Sealers, Washcoats, and Dyes
For good coloring and popped grain, should a washcoat or sealer be applied before the dye? Finishers explain a few fine points. February 13, 2006
Question
I am finishing birdseye maple a bright yellow using Behlen Solar-Lux NGR dye stain. Do I need to seal with sanding sealer first to accentuate the figuring and give more depth? I have received conflicting opinions.
Forum Responses
(Finishing Forum)
From contributor A:
I would suggest that you make up some start to finish samples. That is a concentrated dye, and you need very little color to pop the woods. Reduce the dye with the proper solvent, and you will find that you will need more solvent than dye to get the color.
From the original questioner:
To contributor A: That's what I've heard about that dye. The recommendation was to seal first so that I don't obscure the figuring. I was told I might actually lose all the depth of the birdseye unless I seal first. Is that what you would suggest, or should I simply dilute the dye and forget sealing?
From contributor A:
If you’re spraying the dye, you won't need the sealer. If you never sprayed a dye, you will need to practice - make your passes, then stop and allow to dry, and then make more passes. If you’re wiping or brushing on the dye, then a wash coat sealer will prevent the stain from penetrating the wood. If you’re brushing or wiping I would add a little water to slow down the dye, and make it more workable.
From contributor B:
I’m not sure I understand the concept of sealing a wood before you apply a dye stain. I always dilute my Solar-Lux stains with denatured alcohol so that the dye does not blotch when it hits the wood. If you dilute it and make fairly light passes, you should avoid any blotchiness or color separation or puddling of the dye in one area when applied too heavily. I can understand sealing or washcoating maple if you were using a wiping stain or trying to glaze, but if you sealed the maple and then sprayed dye stain I just picture a runny mess with no penetration of the wood. Maybe someone can explain, perhaps I am missing something. As far as obscuring the grain, you should be able to avoid that problem with a well applied dye stain. This is more often a problem with a dark wiping stain or too much toner. I have found if you do not try and achieve a dark dye stain color all at once you can preserve the figuring of the wood, even on maple that is less figured than a birdseye.
From contributor A:
The reason for wash coating, glue sizing, or wood conditioners is to prevent deep penetration of the stain. These thin films act as a barrier. If you add denatured alcohol to dilute your stain, it’s okay if you are spraying. But alcohol dyes dry very fast and it is difficult to cover large areas if you are wiping or brushing an alcohol stain on raw wood. A little water will make the stain more workable if you are brushing or wiping. Spraying dyes and wiping or brushing dyes involve different techniques. Also, production shops may not work the same as a small shop, as they do not have the time to worry about blotching.
In some shops a dye shading stain or a colored glaze is applied over a wash coat, so that the colorants are not on the wood but are on the wash coats. You may not do your finishing in this manner, but many other shops prefer this finish because they know they will not get any blotching, and may get more uniformity of color on their pieces because the stain cannot penetrate the barrier coats. I do not suggest one way or the other. To me it would depend on the specific job..
From contributor C:
One method to pop grain is to first dye with a dark color (ebony or similar), sand it off, and then go with your intended lighter color.
From contributor A:
Any color will pop the grain. There is not much color in wiping on boiled Linseed oil and then wiping it off, and that's a popular way of doing it. You certainly don't need to use any colorant at full strength to pop the grains. A little dab will do you.
From contributor B:
I do understand the difference between using or not using wash coats, as we use them all the time. According to the original post, he says that he was told to seal the wood first. I think sealing and wash coating are completely different. To me sealing the wood means spraying on sealer 100% straight. Otherwise, when using a wash coat, we always refer to that as a wash coat, and not a sealer. Perhaps this is just semantics but it lead to my confusion. Is there ever a circumstance where you would seal a piece of wood (completely seal, no reduction to the sealer) and then spray on a Solar-Lux stain?
From contributor A:
If you are working on maple or other closed grained wood, then you would be using wash coats. On open grained woods, then seal coats would be a better choice to stop the stains penetration. One technique does not always fit all. Test twice, finish once. Samples, samples, samples.
