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Poly issue im having, please help

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Forum topic by sl877 posted 10-10-2017 01:01 AM 1275 views 0 times favorited 22 replies Add to Favorites Watch
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sl877

4 posts in 68 days


10-10-2017 01:01 AM

Topic tags/keywords: finishing poly polyurethane problems help

[IMG]http://i74.photobucket.com/albums/i272/tegracer877/IMG_20171009_182610599_zpsabtvnjep.jpg[/IMG]
[IMG]http://i74.photobucket.com/albums/i272/tegracer877/IMG_20171009_182556937_zpsbr2nkdqy.jpg[/IMG]

Im pretty new to finishing and Ive never seen this before, this is the second coat, even worst than the first. humidity is mid to low, temps around 70-75, can of poly is aclimated to the temp and surface was sanded with 220 and tacked with regular tack cloth from home depot

theres what looks like totally dry spots all over, brushing over multiple times with more poly doesnt help, it sepparates right back into this mess

poly is Minwax oil base fast dry gloss

I never use Minwax but i figured id try it out this time, ive never had an issue with the semi gloss minwax.

any ideas what happened?

Thank you for any help


22 replies so far

View Redoak49's profile

Redoak49

2904 posts in 1827 days


#1 posted 10-10-2017 01:14 AM

What wood is it?

Looks like the dry spots follow the grain.

View bondogaposis's profile

bondogaposis

4480 posts in 2190 days


#2 posted 10-10-2017 01:28 AM

How many coats is that? I can’t say for sure but it looks like you are putting it on way too thick. The table looks to be red oak and some of the finish is being sucked into the rather large pores that red oak is famous for. Recommendation is to let it fully cure and sand it back to level. Then thin your Poly to 50/50 apply light coats and sand between coats w/ 400 grit.

-- Bondo Gaposis

View Manitario's profile

Manitario

2565 posts in 2722 days


#3 posted 10-10-2017 03:47 AM

Hard to tell from the angle and light in the pic but looks like “fish eye” which happens when silicone somehow contaminates the wood surface, usually from something you’ve used in your shop (silicone or lubricant spray is most common). I don’t use a lot of full strength poly (brush on poly) mostly wipe on for me, but whenever I’ve had a similar result to your pic, it is b/c of something contaminating the finish.

-- Sometimes the creative process requires foul language. -- Charles Neil

View jbay's profile

jbay

1857 posts in 738 days


#4 posted 10-10-2017 03:51 AM



Hard to tell from the angle and light in the pic but looks like “fish eye” which happens when silicone somehow contaminates the wood surface, usually from something you ve used in your shop (silicone or lubricant spray is most common). I don t use a lot of full strength poly (brush on poly) mostly wipe on for me, but whenever I ve had a similar result to your pic, it is b/c of something contaminating the finish.

- Manitario


Yep! I’ve seen tack rags do it.
Need to open them up and let them air for 10 or 15 min before using
and then wait 10 or 15 min after using before applying finish.

-- If anyone would like to see my Portfolio, PM me and I would be glad to send you the link.

View Aj2's profile

Aj2

1178 posts in 1637 days


#5 posted 10-10-2017 04:10 AM

I agree with Jbay tack cloths are worthless in my opinion. Before I apply finished I just use compressed air a clean dry rag and then my hand for a final check. If there’s nothing on my hand it’s ready.

-- Aj

View sl877's profile

sl877

4 posts in 68 days


#6 posted 10-10-2017 04:18 AM

im on coat three now and its still doing it (possibly slightly less) the dry spots are following the grain as was said above, I dont think the tack cloth was contaminated but I wont use it for the next coat just in case

Ive never seen wood soak up poly like this (if thats what its doing)

the only other oak Ive finished was a floor and it didnt do this at all. Ive done walnut and a few others but thats always went pretty smooth.

any idea how many coats its going to soak up? il try thinning it for my next coats, thanks for the help

View MrUnix's profile (online now)

MrUnix

6011 posts in 2038 days


#7 posted 10-10-2017 04:20 AM

That looks like more than just a tack-rag problem – but I stay away from them as well (cloth towel dampened w/mineral spirits works for me). But the problem above looks like it was put on two thick, and it seems to follow the grain. If it’s red oak, that stuff has pores the size of straws. Sand it down and use some wipe-on (mix your poly 50/50 with mineral spirits). You can also do the first coat with something like 320 grit wet-dry sandpaper… the residue and poly mix will help plug up the pores.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View coxhaus's profile

coxhaus

64 posts in 733 days


#8 posted 10-10-2017 06:11 AM

I tried putting poly on some maple doors. I first used a foam brush but I had trouble with the starting point being thicker than the finishing point. I was using full strength poly. I saw a U-tube where they were wiping it on. So I used chemical cleaner and stripped the maple door. I then mixed 8 ounces poly with 2 ounces mineral sprits. I used folded up Tee shirt and wiped it on. It worked so much better. I ended up with a even coat not quit as thick so I added more coats. It dried so much faster I could apply 2 coats per day instead of 1. I think this made for the thinnest of the coats.

