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a question for the experienced foamies
11 replies to this topic
Posted 01 April 2006 - 05:23 PM
OK, i am generally very happy with the foam experiments so far. BUT...
Of my first batch of foam lures, a couple have shown this problem- 1 or 2 bubbles are forming under the paint work and clear coat along the seam line. my guess is that these lures were ones where foam leaked(flashed?) out during curing and the subsequent sanding down i did exposed some opened cells. somehow my sealing(lacquer sanding sealer) was not done properly and the air from inside the lure is trying to escape along the seam line. my question is this- apart from ensuring a more rigid and secure mold clamp, what can used to seal along the seam line to prevent this this bubbling? I'm guessing it has to be thin enough to seep into the open pores along the seam line to properly seal it.
any advice greatly appreciated.
Posted 01 April 2006 - 06:16 PM
Try sealing it with Tally's Plasticoat. Also, wash the lures with hot soapy water to remove any MR before coating. I've started running mine through the dishwasher in a mesh bag after soaping them. Also, give them a full day to "cure out", if time isn't a factor. JMHO
Posted 01 April 2006 - 07:43 PM
If using the plastic dip I have found a few thing to help at times. The bait can be warmed in an oven then dipped. As it cools it often will "suck" in the dip. You can dip baits longer also, and then sand when it hasn't quite set up. This ends up "plugging" any holes during the process. A second dip is required. I also have a jar I made to dip baits in and apply a week vacuum few concerns using this method, volatiles and glass jar implosion. Finally you can take some wood puddy and smear it along the surface of the lure then wipe with damp cloth. This ends up filling any voids also. I seem to see more air bubbles depending upon the mold release I use and the mold. RTV molds almost get a perfect sking everytime. With other molds I have used vasoline, cornstarch, and floor or car wax. I think a light brushing of vasoline followed by powdering of cornstarch works best for me.
Posted 01 April 2006 - 11:21 PM
Hi!I add that bubbles a few times to!?I think that it is almost imposible to do a perfect lure whit foam!??I always have to sand the seam line and add some wood puty and then resand....!!But even if it is not 100% perfect in the end It will work nice !!Cheers,Dan
Posted 02 April 2006 - 12:51 AM
If you are using "silicone j" r.t.v. by Dow Corning;upon release you should see a flash line the thickness of a human hair.I don't use a mold release agent.I simply spray white automotive laquer on the inside of the mold before injecting.Upon release the paint adheres to the foam and not the rubber, giving me a white undercoat to paint over.Colours come up better on a white background.Also the foam should be self skinning after curing; that is a hard plastic outer surface with a honeycombed inner core.If you sand through this outer skin you expose the inner core making it impossible to paint without using putty.Some days I pour up to 50 lures so I can't afford to sand putty each one.Silicone J is expensive but it's the best.
Posted 02 April 2006 - 06:34 AM
For this reason, I finally gave up using foam for lures.
Take one out and lay it in the sun, if you want
to see bubbles.
The whole paint job will raise
up around the entire bait like a dead animal swells
after a couple days in the heat.
You might try heating the mold before pouring and
heating it while curing.
Gasses escaping from the foam is what is causing your
Posted 02 April 2006 - 11:09 AM
That's a bummer! I had the same problem with wood...specifically poplar! Hope you get things figured out, if not go to hard maple and forget about bubbles forever.
Posted 03 April 2006 - 02:37 AM
hi guys!!!!Shit!!!making foam lures is a hard thing!!!but I can make a lot more in the same time!!!!i add my problemes making foam lures but It's whort the time !!!!!It take a few min. to do and I can make a lot in one day!!!!after some wood puty and sanding it's ok so!I like it a lot.Cheers.muskydan6666
Posted 03 April 2006 - 04:00 AM
thanks for the advice guys.
the plasticoat and the wood putty sound like its worth a try.
barramundi, i wish i could get a seam line as fine a a human hair! i think my mold making is not that perfect yet. do you "inject" the foam into a closed mold? i pour the foam into an open mold and then close it. maybe that's why.
coley, what you have described is worrying. I'd better try putting 1 out in the sun. i was hoping to sell a few lures so I'd want to be sure they are durable. has anybody else encountered such severe bubbling?
Posted 03 April 2006 - 08:42 AM
Would simply a coat or two of Envirotex over the lure before painting do the job?
Posted 03 April 2006 - 09:39 AM
Peter, how long do you wait before you begin the finishing Process? JMHO, a good hot water/ soap wash down, and a 24 hour wait period, in a relatively warm place will eliminate a good portion of any finishing problems.
The good new is that I have many finished foamies that are a few years old that are bubble free.
Posted 03 April 2006 - 09:55 AM
hi husky, the wait was a week because i only have time to work on the lures during weekends! i will try to wash the lures more thoroughly on my next batch.
although the bubbling is not a major problem it would be good to eliminate this altogether (from a batch of 10, 2 have shown bubbling- very slight, and along the top seam line only).
i didn't take note which was which before finishing them- but some of the lures had a more open seam line due to sanding down the leaked foam caused by poor mold clamping. the bubbles do not appear elsewhere except along the seam. my guess is that this is my problem. i need to seal the sanded area, or to avoid the need for sanding.