Tman2 Posted April 6, 2008 Report Share Posted April 6, 2008 I tried making my first mold out of some existing small chunk trailers I had on hand. I ended up with a working mold, but it has a lot of air bubbles. Can these be fixed easily? There's enough bubbles in there, and POP is cheap enough that I think I might just toss the molds, or keep them nailed to the wall to remember them. I pushed the masters down from the top. How do I prevent this from happening again? I read something about pre-coating them, but that was if you glued them down, does that apply this way to? Quote Link to comment Share on other sites More sharing options...
nova Posted April 6, 2008 Report Share Posted April 6, 2008 (edited) What you can do is take the mold out before it dries completely; mix up a small amount of pop and fill the holes making sure it's smooth and level. Then just clean up the molds and seal them. The real trick is to get them without too many bubbles. Make sure the baits are flat to the bottom of the mold because the trapped air will rise out from under the baits. Also, it helps to coat the baits with the pop before you pour the rest in the mold. Another tip would be to not stir the pop any more than you need to mix it and allow the bubbles in the mixture time to rise to the surface where you can take care of them before you pour. www.novalures.com Edited April 6, 2008 by nova Quote Link to comment Share on other sites More sharing options...
rr316 Posted April 7, 2008 Report Share Posted April 7, 2008 What I do is after I pour in the pop I take the tupperware container and tap the bottom against the counter a couple times, this gets the bubbles to rise to the top and usually leaves a good looking mold. Just make sure you have the master glued in there good! Quote Link to comment Share on other sites More sharing options...
squigster Posted April 7, 2008 Report Share Posted April 7, 2008 The way that works everytime for me is to glue the baits to a sheet of lexan, then use a small detail paint brush and brush the POP on them and also seal between the bait and the lexan. Usually three coats (wait a few minutes in between each one until it is covered and let it almost completely dry. Set the lexan in the bottom of a pan then pour in the pop and vibrate (tap) a little bit and let it set. When its done extract the mold from the pan and flip it over and carefully pull the lexan away from the POP. No bubbles and no POP getting underneath the baits. Quote Link to comment Share on other sites More sharing options...
Vodkaman Posted April 7, 2008 Report Share Posted April 7, 2008 The excess of bubbles may be an indication that your PoP mix is too thick. I tried following the instructions obtained from a web search, but this too left me with a lot of bubbles. My latest pour, I measured the water and plaster powder by weight (50/50). I mixed the PoP as directed in the web instructions, by pouring the water into a suitable container (a plastic ice cream tub with round, molded corners for wasy access) and sprinkled the powder through my fingers, slowly. I then mixed with my fingers, very slowly, so as not to introduce any air. What bubbles existed, rose to the top fairly quickly and my finished mold was clean and bubble free. The question will remain as to what is the ideal mix ratio for the plaster strength, but I was very happy with this pour and the strength seems fine to me and I will be using it again. 10% of the water was elmers glue-all. But the best way to avoid bubbles is to bottom mount the masters, as outlines by Nova (above post No2). This way, the bubbles rise away from your working surfaces. I would be interested to read what ratio other members are mixing successfully to avoid this problem. Quote Link to comment Share on other sites More sharing options...
nova Posted April 7, 2008 Report Share Posted April 7, 2008 I make my pop completely by eye. I know what thickness I'm looking for(hard to discribe in words) and when I reach that I'm ready to pour. I heat my plastic the same way. In both cases there were some disasters I settled into a pattern. www.novalures.com Quote Link to comment Share on other sites More sharing options...
Tman2 Posted April 7, 2008 Author Report Share Posted April 7, 2008 What are you using to glue these down? I'm thinking it's either super glue,or hot melt? Not sure what's the easiest. A bunch of posts talk about gluing it down, but don't actually give specifics. I tried the search, but must not be using the correct terms, or too many. Quote Link to comment Share on other sites More sharing options...
