Spraying a Washcoat

      Achieving a smooth, consistent application. August 26, 2004

Question
I've done some finishing with washcoats before, but now I've got a large cherry kitchen coming up and I have a couple of questions.

I'll be using my vinyl sealer cut 1-2. I know how much of the washcoat that is sprayed on affects the absorption of the stain. How do you do it? Do you normally put on a good wet coat or just a quick pass? I can spray the washcoat on with a 1.3 or 1.5 tip. Which would you recommend?

What do I have to watch out for in order to get it even on a large job like this?

Forum Responses
From contributor D:
We make our washcoats four parts thinner, one part vinyl sealer. We also add dyes into our washcoat to shade the wood as needed before staining.



From contributor M:
I do my wash coat clear or pigmented with one part polyurethane post catalyzed lacquer to half catalyzer and half part tenner and then add as much tenner as the quantity I got or more, depending on what color I want. Do trials and practice.


From the original questioner:
Do you guys sand or scuff after the wash coat?


From contributor T:
Yes - sand/scuff sand - my coatings rep says to sand right before you spray. Don't do it the night before. This helps with the mechanical bonding process, or so he says.


From the original questioner:
When you spray clear washcoat, are you putting a full wet coat on like when you are spraying a top coat, or is it a faster coat normally? SW recommends 1-2 with the vinyl sealer. I know everyone has their own recipe, but is it normal to put a full coat on (maybe adjusting viscosity to achieve proper sealing) rather than a lighter coat?


From contributor R:
We spray a full wet coat. Knock the hair off with 400, then stain with oil stain.


From contributor M:
I usually wash coat over birch or maple, sometimes even pine, but no others. And I go over it with 400 and then stain with water base stains.


From Paul Snyder, forum technical advisor:
I get the best results by reducing the solids content (by volume) in the washcoat to around 5%. Depending on the solids content of the product you're using, the amount of thinner required will vary. Then spray the washcoat at the same speed as you would normally apply a topcoat. Because the washcoat viscosity is so low, you'll need to cut the fluid flow back. The only difference you'll see is the washcoat leaves less of a film on the wood once it dries. After it dries, scuff sand to smooth. If you're using a wiping stain over the washcoat, you'll want to make sure the solvents in the stain don't dissolve the washcoat and make a mess.

What finish are you planning on the cherry kitchen? Depending on the finish and products you use, you may or may not need a washcoat in the schedule. The cherry entertainment center below is typical of the look that's often requested in my area - no washcoat is involved though glaze and toner are.




From contributor E:
Contributor P, could you tell me your finish schedule for the cherry entertainment center?


From contributor K:
Very nice job on that piece. What type of gun do you use to spray your dyes and at what pressure?

I'm rather new to dyes and have had some problems with not getting the whole piece to be totally consistent. Sometimes I'll get lap marks. I've tried to turn down the pressure, widen my pattern, etc, but with not much luck.

The company who has started doing all of my finish work says part of it is experience.



From contributor B:
Most all of it is experience.


From Paul Snyder, forum technical advisor:
Here's the schedule;

- Sand to 150
- Spray and wipe ML Campbell's WoodSong II cherry stain. The color "Traditional Cherry" is a little redder.
- After an hour, one coat of vinyl sealer. Let dry and sand smooth. Remove the dust.
- Glaze the raised panels, flutes, trim, and moldings for effect.
- One coat of toner over the glaze. The toner was 1 1/2 ounce Microton "Cherry" dye per quart of highly thinned finish (1.5 ounce dye, 4 ounce finish, 28 ounce thinner).
- Two topcoats over the toner (don't scuff the toner), scuff sanding between coats. I use Chemcraft Opticlear pre-cat for the topcoats (and their vinyl sealer over the stain). I spray the toner and immediately follow with the first topcoat (two spray guns).

In the picture below, the cabinet on the left is stain only and the one on the right is glazed and toned. The glazing and toning adds a lot to the finish.

I use either a gun connected to a pot or a cup gun to spray dyes and toners. I don't know what pressure I use; I set my supply pressure to 80 PSI and control the air at the gun with a "cheater valve." The valve controls the amount of air to the gun but doesn't display a pressure. I just adjust it until I get good atomization for the current fan width with minimal overspray.

For dyes and toners, I have the settings a little lower than I would for a topcoat and move a little slower and more carefully to ensure even coverage. It does take some practice.

Here's a gun I have connected to a pot showing the cheater valve.




From contributor K:
That's quite interesting because I was using the same exact gun, but on a pressure cup. I'm considering moving it to a 2qt pot. Does it spray better by having it run off of a hose/pressure pot than a cup? I also hate/pull my hair out when I get a drip onto the piece I just dyed that leaked out of the top hole from the gun.


From Paul Snyder, forum technical advisor:
I've never attached the gun to a cup. I'd guess the cup would have to be pressurized.

