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Old 12-09-2015, 21:46   #1
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Solvent Testing for Two-Part Polyurethane

I have some worn-out painted nonskid that I want to repaint, hopefully with a two-part polyurethane. What is a universal solvent that will dissolve one-part polyurethane, hopefully available at my local hardware store, rather than a marine supply store?

I plan to soak a rag with the solvent, place it on the existing paint, and cover with plastic for 24 hours and see if the finish lifts or curdles.

If the two-part poly is not compatible with the current paint I might try the Kiwi Grip product.

TIA
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Old 12-09-2015, 22:34   #2
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Re: Solvent Testing for Two-Part Polyurethane

Lacquer thinner.
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Old 12-09-2015, 23:13   #3
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Re: Solvent Testing for Two-Part Polyurethane

Awl Grip suggests using the solvent that will be used to thin the 2 part paint you plan to use. They also say to scratch the surface with a razor blade. It's been a long time since I've seen it, but I think the instructions are still on their website.
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Old 13-09-2015, 01:05   #4
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Re: Solvent Testing for Two-Part Polyurethane

Seems like one of the standard domestic paint removers would work. You might try one of the citrus based ones first, for they are far less lethal to your body than the more robust ones! From memory, there is one called "Citri-Strip" or something like that which I have used on non-two pot paints with reasonable success.

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Old 13-09-2015, 06:50   #5
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Re: Solvent Testing for Two-Part Polyurethane

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Originally Posted by Jim Cate View Post
... From memory, there is one called "Citri-Strip" or something like that which I have used on non-two pot paints with reasonable success.
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Citristripís compatibility with fiberglass is stated on their web site.
"It will leave the fiberglass sticky. Fiberglass stripper is the best choice."
CitriStrip | Questions?
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Old 13-09-2015, 08:15   #6
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Re: Solvent Testing for Two-Part Polyurethane

Not wanting to remove the existing non-skid paint. Just want to find out if I can use 2-part poly on top of the existing.

Each manufacturer of 2-part polyurethane says to use their proprietary solvent for testing, but I haven't decided on a brand of paint yet.

Trying to find a representative solvent. Hadn't thought of lacquer thinner.
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Old 13-09-2015, 09:34   #7
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Re: Solvent Testing for Two-Part Polyurethane

The labor involved and the cost of two part paints makes it imperative that you test using the correct solvent. If you really can't decide which paint to use, buy all of the solvents and test each one. The biggest part of painting is the prep work, why put all of that work at risk for the cost of a quart of thinner.
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Old 13-09-2015, 10:12   #8
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Re: Solvent Testing for Two-Part Polyurethane

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The labor involved and the cost of two part paints makes it imperative that you test using the correct solvent. If you really can't decide which paint to use, buy all of the solvents and test each one. The biggest part of painting is the prep work, why put all of that work at risk for the cost of a quart of thinner.

I suspect that makes the most sense

Leaning toward Interlux Perfection, with Alexseal a close second. Guess I will get a sample of each.
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Old 13-09-2015, 11:45   #9
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Re: Solvent Testing for Two-Part Polyurethane

Though that sounds like a pretty good strategy-my rule of thumb is to not put 2 part over 1 part (and certainly not enamel)---ever. Solvent concerns are not the only issue- adhesion, especially through the change of seasons-is a huge concern. My rule of thumb, which has served me well for years, is that its OK to put lower tech over higher tech, but not the reverse. 1 and 2 part LPUs are not kissin cousins. 1 part is actually a modified enamel-If that's what you've got I would stick with it-it's a very good product though admittedly with less durability.

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Originally Posted by redsky49 View Post
I have some worn-out painted nonskid that I want to repaint, hopefully with a two-part polyurethane. What is a universal solvent that will dissolve one-part polyurethane, hopefully available at my local hardware store, rather than a marine supply store?

I plan to soak a rag with the solvent, place it on the existing paint, and cover with plastic for 24 hours and see if the finish lifts or curdles.

If the two-part poly is not compatible with the current paint I might try the Kiwi Grip product.

TIA
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Old 13-09-2015, 13:25   #10
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Re: Solvent Testing for Two-Part Polyurethane

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Originally Posted by mainesail View Post
Though that sounds like a pretty good strategy-my rule of thumb is to not put 2 part over 1 part (and certainly not enamel)---ever. Solvent concerns are not the only issue- adhesion, especially through the change of seasons-is a huge concern. My rule of thumb, which has served me well for years, is that its OK to put lower tech over higher tech, but not the reverse. 1 and 2 part LPUs are not kissin cousins. 1 part is actually a modified enamel-If that's what you've got I would stick with it-it's a very good product though admittedly with less durability.

Cheers.

Agreed. The issue is I have no idea what the current paint is - one part or two part poly or even enamel (though I don't think it's enamel).
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Old 13-09-2015, 15:59   #11
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Re: Solvent Testing for Two-Part Polyurethane

I've also been thinking about trying the Kiwigrip. Seems to be getting good reviews & appears to be pretty easy to use. You would probably save yourself a lot of work by just going with that.
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Old 13-09-2015, 20:32   #12
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Re: Solvent Testing for Two-Part Polyurethane

You should probably decide what paint you want to use before you do your test. Thinners for two part paints aren't cheap. If the base coat passes the test, you already have the thinner you'll need.
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Old 13-09-2015, 21:30   #13
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Re: Solvent Testing for Two-Part Polyurethane

Used Kiwi Grip in the cockpit of our Cat 3 years ago and it's holding up well in the Florida/Bahamas weather. But make sure it doesn't get rained on for the first 24 hrs and and stay the hell off it for 4-5 days until it cures real well has been our experience.
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Old 14-09-2015, 03:59   #14
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Re: Solvent Testing for Two-Part Polyurethane

You can overcoat old well hardened one pack paints with a high solids epoxy as a barrier coat. It's not ideal, but it has worked for me in the past. Something like 80% solids epoxy from memory.

In my case I used jotamastic 87 over an old but sound unknown one pack paint that didn't stand the solvent test. It worked well, with a two pack polyurethane topcoat over the epoxy.

The softer substrate made it more prone to dings, but other than that it was Ok. And the topcoat stayed bright for about 7 years and serviceable for longer.

I don't recommend this, but it can be done. I'd test a hidden part first! But kiwi grip sounds like a much better bet.

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Old 14-09-2015, 05:44   #15
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Re: Solvent Testing for Two-Part Polyurethane

there are universal primers available to go over single pack paints but then you are relying on the adhesion qualities of the existing single pack not what I would recommend as this is my trade removal of existing single pack with a stripper designed for it is the way to go a lot less pain if the 2 pack lifts down the track
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