jm Posted June 15, 2005 Report Share Posted June 15, 2005 Hi, I'm new at making molds, but have been pouring plastic for years. I've scoured the boards here and am grateful for the great advice. I just tried out USG's Ultracal 30. It seems to be similar to Durham's. The first lure I tried to mold was a deep zipper, and it almost came out. The mold was hard enough to extract the worm in about an hour, and at that time I was able to detail some of the trouble caused by the lure floating up, and bubbles. It ain't pretty, but I'll be able to pour a few worms to see how the finish is. It looks pretty good for a first try. Is anybody here playing around with small scale injection, laminated injection, or small scale robotics. I think that is the way this half burned out engineer/bass tackle wannabee is heading. Maybe a small business will grow out of it. Thanks for the help. jm Quote Link to comment Share on other sites More sharing options...
jm Posted June 16, 2005 Author Report Share Posted June 16, 2005 I Tried again to pour a deep pockets mold using USG UltraCal 30. This time I remembered what I had seen here, especially the tips from NJFishRGuy. Thanks, Charlie. I glued the lure to be copied to a sheet of meat wrapping paper, (the plastic coated stuff) with pvc glue and laid it on the kitchen counter. I Made a wooden form around it. Mixed up the UltraCal per instructions, 38 parts water to 100 parts powder, add powder to the water, let set for a few minutes, and mix carefully with a figure 8 motion. Then I tapped the container on the table a few times to cause any bubbles to come to the top. This batch was a little wetter than my first batch, and poured like honey. I poured a little in the mold beside the pattern, and nudged it into the pattern so that it oozed up from the bottom and filled all the gaps. I continued to pour to the side and let it run into the details until the pattern was covered. Then I filled the form. It formed a sheet of water on top, and reabsorbed it in a few minutes. I pulled the pattern at about an hour and a half, and detailed the soft mold with an exacto knife. The pattern did not maintain full contact with the paper, so there was a little plaster to remove from over most of the ribs in the form. The mold came out excellent. There are no bubbles, and the detail is very good. The meat wrapping paper left a dead flat, smooth top. Now if I can get this thing to multiply....... The first mold cured hard as a rock, then I baked it and coated it with a gloss acrylic sealer. I couldn't get valspar, so I used MinWax PolyCrylic Protective Finish instead. It worked the same, I'm sure, and put on a gloss finish that is very tough. The key words, I think, are Acrylic, or some morf of it, Clear, Gloss, and water cleanup. I poured a few baits with Calhoun plastic. I had to wait until they were quite cool to remove them. They pulled out hard, but they stayed intact. UltraCal 30 is a product specifically designed for casting, a very good compromise between strength, (about 4000 psi, vs plaster of paris at 1000 psi) and detail. Here's USG's page on it http://www.plaster.com/Ultracal.html Like most of the hard plasters, it is a mix of plaster of paris and portland cement. From the name I'd suspect it's about 30% portland. I think it must have some other secrets, though, because it handles very nicely, wetting the form, curing fast (and hot enough to hurt), and curing to a stone that goes "clink" when you tap it. With the portland component, I would let it stay moist and cure for a few days if you want a really hard, permanent mold. In 6 hours, it is already hard enough to wreck havoc on files and knives used to trim it. It costs about $20.00 per 50 pound bag or bucket, which puts it into the downright cheap range. Charlie, someone else asked the question, but I didn't see an answer. Do you use 1 coat or 2 of Valspar? jm Quote Link to comment Share on other sites More sharing options...
CrawChuck Posted February 24, 2006 Report Share Posted February 24, 2006 Mixed up the UltraCal per instructions' date=' [b']38 parts water to 100 parts powder[/b], add powder to the water, let set for a few minutes, and mix carefully with a figure 8 motion. Then I tapped the container on the table a few times to cause any bubbles to come to the top. jm I got the bucket of UltraCal. Am wondering if anyone here might know the conversion from weights to measurements in the mix ratio. I'm probably needing a good set of scales anyway but was hoping somebody already had it figured out. Thanks. Quote Link to comment Share on other sites More sharing options...
Predator Bass Baits Posted February 24, 2006 Report Share Posted February 24, 2006 Does plaster make that much nicer of a bait compaired to a cyclicon type mold ? Seeing that the plaster could be broke. Quote Link to comment Share on other sites More sharing options...
CrawChuck Posted February 24, 2006 Report Share Posted February 24, 2006 I have yet to make a silicone mold but am looking forward to getting some delivered any day now. All the plaster molds I made back in the 80's are still in use. Some of the early ones developed a hairline crack at the pourspace running down about 1/3 of the top of the molds but never actually broke apart. A piece of aluminum screen cut about one inch wide, laid in the mold near the top fixed this, kinda like rebar in concrete. I see alot of guys use different things to seal the cavity. I always used Envirotex. First coat soaked in and let fully cure, second coat brushed on very thin and fully cure. The only problem ever with Envirotex was trying to pour too hot plastic which caused it to become sticky. If you treat it right a good plaster mold will last for at least 20 years since the first ones I made were in 1985! I always tell the guys borrowing my molds, if you get your plastic so hot it changes color, don't pour it! Even those that have become sticky can be brushed with some oil which is usually good for two or three pours. Another problem with Envirotex is trying to recoat a sticky mold. It beads up and doesn't cover. I don't know if other epoxies do this. As for a nicer bait, I hear silicone catches all the detail so that's what I'm after molding from real critters. I hope it does! Quote Link to comment Share on other sites More sharing options...
jm Posted February 24, 2006 Author Report Share Posted February 24, 2006 On Ultracal: I always weigh the ingredients. You can't really tell by how it feels, because the feel, like all portland, varies at a variable rate over time as you mix and use it. Also, the powder will pack down quite a bit, so you can't tell how much you have by volume very accurately. If you get it into the mold and settled down early, it'll likely form a layer of liquid on the top, which is absorbed after a short while by the mold. Don't remove it. It is critical that there is enough moisture for a complete hydroset of the plaster. It's just a sign that you're not trying to work half cured plaster. I bought a 13 pound electronic scale on eBay for about $20 It's just perfect for weighing mold ingredients. jm Quote Link to comment Share on other sites More sharing options...
Senkosam Posted February 24, 2006 Report Share Posted February 24, 2006 Do you use 1 coat or 2 of Valspar? One. Recoat in a year if needed. Holds up to hot plastic better than other sealers I've used and doesn't get absorbed, requiring a base coat. Quote Link to comment Share on other sites More sharing options...
