BM alkyd Satin Impervo HVLP dries dull

[alexh]

Hi all,

I have been spraying alkyd SI with HVLP for quite some time (mostly built-ins or furniture) and I always get great results. I thin with mineral spirits to about 40 secs using a Ford cup.

I recently sprayed a large room full of trim but the sheen is very low compared to what I normally see. The painted surface feels very smooth so I don't think dust is the issue. I then sprayed a second coat (after sanding lightly with 320), with a little less thinning  and spraying as thick as I dare. The flow out was excellent - like glass. The room took about 5 hours to spray (I'm dead on my feet when done). I run a fan in the doorway to get rid of overspray. The sheen improved a little but it's still much less than say the crown molding in the same room which I sprayed a few years ago (yes, it took me that long to finish trimming the room ).

I have been racking my brain trying to figure out what would account for the noticeable difference compared to earlier work and the only explanation I can come up with is the cure temps. We recently started getting much lower overnight temps here. I know when I sprayed it was about 70 degs. I finished about 6:00 pm and the temps were about low 60's. I can't imagine indoor temps went much below 60 overnight. I closed off the room after 8:00 or so so ventilation was nil after that.  I did see a weird effect with the painted surfaces after 8 hours of dry time - many areas had a shiny, wet look surface but when I touched it, it disappeared. Like there was a sweat on the surface. I have never seen this before.

I know that SI is chameleon like with regards to sheen. Sometimes I spray an object and it almost looks like semi gloss (seems like this happens when temps are 80+ and I'm spraying in direct sun), othertimes it's satin at best. Of course over time even unthinned, brushed SI seems to always go to a satin although it takes longer than 1 week IMO.

Anyone know how much of a factor temps or ventilation are with regards to alkyd SI sheen?

Thanks

[rmichael]

Could be moisture forming on the surface before it completely dries ( dew effect ) it will dull out alkyd paints.

[alexh]

"Could be moisture forming on the surface before it completely dries ( dew effect ) it will dull out alkyd paints"

Thanks, I'm thinking perhaps the drying/curing was slowed down because of poor ventilation. Humidity is not that high here at about 50%. I did not use any cleaning products on the trim before painting except to run a tack cloth over it.

Would a good strategy be to start as early in the day as possible and perhaps even run the heat after paint is dry to the touch?

I looked at some of my misc painted parts (painted outside earlier in the year) and they look almost semi gloss in comparison.

Thanks again, this was driving me nuts. Takes at least a whole day to sand/prep and another to spray.

Edit - I brush painted a small test piece from my thinned SI late last night in my garage (attached, temps don't go lower than 60) and in the morning it was cured but it had the film all over it. I wipe the film with my finger and ther is no odor so it's probably water. I think that the temperature during curing has to remain stable, it should not decrease even if it remains above 50 deg. Just when you thought you knew eveerything about a product....

[alexh]

Update,

I think the film I'm seeing is actually an oil that is being "sweated" by the paint. I say this because the test piece that I painted in the evening had a film on it the next morning and it took all day to disappear.

I think I know the solution  - paint only when temps are rising - but the effect is so dramatic this really confounds me.

[JSheridan]

Alex, simple question, why don't you have heat on in the first place? I doubt if 60 degrees would be too low to have any bearing on the results anyway, except slowing the drying/recoat. I also doubt pretty much that it's moisture as that doesn't sound like condensation would form there or at that temp. The paint you sprayed a few years ago is very much different than the paint you're spraying today. The government forced reformulations are playing havoc with most all finishes. My trusted BM guy, very long term guy, told me the new mix is junk, which saddens me as an SI fan. I recently used BM Muresco ceiling finish, which is supposed to be dead flat. Not now, at least on the last ceiling I did. It had a definite angular sheen. I had rust flashing on a job I did with BM DTM, which I found out was due to surface profiles and dry film thickness. I've never had a concern before about DFT, but I do now. I'm finding coverage a little more shadowy with whites on repaints, with MAB products, an historical work horse when it comes to hide. Stop driving yourself nuts, I don't think it's you, especially with your long term experience and results.
Joe

[chrisn]

I agree. I am finding that there are no more paints that hide very well.  bummer.

