white patches after polyurethane coat


Awasn

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Well unless it's extremely humid in your area at the moment, the only thing I can think of is the stain wasn't fully dried.  I know you said you let it dry for over a week - and that certainly seems like it should be long enough - but oil-based stains can take quite a long time to fully dry, especially, again, if it's very very humid.  Where are you located?  There's been a ton of rain in a lot of the US this past week...could be a factor.

Although - I don't know how likely it is that one oil-based material would cause those white blemishes on another oil-based material...I think that typically happens when water-based moisture is involved.  I've never had this issue so I'm far from an expert on the matter.  @Mike. might have some better ideas.

How old is the stain/finish?

Was your poplar kiln dried?

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A couple of ideas:

1) your stain lifted, so those white streaks are actually bare poplar.  If the stain was not thoroughly dry this can happen.  the solvent in the top coat can cause the stain  to lift.  

Did you wipe away the extra stain when you applied it? if not, it can take a very long time to dry.  

2) your brush was contaminated with something.  Did you use a new brush? If it was an old brush, had you previously used it for latex or waterbased product? 

you have three options:

1) strip and start over  -or-

2) get a gel stain in a slightly darker color. LIGHTLY Scuff sand the entire door with 220.   Put the gel stain on, let dry and then top coat.  gel stains sit on the surface, like a translucent paint so it might cover up all rhat mess -or-

3) paint :) 

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I'm in San Diego, Southern California, so I seriously doubt that it's the weather.

I dont think the wood was kiln dried, I bought it from Home Depot. The stain and varnish were purchased with the wood and never used before and I used a brand new brush specifically made for doing varnish and such...

Ive really been taking my time. The original layer of stain was done over a month ago, before the door was put together, I added the second coat closer to 2 weeks before I applied the varnish. I did not rub off the extra stain when I applied it(either time)so I'm guessing your both correct but it's hard to believe, I even rubbed down the entire door with an old white shirt before varnishing and had absolutely nothing come off. I wish they'd put some sort of warning or something... :angry::angry::angry:

Also I just sanded and stained the sides a few days before and I didn't get any streaks so it must be that second coat of stain that does it...

Painting is out of the question! I didn't spend all that time making a custom door just to paint it. 

I guess I'll take some more pics and go interrogate the home depot guys about gel stains

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7 minutes ago, BLQQD said:

I dont think the wood was kiln dried, I bought it from Home Depot.

HD lumber is generally garbage, but I'm sure it was kiln dried.  How well it was dried, up for suspicion...but I'm sure it spent at least some time in a kiln.  I seriously doubt they'd be selling green or air dried poplar.  I don't think that's your issue.

Sounds like Mike's gel stain idea is probably your best route.  I'd probably go to a woodworking store to buy the stain and ask those guys for advice.  The people who work at HD know as much about stains as your next door neighbor.

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15 minutes ago, BLQQD said:

 

I did not rub off the extra stain when I applied it(either time)... I wish they'd put some sort of warning or something... :angry::angry::angry:

 

Did you read the can?  it specifically says not to let the stain dry on the surface   :) 

also you don't want to use multiple coats. You want a penetrating stain in the wood, not on the wood  

http://www.minwax.com/wood-products/stains/minwax-wood-finish

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And for future reference (if applicable)...gel stain would be a better way to go any time you stain poplar...it's a very blotchy species and wiping an oil-based stain directly on raw wood is a great way to end up with a completely ugly finish.  I'm surprised you weren't disappointed with this aspect to begin with, honestly.  Perhaps because it's a lighter color stain it didn't make such a horrible mess as a darker color would have...but next time...coat of shellac, gel stain, then top coat. 

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This product has a bad reputation for this. That "fast dry" did some of this on hundred year old stair tread of I stained white oak on a 40% humidity 80° day for me. I don't know what to tell you except I stopped using that product. 

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  • 2 months later...
  • 1 month later...

EASY FIX!! Just take a standard bathroom blow dryer to it. It takes a little time, but works like magic and stays fixed. Minwax really needs to include this tip on their label to safe people a lot of grief!

*Note - I did this outside (in shade) when the temp was in the 90s. It didn't work so well when temp was mid 70s.

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  • 2 months later...

Thanks Bing !!

i just stained and then put a urethane coating using the Minwax fast drying version. 

End up with white spots in places and used a blow dryer on high heat and it actually went away in most spots.  

I did this about 2 hours after i did the urethane coating if that makes a differenence.

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  • 4 months later...

I had the first coat of polyurethane due the same on these wood floors I'm refinishing. Might try sanding/staining/sealing again. It is old floor but would the wood conditioner help? It doesn't seem to be an expired can, as a lot of the floor came out really well. I used a soft roller not a brush, but brushed on the stain. Left hard bubbles. Might start fresh for the whole floor. 

