Whats a good primer for painting wood boat

[nothinbutwood]

I am having paint adhesion problems on my 66 Chris Craft. Every year we paint it the paint seems to peel back at the seams and bubble up in small areas. We wipe down with alchohol before painting/priming, nothing seems to help. We are using Petit white yacht undercoat for primer and Petit yacht white gloss for finish paint.

Any relevant experience would be greatly appreciated.

[Wayne Jeffers]

Welcome!

A lot of people here swear by a product called Clear Penetrating Epoxy Sealer (CPES) as a primer to assure adhesion of topcoats to wood.

Use the "search" feature to find discussions on CPES.

Wayne

The following post by Bob Cleek from a couple of weeks ago in another thread provides what appears to be some good product information:

Okay... this may be helpful. A quote from the 1981 booklet: "How to Fix Your Wooden Boat, being #3 in a series of compleat guides for the able person, a vritable cornucopia of knowledge gleaned through the ages, selected by our panel of experts for most expedient rectification of the more common conditions of such craft... Extra added attraction: several delightful illustrations, pleasingly located throughout the text." Copyright 1981, Smith and Co. and with a title like that, ya just gotta love Steve Smith!

Now, this was written twenty years ago long before the Rot Doctor and others started hawking the stuff in their own cans as the cure-all for eveything from hang nails to hoof and mouth.

To quote Steve (with emphasis added):

A while back we mentioned SEALING WOOD with clear penetrating epoxy sealer (CPES). THIS IS A MAJOR USE, ACCOUNTING FOR THREE-QUARTERS OF THE WORLD'S CONSUMPTION OF THE SEALER.

CPES IS USED TO SEAL WOOD SURFACES prepatory to adhesive bonding, or to obtain higher bond strengths (in come cases, to obtain any bond at all). The sealer is particularly formulated to provide enhanced chemical adhesion to both epoxy resins and polysulfides. It provides a bond between microscopically rough wood surfaces and the adhesive, which is often viscous and cannot penetrate and saturate the microscopic fibers and spaces that make up the surface of the wood.

...

Most adhesives and paints are relatively viscous and will not penetrate past the loosened and roughened fibrous surface to attach themselves to the intact bulk of the wood. In fact, the loosely attached fibers at the surface tend to shield the underlying bulk of the wood from the wetting action of adhesives or coatings. The moisture and oils or saps in the wood can also act to prevent many materials from wetting the wood itself, just as oils in a concrete surface will prevent water from wetting the concrete. Resin systems which contain no solvents and which contain pigments, fillers, or thickeners will do a relatively POOR job of wetting and bonding to the intact bulk of the wood. (Comment: So much for the argument in favor of just thinning WEST System epoxy with alcohol or acetone for the same purpose.) However, FLEXIBLE epoxy adhesives with SPECIAL ADHESION ADDITIIVES applied to a FRESHLY CUT OR SANDED surface give excellent bonds to OILY or exotic hardwoods such as apetong, araki, and lignam vitae.

FOR THIS REASON WE HAVE FORMULATED the product we call CLEAR PENETRATING EPOXY SEALER. (Note: Apparently its original purpose was not to "restore" rotten wood.) It consists of an epoxy resin and a curing agent which, when cured, have a toughness and FLEXIBILITY COMPARABLE TO MOST WOODS. The CPES is formulated with the epoxy resins DISSOLVED IN A CAREFULLY SELECTED BLEND OF SOLVENTS DESIGNED TO DISSOLVE NOT ONLY THE WATER, BUT THE OILS AND SAPS FOUND IN WOODS. The wood is strengthened without making it excessively brittle, and NORMAL EXPANSION AND CONTRACTION OF THE WOOD WITH CHANGES IN TEMPERATURE AND HUMIDITY ARE ALLOWED.

AN EPOXY RESIN SEALER SYSTEM WHICH DOES NOT CONTAIN WATER-DISSOLVING SOLVENTS CANNOT PENETRATE WOOD AS EFFECTIVELY AS THIS SYSTEM. This is particularly apparent when repairing wood that has MILD dry rot. The CPES can be fed into an area, and it will migrate along the fibres of dry rot within the wood AS LONG AS IT CONTINUES TO BE FED IN.

The LONG WORKING TIME of this product (about 36 hours at 72 degrees F) means it will be very runny and RETAIN ITS MOISTURE DISSOLVING ABILITY FOR A GREAT LENGTH OF TIME. In one case we have heard of, the sealer was fed into a dry-rotted deck beam CONTINUOUSLY through a 1/4 inch hole, and six hours later began to drip out the far end of the same deck beam because the dry rot ran the entire 10 foot length. No other product available can penetrate and impregnate dry rotted wood so effectively.

In butt joints the CPES will also soak in great distances, so two or three coats several days apart may be necessary to completely seal the wood.

When two pieces of wood have been treated the day before with CPES, an adhesive will achieve the ultimate strength of bond between the two members. The sealer has provided a bond between the surface of each wooden member and the bulk of the wood itself. When applying a paint or varnish to wood, the durability of the coating will be exceptional becaue the paint has a strongly attached, chemically compatable surface to bond onto. Varnish applied over wood which has been treated with CPES has lasted more than three years (Comment: I can vouch for that!), whereas varnish on bare wood often peels in six to 12 months.

The two-component polysulfide rubber caulking and sealing compounds are among the best adhesives and sealants, but are so viscous they will not form a high-strength bond with bare wood. Yet when the wood has been treated with CPES a day or two before polysulfide caulking is applied, a very high strength, permanently waterproof joints are obtainable.

***************************************

So, with a nod to Steve's copyright, that's what he has to say about CPES. Or at least had to say twenty years ago. It seems to definitively answer many of the questions raised in this thread. It was a pain in the ass to type it all out, but maybe it helps those who are new to the applications of this product.

[ 07-12-2002, 04:52 PM: Message edited by: Wayne Jeffers ]

[DougWilde]

I like Pettit paints. You might consider applying one of their sanding sealers first. When I had problems painting some epoxy-coated ply I put on a coat of their fast drying (or oily wood) sanding sealers and the next coat of paint behaved beautifully. Make sure you have adequate ventilation with this stuff!

Doug Wilde