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Basecoat On Resin Baits
14 replies to this topic
Posted 16 April 2010 - 09:29 PM
I have been using white enamel from the spray cans for a basecoat on my molded resin baits and am getting a dimpled finish as if something is repelling the paint away from the lure. The paint adheres fine where it settles but if is obvious something is not right.
Before painting I finish sand, bake in the oven for up to 24 hours at 200 degrees, wash in the dishwasher, and only handle with gloves from this point on.
Any thoughts or advise on the painting process with molded baits.
Thanks in advance.
Posted 16 April 2010 - 09:45 PM
Might be the surfactant action of residual detergent on the bait adversly affecting the paint. A picture would really help in determining the possible cause
Posted 17 April 2010 - 12:41 AM
I think KC is barking up the right tree. I would wipe down the bait with Denatured alcohol prior to painting. Also do you apply the paint lightly or get a 100% cover straight away ?. Several light coats, letting almost dry between, will have a lesser tendency to dimple. It could possibly be air escaping from the paint itself so with a light coat this would not happen but of course patience is the key here.
Posted 17 April 2010 - 05:32 AM
You might try "heat setting" the primer, like you would a water based/bourne T shirt paint like Createx, to simulate oven baking, and drive out all the solvents.
Most rattle can primers say dry to the touch in an hour+-. After that, heat setting shouldn't hurt the strength of the paint film.
Posted 17 April 2010 - 06:41 AM
The baking sounds a bit over the top and unnecessary. When I used fibreglass resin, I had no such problems, but you are probably using a different type of resin. I just left the bodies for 24 hours, then a light sanding to remove seam lines and any blemishes.
Are you letting the bodies cool before applying the paint? If not cool, this could be causing a problem.
A picture would help.
Posted 17 April 2010 - 11:33 AM
I do not believe it is detergent residue as it has done the same thing without washing the baits.
I have not tried wiping down with Denatured Alcohol would be worth a try and the paint goes on in light passes and immediately starts wicking away.
The basecoat is going on the naked bait and wicking immediately prior to even getting into the real painting. I always heat set between coats.
All of the methods involved in the "prep work" were aquired at some point from this forum by those who seem to have success with them, I just put them all together. The baits are fully cooled before attempting any painting. The resin is a two-part urethane.
As a point of interest and possible help I used the same process today on a few baits but also grabbed some defected baits that have been sitting around for a few weeks and painted them as well. The paint went on just fine with the baits that had been sitting around for a while. Could it be an issue of the baits still de-gassing? My recollection of the reason for baking the baits was to speed up that process. Back to the search function but help is still appreciated. I will see what I can do about a picture.
Posted 17 April 2010 - 11:47 AM
It could still be a contaminate affecting the paint, especially when working with enamel. Once the intial coat has dried this will offer a base for the subsquent coat to adhere to.
Might be something as simple as not agitating the the spray bomb enough to thoroughly mix the paint. Which can produce the results you have mentioned.
Edited by KcDano, 17 April 2010 - 11:48 AM.
Posted 17 April 2010 - 02:49 PM
It sounds like you pay attention to details but; how well are you mixing the resin?
What are you using to stir it, and what do you stir it in.?
Are you using a mold release?
Posted 17 April 2010 - 03:24 PM
Stirring thoroughly in disposable plastic cups with wooden craft sticks. I am not currently using any type of mold release. Are you thinking something in the mold release may cause this or lack of a mold release may cause the problem.
Edited by KelpKritter, 17 April 2010 - 03:26 PM.
Posted 17 April 2010 - 05:28 PM
No, I don't with RTV molds. Did you use any on the model when you made the mold? The cavity could have residue if you did. If so, try washing the mold.
Posted 17 April 2010 - 08:53 PM
Just a thought but are you letting the bodies cure long enough I know with alumilite I usually let them cure five to seven days. Not sure if that's it but I have had trouble with that happening to my baits.
Posted 17 April 2010 - 10:17 PM
Thanks for all of the insight everyone. A lot of good thoughts and things I will work on this week as I mold some new baits. I will do some more painting next weekend and will report what I find.
Also changed to a different paint for the second coat on some baits today and it went on much better than the other paint was going on for the second coat. Could very well have been an issue with the paint although I believe some of it has to do with the time I was waiting before painting.
Will report back on the results next week.
Posted 18 April 2010 - 03:16 AM
Do you have any pitting in the bodies after you pour them? If so are these the areas your having difficulty with?
Posted 21 April 2010 - 05:48 PM
I used smooth on urethane and they suggested using plasti kote primers for it and they seem to work the best. I still notice the paint kicks sometimes even after using alcohol wipes. Maybe an adhesion promoter might work also. I don't know if putting a coat of etex would help first. Also try dusting the mold with talc, it will give the paint something to hold on to.
Edited by rustyman, 21 April 2010 - 05:50 PM.
Posted 21 April 2010 - 08:07 PM
Did you use a release agent on your molds when you were casting your parts? I do, and i was advised to soak the parts in a bleach/water solution for about an hour to remove the release agent. You will have to be careful which brand of bleach you use as some turn the parts yellowish.