Similar results except some woods are harder to cut than aluminum and running coolant really isn't an option. If I coated the wood with a hard clear finish (used high solids epoxy clear) and lightly oiled it the results were ok. If you didn't treat the wood the plastisol soaked right into it. ~~~~ Now if I could just get that darn restaurant supply company to stop sending me daily spam trying to sell me bulk coffee filters... Edited September 1, 2016 by Bob La Londe 1 Quote Link to comment Share on other sites More sharing options...
andy1976 Posted September 1, 2016 Author Report Share Posted September 1, 2016 Thanks Bob I can't help but wonder. Appreciate the advice. Quote Link to comment Share on other sites More sharing options...
MonteSS Posted September 1, 2016 Report Share Posted September 1, 2016 Plastic is not gonna machine much easier if at all. Some will be even harder on your tooling. Ahhh...Whatta you kno Quote Link to comment Share on other sites More sharing options...
Baitjunkys Posted September 1, 2016 Report Share Posted September 1, 2016 Ahhh...Whatta you kno LOL, I dont. Quote Link to comment Share on other sites More sharing options...
dlaery Posted September 1, 2016 Report Share Posted September 1, 2016 I have some of this HDPE. do you make crank baits out of it? Quote Link to comment Share on other sites More sharing options...
SlowFISH Posted September 1, 2016 Report Share Posted September 1, 2016 (edited) There are materials.... Check the Freeman Supply site... they make urethane boards for a whole lot of different applications and most of these items DON'T need coolant running and cut much faster and easier than aluminum. I use the REN 5169 for all my stuff. IT IS MUCH MORE FORGIVING than aluminum... so for a hobbist that has a little benchtop TAIG, makes mistakes and still learning - it's a good material. There are some downsides to this stuff though.... Assuming your cutting cavities to pour/shot into and not making masters.... It will warp/deform slightly as it takes on heat - so you need to make sure you clamp it reasonably tight as it takes on heat. I have some molds that never move/warp as they are relatively small baits - and I have some test baits (BIG AND THICK) I cheeped out on using a proper sized block and those distort more... never to a point they won't work - but you need to make sure you aren't sloppy when clamping. So if you use a proper size piece of material for the bait your cutting - you'll be fine in most cases. I said it takes on heat.... so your baits will take longer to cool down slowing your demold times. It's not as bad as a silicone mold - but has nowhere near the ability of aluminum to dissipate heat. Probably close to Plaster of Paris. While it is slower as the mold heats.... There is a benefit to this... you can make baits with very fine appendages or thin sections and almost ALWAYS fill them as the mold won't close off sections as fast as aluminum. Also - you can cut/glue this stuff if necessary. They sell a special glue - but clamping two pieces with some epoxy works just fine as well. I've filled parts of cavities I screwed up or wanted to change - re-clamped and machined the new areas without cutting a whole new mold... so it's friendly in that respect as well. I don't know if I would recommend this stuff for a production type mold... but it's real good for prototyping or if your a hobbist and the flexibilty/easy machining is of value to you. As for cost - it's comparable to Aluminum.... so your not gonna save on materials - you'll only save by not breaking as many end mills, machining a bit faster and having the flexibilty I spoke of. J. Edited September 1, 2016 by SlowFISH 3 Quote Link to comment Share on other sites More sharing options...
CNC Molds N Stuff Posted September 1, 2016 Report Share Posted September 1, 2016 Great post. Thank you. That's the thing about material science. There is always more to learn than you ever will. Interestingly I've learned more about some materials from my interest in high power airguns than anything. (No not the over hyped springers they hawk with misleading numbers in the box stores.) Quote Link to comment Share on other sites More sharing options...
andy1976 Posted September 2, 2016 Author Report Share Posted September 2, 2016 Thank you SlowFish I'll try that plastic. The phenolic handles on my lead molds seems like a good potential candidate too. Quote Link to comment Share on other sites More sharing options...
SlowFISH Posted September 2, 2016 Report Share Posted September 2, 2016 (edited) Thank you SlowFish I'll try that plastic. The phenolic handles on my lead molds seems like a good potential candidate too. They have a few others you may want to investigate... if I were buying more today - I'd be tempted to try the 5179.... seems to have a higher glass trans temp. They also have epoxy based materials that handle higher temps better than the 519/5179 - the Epoxy 5065 looks like a good candidate - but with the 49lb density I'm not sure how smooth the mold will be - might give a textured finish. The 5169 stuff makes parts that are nice and smooth provided you don't have alot of grooves from tool paths... and a little sandpaper and water helps smooth areas out as well if necessary. Also - it's hard to find - but the have a clearance section.... sometimes you'll find tooling boards in there as well - say someone gets it shipped and they drop it and bust a corner in shipping- they send it back.... it will end up on the clearance section - usually considerable cheaper. Let me know how the stuff works out for you. I've used other materials like the materials in the 400 series (REN). They machine so easily.... you can blast through that stuff... but you'll have to seal it off for making baits... the finish is similar to a POP mold... so you'll have to coat it with clear coat or sealer before you can use it. It is also worse from a heat perspective.... but if you just wanted to make something as fast as you could to test - it's cheaper than 5169/5179 and works if you can live with long demold times, deformation and sealing up a mold. J. Edited September 2, 2016 by SlowFISH 1 Quote Link to comment Share on other sites More sharing options...
andy1976 Posted September 16, 2016 Author Report Share Posted September 16, 2016 Found a YouTube video. Thanks for the info SlowFish Quote Link to comment Share on other sites More sharing options...
Baitjunkys Posted September 16, 2016 Report Share Posted September 16, 2016 I still dont see any advantage to using plastic. Especially on that Haas mini mill Andy.. Quote Link to comment Share on other sites More sharing options...
andy1976 Posted September 16, 2016 Author Report Share Posted September 16, 2016 Yeah no advatage just that it's possible. Quote Link to comment Share on other sites More sharing options...
rayhorse Posted September 24, 2016 Report Share Posted September 24, 2016 Hi guys. For plastisol baits aluminum is for me the best choice. Like slowfish said nowhere near the ability of aluminum to dissipate heat, and if you add cooling to your aluminum everything will go faster. About machinig aluminum I prefer slow and non deep cuts, it will take more time to finish but I will save endmills and I could leave the machine almost alone without worry about broken endmill. 1 Quote Link to comment Share on other sites More sharing options...
Ultimate Predators Posted October 4, 2016 Report Share Posted October 4, 2016 What machine are you using to make aluminum molds for hobby use ? Quote Link to comment Share on other sites More sharing options...
CNC Molds N Stuff Posted October 4, 2016 Report Share Posted October 4, 2016 If you don't mind taking all day and all night even the little baby Taig can do the job. Quote Link to comment Share on other sites More sharing options...
Fliegenfisch Posted October 4, 2016 Report Share Posted October 4, 2016 (edited) Hi here a Form from my in Corian Edited October 4, 2016 by Fliegenfisch 1 Quote Link to comment Share on other sites More sharing options...
CNC Molds N Stuff Posted October 4, 2016 Report Share Posted October 4, 2016 Hi here a Form from my in Corian Nice work, but the venting doesn't need to be anywhere near that deep. Quote Link to comment Share on other sites More sharing options...
