kidlizard Posted August 26, 2003 Report Share Posted August 26, 2003 Has anyone ever tried to spray polyurethane (sp ???) on plaster molds? It would be great to get away from devcon and the brushes. I love the results, but it takes so much time. Let me know what you have tried. Thanks John Quote Link to comment Share on other sites More sharing options...
Ryno Plastics Posted August 26, 2003 Report Share Posted August 26, 2003 John - I've used Minwax brand clear polyeruathane on just about every one of my plaster molds. Wal-Mart has it in their paint department. I like using the spray can...makes it real quick and easy. Make sure to allow a day or two to completely dry. If you try to pour too soon the eruathane will start to bubble Ryan Quote Link to comment Share on other sites More sharing options...
redg8r Posted August 26, 2003 Report Share Posted August 26, 2003 Cant help ya on the polyurethane, except you spelled it right I got the bright idea of brushing the mold with super glue. big mistake...it peeled completely in 2 days Quote Link to comment Share on other sites More sharing options...
kidlizard Posted August 27, 2003 Author Report Share Posted August 27, 2003 Thanks Ryno, I will give it a try. A spray can would definatley speed up the process. G8R, Superglue?????? Well I guess anything is worth a try once.....lol Quote Link to comment Share on other sites More sharing options...
kidlizard Posted September 3, 2003 Author Report Share Posted September 3, 2003 Ryno, How many coats does it normally take, and whats the drying time between coats. The can says at least 24 hours, but the plaster seemed to really soak up the coating. Thanks John Quote Link to comment Share on other sites More sharing options...
alsworms Posted September 3, 2003 Report Share Posted September 3, 2003 Hey John, Just my 2 cents worth here on the poly.............. It works great, but patience is the key. Here's the "one week" process I use: Day 1: Spray the top side, then give it another coat a few hours later until it turns a yellowish color, all the while tipping the mold back and forth to prevent puddling. Wait 2 days. Day 3: Flip it over and repeat the process on the bottom. Wait another 2 days. Day 5: Give the top side another good shot. You don't need to repeat the process on the bottom of the mold. Day 7: You're ready to pour. It sounds like a pain, but if you use a rotation process, you can kick out molds at a pretty good rate. A couple things to keep in mind............... You have to be pretty liberal with the polyurethane. I use about a half can per mold; sometimes more depending on the size. Also, you will need to respray your molds from time to time; usually after every 500 baits or so. Keep a few cans of poly on hand and you should be in good shape. Hate to horn in on Ryno's question, but I've had my share of hard times with plaster and polyurethane. Give a shout if you have any problems. Chris Quote Link to comment Share on other sites More sharing options...
alsworms Posted September 3, 2003 Report Share Posted September 3, 2003 One more thing I forgot to mention........... if you live in a high humidity area, you might need to wait another day or so in between coats. 70 to 80 degree weather is ideal for making plaster molds. Don't be in a hurry to pour over drying polyurethane. Like Ryno said, it will bubble and once that happens you might as well toss it out. Chris Quote Link to comment Share on other sites More sharing options...
kidlizard Posted September 3, 2003 Author Report Share Posted September 3, 2003 Thanks Chris, I was getting the picture that it might take a while last night. I will try it out for a few molds and let you know how it works, or if I have any problems. John Quote Link to comment Share on other sites More sharing options...
Blazer202 Posted September 3, 2003 Report Share Posted September 3, 2003 Try using engine enemel by Plasti-Cote. It is good for high temps and comes in spray cans. I use it on all my plaster molds and have made hundreds of pours without recoating. It can be purchased at Wal-Mary or any auto parts store. Cost is $3 - $4 and a can will paint several molds. It usually takes 3-4 coats with only an hour or so between coats. Have built , painted and poured in the same day!!! Quote Link to comment Share on other sites More sharing options...
