Painting tubes

[saver]

I casted a pen blank using water clear alumilite. I painted the pen tube with testors enamel. The casting come out with no air bubbles. The problem is some of the paint came off of the tube. The paint cured for 5 days and also baked at 200 deg. for 15 min. before casting was done.Do not know what went wrong.

 

[Kenny Durrant]

If it looks like the resin attacked the paint then I wouldn't think there was a curing problem just a compatibility problem. I would paint the tube let dry for a least a day then coat it with CA Glue. I use different paints and I noticed if I sealed them with CA if took care of that problem.

 

[KenV]

The separation can also come from lack of bond between the paint and brass tube. There are lubricants used in the forming of brass tubes that can interfere with adhesion. Did you clean the tube with solvent or abrade it to get a clean surface before painting?

Could the tube have been contaminated in your shop?? Silicones are nasty for doing that and can migrate easily in traces and contaminate surfaces.

 

[saver]

Thanks for the info

 

[CrimsonKeel]

Did it come off in flakes or look like it dissolved? flakes would be an adhesion issue and dissolved would be a compatability issue. dissolved means try another paint type or brand and flakes would mean you need to sand or clean your tubes better. also 15 minutes in a 200 oven isnt enough imo. I bake mine at 285°f for 30-40 minutes. need to be careful on white at that temp as it may yellow it a bit.

 

[jttheclockman]

Forget painting the tube and reverse paint the blank. That is where it counts the most.