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Old October 22nd 15, 07:21 PM posted to rec.woodworking
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Default Minwax fast drying polyurethane dries to white haze

On 10/22/2015 12:02 PM, wrote:
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


A long time ago, I sprayed regularly (lacquer (automotive) , dope
(airplanes) imron (airplanes (both models and full size), buses, some
cars) ) . Both for myself and for other people. Up here in the North
East when it gets humid, I would have problems with hazing. So a little
retarder would allow it to slow the drying process, and not fully trap
the humidity into the finish.
Without knowing the chemistry of it, I assumed it was :
By slow drying it would get pushed out in the gassing off process of drying.

The retarder idea came from the supply shop I used to get all my paints
from.

--
Jeff

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Old October 23rd 15, 12:47 AM posted to rec.woodworking
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Default Minwax fast drying polyurethane dries to white haze

woodchucker wrote:


A long time ago, I sprayed regularly (lacquer (automotive) , dope
(airplanes) imron (airplanes (both models and full size), buses, some
cars) ) . Both for myself and for other people. Up here in the North
East when it gets humid, I would have problems with hazing. So a
little retarder would allow it to slow the drying process, and not
fully trap the humidity into the finish.
Without knowing the chemistry of it, I assumed it was :
By slow drying it would get pushed out in the gassing off process of
drying.
The retarder idea came from the supply shop I used to get all my
paints from.


That explains a lot Jeff. Most of today's finishes are not lacquer - which
did indeed suffer those issues like you experienced back then. Not so much
today - not at all. I'm still thinking about the OP's post - if he used
poly then I really can't understand why he experienced what he did,

--

-Mike-



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Old October 23rd 15, 04:21 AM posted to rec.woodworking
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Default Minwax fast drying polyurethane dries to white haze

One can never really get a good paint job in humidity. Paint haze
or eyes... Modern paints are often a plastic form or enamel form
of water based paint. Both can seal and trap under the sealed surface.

We have some 'dried' enamel paint that is poly based and it is still
sticky and out-gasses. Just not much there good.

The underlying material might be the problem also. Wrong paint for the
job. e.g. painting plastic without plastic qualified paint.

Martin

On 10/22/2015 5:47 PM, Mike Marlow wrote:
woodchucker wrote:


A long time ago, I sprayed regularly (lacquer (automotive) , dope
(airplanes) imron (airplanes (both models and full size), buses, some
cars) ) . Both for myself and for other people. Up here in the North
East when it gets humid, I would have problems with hazing. So a
little retarder would allow it to slow the drying process, and not
fully trap the humidity into the finish.
Without knowing the chemistry of it, I assumed it was :
By slow drying it would get pushed out in the gassing off process of
drying.
The retarder idea came from the supply shop I used to get all my
paints from.


That explains a lot Jeff. Most of today's finishes are not lacquer - which
did indeed suffer those issues like you experienced back then. Not so much
today - not at all. I'm still thinking about the OP's post - if he used
poly then I really can't understand why he experienced what he did,

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Old October 24th 15, 07:33 PM posted to rec.woodworking
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Default Minwax fast drying polyurethane dries to white haze

On Thursday, October 22, 2015 at 5:48:22 PM UTC-5, Mike Marlow wrote:
woodchucker wrote:


A long time ago, I sprayed regularly (lacquer (automotive) , dope
(airplanes) imron (airplanes (both models and full size), buses, some
cars) ) . Both for myself and for other people. Up here in the North
East when it gets humid, I would have problems with hazing. So a
little retarder would allow it to slow the drying process, and not
fully trap the humidity into the finish.
Without knowing the chemistry of it, I assumed it was :
By slow drying it would get pushed out in the gassing off process of
drying.
The retarder idea came from the supply shop I used to get all my
paints from.


That explains a lot Jeff. Most of today's finishes are not lacquer - which
did indeed suffer those issues like you experienced back then. Not so much
today - not at all. I'm still thinking about the OP's post - if he used
poly then I really can't understand why he experienced what he did,


I am with you on this one, Mike. In context, using the reference point set out in the post as using off the shelf polyurethane I haven't seen hazing. That is my personal experience from many years, but certainly doesn't mean that will be everyone's experience. I shoot poly, high VOC alkyds, etc. with no concerning even when it is raining outside and I can shoot parts and pieces in a garage. During the winter it rains a lot down here in South Texas (our version of snow) and during the summer we have have about 3 months where temps hover around 100 during the day with humidity around 75%. Different challenges for any finisher. Add to the fact that we sometimes have 25 degree changes in a day, and you mixes change drastically from morning to afternoon.

