Small Bubbles In Swimbait Tail - Help

[Tenacious Baits]

I've been pouring swimbaits and have been able to get rid of almost all my bubbles. I get a lot of small bubbles in the tail portion. I'm using an rtv mold and mf plastic. I do not have bubbles in my plastic before I pour. I don't get bubbles in any other parts of the bait. I heated my molds in the oven for an hour to sweat out the oils. Washed with soap and water. I keep them in an airtight container in my house.

I need help getting the small bubbles out of the tail. Any suggestions?

[Richard Prager]

I used M-F plastic for several years along with RTV molds, aluminum, resin, etc. I've never had the problem you are encountering. I never heated nor washed any of my rtv molds and had some that were about 20 years old. Could heating and washing them be the culprit? The only thing I did to rtv molds prior to pouring , was to apply a little worm oil or scent with a sponge brush to get a shiny finish on my baits.

[Tenacious Baits]

I used M-F plastic for several years along with RTV molds, aluminum, resin, etc. I've never had the problem you are encountering. I never heated nor washed any of my rtv molds and had some that were about 20 years old. Could heating and washing them be the culprit? The only thing I did to rtv molds prior to pouring , was to apply a little worm oil or scent with a sponge brush to get a shiny finish on my baits.

I just heated and washed the rtv molds within the past week. I was having the problem prior to that.

[mark poulson]

If it's an open pour mold, do you start at the tail?

[Tenacious Baits]

If it's an open pour mold, do you start at the tail?

Yes, it's an open pour mold and I start at the tail.

[Long Lake Lures]

I, like Richard, never heated or wash my RTV molds before pouring, and I don't get bubbles in the tail. How many times do you pour in the cavities at one sitting? does it get better after repeated pourings? if it's not residual moisture in the tail, I am at a loss. Please tell us when you find out! Thanks, Dave

[mark poulson]

Without seeing the actual bubbles, I'd say the problem you have is shrinkage of the plastic.

I'd guess that the plastic is hottest, and therefore shrinks the most, when you pour the tail first, and that might be causing your bubbles.

Typically, the srinkage in a open mold shows up as a dishing of the back. Even Roboworms' top pours, which are computer controlled, have dished faces. Pull one out and check it.

The tail is tall and thin, and that may exaggerate the shrinkage from the hot plastic.

Since it's an open mold, you might start pouring from the head to the tail, and only fill the whole mold partially to begin with.

The plastic will still be hot enough to melt into itself if you go over it again right away, but that might cut down on the amount of shrinkage in the tail.

Hope this helps.

[Vodkaman]

Yes, it's an open pour mold and I start at the tail.

You may be introducing the bubbles when you pour. After stirring the plastic in your pyrex, all the bubbles rise to the top and collect around the edge. Your initial pour into the tail is carrying some of these bubbles. You could prove or disprove this theory by pouring the head first and see if the tail clears.

152nd Street Baits post earlier today made me think of this possibility.

Dave

Edited September 26, 2010 by Vodkaman

[Tenacious Baits]

Thanks for the tips! I'll give them a try and let you guys know how it goes.