Tman2 Posted April 7, 2008 Author Report Share Posted April 7, 2008 I'm just thinking a bit more.... I was hoping to not wreck the prototype plastic bait, but maybe that's just a given. It's that ultra-cheap part of me creeping in! Quote Link to comment Share on other sites More sharing options...
nova Posted April 7, 2008 Report Share Posted April 7, 2008 I use the cheapest super glue I can find.(get mine at the $ store) It may ruin the master if it's just plastic but you will have a mold to pour many more. Once I get the master mold done (sealed) I then pour out about 15 or 20 baits; pick the best 10 and make my main mold. I then put away the master mold and only use it when I want to make another pouring mold. www.novalures.com Quote Link to comment Share on other sites More sharing options...
King Bait Co. Posted April 7, 2008 Report Share Posted April 7, 2008 On chunk molds I put them on the bottom and pour POP over the top of them. I make the POP thicker so they Won't float up. It Seems to get rid of 99% of the bubbles If not all of them. I am Going to try it with all my flat bottom baits. Quote Link to comment Share on other sites More sharing options...
Smallie Posted April 8, 2008 Report Share Posted April 8, 2008 I would just seal them and make your baits. Most of the bubble holes will go away and the few that remain - who cares, the fish won't. Quote Link to comment Share on other sites More sharing options...
longhorn Posted April 8, 2008 Report Share Posted April 8, 2008 another way to stick masters to the bottom of the mold container is permanent double-sided scotch tape...the masters will have a little sticky residue but that can be washed off. Quote Link to comment Share on other sites More sharing options...
Gloomisman Posted April 9, 2008 Report Share Posted April 9, 2008 The excess of bubbles may be an indication that your PoP mix is too thick. I tried following the instructions obtained from a web search, but this too left me with a lot of bubbles. My latest pour, I measured the water and plaster powder by weight (50/50). I mixed the PoP as directed in the web instructions, by pouring the water into a suitable container (a plastic ice cream tub with round, molded corners for wasy access) and sprinkled the powder through my fingers, slowly. I then mixed with my fingers, very slowly, so as not to introduce any air.What bubbles existed, rose to the top fairly quickly and my finished mold was clean and bubble free. The question will remain as to what is the ideal mix ratio for the plaster strength, but I was very happy with this pour and the strength seems fine to me and I will be using it again. 10% of the water was elmers glue-all. But the best way to avoid bubbles is to bottom mount the masters, as outlines by Nova (above post No2). This way, the bubbles rise away from your working surfaces. I would be interested to read what ratio other members are mixing successfully to avoid this problem. I have found the same thing Vodkaman. I mix a little more water then the directions call for. This helps alot with the bubbles. Plus if you mix do not slop the pop that keeps air bubbles out. With the extra water in there if you mix it long enough all of the bubbles will come to the top leaving pure plaster. I have poured several molds like this and I no longer have a bubble issue. It leaves a clean detailed mold. plus the runnier pop flows better around the bait. Pour slow steady stream so it doesnt create air pockets. Quote Link to comment Share on other sites More sharing options...
Tman2 Posted April 9, 2008 Author Report Share Posted April 9, 2008 So, all of these answers are directed to pouring over your master, however, my initial question had to do with placing the master in afterwards from the top. Should I assume my method is a big no-no from your responses? Quote Link to comment Share on other sites More sharing options...
Gloomisman Posted April 9, 2008 Report Share Posted April 9, 2008 I wouldnt do it. You get alot better molding on a flat bait by gluing it down. When you press it in you can create air pockets alot easier. Flat baits imo need to always be glued down. Quote Link to comment Share on other sites More sharing options...
King Bait Co. Posted April 9, 2008 Report Share Posted April 9, 2008 You can put them on the top. Their is no right or wrong way its what YOU whant to do. People seem to forget their way may not be the best way for others. The one thing not to many people touched on is how to mix the plaster. I mix mine 1 cup ice cold water in mixing cup , 2 1/4 to 2 1/2 cups plaster second. I use a paint stirer to mix with I tilt the mixing cup at a 45 degree angle. Stiring slow so the stick doesn't leve the mix until it becomes like cake batter with no lumps. Then pour it in slow as not to over lap where you are pouring so not to trap air. Place bait in heavy side in first ( two hands needed) while holding the thin wide parts up. Then start to push in on the heavy side working twoards the claw. Kinda of like rolling it on. Little air if any should get traped under the claws. It will take a few times to get it down. It will come to you the more you do. Quote Link to comment Share on other sites More sharing options...
nova Posted April 10, 2008 Report Share Posted April 10, 2008 The one problem I found with putting the bait in the pop from the top is that bubbles rise and if they come up underneath your bait you'll wind up with the same thing again. www.novalures.com Quote Link to comment Share on other sites More sharing options...
