stop the bleeding

[Dave Fritz]

I'm dying the front of a pendant but want the back to remain undyed. I've sprayed several coats of shellac yet the dye will bleed around the back of the piece. Does anyone else have a solution? I'm almost resigned to leaving the wood bare and sand the back to get a nice crisp transition from dyed surface to natural.

 

[hockenbery]

With thin pieces dye Will penetrate and show through the back side.
it will vary with the density of the wood.
I have finished the outside of hollowforms with several coats of Waterlox Then dyed the inside Black.
the outside darkened

you can get close to the same effect using transparent airbrush paint.
the paint stays on the surface.

 

[Richard Coers]

If you are using an alcohol based dye, it will penetrate shellac. The solvent for shellac is alcohol. I wouldn't be a fan of shellac finish on human skin either. Shellac can have pretty low moisture resistance.

 

[Dave Fritz]

I'm using dye to be able to sand back black and cover with another color. These are covers for recyled Oui containers (thank you Sally Ault). I suppose lacquer would be a better option rather than shelac. I would think glu boost would also work? John Lucas mentioned somewhere about useing clear gesso also. Anyone think these might be better?

 

[Brian Gustin]

I wouldn't be a fan of shellac finish on human skin either.

Why not? shellac is also the coating on many over the counter pills/medicines...

 

[Clifton C]

Because...

Shellac can have pretty low moisture resistance.

As Paul Harvey said... "And now you know...the rest of the story."

 

[Clifton C]

Dave, re reading your post, are you saying the dye is bleeding thru to the back, or migrating around the sides to the back?

the dye will bleed around the back

If it's migrating around the sides to the back, I have heard (as in, I haven't tried this) that a burned line will stop dye migration. Something like a wire, or piece of formica to burn a fine line around the edge. Formica can be sanded to a knife edge for super fine lines.
If I'm out in left field... Disregard...

 

[Dave Fritz]

Clifton, you're right on the mark. It's migrating around the sides to the back.

 

[Clifton C]

Well, I had my burner out so... Burning a line seems to help somewhat sometimes... so a little more experimenting maybe. I put a drip (eye dropper) next to the line, maybe too much, but you can see the results. The two lines on the left were a little hotter and a little deeper. The lines with the grain surprised me, I would have thought just the opposite of what 's shown. Burning a line around the circumference of your tops with a wire might help, but would also change the design.

Ps. Chroma Craft dye, not sure it matters, just what I had...

 

[Dave Fritz]

Thanks for that Clifton. I suspect the best solution will be return the piece and recut the bottom edge. I have a small vacuum chuck I got from Rubber Chucky. I'll try that.