Question
I am fairly new to spraying stain but so far am loving the switch over from wiping. I am spraying Sherwood stains mixed 3/1 with tolulene. I have found that there is a fine line on how much material to lay down. Too much and it will puddle, not enough and you feel like you are starving the wood. I am having trouble with crevices in the profiles not getting any stain. The flat services get plenty and the nooks and crannies seem to be missed. Are there any tricks to getting it all coated and it still being uniform?
Forum Responses
(Finishing Forum)
From contributor H:
It sounds as if you are getting a lot of bounce back from your spray. Try starting your atomizing pressure at 15 psi. It is thick, will reduce the bounce, and will get into the corners. Increase by 5 lbs to get the right look.
I have an HVLP that does fine at 12-14psi. A conventional may yield the same results at 25-30psi. That difference is huge in a spray stain. All that being said, set the gun to where it is atomizing at its peak and keep the gun perpendicular to the work at all times. None of those arc and pendulum techniques! If you try to intentionally spray the stain into the corners it will end up looking worse. The most forgiving spray stain that I have used is MLC'S Amazing stain. It hides overlaps very well and there is no thinning. It can also be used in between sealer/topcoats and as a shading additive up to10%.
To the original questioner: I spray them all the time, except I am using Valspar stains. I think your problem may be the solvent and the ratio. I use Naphtha mixed 5:1. I don’t know how fast toluene is compared to naphtha, but I have experimented with standard thinner and found it flashed off to fast making application difficult. Also, by thinning more than three to one you get more control as you can build the color slower and more controlled.
Try 5:1 with naphtha, spray door edges lightly to avoid runs, and then quickly blow in the face to even out the color that blew by when spraying the edges. Now make a wet pass across the face. Spray so it’s at the point where it’s just about to pool on the surface. Hold the gun at an angle so the stain blows in to the crack where the panel meets the frame a little easier, maybe 10 or 15 degrees off vertical. Spray to the halfway point on the door, then rotate the door and keep going so you get the stain in the opposite panel/frame crack.
Give it a few minutes to dry, flip the door, and repeat starting with the edges again. You will never wipe a door again once you get this figured out. It just takes a little practice.
Chemically there is a bigger issue as well. Spray/wipe stains are meant to be wiped after application. The oils and resins are left on the woods surface if not wiped and then the coatings are expected to penetrate through them to get adhesion to the wood. If they penetrate you run the risk of coating migration, creating a hybrid coating to where the next coat doesn't know what it is sticking to and then wrinkling can occur as well. Just like oil and water don't mix nor does oil and lacquer, pre-cat, post-cat, conversion varnish and so on. I know what you may be thinking, "I've done this for years without any problems". You may have but sooner or later the odds are that it will bite really bad. If I'm doing a set of 40k cabinets that is just not the type of gamble that I am going to take. I'm not eating $40k especially when there are products that don't have to be thinned, (we rent solvent, we aren't able to keep something that evaporates so why add something if I don't have to?) and are chemically matched with the coatings that are going on top.
I am assuming you have no experience with this technique. I too felt exactly as you did, until my chemical rep suggested it and I tried it. You want a little pooling, very little, and you don’t want it to flash off too fast so it has a chance to soak in to the wood. This is why the fast acting solvents don’t work as well. It’s not the same as spraying a dye/NGR.
The product I mentioned earlier (it isn't an NGR or a dye) if sprayed med. wet will yield a nice grain popping effect while multiple light coats will give the "multi piece door being one color" that women think that wood should be. Plus the other advantages that I mentioned with the ability to add after the seal coat in case parts are a little different in color or using as a shading additive. It also can be tinted to where extremely dark colors can be achieved with one-two passes. It can be used as a pre-stain conditioner or applied after a wipe stain to achieve a more uniform look.
Back to the original issue with halo - I don't try to intentionally spray into profile. I think that it makes things worse. If you have a chance to see a high ene flatline in use you will notice that the heads are tilted at an angle to get coverage on the edges as well as flat surfaces but not just to get into profile. Even these monsters still end up with a little halo especially after the panel starts to move. Kraftmade definitely has these issues.
