Author Topic: Paint restoration over canvas  (Read 557 times)

DpMorton

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Paint restoration over canvas
« on: January 25, 2019, 07:25:49 PM »
I am a painting newbie, no doubt.
My H12 has a plywood foredeck with cracking, peeling paint. I had originally assumed that the foredeck had been restored at some point and the original cedar planks had been replaced with plywood, or plywood was originally used as it was in some boats. In any event, cursory exam seemed to indicate that there was no canvas on the wood, as was typical of HMC builds, only primer and paint applied directly. As I proceeded to sand, however, residual canvas was revealed under the paint with cracks thru the paint showing canvas underneath. Whether the canvas is complete or only remnant I cannot tell. My question is how to proceed. Aggressive sanding to remove all paint will tear into the canvas. My inclination is to sand as much paint off as possible without damaging the canvas, then prime and paint. Am I correct in assuming that the primer coat will fill the cracks and create a smooth surface for the top coat? Will the primer adhere well to the residual paint, old primer and topcoat, left on the canvas?

David

Charles Barclay

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Re: Paint restoration over canvas
« Reply #1 on: January 28, 2019, 07:35:55 PM »
David--

Great question(s). 

Painted canvas creates a non-skid surface. 

Deck materials have evolved quite a bit; however, plywood under the canvas may well be original depending on the vintage Herreshoff 12 1/2.  Plywood was introduced in the 30's but became much more prominent post WWII as the war helped improve ply technology.  Plywood would be used for structural elements like bulkheads.  PT boats were made with plywood.  Post war, Luders 16 and 24 race boat hulls were made with hot molded plywood.  Many of these 70 year old boats are still viable today.  As with planked boats off season storage and routine maintenance practices are key to long term viability. 

You have several choices of plywood including one formulated for the marine environment.  Marine Ply is your best (only good) choice for decks, bulkheads or any surface exposed to the elements. 

The original decks were canvas.  Lead paint was used to bed and coat the canvas over both planked and ply decks.  Lead paint is toxic by today's standards and proper care should be used in working with it including sanding and disposal.  This means a respirator and gloves and sweeping/vacuuming the debris. 

The other problem with sanding the painted canvas is ruining the non-skid surface.  If you are a painting newbie, you are probably also a foredeck newbie.  Non-skid surfaces are critical safety gear for that reach to reach spinnaker jibe at the wing mark in big breeze!  Not that you would ever do such a thing, but knowing you can is critical. 

Seriously, restoration/replacement is not that big of a deal.  You can source Dynel fabric which mimics texture of canvas at Jamestown Distributors.  It's a DIY thing.  You can also use the plywood or sand and fill the existing surface with thickened epoxy (using microballoons and thicksil) then use interlux deck particles or another similar anti-skid material or even Kiwi Grip on the deck if you are not doing a museum quality restoration. 

Dynel has been the choice I've seen most frequently for good looking, durable, well used decks. 

Good luck,

Charles
« Last Edit: January 28, 2019, 07:56:04 PM by Charles Barclay »