[alexh]

Thanks all,

Just wanted to make sure my thinking was right... There's no question the SI is very temp sensitive as far as sheen goes. I did multiple experiments. Basically, you should not let the temp drop after application - even 5 degs may foul it up.

As far as the alkyd SI, I would only bother to use it on new, flawless trim. Especially on very wide trim or panels like wainscot I don't think it has any equal. It's not just the way it levels but also that it reflects light like a pearl. Of course there are great commercial coatings made for spray application that are much more predictable but the problem is that many people are now tying the cabinetry, builtins etc into the house trim so they need the same finish everywhere.

I have tried brushing the WB SI and it's levels even better than the oil but it's hard to use and I found it sands poorly - almost like latex.

At least they are trying to come up with new options - I remember my first high end attempt at trim painting by brush and the best they had in waterbase was Regal. It was like brushing pancake batter and I said to myself "this is the best they got?"

[rmichael]

We used BM WB SI on a large job this past summer . It had absolutely no hide ( four coats to fullness ) It runs and crawls even with your best strokes, you have to check every inch for runs ten minutes after you laid it on... and at 50 bucks a gallon.... never again. 

PS The mineral spirits might be cooking the new SI alkyd formula... which would cause dulling, try using XIM extender for oil paint and less spirits..

[chrisn]

We used BM WB SI on a large job this past summer . It had absolutely no hide ( four coats to fullness ) It runs and crawls even with your best strokes, you have to check every inch for runs ten minutes after you laid it on... and at 50 bucks a gallon.... never again. 

PS The mineral spirits might be cooking the new SI alkyd formula... which would cause dulling, try using XIM extender for oil paint and less spirits..

I like the waterborne but as you said it is a pain in the butt to work with.
I think you may have solved the problem with the spirits! makes sense to me anyway

[ProWallGuy]

I'm a huge fan of the WB Satin Impervo. It does have a learning curve, but for me it handles well, looks great when dry. I found it to have superb coverage when I used it over dingy white on some french windows recently.

[rmichael]

What we used was a custom color (match) and it was mixed in a pastel base, it had absolutely no hide, I asked to have it mixed in a white base and was told that it could not be done and keep the color true. so we suffered through it and lost our ass in labor..     The finished look is great if you can get to it.

[Hangman]

finish sheen is a matter of personal preference and lots of people like the Satin in the Impervo but it has always been a bit dull for my taste. I just did a job with SW Pro Classic Oil (white) and it covered great and had a good semi gloss sheen with one coat, and I'm generally a 2 coat guy.

[JSheridan]

What we used was a custom color (match) and it was mixed in a pastel base, it had absolutely no hide, I asked to have it mixed in a white base and was told that it could not be done and keep the color true. so we suffered through it and lost our ass in labor..     The finished look is great if you can get to it.

IMO, with BM, whites/off-whites have never had great hide. This even going back to the late '80's.  I did a sun room two years ago (pictured on my gallery), where I put a coat of Cover Stain and tried to do two coats of Aura tinted off white. No go. Had to switch to MAB to get the hide. As new rounds of VOC reduction roll over us, the future will have all white/off-white jobs requiring three coats. Bet on it. I just had to do a three coat job to get coverage. Luckily for me it was T&M, and the customer recognized the need, so I didn't lose my ass. Three coats are the future, and I've started alerting my customers to that, and the reasons why. This of course if the paint cos can't pull their ass out of a hat.   

[rmichael]

What we used was a custom color (match) and it was mixed in a pastel base, it had absolutely no hide, I asked to have it mixed in a white base and was told that it could not be done and keep the color true. so we suffered through it and lost our ass in labor..     The finished look is great if you can get to it.

IMO, with BM, whites/off-whites have never had great hide. This even going back to the late '80's.  I did a sun room two years ago (pictured on my gallery), where I put a coat of Cover Stain and tried to do two coats of Aura tinted off white. No go. Had to switch to MAB to get the hide. As new rounds of VOC reduction roll over us, the future will have all white/off-white jobs requiring three coats. Bet on it. I just had to do a three coat job to get coverage. Luckily for me it was T&M, and the customer recognized the need, so I didn't lose my ass. Three coats are the future, and I've started alerting my customers to that, and the reasons why. This of course if the paint cos can't pull their ass out of a hat.

Well said.. 

[JSheridan]

Thanks Rmichael. Is there a thanks button on this forum?