basskat Posted January 19, 2005 Report Share Posted January 19, 2005 Maybe some of you guys have had this problem. I completed a new mold, it's made from Durham's. I baked the mold and covered it with Devcon. Tonight when I would pour air bubbles would come through my plastic and bubble up. Any idea what's causing this? I sure hate to trash this mold since it has a lot of small detail work and was a pain to make. I've got 50 molds made from plaster and Durham's. None have ever reacted this way. Quote Link to comment Share on other sites More sharing options...
vishezfish Posted January 19, 2005 Report Share Posted January 19, 2005 I am having the same problem except with plaster...? I made a one part mold, sprayed engine paint over it like all my other molds and I'm getting air bubbles at the top of the pour.... Cold weather maybe? The plastic too hot? Thanks to anyone who might know the answer!!! VF Quote Link to comment Share on other sites More sharing options...
basskat Posted January 19, 2005 Author Report Share Posted January 19, 2005 I've tried different plastic temps, changed the way I was pouring, even layered the pouring. Still get it. Can't find an air pocket in the mold. Been pouring for ten years and never had this problem. Quote Link to comment Share on other sites More sharing options...
Senkosam Posted January 19, 2005 Report Share Posted January 19, 2005 Something you might want to try - Pour a bait, pull it out once cooled, pour a bait in the same cavity with a sample of clear plastic (no additives). Note where the bubbles originate. If the bubbles are rising from pores in the epoxy (just about impossible), that may be the source. If the bubbles are originating in the plastic, moisture in the plastic causes bubbles, though usually only in the pyrex when first heated. Low humidity is the best. Is the room 65 or above? Pouring in a cold garage might contribute (doubt it though). Sam Quote Link to comment Share on other sites More sharing options...
The Dutchman Posted January 19, 2005 Report Share Posted January 19, 2005 Are you sure the cavity is completely covered with devcon? If you missed a spot you could be getting air from this spot. Also, did you cure your mold sufficiently in the oven? Moisture will find a way out - just like on a house that is painted. If there is moisture in the wood - it will work out and cause the paint to blister. Good Luck! Quote Link to comment Share on other sites More sharing options...
D.J. Posted January 19, 2005 Report Share Posted January 19, 2005 I wonder if a cold garage is the culprit. I just started having that problem too. My garage is a little on the cold side. All I have is a small heater pointed at my work bench. I guess it could be the molds. It happens to me when I pour in the water putty molds. : Quote Link to comment Share on other sites More sharing options...
nova Posted January 19, 2005 Report Share Posted January 19, 2005 I think Senkosam has it. I used to have the same problem every once and a while. Now I used resin, no more prblem. Quote Link to comment Share on other sites More sharing options...
GB GONE Posted January 19, 2005 Report Share Posted January 19, 2005 I have had this exact problem...there were gaps in where I thought I had completely devconed the mold. Kidlizard gave me a valuable tip when I was having this problem. Add some food coloring (just a little red or something) to your devcon. After coating, you can tell instantly which areas have been covered good or not. I can promise you I thought I was giving these molds a great coating however found that after adding the food coloring and then coating..areas that looked coated to me, where not coated well enough. Also, if you are not getting bubbles when using your other molds with the same plastic, additives etc. then there is no way it could be related to those items. I do get bubbles from the humidity and cold but they are in the plastic when I heat it, not originating from when I pour the mold. Just my 2 cents!! Jim Quote Link to comment Share on other sites More sharing options...
basskat Posted January 19, 2005 Author Report Share Posted January 19, 2005 My shop stays a constant 70 degrees. I'll go back and recoat with Devcon. There's got to be some uncovered areas. All the bubbles are in one area of the mold. Thanks guys! Quote Link to comment Share on other sites More sharing options...
charkins Posted January 19, 2005 Report Share Posted January 19, 2005 Been having the same problem with ceramic mold coated with devcon. I coated the molds twice. Heater keeps the building about 60 or above. I pour a couple of baits in the mold, then it stops. Only the fluke molds are doing that. ?? Cal Quote Link to comment Share on other sites More sharing options...
vishezfish Posted January 19, 2005 Report Share Posted January 19, 2005 I been pouring in a cold enviroment myself, Maybe it is the cold!! I did a second coat with the paint so I have to check it out this weekend... Thank you for all your help! Quote Link to comment Share on other sites More sharing options...
basskat Posted January 21, 2005 Author Report Share Posted January 21, 2005 I applied a secong coat of Devcon and it corrected the problem. Apparently I left a spot uncoated. Thanks for all the help guys. Quote Link to comment Share on other sites More sharing options...