View Andybb's profile

Andybb

554 posts in 442 days


#9 posted 10-10-2017 06:20 AM


I agree with Jbay tack cloths are worthless in my opinion. Before I apply finished I just use compressed air a clean dry rag and then my hand for a final check. If there s nothing on my hand it s ready.

- Aj2


+1 ^ (or vacuum)

Unless the wood is somehow contaminated I also think it just looks too thick, plus you said it was fast dry. Looks kike it may have I like to thin then wipe on a VERY thin first coat or two with the grain to seal the wood. I find it hard to brush poly thinly. I like to wipe it. If it’s only 2 coats sand it off with 120 then start over to 220. It looks too thick to try and smooth. Skip the tack cloth.

JMHO

PS Do you have ventilation? I’ve become a huge fan of Deft rattle can lacquer. You can put on 5 or 6 coats with 30 mins,between coats, hit the last coat with a white scuff pad, hand buff and be done. If you want semi gloss use gloss then semi as the last coat. Home Depot sells it for $5.50 a can.

-- Andybb - GO HAWKS!

View AlaskaGuy's profile

AlaskaGuy

3661 posts in 2148 days


#10 posted 10-10-2017 07:16 AM

I too learned the hard way about tack cloths. I vacuum first then a rag damped with mineral spirits. I don’t use any compressed air in the shop while finishing. Compressed doesn’t get rid of dust, it just redistributes in to the air where in can fall back on your work.

-- Alaskan's for Global warming!

View Andybb's profile

Andybb

554 posts in 442 days


#11 posted 10-10-2017 07:33 AM


I too learned the hard way about tack cloths. I vacuum first then a rag damped with mineral spirits. I don t use any compressed air in the shop while finishing. Compressed doesn t get rid of dust, it just redistributes in to the air where in can fall back on your work.

- AlaskaGuy


+1
You might also use Naphtha which evaporates quicker than MS which sticks around longer that you might think.

-- Andybb - GO HAWKS!

View Redoak49's profile

Redoak49

2904 posts in 1827 days


#12 posted 10-10-2017 11:36 AM

Please we need better pictures. Your Photobucket pics do not show up.

I use red oak a lot and never had the problem. What kind of oak and where did you get it.

I also use Minwax on red oak and never had a problem. I typically use an oil base stain, a coat or two of poly with foam brush and end up with a couple coats of wipe on poly. This has always worked great.

It is apparent that it is following the grain and likely something got into the grain before finishing. Maybe try a sealer first next time.

View jbay's profile

jbay

1857 posts in 738 days


#13 posted 10-10-2017 01:12 PM


im on coat three now and its still doing it (possibly slightly less) the dry spots are following the grain as was said above, I dont think the tack cloth was contaminated but I wont use it for the next coat just in case

Ive never seen wood soak up poly like this (if thats what its doing)

the only other oak Ive finished was a floor and it didnt do this at all. Ive done walnut and a few others but thats always went pretty smooth.

any idea how many coats its going to soak up? il try thinning it for my next coats, thanks for the help

- sl877

It’s going to keep doing it until those spots are sanded smooth and the contamination is out of them.
It’s more than a red oak pore thing.

If it was because of the tack rag, it’s not because the rag was contaminated, it’s the material they use to make the rag tacky. I don’t know what that material is, but it has done this to me before.

What kind of sandpaper did you use? Wondering if stearate could of contributed. Maybe some of the dust was left in the pores?

-- If anyone would like to see my Portfolio, PM me and I would be glad to send you the link.

View Lazyman's profile

Lazyman

1506 posts in 1226 days


#14 posted 10-10-2017 01:54 PM

+1 on you put on too thick a coat and skip the tack cloth. Mineral spirits on a clean rag works great to remove dust and it will also help you spot any areas where you might have some glue or other surface contaminants you didn’t get cleaned off. You also didn’t mention whether you scuff sanded between coats. This is essential with poly. I like to use the 3M pads for this. As long as it isn’t a water based finish, you can also use 0000 steel wool, just make sure you vacuum off any little pieces of steel when you are done.

To fix, you will probably have to sand it smooth, wipe off the residue and apply multiple light coats using a high quality natural bristle brush, scuff sanding between coats.

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

View sl877's profile

sl877

4 posts in 68 days


#15 posted 10-10-2017 03:01 PM

One thing I dont get is how thin coats are supposed to solve the issue? it seems like that would just keep the pores open and the table would not be suitable for use

common sense tells me I need to fill up the pores until they quit soaking it up

this is coat three, dry, its 100% following the dark grain, the light sections look fine

im thinking i keep the sanding dust in the pores and coat over them as was said above, i dont see how else to seal it

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to answer a couple of the other questions yes im sanding between coats and im not really going any thicker than ive gone in the past and its always worked well untill now.

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