Connected to a pot, I've had good success with the gun in a variety of situations ranging from finely controlled patterns to wide open production panel spraying. It seems pretty versatile. If your gun is leaking at the nozzle, I'd clean and lubricate the needle where it goes through the packing, make sure the packing nut is not too tight, make sure the needle spring is still strong, check the nozzle for blockage, or replace the needle/nozzle if it's worn or damaged. The gun shouldn't leak. It's a huge pain when a spray gun leaks; especially with a toner.



From contributor M:
This is a wash coat colored example. I did my wash coat from a P.U. catalyzed lacquer made as described by the manufacturer and then added the same amount of the coat I have thinner, which means I did 2 P.U. base coat, 1 catalyzer and 1 thinner and then added 4-6 thinner. After spraying full coat to the left half of the board, after the base coat had cured I light sanded it with hand 400 sanding paper and then applied the same dye to both sides of the board. After that I did the base coat again and then sanded and at last topcoat.




From contributor K:
It actually leaks from the little hole on the top of the cup part which used to have that plastic/rubber clear hose. I took it off because it clogged too much.

I'll have to look into switching my ways of doing dyes.



From the original questioner:
Contributor P, appreciate your info. The reason I decided to go with the dye and wash coat was that I was concerned with the stain blotching the cherry and getting the depth of color. I'm using SW finishing system with the stain is commercial wiping stain. The colors I ended up with to get it right for the customers was 'Traditional Cherry' and 'Cordovan'. The Traditional Cherry is very thick and hard to work with and my experience has shown it to blotch badly. I wanted to thin it a little to make it work better in the stain mixture, but this with the wash coat made it a lot lighter in color, so I ended up dying it first. A lot of work. I think it will look fine when it's done. I'll be glazing it then top coating it with 2 coats CV.

Thanks for the thoughts on the wash coat - that will help me.

The photos you included showed off your beautiful finish. Even the plain stained wood was nice. I started a thread some time ago about 'Amazing Glaze' and you put in some thoughts there also. I have attended a finishing seminar about ML Campbell finishing products and it seemed that it would be too hard to me to work with their glazing system. I wasn't sure that a dry glaze would be what I wanted, and their system for their standard glaze was too labor intensive. They required that you isolate the liquid glaze with vinyl sealer. Sherwin Williams doesn't require this, so after I seal with the catalyzed sealer, sand and glaze, I can go right to the CV topcoat.

Are you happy with the ML Campbell stains? It didn't look like it was blotching very much at all. Do you treat your cherry special? I have read in some old threads of problems using the Woodsong 2 stain. This made me leery of changing over to it. What has been your experience?

I really liked the service offered from my local ML Campbell dealer. I was considering switching everything over to them, but had these questions about the products. 80% of the finishes I do are glazes and I didn't want to get a bunch of problems.

Your work looks great. How long have you used their products? What products do you topcoat with?

On my first set of cherry cabinets years ago, my customers wanted the color Autumn Blush offered by Kraftmaid. We ended up getting it from them but had to buy it in quarts, as this was the only way they'd sell it to consumers. $25.00/ quart, but the customers picked up the tab. It was beautiful stain to work with, easy to wipe and didn't blotch at all. Very deep color. I'd love to get hold of a line of stain like that. Still looking.



From Paul Snyder, forum technical advisor:
I'd read the old posts about problems with the WoodSong II stains as well (adhesion). I told the local rep I wasn't interested based on those posts and he was persuasive that the problem had been fixed and to give them a try a couple years ago. Not all of their stains work well on cherry, but the "Cherry," "Traditional Cherry," and "Cinamon" stains do a nice job with very little blotching and all three colors work well with the wood. All I do is sand the wood to 150 just before staining (spray and wipe) and it comes out fine.

For sealers and topcoats I'm using Chemcraft. I like them a little better than ML Campbell, though Campbell's products aren't bad. I've used a number of pails of their vinyl sealer and Magnamax and they did a good job; the Chemcraft is just a little better in my opinion.

The Kraftmaid stains are probably made by Lilly. I've used a number of them and they do a nice job. The three Campbell stains I listed work pretty much the same as the Lilly stains; the "Walnut" is also a stain that doesn't blotch much but I wouldn't use it on cherry - works fine on maple. Some of the Campbell stains seem to be a pigment/dye combination (their mahogany colors for example) and they work well on woods that don't blotch (e.g., oak and mahogany).

I think Mohawk has a similar line of stains as well. ICA is another stain line that gets good reviews.

As long as I don't run into any compatibility issues, I don't have a problem picking and choosing different products from different suppliers. It seems like they all have their strengths and weaknesses. Some of the independent suppliers do the same thing; they sell one brand of stains, another brand of dye, another brand of glaze, and another brand of topcoats.

If the stain you're using has blotching problems, the dye, washcoat, stain routine is a good approach. I use it sometimes to get custom colors and the unique look it provides. A light, even wet coat of the dye seems the most critical part of the operation.



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