# WTF did I just do?!?



## cdkoch (Feb 29, 2012)

Went to put a second coat of oil based Minwax quick dry poly on a door and it immediately bubbled and then dried into a cracked pattern. It's a little cool in the garage, but I put a coat on this morning and it worked fine. It's definitely not colder now. This morning I used a brand new brush with no problems. Cleaned with mineral spirits then soap and water when I was done. I also just opened a brand new can of poly for the problem coat. I'm guessing it's a contamination problem with the brush? I guess I don't remember if it was completely dry or not…I thought it was. Maybe this is an easy answer, but I'd appreciate some education if anyone cares to give it.


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## a1Jim (Aug 9, 2008)

I"m guessing your base coat was not dry,Minwax is not a finish I would recommend party because it dries slow.


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## skywalker01 (May 19, 2009)

Got to have more info. Not sure what, but more info. Did you use the same minwax poly on the second coat? This looks like a common problem had in paints where you use an oil based on top of a water based and it eats the under coat resulting in the crackling. It's not a contamination issue with the brush. Give us a pic of the first can you used and then a pic of the second can you used. If you wipe on poly before the undercoat of the same thing is dry you will only result in smearing the finish, which would not look like your pics above. Your pics are of a chemical reaction.


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## cdkoch (Feb 29, 2012)

Hmmm…I didn't even think about the base coat itself. I did lightly sand before putting this coat on and it felt dry to the touch, but I didn't get as much "dust", so maybe it was just wet enough. The can says it's supposed to dry in 3-4 hours and it has been over 12, but it is getting cool in the garage and I don't recall what the recommended temp range is. I'll rewash the brush and try again in the morning. Hopefully everything is nice and dry by then and I dont have any issues. Thanks!


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## cdkoch (Feb 29, 2012)

Luke,
I believe both cans are exactly the same. They are different lots, but I wouldn't think that would matter. I guess it's a possibility that they have a bad lot of poly, but unlikely. Far more likely is something I did. Here are the two cans. The one on the left was used this morning with no problems, the one on the right created the issues. 









I don't think it is pertinent, but I am using 3 coats of sanding sealer and 2 coats of poly. The sanding sealer is water-based, but it's acceptable to use oil poly over it. I'm doing this to attempt to keep the doors from getting too shinny (vs with 5 layers of poly). I've done all of my basement doors like this so far with out any issues, so I don't think it has anything to do with this. Also, this was my 5th and final coat, so I already had one coat of poly successfully on (on my last set of doors too…uhg!). Just for fun, here is the sanding sealer:


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## cdkoch (Feb 29, 2012)

Just thinking of all sources of contamination….I should also mention that I've been wiping the doors after sanding with tack cloth. Not sure if the sticky stuff leaves a residue that would do this?? Again, I've been doing all of my doors the exact same way and never had this issue. If soap residue was still in the brush, could that cause this issue?


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## skywalker01 (May 19, 2009)

Looks like you've got the right stuff. So here's what I'm getting. You've been doing it this way without any problems until now on this 5th and final coat something happened. You're saying that you didn't change anything at all except the can which is the same stuff and is controlled nicely and I agree, by minwax. Is it possible that there was condensation on the board when you went to put the second coat on? Honestly, it looks like an oil and water mix problem, especially if your saying that the temperature was no different on the second coat than on the first. Does the whole door look like this or only part of it? Do you thin it at all with anything? What we have to get at is if there were any changes from the 4th coat to the 5th coat that would have caused the problem. It seems easy, but only you will be able to determine what the difference is. The only other option would be that some one snuck in your shop and sabatoged the work or the new can of minwax is just plain bad. Did you stir up the new can really well before using? A wet brush could also be an issue but would only be a problem for the first couple swipes as the water would thin itself out in a hurry on your brush strokes and eventually not be a problem. In other words it would get better as you went.

Soap residue could definitely cause the issue. Try a new clean brush or heck just wipe some on with a clean cloth and see if the same thing happens.


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## JGM0658 (Aug 16, 2011)

Jim got it right. I have had the same thing happened to me, when this happened, it was too cold and I did not let the previous coat dry long enough. 
The bad news is that you are now going to have to let it dry and then sand all of it off, that wrinkled finish is impossible to fix.


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## skywalker01 (May 19, 2009)

The problem is he's saying his first coat of poly was fine and done under the same temperature. I guess it might be true as his second coat is going on top of a non-dry coat in a cold temperature. The first coat would be okay cause it wasn't being laid on top of another coat, regardless of temperature.