So back to the question of fast dry Minwax. Even as a fast dry product, it is a 2 to four dry period when applied as a first coat, which means it fast dry for poly, NOT for a finish. The super high performance product I shoot on kitchen cabinets has a 20 minute dry/recoat. That's fast. Any mistakes in prep and your finish is fouled. Two to four hours of drying is a lot more forgiving, and should be plenty of time for outgassing. The only time I have ever had any blush was when I was "pushing" lacquer finishes on cabinets I was shooting in a warehouse while it was raining outside and I was coating every thirty minutes. Four coats later, and there was blushing (haze)in certain areas.

I would bet that the reason there was blushing on the Minwax finish (which I know many folks hate, but having shot/padded/brushed many gallons of it like)is incorrect surface prep. If you target isn't properly stored, the surfaces can hold a great deal of humidity, making the surface nearly wet. A perfect storm would be to have a lot of humid weather and have your project out in a shop or garage that isn't under humidity control, and go out and finish it on the first sunny day. The wood is full of moisture, and a warm day will cause the poly to cure from the top down, trapping the outgassing solvents.

As a tip to anyone that might still be reading this thread, if you are in a humid area and still need to do some poly finishing, get the slow dry products (hence the retarder Jeff referenced, although I know of none for over the counter poly for wood workers)that are the old fashioned oil based 6 to 8 hour dry. Before you apply your finish, wipe it down well with cheap lacquer thinner and it will dry out the surfaces very well and should eliminate blushing from simply moisture contamination.

Robert


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Old October 26th 15, 07:48 AM posted to rec.woodworking
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Default Minwax fast drying polyurethane dries to white haze

On Saturday, October 24, 2015 at 2:01:26 PM UTC-5, dadiOH wrote:

Where do you get cheap lacquer thinner? Or maybe we differ in definitions
of "cheap"? Last I bought was $16+/gallon.

I also miss $1.49/gallon paint thinner sigh


No kidding! I used to buy this stuff just called "mineral spirits" that was didn't even have a name on it. Just a distributor. It came in a blue and white can and was something like $1.99 a gallon, occasionally on sale for less. I was warned NOT to thin paint or coatings with it but it was dandy for cleaning brushes and equipment. It smelled a lot like motor oil. But it was about .75 to a buck less than real thinner.

From time to time I find Sherwin Williams with one of their "economy" brands like Sunnyvale. (Again, warned NOT to use this to thin good product!) Sunnyvale will go on sale for about $9.99 a gallon, sometimes less. StarTex at SW is usually around $14 or so a gallon, but I wait until they have their 35% off sale and buy a couple of gallons. I don't use it that much, so it lasts a while.

I have been surprised over the last year how much paint, solvents and thinners have jumped in price, and for the life of me have no idea why so much. Any ideas?

Robert
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Old October 26th 15, 02:52 PM posted to rec.woodworking
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Default Minwax fast drying polyurethane dries to white haze

On 10/26/2015 1:48 AM, wrote:
On Saturday, October 24, 2015 at 2:01:26 PM UTC-5, dadiOH wrote:

Where do you get cheap lacquer thinner? Or maybe we differ in
definitions of "cheap"? Last I bought was $16+/gallon.

I also miss $1.49/gallon paint thinner sigh


No kidding! I used to buy this stuff just called "mineral spirits"
that was didn't even have a name on it. Just a distributor. It came
in a blue and white can and was something like $1.99 a gallon,
occasionally on sale for less. I was warned NOT to thin paint or
coatings with it but it was dandy for cleaning brushes and equipment.
It smelled a lot like motor oil. But it was about .75 to a buck less
than real thinner.

From time to time I find Sherwin Williams with one of their "economy"
brands like Sunnyvale. (Again, warned NOT to use this to thin good
product!) Sunnyvale will go on sale for about $9.99 a gallon,
sometimes less. StarTex at SW is usually around $14 or so a gallon,
but I wait until they have their 35% off sale and buy a couple of
gallons. I don't use it that much, so it lasts a while.


Robert you might entertain checking with an "automotive" paint supplier.
I know that they typically sell 55 gal drums to body shops and they do
have different grades. We used to buy 55 gal drums of thinner to clean
the guns. We bought the better stuff for mixing to the paint. Anyway
they might be a bit less expensive since they deal in higher volumes.



