Cloudy Polyurethane...

I just finished assembling the frames I made for a mobile trolley to carry my printer and decided to apply 3 coats of 50:50 polyurethane/turps before assembling the lot together. The frames are made of 42 x 19mm DAR radiata pine and were sanded from 120 to 320 grit before the 1st coat.

First coat was applied with a brush and was absorbed "immediately"and left to dry 24hrs. I did not sand this first coat.
As an experiment, I applied the second coat with a clean, lint-free pad, to see if the application would be easier than using a brush, and let it dry 24hrs. As I tried to sand that coat, I found it was still tacky and "oily". I had a look at my 50:50 poly/turps mix and noticed it was cloudy.

I can't figure out why it would be cloudy as I used a new can of Cabbot oil-based poly and opened a new bottle of mineral turps (Diggers) to prepare the mix. Could an experienced finisher offer a possible explanation for this?

Not a drama, just curious !!!

Yvan

First thought is moisture absorption. Does it go away when stirred?

I'm not overly experienced, but my first thoughts would be how cool did it get overnight? If it's to cold, I've known poly urethane to simply not set/dry properly.

Thanks G9. Will check & report. Yvan

PJM16, I just had a quick look at the Bureau of Met temperatures for the last 4 nights and the lowest temp was 11.9oC.
So, the temperature inside my workshop would have been a tad higher, say 13-14o. Which could be cold enough to slow down the drying process?

Yvan

As G9 says - moisture.

Turps from diggers can be up to 20% water.

This can be overcome by buying IMS from a painting shop... Such as The Paint Place.

Also, many thin light coats are better than a thick one.

How about a few pictures :)

Hell. I would have thought that 20% moisture in the turps would be enough to separate into 2 layers - obviously not!
Will get IMS and prepare a fresh batch!

Pictures...you are now throwing a biiig challenge :). I'll have to visit the FAQ's and have a good read. Will try to accommodate!!

Cheers Yvan

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Originally Posted by yvan

...... I'll have to visit the FAQ's and have a good read. ....

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https://www.woodworkforums.com/f36/up...chments-168803

Silly question, isn't IMS metho, not turps? Perhaps there is some solvent confusion going on?

Cloudy would still indicate moisture and tacky after a 13deg night wouldn't be unexpected, but I would think that 20% w/w water in turps would formm a layer unless emulsified.

The other options for cloudy poly in the tin is LOTS of entrained air or your pot is near end of shelf life.

Quote:

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Originally Posted by themage21

Silly question, isn't IMS metho, not turps? Perhaps there is some solvent confusion going on?.

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Gak! Of course, how incredibly stupid of me. I wasn't thinking. You are of course right.

100 apologies.

Quote:

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Originally Posted by woodPixel

Gak! Of course, how incredibly stupid of me. I wasn't thinking. You are of course right.

100 apologies.

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This is the main reason I hate the use of acronyms!