painting problems

Builder's Forum
1

I'm new to all this and tried to find an answer to this on the forum, couldn't.

So, built my Chesapeake 16 in an all woman's class and time constraints meant finishing it at home.  The paint given us for the hull seems like a fine quality, I think I am the problem.  The paint does not  cover the fiber glass cloth evenly.  Parts of the boat (3rd coat) are fine and other areas show the weave of the fiberglass.  I have sanded between coats with 220, which the can suggests, and cleaned off the boat with paper towels and then a tack cloth, again as the can suggests.  I have allowed at least a day between coats. The problem may have preceded the first coat which was done in class.  The boat was wiped down with white vinegar but never washed with soap and water.

No one to ask here.  My husband has no idea what I should do, but you must.

Thanks, Karin

2

The bad news is that paint is not going to fix the problem of the weave showing through. Paint, when dry, is going to be quite thin. Generally speaking, whatever defects you see in the substrate prior to painting you will see in the paint coat. Counterintuitively, paint actually shows more flaws than varnish.

The good news is that the fix is pretty easy. You'll probably have to remove most of the paint, though. Take a look at the weave that's showing through. If it's not pronounced you can probably put down two or three coats of primer, sand out and starting painting. If you can spray on the primer, so much the better. I would avoid high build primers that have a lot talc in them. They're not for below waterline at all.

If pronounced you will probably have to apply some more epoxy to fill the weave. Put on as many coats as needed, then one more. Let it cure for a week or more, more being better. Wash off any blush prior to final sanding, sand out and then wash again. You can skip the primer coat if you're happy with the surface of the final coat but re-read my first paragraph. I find applying primer to ultimately be less total work when doing a paint finish.

Also remember that regardless of how well you finish your surfaces you are always going to get "print through" to some degree of the glass pattern after your boat has spent some time in the hot sun. This is due to the differing expansion/contraction rates of paint and epoxy/glass.

 Dusty

3

Thanks Dusty for your quick response.  I do feel a bit overwhelmed and wonder if I can just leave the hull as is and use the boat until Fall when I can do what you suggest?  But, by tomorrow I may feel ready to tackle your instructions.  Hence, the following follow up questions.

I don't know what makes the weave pronounced or not.  Is it pronounced if I can feel it through the paint or are there other criteria?

If I do the primer, what grit sandpaper do I use to remove the paint?  Paint will be trapped in the fiberglass weave which I can't sand out without sanding through the fiberglass.  Do I just leave the paint in the weave?

So, I sand the whole boat, I presume?

Can I purchase a proper primer in a hardware store?  What would you recommend?

Thanks again, Karin 

4

Waiting until the Fall to fix the paint is a very good idea, for several reasons:

 The problems with the paint and the prominent weave are strictly aesthetic. As long as you have paint and varnish on the epoxy, no harm will come to the expoxy from UV degradation. Even then it takes quite a bit of exposure to seriously degrade epoxy.

Next reason is that, if you're painting outdoors, summer is a very challenging time to paint. The ideal painting conditions are 70 degrees and 50% humidity, conditions not often found in summer. Hot, humid days are some of the very worst conditions for painting.

Lastly, paint takes about a month to fully cure. If you paddle your boat shortly after painting the hull, you will get big scratches in the still soft paint. If you paint in the fall after you've finished paddling for the year, the paint will have four or five months to form a very durable surface.

As far as the weave goes, you shouldn't be able to feel any texture at all prior to painting. I can't say how bad this is on your boat without actually seeing it in person. Primer will only cover up a minor amount of texture. Try a few coats on small area and see if you can get a smooth surface. If not then you will have to fill with expoxy. Since this layer is strictly for aeshetics you can mix epoxy with microballoons and use it as high build, easy sanding fairing compound. If you do this, seal the fairing compound with a coat of straight epoxy.

Which brings us to your next question. Don't worry about removing all the paint because primer and epoxy will readily bond with paint. In fact, all you really need to do is provide a consistent scratch pattern in the paint. This will allow subsequent layers of primer or epoxy to "key" into the paint coat and provide a strong bond. I would try 100 grit because you want a fairly coarse scratch pattern, but don't sand into the glass. If you find this happening go up to 120. Sand out the primer or epoxy  to 220-320 in preparation for paint.

If it was me, I would go ahead and redo the whole hull. Kayaks are small and you will probably work harder to feather-in repairs than just redo the whole shebang.

I've heard of builders who say they are happy with the results of deck/porch paint and primers from the hardware store. Myself, I like Interlux paints and think the small extra expense of getting the recommended primer is a reasonable price to pay for guaranteed compatability.

I can see how this whole process can be overwhelming, but if you break everything down to the constituent steps, it's really quite simple.

Just remember, you never really finish painting a boat. If you own the boat for a while, the annual or bi-annual touchup will be a snap with the skills you will acquire from this process.

Dusty