I have been surprised over the last year how much paint, solvents and
thinners have jumped in price, and for the life of me have no idea
why so much. Any ideas?


Probably environmental taxes.


Robert


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Old October 26th 15, 02:56 PM posted to rec.woodworking
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Default Minwax fast drying polyurethane dries to white haze

On 10/26/2015 8:52 AM, Leon wrote:
On 10/26/2015 1:48 AM, wrote:
On Saturday, October 24, 2015 at 2:01:26 PM UTC-5, dadiOH wrote:

Where do you get cheap lacquer thinner? Or maybe we differ in
definitions of "cheap"? Last I bought was $16+/gallon.

I also miss $1.49/gallon paint thinner sigh


No kidding! I used to buy this stuff just called "mineral spirits"
that was didn't even have a name on it. Just a distributor. It came
in a blue and white can and was something like $1.99 a gallon,
occasionally on sale for less. I was warned NOT to thin paint or
coatings with it but it was dandy for cleaning brushes and equipment.
It smelled a lot like motor oil. But it was about .75 to a buck less
than real thinner.

From time to time I find Sherwin Williams with one of their "economy"
brands like Sunnyvale. (Again, warned NOT to use this to thin good
product!) Sunnyvale will go on sale for about $9.99 a gallon,
sometimes less. StarTex at SW is usually around $14 or so a gallon,
but I wait until they have their 35% off sale and buy a couple of
gallons. I don't use it that much, so it lasts a while.


Robert you might entertain checking with an "automotive" paint supplier.
I know that they typically sell 55 gal drums to body shops and they do
have different grades. We used to buy 55 gal drums of thinner to clean
the guns. We bought the better stuff for mixing to the paint. Anyway
they might be a bit less expensive since they deal in higher volumes.



I have been surprised over the last year how much paint, solvents and
thinners have jumped in price, and for the life of me have no idea
why so much. Any ideas?


Probably environmental taxes.


Robert


One last thing. Are you on SW's mailing list? I get adds a few times a
month listing sales. They very often offer 30~40% off of paints and 30%
off of painting supplies. And just for joining the email list you get
an automatic 10% discount even when there is no sale.
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Old October 26th 15, 05:36 PM posted to rec.woodworking
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Default Minwax fast drying polyurethane dries to white haze

Leon wrote:

..

Robert you might entertain checking with an "automotive" paint
supplier. I know that they typically sell 55 gal drums to body shops
and they do have different grades. We used to buy 55 gal drums of
thinner to clean the guns. We bought the better stuff for mixing to
the paint. Anyway they might be a bit less expensive since they deal
in higher volumes.


I agree that this would likely be cheaper, but it's a lot more expensive
than what you recall Leon. My price on gun wash has more than doubled over
the past 5 years or so. Still cheaper than buying it by the gallon, but a
lot more expensive than what is was only a short time ago.

--

-Mike-



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Old October 26th 15, 05:49 PM posted to rec.woodworking
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Default Minwax fast drying polyurethane dries to white haze

On Monday, October 26, 2015 at 8:56:48 AM UTC-5, Leon wrote:

One last thing. Are you on SW's mailing list? I get adds a few times a
month listing sales. They very often offer 30~40% off of paints and 30%
off of painting supplies. And just for joining the email list you get
an automatic 10% discount even when there is no sale.


I buy enough that I usually get between 20 - 30% off with no sale. It depends on what products I am buying. For "pro" accounts, they will give me special deals on certain products, and they also have "pro" only discounts. For example,I redeemed an email only coupon for a product that had to be charged to my account there (proof I was who I said I was) that gave me buy one get one free on enamels. Just so happened I was painting the house I had gutted and rebuilt, so I did that for all the cabinets in the kitchen and all door, trims and moldings.

That's OK. SW's normal prices are so high they can easily afford it. When they have a sale of a non branded product, they can price things really well, and when I have a project coming up I try to keep an eye out for their specials.
Last time I bought lacquer thinner for example, I bought their generic material
I like to call "gun wash" for about $8 in a five gallon container. Since I don't use that much anymore I have to be careful how much I buy as I don't like storing that really high VOC stuff with our huge fluctuations in heat. Out in my shed, I have had lacquer thinner blow the tops off the 5 gal containers and the remaining material is ruined. Not to mention how dangerous that stuff is.

Robert


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