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Take a step back, what product is this? water based or oil based? Did you sand it down to fresh wood? did you wash it after sanding?

What was your finishing process/sequence?

Was this location the last area to be washed/dried? Also, was it the first, middle or last area to be finished? We need more information to figure out potential causes. 

Has it changed in appearance since you noticed it?

Are those round bubbles, or more of an orange peel?

Bubbles can result from contaminants on the floor, such as soap.

Bubbles can also result from excessive shaking of the can prior to application.

Orange peel can result from applying too heavy a coat, if you laid it on thicker in this area for some reason. 

Trapped moisture under the finish can cause haziness as well.

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  • 8 months later...

Bing! You are my hero! This worked for me. This is really my first large wood working project and I spent 5 weeks off and on getting this aquarium ready. I put the Minwax Prestain down, then stained it with Mixwax 3 times and it was almost perfectly match to my kitchen cabinets... then I put down the Minwax poly (everything was oil based and plenty of days to dry). WOW... it was so disheartening! Hair dryer surprisingly worked, but mine was so bad it was going to take forever, as you can see in the pictures (took pictures 1/2 way through the heatgun to show people what a difference it made) i attached. I went to Lowe’s and bought a heat gun and it worked liked a charm... sped it up probably 200%. 

Thank you so much!!!!!! Sure would like to know what I did wrong or what happened?

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  • 1 year later...

OK, this white powdery look happened to me with my solid wood front door.  I used MinWax pre-stain wood conditioner first, let it dry the recommended amount of time.  Then put first coat of stain on it and that didn't seem to dry. I went back after 2 hours (dry time recommended on the can between coats) and ended up waiting 3.5 hours to put the second coat of stain on it, because it took that long to dry, again following directions on the can closely.  I let it dry 36+ hours, then applied the first coat of Helmsman spar urethane (recommended on the stain can for outdoor use.)  Within 20 minutes many of the areas I was coating with the urethane started turning blotchy white!  It looked worse than hideous.  I found Bing's post about using a blow dryer after the first coat of urethane had been on the door about 2 hours.  It took about 90 minutes of blow drying with two blow dryers, but VOILA!  Absolutely amazing!  Not sure how Bing knew about this but it is spot on!  I couldn't be happier!  THANK YOU, BING!!!!

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  • 3 weeks later...
  • 1 month later...

Same problem on 2 very basic dining chairs —well actually all 4– but the last 2 were hideous with the white blotches after using minwax  satin wipe on poly. These are chairs that are used in my cabin so they don’t need to be perfect; just refreshed. I cleaned them, sanded them with 220 grit sand paper, etched the remaining finish with lacquer thinner and 000 steel wool. Wiped them down to hopefully remove any remaining finish residue, then rubbed on Minwax natural color stain ( the chairs are 1980’s natural look). They dried overnight. We live in Colorado so things dry quickly. I rubbed on Minwax wipe on poly and the ugliness began. White blotches all over. This Initially happened to a small degree on one chair of the first 2 I did and was able to touch it up by sanding the spots, etching with lacquer thinner, restaining and re varnishing and the chair turned out fine. 

I followed the same process on the second 2 chairs  but they looked like had pickled them after I applied the satin wipe on poly. UGh. Repeated the process above to remove the blotches. Dried for about 6 days before wiping on Minwax poly. Immediately started to get white blotches .

Thank goodness to have found this post about blow drying the blotches. Seems to work like a charm. 
 

 

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  • 9 months later...

Well, we re-did our kitchen back in 2015, and we have the same problem.  We have stained our entire house, all the trim, woodwork, doors, wainscoting, etc... with Minwax, colonial maple since 1997, and we have never had this problem, until the kitchen that we re-did it in 2015.  I think it was a bad batch of Minwax.  My husband could not figure out what he had done wrong, and after seeing all of your pictures and looking at the time frame, he did nothing wrong, it was a bad batch of stain or poly!

 

And AceHoleInOne, I completely agree with you....Here I am in 2021 and this post is still helpful, as I just was coming on as we are going to try and go around the kitchen and fix all the pieces that have the white marks.  Not ALL of the trim, just some of them appeared with the white marks.  Very strange.   I have been able to deal with this for years because I would use Old English furniture oil and I'm able to get the white marks to disappear for a few days, but then they come back.  Anyway,  as you can see from my pictures, it's nothing you all did wrong, because like I said, we have been staining all the trim and wood in our home with the same method for years, and we always did it in our garage in all types of weather and never had this issue!

 

Well, thank you for this forum as my husband is happy to know it's nothing he did wrong.  I will be contacting Minwax to let them know.  Maybe they are already aware of the issue.  Good Luck!

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