Beech being blotchy, any solution for staining?

[Bencuri]

I am trying to color beech blocks with dye. They come in powder form where I live, and they are soluble in water or alcohol. The problem is the results are not very satisfying. You can see it on the photo. The upper one was painted with the version that was dissolved in alcohol, it gives a terrible result. With the one dissolved in water, the result is better, but a bit of cloudiness can be seen. It is not a problem until you add a glossy varnish on top, that will make it look blotchy again. So maybe it only works with matte varnish. I tried to prepare the wood with different methods: smoothplaned only, scrapped, sanded up to 180 grit paper. The result is the same. Maybe the best result comes when the wood is left rough-sawn, then the outcome is even at least.

I wonder if you could color these blocks anyhow that gives good result with any kind of dye or stain? I saw a video on Youtube about how to color wood evenly with gel stain, that is fine, but the problem is gel stain is not available where I live. Secondly, I know that you can apply a coat of shellac washcoat before coloring, but that will result in very light color, so I would avoid that if possible. Maybe mixing the dye or satin with varnish and apply the two together could help? Or using colored varnish?






 

[jteneyck]

Do you have spray equipment?  If so, spray the dye on, just enough to wet the wood and not enough for any excess to accumulate and migrate or it will blotch.  If you don't have spray equipment, apply a coat of shellac to the bare wood.  Then add some dye to shellac, at low concentration, and brush on 2 or 3 light coats.  Brushing shellac isn't easy, be warned.  Practice on scrap.  

John

[Bencuri]

Do you have spray equipment?  If so, spray the dye on, just enough to wet the wood and not enough for any excess to accumulate and migrate or it will blotch.  If you don't have spray equipment, apply a coat of shellac to the bare wood.  Then add some dye to shellac, at low concentration, and brush on 2 or 3 light coats.  Brushing shellac isn't easy, be warned.  Practice on scrap.  

John

I am not an expert by far, but I think this pattern is not because of the colorant migrating. Some of the light sports were actually the sections where the water or alcohol survived the longest before evaporating. I noticed that until 180 grit, these blocks soak in the colorant quite well, so little surface unevenness doesn't affect the color that much, it seems to me these are the pores that soaks the dye in differently. On the other hand, I noticed, that when I sand to 180 grit, then wet the surface with water to raise the grain, then sand the hairs off with 220 grit paper, then repeat this raising the grain process 2 more times, I get a very smooth surface. In case I apply the dye for that surface, then comes the effect you talk about: the dye migration problems and differences due to how much dye was left in the bursh. Probably because at that smoothness the pores are unable to absorb the dye effectively, more of it remains on the surface and start causing the problems you mentioned. I guess that would be the situation when a spray gun was useful. Anyway, even if I apply the dye manually for that surface, I can see that the problems from the pore differences are gone, so I wondered what if I tried oil based stain to apply it manually, then I had time to spread it evenly, and wipe the excess, unlike with dye. This dye cures too fast, so on this mirror surface there is no chance to compensate the uneven brushing lines. This is what I observed.

[jteneyck]

I am not an expert by far, but I think this pattern is not because of the colorant migrating. Some of the light sports were actually the sections where the water or alcohol survived the longest before evaporating. I noticed that until 180 grit, these blocks soak in the colorant quite well, so little surface unevenness doesn't affect the color that much, it seems to me these are the pores that soaks the dye in differently. On the other hand, I noticed, that when I sand to 180 grit, then wet the surface with water to raise the grain, then sand the hairs off with 220 grit paper, then repeat this raising the grain process 2 more times, I get a very smooth surface. In case I apply the dye for that surface, then comes the effect you talk about: the dye migration problems and differences due to how much dye was left in the bursh. Probably because at that smoothness the pores are unable to absorb the dye effectively, more of it remains on the surface and start causing the problems you mentioned. I guess that would be the situation when a spray gun was useful. Anyway, even if I apply the dye manually for that surface, I can see that the problems from the pore differences are gone, so I wondered what if I tried oil based stain to apply it manually, then I had time to spread it evenly, and wipe the excess, unlike with dye. This dye cures too fast, so on this mirror surface there is no chance to compensate the uneven brushing lines. This is what I observed.

If you use a pigmented stain you will get a more uniform color the higher the grit you sand to.  The downside is the overall color will be lighter the higher the grit, too.  

My general strategy to avoid blotching is:

Spray dye
Seal with Sealcoat shellac - sprayed
Glaze with a gel stain if I need a darker color or to add depth - by hand
Seal with Sealcoat shellac - sprayed
Apply topcoats - any way I want.  

John

[Bencuri]

I have been experimenting meanwhile. As a main direction, I would like to stick to as deep color as possible. So far I had the best results with water dye. I also looked up some old test pieces from the same batch of blocks, and I found one where I tested the shellac + colorant mixture (I think it was alcohol based dye powder mixed in). The color is unfortunately light, but uniform, so maybe I will accept that compromise for certain projects, because that piece looks way much better than I remembered. I checked how glaze looks, but I don't really like that option. Unfortunately spray gun is not available. So colored shellac or water based dye so far. But I am still testing other options.