rdhammah Posted September 26, 2018 Report Share Posted September 26, 2018 Tried searching this topic but could not find anything on it but I know this has come up before. When I make a POP mold, the bottom comes out perfect. No residual bubbles. after it dries for a day, I apply a small amount of Vaseline to aid in demolding. I Mix the POP/water 2:1 and slowly mix. Before I pour the mix into the mold to make the top half, I tap the cup to get rid of bubbles. I pour the mix and tap to make the bubbles rise. I demold after a day. there are a ton of fairly large bubbles. I have tried using a thinner mix with the same results. How do I get rid of these bubbles? Quote Link to comment Share on other sites More sharing options...
Travis Posted September 26, 2018 Report Share Posted September 26, 2018 (edited) Paint a coat onto your master before you add the bulk of the plaster. Should take care of any issues as seams you have addressed viscosity, removal of bubbles with agitation, etc.... Also make sure you master is seated well in the other half. Air can get trapped and work it way up as things heat up. Edited September 26, 2018 by Travis 1 Quote Link to comment Share on other sites More sharing options...
rdhammah Posted September 26, 2018 Author Report Share Posted September 26, 2018 will try that next time I make a mold. thanks. Any other suggestions would be welcomed. willing to try them all Quote Link to comment Share on other sites More sharing options...
Travis Posted September 27, 2018 Report Share Posted September 27, 2018 I typically pour the top portion along the outer areas and work the plaster in with a toothpick or cheap paint brush if needed and then typically just carefully rub some plaster of paris with my finger over the master carefully so not to disturb it. Any tiny bubbles can be fixed later with a pop mixed with less water to make a paste. Pack it into the bubbles and blend out to the surface. I have a set of small curved files, spatulas, and dental probes that are used to clean up molds add detail etc.. before I clear coat the mold. Quote Link to comment Share on other sites More sharing options...
rdhammah Posted October 6, 2018 Author Report Share Posted October 6, 2018 On 9/26/2018 at 6:41 PM, Travis said: Paint a coat onto your master before you add the bulk of the plaster. Should take care of any issues as seams you have addressed viscosity, removal of bubbles with agitation, etc.... Also make sure you master is seated well in the other half. Air can get trapped and work it way up as things heat up. it works! only had 3 minor bubbles that I filled all on the same bait. the other 2 were flawless (almost) Quote Link to comment Share on other sites More sharing options...
Roger Linnell Posted October 6, 2018 Report Share Posted October 6, 2018 Painting the plaster on is only thing that works, I Iearned that years ago in the foundry I worked at 1 Quote Link to comment Share on other sites More sharing options...
