I just finished my CV on all carcasses and frames, assembled and installed. I'm moving on to my doors and trim, which now need glaze.
The schedule before was as follows:
SW cat vinyl sealer
SW Kemvar primer surfacer
150 sand (transparency was brought back and most product was sanded off; mostly used as a slight grain fill and leveler)
SW pigmented CV
2nd coat SW pigmented CV
1 coat clear Kemvar WW CV
The results are great and from what I've seen, the dft is under 5 mils on frames where there were a lot of overlapping passes. Now I need to add a glaze coat in on the next few runs of finishing. I really don't want to glaze over the white, as I've heard it stains (going to test tomorrow), but that would add another coat. Anybody put a Kemvar glaze on their pigmented CV? The reps have all told me that there is no need to sandwich the newer Kemvar glaze with vinyl.
Some will say the sanding is too fine, but the tech sheet for the primer says 400-600 to keep scratches down. I've stuck with 320 max, but I get burn-throughs on the edges. What do you guys use on your routed edges that need to be sanded for glaze? I've tried the red scotchbrites with a few burn-throughs, and I think the greys are a little too fine. The SW reps keep telling me that if I just knock the gloss out, I've opened the pores and I sanded enough. One even said that he just finished his personal kitchen and didn't sand between the three final coats. He said that the product will chemically adhere as long as the recoat window is maintained.
All of my work from first sand to last coat is being done in an 8 hour day. Temps are right around 70-72 degrees and the finished items are kept in a temp controlled room for at least a 72 hour initial cure (they won't see less that 65 probably ever). Any opinions?
From contributor J:
I've always found glazing and CV to be a bit problematic at best, and try to stick with pre-cats when glazing if I can. The trouble comes with the recoating of the CV after glazing. If you don't scuff the previous coat of CV well enough, adhesion is a problem. If you do scuff well enough that you don't have to worry about adhesion, then the glaze wants to take into the sanding scratches. If you rush the glaze while the base coat of CV is still green, then the glaze bites into it and changes the color.
I found that using an uncatalyzed vinyl sealer before glazing helps even when the glaze does not call for a vinyl sealer. The CV ends up getting some solvent bite through the glaze and into the vinyl. Just out of curiosity, what is the purpose of the vinyl sealer under the primer surfacer in your schedule? I put primers, surfacers straight to the wood under opaque finishes.
Other than that your schedule looks fine. The 180 scuff of the first CV coat is rougher than what I would I use, but if it works for you, great. Oh, and I would be very cautious of overall mil thickness too.
SW has said that 4 mils is a guideline and that one of their larger production shops (in So Cal area) won't go below 8 mils on their pigmented jobs. My dft has been between 3.5 and 4.5 on my non-glazed items.
As to your problem with sanding spots, I have had the same issue and found the best way to avoid it is not to sand my second color coat or the clear coat before glazing, which is why I like to stick with uncatalyzed vinyl and pre-cats for the solvent bite. Post-cats would have some definite adhesion issues with this method.
1) Sand all panels with 180, or no finer than 220.
2) Apply a coat at 5 wet mils of their post-catalyzed Clawlock primer. This is a very high solids primer and sands like a dream. It can also be tinted to any color so this satisfies the color issue as well. Give it an hour to dry, then sand with 320 foam backed paper. Apply another coat of your tinted primer, same mils and application procedure.
3) After an hour dry time, sand the primer with 320 grit foam backed sanding paper. This is where good technique pays because you don't want any burn through.
4) If you typically use a wiping glaze, they offer the Vintage Alkyd Base wiping glaze. It does not require sandwiching between vinyl coats. Some in the industry call this product simply "no vinyl glaze." It does require about an hour for dry time, but it is very workable, and is great for antique looks. If application and dry time is an issue, try Campbell's Amazing Glaze. It is spray only and very acidic as far as biting into anything less durable than Magnamax (cured at least 12 hrs) or any of their post-cats (only 1 hour dry time necessary). Once applied, this stuff dries in seconds, and works off where you don't want it with a scotch-brite pad. CATech offers a glazing tip (looks a lot like a basketball pump needle) that replaces the tip on the gun, and allows the glaze to flow into the details and only in the areas you want it. Again, you get a very fast application, as well as dry time.
5) Apply a clear topcoat (would recommend at least Magnamax but prefer Krystal post-cat over top). Sprayed at the right mils (4-5 wet), one coat of clear on top is enough, but two coats is superior.
Using these products, you can achieve a very durable, very nice looking, and very fast project. The pricing up front might be a little higher for materials, but your labor will be reduced with less steps and less down time waiting on paint to dry.