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Polyurethane peels off waterbased stain

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Forum topic by meskin posted 09-23-2020 01:27 PM 491 views 0 times favorited 22 replies Add to Favorites Watch
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meskin

12 posts in 33 days


09-23-2020 01:27 PM

Topic tags/keywords: question

Newby question here -
Could anybody please explain to me what happened here?
I am restoring an old wooden office chair. There is a problem of oil based poly de-laminating from thoroughly dried water based stain.

I stripped the old paint and sanded everything to bare wood. I like to pre-finish parts before assembly, – applied several layers of General Finishes water based stain (ONYX), and let it dry for over 24 hours. In some areas, the stain was very heavy, almost like paint – even glossy in some areas. I did not sand the stain. Over the stain, I applied 3 or 4 coats of Minwax fast-drying oil-based polyurethane, let everything cure for over 24 hours, and applied a VERY thin layer of Minwax oil based spray poly as top-coat. Everything looked great, – nice, even finish. I had to take one of the chair legs to a disc grinder for a better fit. I used a piece of painters tape to mask off this spot, and refinished it with stain and poly. The problem occurred when I took off the masking tape, – it removed some of the polyurethane! It looks like it cleanly separated from the stain layer. In this particular area, the stain was not too heavy, – just two or three layers, as recommended by GF. I decided to try applying tape to a different part, and it did not pull off anything, then I tried the tape over one more spot, and… it did pull it off again.

I wonder what caused this problem, and also, if it really is a problem! – maybe the tape test is too much for the freshly cured polyurethane? I think I did everything by the book, more or less. I did let everything cure between coats, as directed, did not handle parts with greasy hands… Should I strip the whole thing again, and use a dye stain instead? Any advice will be greatly appreciated!


22 replies so far

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Sark

339 posts in 1243 days


#1 posted 09-23-2020 02:59 PM

I always use a sanding sealer between the stained (or glazed) wood and the topcoat. Those more expert than I will weigh in on your problem, but clearly there was not good adherence between the poly and the stained wood. If I’m top coating with an oil based finish, then I use a vinyl sanding sealer, which goes on quite thin, dries rapidly and allows you to sand before topcoating.

Vinyl sealer has better moisture resistance than lacquer based sanding sealer. But I guess that any sealer would have improved the quality of the bond between the stained wood and the topcoat.

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meskin

12 posts in 33 days


#2 posted 09-23-2020 03:13 PM

Thank you for your advice!, – I have never heard of sanding sealers. Looks interesting, I wish I knew about this before I messed up the project! I assume it probably minimizes grain texture too.


I always use a sanding sealer between the stain and the topcoat. Those more expert than I will weigh in on your problem, but clearly there was not good adherence between the poly and the stained wood. If I’m top coating with an oil based finish, then I use a vinyl sanding sealer, which goes on quite thin, dries rapidly and allows you to sand before topcoating.

Vinyl sealer has better moisture resistance than lacquer based sanding sealer. But I guess that any sealer would have improved the quality of the bond between the stained wood and the topcoat.

- Sark


View woodbutcherbynight's profile

woodbutcherbynight

6297 posts in 3292 days


#3 posted 09-23-2020 03:31 PM


I stripped the old paint and sanded everything to bare wood. I like to pre-finish parts before assembly, – applied several layers of General Finishes water based stain (ONYX), and let it dry for over 24 hours. In some areas, the stain was very heavy, almost like paint – even glossy in some areas. I did not sand the stain. Over the stain, I applied 3 or 4 coats of Minwax fast-drying oil-based polyurethane, let everything cure for over 24 hours, and applied a VERY thin layer of Minwax oil based spray poly as top-coat. Everything looked great, – nice, even finish. I had to take one of the chair legs to a disc grinder for a better fit. I used a piece of painters tape to mask off this spot, and refinished it with stain and poly. The problem occurred when I took off the masking tape, – it removed some of the polyurethane! It looks like it cleanly separated from the stain layer. In this particular area, the stain was not too heavy, – just two or three layers, as recommended by GF. I decided to try applying tape to a different part, and it did not pull off anything, then I tried the tape over one more spot, and… it did pull it off again.

I wonder what caused this problem, and also, if it really is a problem! – maybe the tape test is too much for the freshly cured polyurethane? I think I did everything by the book, more or less. I did let everything cure between coats, as directed, did not handle parts with greasy hands… Should I strip the whole thing again, and use a dye stain instead? Any advice will be greatly appreciated!

- meskin

Some things to consider.

1. How long did you let the poly dry between coats?
2. Poly, especially the Miniwax brand requires several days at normal temp and humidity to not just DRY but to CURE. You don’t want to mess with it during this time for any reason. Wait to do repairs, or touch ups.
3. Painters tape despite the best of intentions is still an adhesive meant to hold onto something.

Could you post a picture of this? Much can be deduced from pictures verses an explanation .

-- Live to tell the stories, they sound better that way.

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meskin

12 posts in 33 days


#4 posted 09-23-2020 04:17 PM

@woodbutcherbynight – I followed the instructions on the Minwax can and let the poly layers dry 4+ hours each, and then 24 hours before I put a very thin final layer of spray poly over it. Your idea of letting it really cure before repeating the tape test sounds pretty good to me! I dread having to re-finish it. Here is the photo. Thank you!
https://s3.amazonaws.com/vs-lumberjocks.com/qh4d5nn.jpg!

