Staining Pine Cabinets
We received a few small samples from a designer that were generated from a larger company out of Canada. These samples were all on 1/4" MDF (12"x12") with a heavy pine veneer (ideal for an even finish). The samples came with formulas and instructions on procedure. The instructions clearly say that he sanded only to 120 (which jumped out at me as asking for trouble from the get go).
I have now been presented with the challenge of finishing a huge project consisting of various mouldings, hardwood frames, cabinetry, and panels made of both MDF and plywood core (some sheets were also from different distributors, to make things even easier). I did a lot of experimenting and was able to obtain a uniform finish on some of the MDF core panels and even some of the hardwood. But at the same time, the higher grit I finished out at (180, for example), the more even all the different materials ended up. Since I have been instructed to only sand up to 120 on hardwood and panels alike, I'd like to get some advice on how to go about this. I have successfully stained and finished about 1000' of moulding but did run into some pieces that stained up pretty unevenly (even with a wash coat and spraying on the stain). Right now I am most concerned with making sure the panels and frames all come out even.
The solid woods you are calling "hardwoods". Not to be anal, but pine is a softwood. I think that you mean to call these pieces "solids".
After the tinting toners, I find it useful to use a toner spray with dye stains to get the coloring that you need. If the equalizing toners are made with pigment colorants (which in this case I prefer), then go onto the sprayed dye stain as the next step, as I already said.
From the original questioner:
Yes, I know that pine is a softwood, but we refer to all wood that comes into the shop in board form as "hardwood". Anyway, I should have made clear that I know the correct way to do this, but find my hands are tied by management. I can't argue with the people who sign the check. The fact that it has all been sanded to only 120, and that I was instructed to limit the amount of steps (would have liked to spray a coat or two of dye before the washcoat) in the finishing process is what has me frazzled. Also, I am actually spraying/misting the stain out of a pressure pot, because it seems to sit on top of the wash coat and allows me to rag it out evenly without penetrating the pine too much. Do you think wiping would be better in this case? Basically, I want to know if it is a losing battle to stain pine that has only been sanded to 120.
From contributor R:
What kind of color are you trying to achieve - light, dark, whitewash, etc? I think it is difficult to give advice without a little more info. By the way, European cabinetmakers usually don't like to sand any finer than 120 grit. This can cause problems with cross grain scratches on face frames, for example, unless you are dealing with highly skilled craftsmen. Other than that, pine can be finished with 120 sanding. I don't think I would want to sand pine veneer much more after it had been sanded with 120 grit by someone else anyway.
From contributor M:
I suggest you make up your own complete start to finish samples, and then decide what's best for you.
From Paul Snyder, forum technical advisor:
As long as it was sanded carefully, 120 grit is fine. Some stains even specify sanding no finer than 120. Here are some questions that come to mind:
Are you letting the stain flash before wiping?
If you're getting blotching, I'd say the washcoat isn't sealing the wood enough for the stain you're using. A small increase in the solids content of the washcoat can make a big difference in avoiding the problem.
If the stain is compatible with your topcoats, you can add some of it to a measured amount of thinned finish for use as a toner (e.g., 2 ounces of stain per quart thinned finish). To avoid making the color too dark, you can reduce the stain with the clear stain base and use that over the washcoat. The lighter stain will also show less blotching and the toner will add the rest of the color and make it more even at the same time. It doesn't really add more steps to the finish, but does make the color a lot more even as well as give you more control over the color.
I've used this technique at times, for various reasons, and it works well. Not too long ago I had a pine wall unit that was a mix of solid and veneer. The customer wanted a light color, but the stain caused some unsightly blotching and there was a color difference between the veneer and solid wood (doing samples before starting the wall unit made the problem obvious). Here's a shot of the wall unit before finishing:
To avoid the blotching and make the color even on the veneer and solid wood, I reduced the stain with the clear stain base and used that on the bare wood. In this case, since the color was so light, I didn't need a washcoat first.
Next I sealed the stain with a coat of finish. Then I added some of the stain to some thinned finish and sprayed that over the sealer coat after I sanded it smooth. The toner gave me the rest of the color and made everything nice and even.
In this picture, the cabinet on the left is stained (very light), and the one on the right has toner:
Here's a shot of the corner cabinet with a couple coats of finish over the toner:
If you're going for a darker color, you probably won't be able to skip the washcoat, but you may need to adjust the solids content a little. If the stain comes out lighter with the higher solids washcoat, just add a little more stain to your toner to compensate.
From contributor B:
I had a similar job a few years. I sanded to 220, but I think that is relatively unimportant if you use a gel stain. Don't ask me about the physics of it, but the pigment in the stain doesn't grab the grain or highlight the sanding scratches. After this, to tweak the color just a hair, I used Mohawk NGR stains followed by a heavy coat of lacquer to lock in the color. I sanded flat and the customer loved the finished product. I think a gel stain is the key if you are only going to sand to 120. It gives a smooth, very nice and even coloring without the blotching that happens a lot in pine. Plus it will not reverse stain on you, meaning it will not color the early wood darker than the latewood in pine grain like some pigment stains do.
From the original questioner:
Paul, thanks for the detailed response. I am using 70% thinner and 30% chemvinyl sealer (Chemcraft). Do you think I can afford more solids? I do not want this to be a glaze, but I do not want it to penetrate entirely. Mostly looking for an even stain, with enough definition of the grain to show nicely through the toner. This is a pretty dark color (walnut). As for letting the stain flash, I am not leaving it on that long. I find the sooner I wipe it off (I am spraying/misting it from a gun), the less chance of it blotching. I suppose this is why you are saying that I should reduce it, which is exactly what I was experimenting with today, with good results. I hope to come up with a final sample tomorrow because I am ready to move from mouldings (which are about 20' in the air, also the reason I started with them) to more important pieces such as the wall panels and bar cabinets.
From Paul Snyder, forum technical advisor:
If you're using the 8002 vinyl sealer, the washcoat you're making is about 3.5% solids (if I'm calculating correctly). If you increase the solids to 5% (or a little more), you should see the blotching disappear. When I use Chemcraft Cinnamon stain on cherry, I use a 5% solids washcoat with good results. Any thinner and it blotches. The 8002 sealer has 11.8% solids before thinning. I have an example of the math to reduce it to 5% solids at http://www.furniturefinishwizard.com/washcoatsolids.htm.
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