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Recoat time for poly

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Forum topic by JustLikeJames posted 05-13-2014 01:19 AM 583 views 0 times favorited 11 replies Add to Favorites Watch
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JustLikeJames

29 posts in 307 days


05-13-2014 01:19 AM

Topic tags/keywords: poly

When using poly, how soon can I recoat if I’m going to skip a sanding between coats? My coats are drying pretty dust and debris free and I’d like to speed up the process. Will I be hurting anything if I recoat before the last coat is totally dry? If I have to wait until it’s dry, I might as well sand it at that point.
Thanks.


11 replies so far

View NiteWalker's profile

NiteWalker

2710 posts in 1322 days


#1 posted 05-13-2014 01:24 AM

Depends on if it’s waterborne or oil based.
I use waterbornes, so my recoat time is typically about an hour or less.

You don’t want to recoat before the previous coat is dry.

-- He who dies with the most tools... dies with the emptiest wallet.

View Craftsman on the lake's profile

Craftsman on the lake

2418 posts in 2183 days


#2 posted 05-13-2014 01:25 AM

I use poly a lot.. what nitewalker said would be my advice.

-- The smell of wood, coffee in the cup, the wife let's me do my thing, the lake is peaceful.

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JustLikeJames

29 posts in 307 days


#3 posted 05-13-2014 01:34 AM

I’m using oil based. By the time I get off work I only have time for one coat a day. Seems like Bob Flexner implies that it’s ok to skip the sanding as long as the finish isn’t too rough from dust and stuff. Do you guys ever skip the sanding when using oil based poly? Any adhesion problems?

View upinflames's profile

upinflames

96 posts in 907 days


#4 posted 05-13-2014 02:02 AM

Since you’re using oil based you can run over it with 0000 steel wool, knocks off any nubs, then wipe it down with mineral spirits or naptha to clean the dust off. With oil based, depending on humidity and temp about one coat a day is fine, you don’t want to rush it. You want each coat to be dry before the next or you end up with a gooey mess.

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JustLikeJames

29 posts in 307 days


#5 posted 05-13-2014 02:12 AM

Ok. I’ll just be patient but will use the steel wool instead of scuffing with 320 grit sandpaper. Maybe my coats will build a little faster that way at least.
Thanks for the advice everyone.

View NiteWalker's profile

NiteWalker

2710 posts in 1322 days


#6 posted 05-13-2014 03:16 AM

What they said regarding oil based, but consider giving waterbornes a try. General finishes’ enduro-var and enduro clear poly are both great finishes. Crystalac too, but it’s not easily available for the time being it seems.

-- He who dies with the most tools... dies with the emptiest wallet.

View jimr1cos's profile

jimr1cos

14 posts in 631 days


#7 posted 05-13-2014 03:36 AM

I only ever rushed a second coat on oil based poly one time and boy did I regret it. Never did properly dry and i had to redo the entire finish. Live & learn!

View Finisherman's profile

Finisherman

210 posts in 594 days


#8 posted 05-13-2014 04:36 AM

Never recoat before the previous coat is fully dry. Oil based poly cures through oxidation. Therefore, if you cut off the oxygen with another coat of finish, the bottom coat will have a very difficult time in curing completely. In theory, you can speed up the flash time by thinning the poly with VM&P naphtha and you can speed up the curing time, at least a little bit, by adding a few drops of Japan dryer. As for sanding between coats, you need to. Poly, unlike lacquer or shellac, doesn’t burn in, or chemically fuse to itself. Therefore, you need to sand between coats so that each new coat of finish can achieve a mechanical bond.

View kdc68's profile

kdc68

2068 posts in 1022 days


#9 posted 05-13-2014 10:18 AM

+1 Finisherman

-- Measure "at least" twice and cut once

View Clint Searl's profile

Clint Searl

1479 posts in 1106 days


#10 posted 05-13-2014 12:57 PM

It’s been my experience that oil poly does not have to be sanded between coats unless recoat time is longer than around 24-36 hours. Recoating as soon as it’s dry to the touch is preferred because the new coat WILL chemically integrate (polymerize) with the still curing undercoat, creating a much stronger bond than one depending on just mechanical adhesion.

-- Clint Searl....Ya can no more do what ya don't know how than ya can git back from where ya ain't been

View wncguy's profile

wncguy

227 posts in 1057 days


#11 posted 05-13-2014 01:09 PM

I’ve been using Arm-R-Seal (wiped on) for my boxes. Typically I allow 1st coat to dry to touch & then add the 2nd coat. I then allow to dry about 24 hours & do a light sand with 320 grit Industrial Adhesive foam back pads to remove any nubs, etc. that are there (and they are for me), then 3rd coat – dry to touch & then 4th coat. Final very light with 600 IA foam pad & I’m done. This has worked good for me.

-- Any man can be a father, but it takes someone special to be a Dad

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