Below is the post I responded to:

On 6/1/2014 5:43 PM, wrote:

Just bought a spray can of minwax polyurathane for my final coat on an old walnut table. Previous coats had been minwax polyurathane fast drying rub-on with sanding in between. I live in a arid region of the country, so I know moisture is not a problem. The spray can of minwax left a milky, rough finish. I will sand it off tomorrow and go back to my hand rub routine. Very disappointing product and waste of money!



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On 6/3/2014 11:49 AM, Sonny wrote:
On Tuesday, June 3, 2014 11:44:17 AM UTC-5, Mike Marlow wrote:

Mike, here's what I'm seeing, additional to the original post:

bw, the poster's follow-up posts:

"-----------------------------------------------
Doubt it, it's been very dry around here this winter. Wood stored on high
rack in garage.
Test piece was sanded as usual along the grain. Wood does "feel" moist or
greasy to touch.
It might be that I'm not that experienced with tropical wood.

Tested another piece with mineral oil and it really looks good so I'll skip
the poly."

Then he later posted:

"Excellent !! I do have a paint mixer bit, but it seemed aggressive for a
quart of poly.
My work area is a partially heated enclosed porch, the temp was lower than
RT.
My poly experience had been with "gloss" or "stain" and used right after
purchase.
Now I'm confident that poor mixing was my problem. Thanks for responding."

Sonny

Saw none of that ... go figure!


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On Tuesday, June 3, 2014 12:35:04 PM UTC-5, Swingman wrote:
Saw none of that ... go figure!




And here's another of his replies (to SonomoProducts), where he mentions the can's lid.

"Oil based, satin. It's a quart can.
Now that I think about it, while I stirred the can to mix the bottom layer
for a while I looked at the lid and noticed it had the white soapy color, so
then I touched the white with the foam brush first to see what it would do.
Some of the white was already soaked in the brush when I dipped it in the
main can.

I ended up sanding the white off and trying something else. Now I'll take
more time mixing, I didn't know that the sheen killers were white pigment."

______________________________

No telling what all may have been going on with his finishing, including a comparison to his previous project. The posts didn't give us enough info or was vague, to me, to some degree, hence all my assuming. I may not have had access to all the posts, also, as with your not seeing the posts I saw.

Anyway, my idea of relevance, for any finishing, should include paying attention to possible differing temps for wood, work place, poly, etc., to prevent possible condensation problems.

Sonny

On 6/2/2014 6:37 AM, Swingman wrote:
On 6/1/2014 5:43 PM, wrote:

Just bought a spray can of minwax polyurathane for my final coat on an
old walnut table. Previous coats had been minwax polyurathane fast
drying rub-on with sanding in between. I live in a arid region of the
country, so I know moisture is not a problem. The spray can of minwax
left a milky, rough finish. I will sand it off tomorrow and go back to
my hand rub routine. Very disappointing product and waste of money!


I have used two separate cans, satin and semi-gloss, almost every day
this past week of this exact product, making stain samples for color
decisions for a client, and have not had a problem.

Funny thing ... I was using these same rattle cans yesterday to do
another couple of stain color samples and decided to change the spray
pattern from vertical to horizontal; something that can be done with
these new rattle cans with a twist of the nozzle, as you would expect
with today's technology.

Lo and behold ... after making a few normal passes with the spray
pattern to vertical, I changed the spray pattern to horizontal and the
spray immediately came out milky/cloudy on the surface of the piece.

(Obviously a _moisture related_ phenomenon - most likely due to the
expansion of the compressed gas changing the relative temperature
(PV=nRT) of the different nozzle passages, then reacting with the hot
humid air).

Didn't last long, but my initial reaction, and remembering this thread,
was WTF??

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Swingman wrote:


Lo and behold ... after making a few normal passes with the spray
pattern to vertical, I changed the spray pattern to horizontal and the
spray immediately came out milky/cloudy on the surface of the piece.

(Obviously a _moisture related_ phenomenon - most likely due to the
expansion of the compressed gas changing the relative temperature
(PV=nRT) of the different nozzle passages, then reacting with the hot
humid air).

Didn't last long, but my initial reaction, and remembering this
thread, was WTF??

Guessing here, but maybe close...but a little different. Not so much
moisture related, as simply related to the atomization of the product. When
you switch over, it probably takes a short bit for the nozzle to properly
re-adjust for proper atomization. Just a guess...

--

-Mike-

I had the same problem. Used a blow dryer.Takes the white out!

This JUST happened to me? It is the oddest thing! I have never seen this happen before. I had stained my fireplace, waited a few days...then put on the polyurethane and it streaked it white...as if I had let water sit on it or something. Did anyone ever give you a reason why this happened? I have used the exact same polyurethane before and the product was great. I am so confused...hence I googled to see if anyone else has had this problem. Let me know if you have any answers.

On 10/21/2015 7:27 PM, wrote:
This JUST happened to me? It is the oddest thing! I have never seen this happen before. I had stained my fireplace, waited a few days...then put on the polyurethane and it streaked it white...as if I had let water sit on it or something. Did anyone ever give you a reason why this happened? I have used the exact same polyurethane before and the product was great. I am so confused...hence I googled to see if anyone else has had this problem. Let me know if you have any answers.

I had this problem with a table top, The way I fixed it was to sand the
top down to nearly bare wood, wipe it good with mineral spirts, and let
dry for several days. Then used a colored (pecan) varnish to finish the
table. I have the first coat of varnish on the table, it has been
drying for a couple days with no white specks

I beleive that some thing in the wood, stain and the clear varnish was
being extracted to create the whiteness. I don't know it was the Minwax
varnish, Minwax stain, or some thing coming out of the wood, or a
combination of the three.

On 10/21/2015 7:27 PM, wrote:
This JUST happened to me? It is the oddest thing! I have never seen this happen before. I had stained my fireplace, waited a few days...then put on the polyurethane and it streaked it white...as if I had let water sit on it or something. Did anyone ever give you a reason why this happened? I have used the exact same polyurethane before and the product was great. I am so confused...hence I googled to see if anyone else has had this problem. Let me know if you have any answers.

well, it's fast drying. So it has no retarder, or has a lot of driers
(metals).

Generally is sounds like a humidity problem. Too high to use a fast
drying product. When the humidity is high, a retarder is generally used.
If you use a fast drying product, you get a haze.

--
Jeff

On Wednesday, October 21, 2015 at 8:28:41 PM UTC-5, woodchucker wrote:

well, it's fast drying. So it has no retarder, or has a lot of driers
(metals).

Metals are sometimes used to assist drying but are more commonly used as hardeners. A world of difference.


Generally is sounds like a humidity problem. Too high to use a fast
drying product. When the humidity is high, a retarder is generally used.
If you use a fast drying product, you get a haze.

Jeff, I have been doing this professionally a long time. Do you mind me asking you how you came up with that? That certainly has not been my experience.

Robert