# Need help with poly finish...



## dirtred9

I put two coats of polyurethane on my project and thought I was finished. I went back over it with 220 sand paper to smooth it out, and when completed, it left a white residue. What happened?

Also, I have a can of polycrylic I was thinking of using. What are your opinions on the polycrylic? Do you brush or wipe on?

Also, I found that the polycrylic leaves some white stuff behind if you are not careful. Does this sound right to anyone?

Thanks for the help!!


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## Fred Hargis

How long did you wait before sanding? If it was cured ( takes a while with varnish) that was likely just specs of finish the sandpaper cut off. It's not possible that was sawdust from the sandpaper being previously used? In any case, just wipe it off.


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## JBSmall

So.
The white residue....would you call that sanding-dust?
Or is there residue under, or in, the second-coat of poly?
If just sanding-dust, good.
The solids-content causes the white-dust. Wipe it off, vacuum, brush, whatever...remove the residue, and re-coat!


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## dirtred9

It almost looks like condensation, though it's not. I will wipe it with a damp cloth and it will go away. Then when it dries, it's white again. Not on the whole piece, just in certain places. Hard to describe, but couldn't get it to go away. 

Any other suggestions on the polycrylic? The white residue that it is leaving behind?


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## Dave66

Poly will leave a very fine, white, powdery, dust when it's sanded. If you can wipe it off with a dry rag, that's all it is. The sanding probably knocked the sheen down a bit and you can get it ack with another light coat of poly.

I usually put on two light coats of poly and sand with a fine sanding sponge after the second coat is dry to knock down any nubs. After sanding and a wipe down, I put on a final coat. If it's very warm in the shop, I dilute it ~10 to get good flow out before it starts setting up.


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## Steve Neul

It is normal for the finish to look white if you sand it or use coarse steel wool on the poly. If your intention was to hand rub the finish then you used far too coarse sandpaper. For that purpose you should have used 1200 to 1500 grit sandpaper and then polish back with rubbing compound. If you were sanding between coats then 220 grit paper was fine and the finish will be clear again when you put another coat of poly over it. 

If you used oil based polyurethane so far, I would continue with the same product. As far as the polycrylic, my opinion is its more expensive, more work and less durable than the oil based polyurethane. You can finish a project faster with it because of the faster drying time. I look at it from a labor perspective. Two coats of the oil based poly and I'm done but it takes me two days to put two coats on, where it takes 5 or 6 coats to achieve the same finish with polycrylic but you could do this in one day. I just don't like all the sanding between coats because the polycrylic being water based raises the grain.


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## HowardAcheson

What you are seeing is the result of sanding the surface. When you sand, you are scratching the surface of the finish and you lose any gloss or sheen. You will also get a sanding dust of the finish you have removed. 

You need to apply another coat of finish to bring the gloss back. Don't sand the surface any more or after the next coat or you will be right back at the same spot. If you have any slight dust nibs, use some crumpled up softened brown kraft paper (supermarket paper bags) and lightly rub the surface. Give you last coat of finish at least 2-3 weeks to fully harden and cure before attempting any smoothing.


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## cabinetman

Steve Neul said:


> I just don't like all the sanding between coats because the polycrylic being water based raises the grain.


I don't find that any of the grain raising with using WB polyurethane to be that much of a problem. It gets taken care of with usually the first coat after sanding. When using a stain, I usually don't sand until the second coat of finish has been applied.

You make a point about not wanting to deal with a grain raising problem, but will power wash wood with water after stripping.









 







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## JBSmall

I usually raise the grain by brushing the raw piece with water, letting it dry, and then sanding with 220 Tri-M-Ite. Then I know that the wood is going to be tamed and not go rough over time, regardless of the finish I use.


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## Steve Neul

cabinetman said:


> I don't find that any of the grain raising with using WB polyurethane to be that much of a problem. It gets taken care of with usually the first coat after sanding. When using a stain, I usually don't sand until the second coat of finish has been applied.
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At one time I tried to use water based lacquer do to being bugged by a fire marshal. I soon had to give up and just move my shop. More recently I've tried to use specifically Polycrylic many times hoping I could use something non flammable in a customers home and the surface is fuzzy until I'm on at least the fourth coat. It just brings back the memories of the water based lacquer. Its too labor intensive for me. 