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## cdkoch (Feb 29, 2012)

Made sure to stir the new can really well. I don't thin it with anything. No visible condensation on the door. Most of what I brushed on "cracked" within 10-20 seconds, so i aborted before doing the entire door. The only thing I can think of that was different is how I cleaned the brush. I've been using an environmentally friendly paint thinner followed by water (no soap). The brush would get more and more stiff with each use and I would eventually need to throw it out. For this new brush (same brand as previous), I cleaned with a newly purchased gallon of mineral spirits (per the poly cleanup instructions) and then with soap (Dawn) and water. I believe I rinsed it well. I didn't pay much attention, but the brush may have been slightly damp still(?). I flexed the bristles and pulled some loose ones out before I used it and don't recall thinking the brush was wet. Needless to say, my first inclination was that the brush cleaning had something to do with the finish issue.


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## cdkoch (Feb 29, 2012)

Top coat not being dry sounds like a plausible explanation. I'll bring the doors into the house for a few hours tomorrow to ensure they are fully dried. I cleaned the brush the same way tonight, so I'm hoping Jim is correct as that would be an easy fix. I'll post my results tomorrow. Thanks for the help!!


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## skywalker01 (May 19, 2009)

If you haven't finished the whole thing yet then let it dry and try it again once it's dried for quite a while. I don't suspect your brush at all or the way you cleaned it. I have a feeling your second coat may have been too soon like others are saying due to the cold. It's hard to remember but in the past do you remember recoating in the same day with really cold temps? Just to rule out the brush try another one or just wipe some on with a cloth and watch for the reaction. Like said above, regardless you'll have to sand it off and start over


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## wormil (Nov 19, 2011)

Sometimes they will say recoat within 2 hours or after 48 hours, check for that.


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## JGM0658 (Aug 16, 2011)

I guess it might be true as his second coat is going on top of a non-dry coat in a cold temperature.

The conclusion I came to was that while the first coat might appear dry on the surface, it is not completely dry underneath. The solvent on the second coat acts as a wick and draws the not cured part of the first coat to the surface, producing the wrinkling. As I said this happened to me before, and if you look carefully at the wrinkles, they look as if they had air inside them, this can only come from a drawing out action.


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## cdkoch (Feb 29, 2012)

So much for "quick-dry" poly, huh? At least I learned a lesson about finishing tonight. Thanks for all of the comments and thoughts!


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## renners (Apr 9, 2010)

Just on the cleaning of the brush, if you use a bit of hair conditioner when you rinse out the brush out, it will leave it really soft. Fabric conditioner works too.


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## LeeBarker (Aug 6, 2010)

Just on the cleaning of the brush, if you use a bit of hair conditioner when you rinse out the brush out, it will leave it really soft. Fabric conditioner works too.

Does that stuff rinse out? Is it a potential contaminant? What is the advantage of softening the bristles?

Kindly,

Lee


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## renners (Apr 9, 2010)

Lee, wash in white spirit, (mineral spirit), then wash in hot soapy water, add conditioner, rinse off, let dry.
Next time you use your brush it will be like new. No residue, no contaminents.

I had a couple of Purdy Monarch Elite brushes that were about $25 each and this kept them like new for years - and they got a lot of use.

Try it, because you're worth it!


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## pintodeluxe (Sep 12, 2010)

Even "quick-dry" poly can take 8 hours to dry at 70 degrees F. For that reason I don't like poly, except for outdoor applications. I prefer pre-catalyzed lacquer, as it dries in 15 minutes - even if it is 40 degrees F. 
The only time I have seen a finish crinkle that bad is when I set some freshly shellaced trim in direct sunlight in the summer. 
I suppose the soap could have contaminated things. I would only use the thinner for your topcoat (mineral spirits in this case) to clean your brush. Also, spraying a finish will eliminate many problems compared to brushing. 
Best of luck!


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## JoeinGa (Nov 26, 2012)

I know I'm late to tis party, but Minwax makes TWO fast-drying polys. The fast dry (pictured above) requires sanding between coats and must be absolutely dry before re-coat. Usually 8 to 12 hours. The one RickM refers to (re-coat in 2 hours or after 48 hours) is labeled SUPER-FAST-DRY. It's more expensive, but the guys that re-finish floors love it. You just gotta read and follow the directions on the can carefully.


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## 33706 (Mar 5, 2008)

Was your project left in the sun after the last coat? The evaporation rate may have been accelerated enough to lower the surface temperature.


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## rossboyle52 (Dec 31, 2012)

Tack rag. I never use one. Had a bad experience years ago with a chemical reaction (same problem as yours) between the poly and the linseed oil used for tack cloth.
Have used a washable soft cloth rags for years. Same type as used for hand buffing wax on an automobile. 
They do a very good job at picking up the fine dust created when sanding between coats.


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