MGrant Posted April 10, 2008 Report Share Posted April 10, 2008 I would first like to say thank you to all that help make this site successful especially in that those with knowledge are so willing to help those without. Being fairly new to pouring I have not had to post becouse of the wealth of existing knowledge on this site which is excellent. Along the bubbles in POP molds I came across something very interesting this evening. I poured the bottom of a two piece mold and placed the masters in from top. I got little bubbles here and there but nothing out of the ordinary. I let the mold set 24hrs, then set up to pour the second half. I put a thin layer of vaseline on top of the bottom half, mixed pop 3 cups plaster to 2 cups cold water, mixed slowly by hand, taped bottom to remove excess air and poured thin layer slowly. The plaster began drying immediatly and large air bubbles began rising like it was slowly boiling. It seemed the lower dry part of the mold was absorbing the water from the wet plaster and releasing air into the fresh plaster. On two piece molds, should I be sealing the first half before pouring the second half, or what the heck? Quote Link to comment Share on other sites More sharing options...
Vodkaman Posted April 10, 2008 Report Share Posted April 10, 2008 Excellent point, one that has not been addressed as far as I can remember. Personally, I dry and seal before casting the second half. The problem is made worse by the fact that the PoP is exothermic and heats up the first mold half. The air within subsequently expands with the heat and escapes into your wet plaster. I have never been happy with petroleum jelly as a release agent for PoP or RTV. These mold materials seem to absorb the jelly, leaving the contact surfaces dry (and sometimes stuck together!). I have just conducted a few experiments by mixing a tea spoon of microspheres in a tablespoon of petroleum jelly and using it as a release agent on an RTV mold. The theory being, that when the jelly is absorbed, it leaves a layer of spheres behind. It worked very well, I don't know if it would work with PoP though. Quote Link to comment Share on other sites More sharing options...
King Bait Co. Posted April 10, 2008 Report Share Posted April 10, 2008 I saw this on a TV show (Lunkerville). Let the bottom half dry then put tin foil over the top of mold (master side) cover it all. Form the tin around the bait and then pour on top of the tin let it dry. Then you should have a good to go mold. I haven't made a full round mold yet I seen them do it and it worked. I think ceran wrap (I don't know if thays spelled right) would work too. I think were getting off track on this post! Sorry! Tman2. Just remember in two weeks you'll be making perfect POP molds or be really CONFUSED!!!!!!! Quote Link to comment Share on other sites More sharing options...
nova Posted April 10, 2008 Report Share Posted April 10, 2008 What I do is make the first half of the mold and let it set up so that it is quite firm but not dry. I then coat the mold with cooking oil using an artist's brush being careful not to get any on the bait itself, but making sure that the pop right up to the bait is coated. I then let it set for a few minutes due to the fact that the oil will soak into the pop. Some areas of the pop will soak up the oil more than others and I will re-coat those areas. Do not flood the oil and there should not be any pools of oil; it must all be absorbed into the pop. After it has set for a few more minutes I then pour the second layer of pop; and after this has set up and dried somewhat I remove it from the frame. Before it has dried I take a table knife and score the joint all the way around both halfs of the mold. Then I start carefully prying the 2 halfs apart. You must take you time here and not be too forceful because the pop is not completely dry. ( I have only ever broken one mold like this). This will give you a mold that is damp enough to make any repairs to (bubbles/defects) because you can actually reshape the pop a little with wet fingers. I then stick the mold into the oven at about 150 and let it dry. Once it dries I then begin my coatings of epoxy with oven curing in between. If I start a mold in the morning, I can be pouring baits by the afternoon. This works for me and it may not work for everyone. www.novalures.com Quote Link to comment Share on other sites More sharing options...
