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Discussion Starter · #1 ·
Hello
I'm new to the forum and thank you in advance.
I attached a pic of a small piece that I'm spraying varathane brand water based polyurethane and I'm getting this pooling effect.
It is 82 deg and a bit humid.
Haven't had this problem before using the same gun and about the same temp.
Any help would be greatly appreciated!
Wood Flooring Font Floor Gas

Thanks again.
 

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I'm relatively new to spraying myself. So, no expert. It looks to me like you are getting way too much material on the surface and the the air from the gun is blowing it around. Not sure that is what it is but that is what it looks like.
 

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I also think you are spraying too much at once. I don't think it's the only problem though. I believe there is some kind of chemical contamination going on too. Might be oil in the air or maybe silicone. Do you use any silicone lubricant in your shop?
 

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I agree with the contamination. Looks like a giant fish eye. That and to heavy an application of material. With the graphics underneath sanding does not look like an option. Maybe???? thorough cleaning with some naphtha. Do not scrub but wipe once, turn the cloth and wipe again. Maybe flood the surface the last time to wash off the contamination. Maybe a light sanding to prep what is there and spray VERY light coats. More like a dusting. Wait the maximum amount of time between coats then another dusting untill you seal in the remaining contamination..... IF you can.

Ken
 

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Another possible cause for the finish not flowing out is if you used stearated sandpaper sanding between coats. It's the white sandpaper used for finishing and can leave a contamination of the sandpaper behind that can affect polyurethane. Most other finishes are alright with that paper but not polyurethane, either oil based or water based.
 

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Discussion Starter · #6 ·
Thanks for the replies...
The last coat i did was fairly thin and it layed down well, it took a few minutes to start pooling.
I'll sand it again and wipe it down then spray a lite dusting over it and see were I'm at.
It is cooler and less humid today, maybe that will help.
Thanks again for the replies, I really appreciate it!
 

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You probably don't need to thin the poly, I've never seen one that needed to be thinned. You may have had the sprayer too close to the work or didn't have the fan pattern wide enough. You should keep the sprayer 10 to 12 inches from the work. You should be laying a find mist instead of a heavy coat.

When you sand you might either fold the paper over a block of wood or attach some paper to a block of wood with spray adhesive. Having the paper backed with wood it will tend to sand the high places and leave the low places along. The low places are where you run the risk of sanding through. Just be patient sanding. It's better to not sand enough and have to put more coats on then to sand through the finish.

Humid weather does affect the drying time of a water based finish. It really needs warm dry weather.
 

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It looks like contamination to me. I've never seen over spraying look like that. You didn't wipe it with mineral spirits or a contaminated rag, did you?
 

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Discussion Starter · #10 ·
Thank you for all the replies
What I ended up doing was to sand it fairly flat with 360 grit, wipe it with a clean dry cloth and reapplied about 6 coats of satin water based polyurethane from a different can I had laying around.
I sprayed it the same way as before, lite dustings and a bit heavier at the end.
I think the original can of poly was contaminated or was too humid that day.
I did keep the old can just to test it out again to see if it was contaminated or the weather.
Learn something new every day!
Have a great day and thanks again!
Wood Wheel Gas Tire Table
 
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