Paint over Spar Urethane

[tonynoriega2]

Hi all... I found a bit on this, but wanted to clarify.

I am in the process of brushing all of my decking platform plywood, and 2x4 framing with some spar urethane.

Since it will be a "semi-permanent" deck, I wanted to ensure at least several years out of it before any wear and tear starts to show.

After the Spar Urethane, can I give it a couple of coats of an oil based "rustoleum" just to lock it all in?

90% of the wood will not be exposed to direct sunlight. And barring any real water in the boat, should not get wet by any standing water.

After that will be contact cement and carpet all around... with my hatch for storage.

Any thoughts or insight is greatly appreciated opinions welcome too.

thx

 

[Bondo]

Re: Paint over Spar Urethane

Ayuh,.... Seems like overkill to Me, but so long as ya sand 'tween coatings, it oughta be just fine,...

I'd let the Rustoleum dry real well, before the carpet glue,...
Addin' hardener to it is probably a good idea too,...

 

[jigngrub]

Re: Paint over Spar Urethane

Which carpet adhesive do you plan to use?

 

[Woodonglass]

Re: Paint over Spar Urethane

I'm all about using Rustoleum but...In this case since you're using Carpet, if you use a good exterior grade water proof carpet adhesive an really apply it thorougly I see not need for the Paint. Just my observation and NOT speaking from experience.

 

[tonynoriega2]

Re: Paint over Spar Urethane

I was planning on using the Dap Contact Cement you can get form lowes.

Yeah, I know its over kill to Spar, Paint, and carpet glue (adhesive), but figured do it now rather than later.

My main concern is the half moon shape that lines the bottom of the hull. Any water in there and the wood is just kind of sitting in it.

 

[Woodonglass]

Re: Paint over Spar Urethane

3-4 coats of the Spar on the underside of the deck should provide ample protection for the wood. If you store the boat "Bow Up" as it should be, it'll last for decades.

 

[jbcurt00]

Re: Paint over Spar Urethane

I'd scuff the spar to give the carpet glue something to bite & skip the paint.

Painting the spar & then applying carpet glue to the painted surface, you'll have carpet glued to paint. Although I'd recommend Rusto Pro w/ enamel hardener for some applications, pre-carpet glue wouldn't be 1 of them.

If this boat will see any rough duty service:
Lots of usage & fishing trips
Mostly a full crew of fishermen
Used IN ALL weather conditions
Wide temperature swings in service or in storage

Anything that might stress the carpet glue's adhesion, or the underlying paint/spar adhesion, particularly expansion & contraction of the plywood is another opportunity for the glue or paint to let go................

If you want the plywood to last longer apply epoxy instead of spar, and skip the paint. If you'd rather not use epoxy or the expense of it, apply 3 or 4 coats (rough/scuff between each coat) of spar to each side of the plywood AND coat the edges w/ every coat (edges then have 6 or 8 coats) and skip the paint.................... Same for the wooden framing below decks.

Keeping the boat bow up & plug pulled.

Using aluminum instead of wood framing, particularly where it's likely to get wet & stay wet while the boat is in use, might have been a better choice too.

 

[Ned L]

Re: Paint over Spar Urethane

Hmm, .... Other than because you have it 'on hand' what are you looking to accomplish by varnishing and then painting over the varnish?? (It will not be more durable or hold up longer than just proper painting.)

 

[jigngrub]

Re: Paint over Spar Urethane

I was planning on using the Dap Contact Cement you can get form lowes.

Yeah, I know its over kill to Spar, Paint, and carpet glue (adhesive), but figured do it now rather than later.

My main concern is the half moon shape that lines the bottom of the hull. Any water in there and the wood is just kind of sitting in it.

I wouldn't paint if you're going to use contact cement, contact cement is some pretty potent stuff and will eat/remove a lot of paints. It does work ok on the spar though.

If you want more protection use more coats of spar.