Primer/sealer for above-waterline timbers?

[Seth Wood]

Hi all --

Question on traditional wood construction. This is a 30' double-ended sailboat, with white oak backbone and stems. As I shape and assemble the backbone, stems and deadwood, I've been sealing the below-waterline surfaces with CPES and then red lead.

What about above the waterline? (Of course, this only refers to the upper 2-3' of the stems...if the backbone is above the waterline then there are Big Problems.)

I don't want to seal them with red lead because then they'll be bright orange. That can't be right. But I'm afraid to leave them as bare wood, especially since the oak will continue to check. Eventually they'll be painted white, like the rest of the hull.

What's the preferred method here? CPES and standard oil primer? No CPES and primer? Thinned red lead? Turps-pine tar-linseed oil? I am at a loss.

Thanks for any advice!

[Venchka]

Originally posted by Seth Wood:
Hi all --

...CPES and standard oil primer?

Thanks for any advice!Heck, I'll jump in here and run my mouth.

Yep. That's what we did. Can't tell you about long term results yet. The theory is sound though. The CPES + primer will give the wood about the same moisture gain/loss as the parts already coated with CPES & red lead. You'll have a good base when you do paint her. With Kirby's paint, of course! smile.gif

[Art Read]

Red lead's about the best primer a boat can get. Why worry about the "orange" color if you're just gonna end up painting over it with an enamel topcoat anyway? "Overkill", perhaps, and certainly more expensive than most garden variety primers out there, but how many boats are you gonna build in this lifetime? Obviously any areas to be finished bright will want a different approach. CPES followed by varnish or Deks Olja, all by itself, is what I decided on.

[ 10-14-2003, 11:38 PM: Message edited by: Art Read ]

[Maranto]

We've been doing alot of topside work this last two years including alot of scraping off of very old paint, some almost 20 years old. After lots of reading and asking around, we opted for the following lengthy process. I can't say anything about the longevity of this or any other method, just that we felt it was well worth the effort if it indeed will give us the protection. If your looking to just prime the above-waterline wood, then I would just do the CPES/red lead primer treatment. We did this in areas that are ultimately not usually visible. But if you are planning on painting over the red lead, then here is our procedure.

We began with sealing the entire bare wood areas with CPES,followed a couple of days later with a thin covering coat of CPES followed by red lead primer within the recommended 24 hours for adhesion with the CPES. After that, we waited a few days for the whole sealer/primer combo to cure then applied Z-Spar 105 white undercoat. This acted as both a good colour transition between the red lead and the topcoats and a high build sanding primer, leaving the red lead at its applied thickness. After that we applied between 3 and 5 colour coats - rolled and tipped or just brushed. The colours we used were cream and off-white and were custom mixed marine enamel from the local paint store. The covering board we did last year has held up very well and shows no signs of bleed through of the red lead - one of our initial concerns. We are just finishing off the entire cockpit area and we are hoping our method works in the long run. This is our first experiment with CPES and we won't know the end results for a few years. Hopefully, it will be alot of years.

That's our little story. Hope it gives you some ideas. Most of the input on CPES was from this forum. The rest was a compilation of seemingly good ideas. So far, its worked very well for us.
One thing we found as an added benefit to using the red lead was that we saw some minor high spots and wear points after the first season where the red started to show through. Sort of a "need -to -paint" indicator!

Regards,

Peter.

[Seth Wood]

Finishing it bright? Yar, not likely! It sounds like CPES then red lead followed by regular white primer is the way to go. George Kirby told me that their red lead won't bleed through as long as you prime with white once or twice on top of it, so that should be safe.

Good! I was not looking forward to figuring out yet another sealer-primer-oil-whatchamajig setup.

Thanks for all the replies! Helpful and prompt -- doesn't get much better than that.

Seth

[Bob Smalser]

I always liked red lead or, when I can't get it, some other poisonous paint like copper thinned to seep as deep into raw wood as possible...minimizes the potential for rot-producing fungi to take hold, I always thought.

So if y'all are sealing your wood with CPES now, and then sanding, what is the advantage of red lead over any other primer or a thinned coat of the topcoat as a primer?

[TimothyB]

Aye Bob, I was wondering that too. Red/white leads are used for their preservative and anti rot properties, but if you CPES the wood then it doesn't matter that much if you are using red/white lead.

The lead compound doesn't really buy you anything if you put a barrier coat between it and the wood. Moisture ingress would get underneath the barrier coat and avoid the lead compound, no? If you use CPES, just use regular alkyd enamel as a primer coat. Get a few 5 gallon jugs of surplus battleship gray for $2 and you're all set for primer smile.gif

Btw any paint afficianados please feel free to correct my assumptions here.

--T

[ 10-15-2003, 12:05 PM: Message edited by: TimothyB ]