# Crap in my Polyurethane



## ROOMINADAY (Mar 20, 2009)

I have tried three trypes of Alkyd Polyurethane (Satin) and all three have what appears to be grains of resin? It has me going crazy. I have sanded, vacuumed, tack clothed, filtered, turned the furnace off, bought new brushes, rollers, etc and it sill appears! Flecto and Minwax are the brands I have tried. This is about all we have around here.

Any advise, or comments why? i called the mfg and they said they have never heard of it. It is not dust you can see it buried in the finish.


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## Ole34 (Jan 24, 2011)

is the crap there in the pot before you apply it or does it appear after you apply it ????...................strain the poly before hand? ........


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## ROOMINADAY (Mar 20, 2009)

New Can, new pot....it is grainy when it dries. My GC was also brushing some poly for some shelves and is he having the same issue. He likened the grain similar to the feel of the gains off a med grit sanding block!? 

When you look at the curing finish, you can see small gelatinous grains and if you try to pick them out they don't feel like hard grains when wet? They are solid when dry. they sand out nice...but i really don't want to do that to a finish coat!

I searched a little on the net and it is described as "seedy" by others.


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## aaron61 (Apr 29, 2007)

When I have this issue I will take a brown paper sack & use it like sand paper to lightly buff the doors.
Works like a charm!


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## daArch (Mar 15, 2008)

"Seeded" coatings are generally caused by moisture.

Happened to us with a S/G paint many years ago. It was the manufacturing that was faulty. Hancock Paint paid for a re-coat. 

I doubt that all your different cans would be the same defect.


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## DeanV (Apr 18, 2007)

I wonder if it could be age of the product. On a very small scale, you can see that effect in a lot of old, interior oil trim paint. Sometimes that is one of the give aways to me that it is oil.

The brown bag/back side of sand paper/crumpled up green masking paper works well to buff overspray off of stuff, but I do not think it would do the trick for this.


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## aaron61 (Apr 29, 2007)

Done it many times. Why wouldn't it work Dean? Just curious!
It's the same principal as buffing a car after a paint job.


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## ROOMINADAY (Mar 20, 2009)

aaron61 said:


> When I have this issue I will take a brown paper sack & use it like sand paper to lightly buff the doors.
> Works like a charm!


Just like a grocery store bag? I was using superfine 0000 steel wool and then buffing with a pad to remove these grains last time. I just feel the last coat should be perfect.


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## DeanV (Apr 18, 2007)

If these a the small, sand grain-like particles I am thinking of, they usually too deep into the finish to smooth up with something as non-abrasive as paper, I would think and they would not buff off. I could be wrong, hope I am wrong. Easy fixes are always best.


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## aaron61 (Apr 29, 2007)

ROOMINADAY said:


> Just like a grocery store bag? I was using superfine 0000 steel wool and then buffing with a pad to remove these grains last time. I just feel the last coat should be perfect.


They buff out a new paint job on a car don't they?:thumbsup:


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## ROOMINADAY (Mar 20, 2009)

DeanV said:


> If these a the small, sand grain-like particles I am thinking of, they usually too deep into the finish to smooth up with something as non-abrasive as paper, I would think and they would not buff off. I could be wrong, hope I am wrong. Easy fixes are always best.



What is the easy fix? I am assuming these are undesolved solid's of the product? It is only the Satin finish I have issues with and I have tried the following; I have rubbed some between my fingers and it is smooth. It is not dried air bubbles either.

Minwax Superfast drying polyurethane 
Minwax " " new low VOC 
Flecto 1100 professional polyurethane in the black can
Polyurethane HomeHardware version - They call it Bowling Alley Tough!


I am hoping a PT'er has had a similar experience and resolution.


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## Lambrecht (Feb 8, 2010)

I have used several layers of t-shirt type rags as filters with success with material that had ultra fine" grains " in it. Takes forever for it to filter but it might work for you.


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## Wood511 (Dec 13, 2010)

I've had the same experience with a few poly coats I've done. The more coats you apply, the smoother it gets. Even after FOUR coats, you still have a few small bits and I have not found a way to get them out (after it dries) as they seem to be embedded.

I've also heard that maybe thinning down the last coat or two is beneficial to getting a smoother finish. I don't do much woodwork - not really my area, but I'll try this next time.