There are many different paint and varnish removers that are formulated to be water wash. Whether you use a garden hose or a low power, power washer it doesn't raise the grain any more or less. The power washer does a better and quicker job of removing the residue of the stripping process and lessens the amount of time the furniture is being exposed to water which could affect the glue joints. I have used this process on anything from cheap junky tables to fine mahogany antiques with great results.


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## JBSmall

EPA - Employment Prevention Administration


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## Al B Thayer

I can't imagine sanding poly with 220. That could have been the last grit on the wood before the poly. I'm posting a finish here In a few days that will be better and easier than using poly. For now. I would sand to 220. Then wipe it down with a wet rag to raise the grain and fine hairs. Let it dry and then sand it again. Now when you finish the grain will not raise so much and you will have already knocked off the fuzz that raises from the first coat. Prep is everything when finishing.

Al

Friends don't let friends use stamped metal tools sold at clothing stores.


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## JBSmall

I'm sure you can imagine this.
Why, in reality, would you not do this?


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## Masterofnone

dirtred9 said:


> I put two coats of polyurethane on my project and thought I was finished. I went back over it with 220 sand paper to smooth it out, and when completed, it left a white residue. What happened?
> 
> Also, I have a can of polycrylic I was thinking of using. What are your opinions on the polycrylic? Do you brush or wipe on?
> 
> Also, I found that the polycrylic leaves some white stuff behind if you are not careful. Does this sound right to anyone?
> 
> Thanks for the help!!


Correct me if I'm wrong...

This reads like you put 2 coats on, but did not sand between the coats. Then you hit it with 220 cause that's what the can says to do, and that's all you did. You did not apply a third coat.

You're not done.

The "cloudy" look is the sanding scratches... you wiping water on it and it goes disappears is a give-away.

First, you need another coat... I would suggest four total, but 3 may do. Also, sand between each coat with at least a 400, maybe even a 600. And once your final coat is applied, DO NOT sand it again.


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## Masterofnone

Steve Neul said:


> At one time I tried to use water based lacquer do to being bugged by a fire marshal. I soon had to give up and just move my shop.


As a fireman, I give you permission to tell the fire marshal where to stick it...


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## scoffey

I agree with steve. I also use 1500 or 2000 grit in between coats. It knocks down any nubs and doesnt leave all that residue after. Makes for a glass smooth finish. Ive never had to sand after the last coat using the super fine paper.


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## tahir_ahmadov

I had the same problem. This is a 1920 house with reddish oak floors. 

I did the following:
1) Drum and edger sanded with 24;
2) Orbital sanded using 60 and 120;
3) Applied a coat of Minwax oil-based stain,
4) Did NOT apply sealer (the stain label read that it seals), 
5) 2 coats of Parks oil-based poly, 
6) Waited for 12-14 hours, 
7) Sanded with 220 paper. 
8) After wiping white dust off, white streaks and spots remained. It looks like I didn't wait long enough, even though it was 80s those days and I established good ventilation in those rooms. 

Interestingly, in one area of one room, I have new oak unfinished flooring I got from HD (repaired a damaged spot), and there were no white spots in that section. Also, stain produced quite a different color between old and new wood, supposedly of the same type.

I got the following advice from different sources:
1) Online, some people suggested to just apply the next coat, that it will absorb the white residue and all will be well.
2) Online and in HD, I was told to let dry for a day or two, sand all the way till the white spots go away, and resume applying poly coats.
3) In HD, someone said mineral spirits can be used to wipe those white spots off. However, someone online wrote that that didn't work, white spots disappeared and reappeared when mineral spirits dried.

I am running short on time, so I went with option 1, and voila! It worked.

I'm going to apply one more coat right now, for a total of 4, and let it dry to completion. So far, so good.


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