I am having trouble with birch ply blotching. I used a 1 lb cut of
shellac to seal it a bit and then applied a dark Lockwood water based
dye. Terrible blotching.
I was thinking about toning the wood to solve the problem. I have
water based Kem Aqua lacquer and sanding sealer. It can take up to 3%
water for spraying. Can I just take the diluted dye and use it or do
I add the dye powder directly to the lacquer? If I use the dilute
dye, is 3% enough to get a reasonable depth of color in 3-5 coats?
Len - there are multiple reasons colorings blotch. Incompatible
products, incorrect preparation, and the worst - contamination.
Contamination can come from anywhere. It could be on the ply when you
buy it, it could be something in your finish, or it could be as simple
as using a rag from the rag bag instead of a clean rag.
The love of my life put softener in every load, even those destined
for the rag bag, so they are loaded with silicones and other agents.
If you are having problems with "terrible" blotching after your
sealer, there is a easy way to test that will give a good idea (not
foolproof) of contamination. Try this to see if you are having a
compatibility or contamination problem.
Put some colorant in a clean spay bottle. You can get these at the $1
store, and it will be worth a buck to see if this is the problem.
Spray it on a couple of the LIGHT areas, not the dark. If the
colorant beads up on the surface into a million little beads, you have
a problem. If it lays flat and simply shrinks at the edges, you are
If you have a contamination problem, start over. Even if you spray a
toned finish on a contaminated surface and it looks fine when
finished, it may not hold up. Finishes today are so good they will
fool you for a while by looking great. But if they don't adhere
properly, there will be problems later.
Birch ply in particular can be tough to get right.
The biggest alarm bell you sounded though was the fact that you were
using a water based dye on top of shellac. Depending on how you
applied your shellac, and how much you sanded, etc., your shellac will
have different levels of porosity and water repellance. Think about
this; if you set a sweating glass of water on a table for a few of
minutes, the water won't penetrate as it has some water repelling
This could easily be the problems with your dye.
And if you are apply the dye with a rag, brush, pad, or anything else
by hand, the dye will be sucked out of the applicator by the more
porous areas of the ply. You don't stand a chance at an even
If it were me, I would recreate exactly what I now have on a few
pieces of scrap. Then i would work on a solution, whether it be
sanding and recoloring, toning, changing finishes, etc. Just applying
a mask over the existing "terrible blotching" may mitigate the poor
appearance, but then you will be making excuses for your work any time
you show it off.
Don't think applying a toner is that easy, either. A tiny bit of
color applied well is in fact pretty easy. But if you are applying
enough color in a finish to cover up problems, you are essentially
adding a thinned, colored paint. Again, try this on your prepared,
blotchy scraps and see what you think before going to your project.
I don't think it is cantamination. The dye sinks in just like there
was no shellac. It dries quickly and evenly - but blotches.
Both the shellac and the dye were sprayed on using an HVLP conversion
gun. In the past, this technique has given me some nice, very even
colors - without the shellac. But, then, I was using light colors.
Now I am spraying a dark red. I want the dark color, but want it to
be transparent so that the grain will show through. I don't know
how to gage how much shellac to put on. Too little is doing
nothing. Too much will stop the dye from penetrating the wood.
As you suggested, I did some samples last night on 3/4 inch stock.
Most were great. One showed blotching. That's when I decided to try
the shellac sealer. Today, I was working with 1/4 inch ply (back of
the cabinets). It is rotary cut (can't find plane cut any more) and
that too may be contributing to the problem.
I tried toning a sample. Nice even color, but not easy to get
adarkcolor on the wood when using water borne lacquer. I would need
to re-do my dye concentration , which would make matching earlier work
My current thinking is to live with it. Yech!
OK... for anyone else that finishes, skip this post. With a few more
details, there are a few more options and ideas.
Here are my thoughts on this, take them for what the are worth.
First of all, I do not like water borne dyes. Tried 'em, didn't like
'em, and I have not revisited. And one of the TransXXX family even
has a warning on the label that the final product doesn't stand up to
light. On a finishing forum I used to frequent, this was mentioned as
an ongoing problem.
And example of a post would be like this: A nice table is finished
and set by a window. A lamp is placed on the table. A year later,
the piece doesn't look like it faded until you move the lamp then you
have a dark spot. Now what?
When dying, I only use Behlen's Solar Lux. I have used them with
great success under all manner of finishes, found them to be reliable
and almost perfectly color fast. I did my own tests to make sure, and
the colors did great under a quality, properly applied finish.
That being said, when I dye a birch door, I don't seal it first. I
cut the dye by about 74% with anhydrous alcohol and spray it with my
HVLP with the 1mm aircap. I spray it as a mist, with a couple of
coats, depending on the amount of color I want. It looks powdery, and
you can't really tell what you have until you apply that first coat of
finish. Then it is magic.
This is not the way the dye is supposed to be used, nor do I know
anyone that does it this way. The dye literally sits on top of the
wood until the sealer is applied, so the color doesn't permeate the
wood. This makes the coloring very uniform as the color doesn't
actually soak into the wood making the dark spots.
I can spray color on a door, and be top coating in 30 minutes with
As far as living with your project, I think everyone has one or two of
those. It just happens, like a not so perfect cut on molding or a
shortcut that comes back to bite you at the end of the project.
I wouldn't worry about it too much. Chances are, you are your own
worst critic, and while they may stand out to you, others may not see
the flaws nearly as well as you do.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.