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## mistcoat (Apr 21, 2007)

Glad I read the rest of the thread as upon reading the Subject line I thought it was an instruction


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## ROOMINADAY (Mar 20, 2009)

Wood511 said:


> I've had the same experience with a few poly coats I've done. The more coats you apply, the smoother it gets. Even after FOUR coats, you still have a few small bits and I have not found a way to get them out (after it dries) as they seem to be embedded.
> 
> I've also heard that maybe thinning down the last coat or two is beneficial to getting a smoother finish. I don't do much woodwork - not really my area, but I'll try this next time.



I did a set of stair treads with 6 coats, and yes the more coats the less grains - what the heck is it! I did thin and strain as well.


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## NCPaint1 (Aug 6, 2009)

Sounds like its old. I've seen alkyd paints do that but never poly...I guess the principle is the same. No amount of straining will remove the "seeds". 

Just a thought though, maybe try a brand new brush. Maybe the solvent is pulling something out of the bristles...long shot I know. I'm still leaning towards seeded.


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## ROOMINADAY (Mar 20, 2009)

NCPaint1 said:


> Sounds like its old. I've seen alkyd paints do that but never poly...I guess the principle is the same. No amount of straining will remove the "seeds".
> 
> Just a thought though, maybe try a brand new brush. Maybe the solvent is pulling something out of the bristles...long shot I know. I'm still leaning towards seeded.


New brush. The old VOC version one would have been old for sure. Not sure why the others would be. I will try to take a pic of it tomorrow.


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## DHlll (Dec 22, 2010)

what kind of strainer did you use? did you try panty hose?


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## Paint and Hammer (Feb 26, 2008)

Any chance it froze?


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## aaron61 (Apr 29, 2007)

:wallbash:


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## Paint and Hammer (Feb 26, 2008)

aaron61 said:


> :wallbash:


Is that for me Aaron? Says right on the can "Prevent from freezing"...just throwing it out there. I'm aware of Alkyd properties.


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## aaron61 (Apr 29, 2007)

Paint and Hammer said:


> Is that for me Aaron? Says right on the can "Prevent from freezing"...just throwing it out there. I'm aware of Alkyd properties.


No it's not for you. 

I would just rather give it a quick buffing than keep putting on more coats,straining product and trying to over think it.


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## johnpaint (Sep 20, 2008)

Is that for me Aaron?


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## aaron61 (Apr 29, 2007)

No not you either John.


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## johnpaint (Sep 20, 2008)

aaron61 said:


> No not you either John.


Thanks Man, just checking.


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## jack pauhl (Nov 10, 2008)

The title was misleading. I thought you had bigger problems.


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## johnpaint (Sep 20, 2008)

ROOMINADAY said:


> I have tried three trypes of Alkyd Polyurethane (Satin) and all three have what appears to be grains of resin? It has me going crazy. I have sanded, vacuumed, tack clothed, filtered, turned the furnace off, bought new brushes, rollers, etc and it sill appears! Flecto and Minwax are the brands I have tried. This is about all we have around here.
> 
> Any advise, or comments why? i called the mfg and they said they have never heard of it. It is not dust you can see it buried in the finish.


Laquer will do that too.


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## SWGuy (Jun 26, 2009)

Are you using "pure" mineral spirits? I have seen reclaimed spirits used and people have had issues similar to what you are describing.


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## daArch (Mar 15, 2008)

SWGuy said:


> Are you using "pure" mineral spirits? I have seen reclaimed spirits used and people have had issues similar to what you are describing.


Good reminder.

I had similar probs with Epiphane Varnish when I used Turps instead of mineral spirits.


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## ROOMINADAY (Mar 20, 2009)

It may have something to do with humidity and the isocyanates in the poly. I will post the outcome next week.


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## daArch (Mar 15, 2008)

ROOMINADAY said:


> It may have something to do with humidity and the isocyanates in the poly. I will post the outcome next week.


'scuse my igerinse but what the frog are "isocyanates".

Paint that seeds is caused (so I was told) by moisture interacting with (being absorbed by) the glycol that are (were) in solvent based solid colors


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## Paint and Hammer (Feb 26, 2008)

Holy Cow Bill, everyone knows they are an atom group made up of 1 nitrogen, 1 carbon and 1 oxygen that reacts with the hydroxyl functional group to form a urethane linkage. If a di-isocyanate is reacted with a compound containing two or more hydroxyl groups (a polyol), long polymer chains are formed, known as polyurethanes.

I mean I was off my rocker suggesting freezing temps, but geez this 'really' is elementary. :jester:


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## daArch (Mar 15, 2008)

Holy Cow, indeed :thumbup:


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## DeanV (Apr 18, 2007)

i believe they also cause painters cancer.


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