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Topcoat for polycrylic

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Forum topic by bhacksaw posted 11-02-2015 07:34 PM 513 views 0 times favorited 11 replies Add to Favorites Watch
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bhacksaw

161 posts in 1291 days


11-02-2015 07:34 PM

Last weekend (Oct. 25), I sprayed 3 coats of polycrylic with sanding in between for some coasters I made. I’ve had them sitting in my kitchen with toothpicks between them for a week, but (when my wife moves them around and neglects the toothpicks) they still stick to the countertop or to each other. There’s nothing smudged or transferred, luckily, when i separate them, but it’s making me nervous. Are they still curing? Will they be done by this weekend? Should I put some other coat over them like wax or something?


11 replies so far

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bhacksaw

161 posts in 1291 days


#1 posted 11-02-2015 07:39 PM

View Fred Hargis's profile

Fred Hargis

3949 posts in 1960 days


#2 posted 11-02-2015 07:48 PM

Was that a fresh can?

-- Our village hasn't lost it's idiot, he was elected to congress.

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pintodeluxe

4859 posts in 2280 days


#3 posted 11-02-2015 08:21 PM

I have found polyurethane can take 24-48 hours for each coat to dry. If each coat doesn’t have time to cure before the next coat is applied, it can take even longer to dry.

Try lacquer next time, which lets you re-coat in an hour.

Good luck with it.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

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Ger21

1047 posts in 2597 days


#4 posted 11-02-2015 08:25 PM

It takes at least 30 days for a lot of water based poly to fully cure.
And I think it’s a bad choice for a coaster finish, as prolonged contact with water will damage it.

-- Gerry, http://www.thecncwoodworker.com/index.html http://www.jointcam.com

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bhacksaw

161 posts in 1291 days


#5 posted 11-02-2015 08:37 PM

Fred, it was a brand new can.

Pinto, the directions said 30 minutes to dry and sand between coats, but if you can’t get to it in that timeframe, you should wait 72 hours between coats. I’m guessing this is because you want to add another coat when it’s dry but before it cures. Something affects the bond in that window, maybe? I have no idea. At any rate, I think I WILL go with Lacquer next time, thanks.

Ger, how will the water affect it? I was lead to believe it’s waterproof. Is there anything I should put over it?

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Ger21

1047 posts in 2597 days


#6 posted 11-02-2015 09:55 PM

Almost no finishes are waterproof. They are water resistant. The longer they are in contact with water, the better the chance that water will start to get through them.
As long as you wipe them off after use if they get wet, they should be fine.
Personally, I’d use an oil based poly for anything that will have a lot of contact with water.

-- Gerry, http://www.thecncwoodworker.com/index.html http://www.jointcam.com

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Bill White

4457 posts in 3427 days


#7 posted 11-02-2015 10:05 PM

Dry and “cure” are very different.
How dry were the components of the stack?
Just a point:
If you’re rushing a finish, you’ll fail.
Bill

-- bill@magraphics.us

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Bill White

4457 posts in 3427 days


#8 posted 11-02-2015 10:07 PM

Dry and “cure” are very different.

Just a point:
If you’re rushing a finish, you’ll fail.
Bill

-- bill@magraphics.us

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Bill White

4457 posts in 3427 days


#9 posted 11-02-2015 10:10 PM

OOOPS! Have no idea as to why the double post.
Bill

-- bill@magraphics.us

View Fred Hargis's profile

Fred Hargis

3949 posts in 1960 days


#10 posted 11-02-2015 10:28 PM

Waterborne finishes should dry to the touch very quickly. True enough that complete curing will take longer, but for them to be “sticky” for that long is curious. I think I would separate them and let them sit a little longer, but I can’t explain why. There was nothing applied to the wood first? What are the predominant woods in the coasters?

-- Our village hasn't lost it's idiot, he was elected to congress.

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bhacksaw

161 posts in 1291 days


#11 posted 11-06-2015 06:26 PM

Pine, walnut, padauk, Purpleheart and zebrawood. They’re actually fine now, I left them stacked with toothpicks. And I’m now in Miami, so if they’re not sticky here…

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