Paint problem - need help

[Coho Ghost]

Gentlemen,

Here's what is going on. I have my transom rebuild ready to paint, I thought. (I'm just painting the transom face) Everything I have done up to the last fairing was with vinyl ester resin. The last skim coat on a patch I had to put in the outer transom skin was with System 3 epoxy thickened with microballons. I let it cure for about a week, then did a lot of sanding to finish things and washed the whole transom face with acetone.

Yesterday I rolled and tipped a coat of standard Rustolem gloss white thinned with 2 oz of Penetrol to 16 oz. of paint on the transom. Any place there is epoxy fairing, the paint is still tacky, over the old gel coat it is bone dry!

I felt fairly sure the amine blush was cured/sanded/washed so no problems would occur. What is going on? Do I need to sand everything off and go to Easy-poxy? or will things eventually dry and I can put on another coat? Where did I go wrong?

Thanks for the help,
Coho Ghost
up in Washington state

 

[ghamby]

Re: Paint problem - need help

You will need to prime that epoxy. A two part epoxy primer is recommended.
You could try some automotive spray primer. Rustolium primer might do the trick.
I used up some old epoxy filler on my house and found I had to spray the spots
with auto primer before the oil based primer would cure. GH

 

[Coho Ghost]

Re: Paint problem - need help

Ghamby,

Thanks for the reply. I assume I will need to sand off ALL of the Rustolem gloss white that is on the epoxy before applying the primer. Correct?

Coho Ghost

 

[ghamby]

Re: Paint problem - need help

The epoxy primer will probably lift the Rustolium. If you only have soft spots
where the fairing is you might be able to spot prime.
Best bet in the long run, sand back to the system 3 and prime with epoxy.
I think the problem is the difference in how clear epoxy cures as opposed to
epoxy mixed with micro-balloons. GH
I might be posting through my hat a little here. I'm going on personal experience
with epoxy and micro-balloon fairing compound.
http://www.systemthree.com/ This site will be more definitive.
http://www.rustoleum.com/CBGBrand.asp?bid=13 This site not so informative.

 

[Coho Ghost]

Re: Paint problem - need help

Ghamby,

I wiped everything down with acetone, and all of the tacky gloss white that was over the epoxy came right off. I then re-sanded everything. Got some Rustolem primer, and made a little test, putting it on a small area of the epoxy. It dryed just fine, not tacky at all after about 20 minutes. I have now coated the entire epoxied area and am letting it dry. I plan to lightly sand it tomorrow and put on one more coat and sand again. I'll give it a couple of days to get fully dry (the weather up here has been lousey for painting) and then start back with the white. Since the primer is gray, I expect it will take about four coats to really cover it.

As a side note, I was amazed at how durable the Rustolem is on the areas where it has dryed properly. The acetone wash would not touch it! I expected paint that fresh to come right up with such a strong solvent.

Coho Ghost

 

[ghamby]

Re: Paint problem - need help

Glad to hear it. When is the weather up there not lousy for painting?