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Using spray-only stains on doors with profiles and projected trim.....9/18
There are times when experienced finishers need a little humbling, I suppose this is my time.
I've been a finisher for around a decade at this point, but have never needed to do a spray-only stain on doors with profiles and projected trim (ogees added around the center panel that project out, such as Conestoga's Verona).
I've done spray-only stains on flat, grain-matched plywood slabs that turned out just fine, so naively I assumed I could replicate this on these projected trim doors with ease. Nope.
What methods are helpful in getting the stain evenly across the door and the trim/profiles? A direct, straight spray patter (like you would do on plywood slabs) doesn't cut it, you get far too little material in the inner corners of the profiles. Sorta the opposite of a glazed look: light spots in the corner instead of dark spots.
I am applying the spray-only stain with a CA Technologies Jaguar HVLP, approx. 20psi. I have thinned the stain enough such that I must make to "foggy" passes to achieve the right color.
Today I used an airbrush (Binks Wren) to get the profiles right, and then just duked it out with the HVLP and a finesse touch.
If I tried that with the HVLP, even dialed in narrow and light, I'd still get a lot of overspray on the door parts/panel, and the profiles would be still hit-or-miss.
End of the day, my first batch of 24 doors looks good, but that's literally half the number I would have gotten if I had the option of a wiping stain.
So what is the trick to getting a decent, even spray pattern with projected mouldings and panel routes?
By the way, the spray-only stain is from Sherwin Williams. I do not recall the product name/number, but this is definitely NOT a wiping stain.
It's nearly identical to ML Campbell's "Amazing Stain" in composition and behavior.
you have to turn your pressure way way down so that the stain going on is just lightly falling on the door. almoat like a misty rain. too much air will make it look foggy and you will get funny appearance around the mouldings. also spray at 45 deg both ways to eliminate the shadow from the mouldings.
Dave is right on. You have to dial pressure way down, almost no atomizing air. The stain with spatter a bit but fill in to cover everything. Spray at an angle both top to bottom and bottom to top so that you get the dges of the mouldings with consecutive passes.
Spot on with using low pressure. I use a 2 gallon pressure pot with separate regulators for the fluid and air. That way I can get the right mix of fluid to air. Too much air and you "blast through" your fan pattern. You want the stain to kind of "float" into the corners. Not sure what you thinned the stain with. If you thinned it with a fast evaporating solvent, you might want to instead try a slower evaporating one. Not super slow, just slow enough that it gives the stain a chance to float into the corners before it drys. Ask SWP what to use. Some times they make spray stains out of P63 vinyl basecoats, in which could use some 305 reducer or a little MAK. If it is made with stain tints, a little Naptha 100 will slow it down a little.
I ditto Dave.
This is the main reason why spray stained doors are glazed. To hide the sins.
OK, thanks for the help there.
I wouldn't have guessed that such low pressure was the trick, but I will try that on the next job.
Matt - you can practice using scraps by connecting 2 or 3 pieces of plywood to form a corner. This will simulate spraying stain inside a cabinet which is very similar to spraying a door - it's tricky to get the color down into the corner - especially a corner with 3 sides (where the bottom, side, and back intersect).
I'd start with 2 long cut-offs connected at 90 degrees and then experiment with the pressure and spray technique to get even color in the corner and blend it out onto the flat surfaces. Once you get that down, add a 3rd piece to form a 3-sided corner.
This practice should make it a lot easier to transition to doors with profiles.
Like Alan, I'm also a fan of using a pressure pot to control the atomization and fluid pressure separately. If it's a small job, I'll use a quart pot. If it's bigger, I may use a pot with a gallon can sitting inside. If it's bigger that that, you'll probably need a pot with an agitator to keep the pigment in the stain mixed. Likewise, you may need to stir the stain in the smaller pots if you don't use it quickly. Otherwise the pigments will settle and some items will be darker than others.
I ditto the low pressure. The higher pressure blows the stain out of the corners. FWIW, I started using Chem-Craft coatings about a year ago. Their Vivid spray stain is the best at avoiding this that I've used.
I do see the advantage of the pressure pots, now that you mention it. The flow rates on a gravity feed HVLP tend to vary as the cup empties out.
By the way Matt, I spray Mohawk ngr dye stain. I've been getting great penetration and adhesion.
another method is to reduce your stain significantly more with solvent so you can spray the stain a little on the wet side... This way your not going to dark too fast... just have to make multiple passes on the door but it sure comes out a lot more even. Most people don't have their sprays stain reduced enough and they end up jacking up the air pressure or moving too fast because the color is getting there too quickly...
I have been using Spray Only stains for many years on Arch. woodworking and furniture.both seating and casegoods with many inside corners,profiles etc. low air pressure and proper reduction is paramount.