View Lazyman's profile

Lazyman

5864 posts in 2270 days


#5 posted 09-23-2020 04:22 PM

You said you applied several coats of the stain? Was the finish not dark enough after the first coat? Did you wipe off the excess after each coat as the directions say? It should not look like it has layers of paint or appear to have any significant thickness after applying the stain. If you don’t wipe it off, the stain solids on the top will just rub or flake off and so will any topcoat you put over it. Pictures might help.

Also, while the Minwax poly should work fine over a properly done stain with proper curing times, etc., I would probably have used one of the General Finishes top coats. I think that I read once that all of their stains and top coats are compatible.

There are some good demos and other information on the General Finishes website, BTW.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View wildwoodbybrianjohns's profile

wildwoodbybrianjohns

2125 posts in 430 days


#6 posted 09-23-2020 04:23 PM

delete

-- Wildwood by Brian Johns: The Big Bang: Nothing - exploded into Everything. Thanks to Nothing.

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Lazyman

5864 posts in 2270 days


#7 posted 09-23-2020 04:25 PM

It looks like you posted the picture while I was typing. That looks more like paint than stain. You cannot see the wood grain at all so you must not have wiped the stain off. If that is the look you want, the stain is probably not the right finish for this. You probably just want to paint it.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

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meskin

12 posts in 33 days


#8 posted 09-23-2020 04:29 PM

I think this is the the problem – I went to town applying stain. In some areas it looked almost like paint. I wanted a very dark finish. Some parts of the chair got only two layers, and some got many more. I think a tape test in about a week will probably show where the problem is. Thank you!


You said you applied several coats of the stain? Was the finish not dark enough after the first coat? Did you wipe off the excess after each coat as the directions say? It should not look like it has layers of paint or appear to have any significant thickness after applying the stain. If you don t wipe it off, the stain solids on the top will just rub or flake off and so will any topcoat you put over it. Pictures might help.

Also, while the Minwax poly should work fine over a properly done stain with proper curing times, etc., I would probably have used one of the General Finishes top coats. I think that I read once that all of there stains and top coats are compatible.

There are some good demos and other information on the General Finishes website, BTW.

- Lazyman


View Murdock's profile

Murdock

158 posts in 3366 days


#9 posted 09-23-2020 04:39 PM

It could be that your stained surface was too smooth.

I had an issue once where I sanded a surface to smooth and it didn’t take finish well at all. Poly needs something to hold onto as it doesn’t soak in like stain does. You did mention that the stain was “even glossy in some areas”...

My opinion on oil over water or water over oil, just fine either way as long as the first layer is fully cured. With that said, in most cases I do stick to just water based or just oil based for every layer.

-- "Anyone who has never made a mistake has never tried anything new." - Albert Einstein

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meskin

12 posts in 33 days


#10 posted 09-23-2020 04:39 PM

I still want some grain pattern to show through, in the few areas where it’s visible, and also I would like a dark, but translucent finish – a clear layer over dark surface. Anyway, it looks like it will have to be stripped or sanded. I would love to avoid using the Agent Orange paint stripper again, maybe just sanding will work…


It looks like you posted the picture while I was typing. That looks more like paint than stain. You cannot see the wood grain at all so you must not have wiped the stain off. If that is the look you want, the stain is probably not the right finish for this. You probably just want to paint it.

- Lazyman


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meskin

12 posts in 33 days


#11 posted 09-23-2020 04:48 PM

It was super-smooth in some areas. and it finished so nicely… but this is the culprit. Thank you!


It could be that your stained surface was too smooth.

I had an issue once where I sanded a surface to smooth and it didn t take finish well at all. Poly needs something to hold onto as it doesn t soak in like stain does. You did mention that the stain was “even glossy in some areas”...

My opinion on oil over water or water over oil, just fine either way as long as the first layer is fully cured. With that said, in most cases I do stick to just water based or just oil based for every layer.

- Murdock


View Lazyman's profile

Lazyman

5864 posts in 2270 days


#12 posted 09-23-2020 04:51 PM

Unfortunately, based upon your photo, you are going to have to strip and sand that down to get all of the poly and excess stain off. Since you are going dark, you don’t have to get it to look like unfinished wood.

For future reference, you use stain when you want the wood grain to show through but want to change the original color of the wood itself. It sounds like you want more of a painted look where the wood is mostly hidden? If so, you can apply a poly over paint to give it more protection but having never done it, I cannot provide much guidance on the best way to do that or even what to expect on how well it will work and hold up to wear.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

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meskin

12 posts in 33 days


#13 posted 09-23-2020 05:01 PM

@Lazyman Thank you for your advise. I will let it cure for a week, then do the tape test on everything, – if the problem is in just a few places, I will strip those parts completely and refinish using the same stain and maybe GF poly, but following the instructions closely this time around. If the whole chair peels with the tape test, then I would look into your suggestion. Also, maybe dye stain and gel stain combination?

View Phil32's profile

Phil32

1144 posts in 786 days


#14 posted 09-23-2020 08:39 PM

I have had good results using water-based sealers, water-based stains, and water-based poly top coats.

-- Phil Allin - There are mountain climbers and people who talk about climbing mountains. The climbers have "selfies" at the summit!

View woodbutcherbynight's profile

woodbutcherbynight

6297 posts in 3292 days


#15 posted 09-23-2020 08:56 PM

Due to this thing called work I am compelled to wait 24 hours between coats of anything. So each coats gets that or sometimes 48 hours before next coat. Putting tape on a finish that has not cured for 7-10 days would be a big no no for me. Paint or otherwise I want the finish to cure well.

You will see alot of epoxy repairs that fail for same reason. Sure it dries in 5 minutes but the chemical reaction is far from over. Much more time is required for a complete cure.

-- Live to tell the stories, they sound better that way.

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