Problem using shellac

[Dick Holt]

I am building a chimney cupboard out of pine for my daughter. I wanted to finish the raised panels before I glued up the doors. I applied two coats of Charles Neil blotch control as per the directions. I them dyed the panels using Transtint (medium brown) dye mixed in water. Once dry, I applied a 2 lb. cut of amber dewaxed shellac with a natural bristle brush. While brushing, I noticed the brush was pushing some of the color from the dye around. I wiped off a section of the shellac with a rag and sure enough, the color of dye was much lighter. The panels had a chance to dry after I applied the dye, one panel overnight, the other for several days. What am I doing wrong?

Dick

[Sam Stephens]

drying wasn't the problem. transtint dye is both water and alcohol soluble. usually folks will carefully spray shellac for this type of application. I think transfast dyes are water soluble but not alcohol soluble and would be a better combo. at this point, you could add transtint dye to your shellac as a toner to try and even out color discrepancies, but not sure how easy a fix this is to do w/a brush or pad. alternative would be to sand back and start over w/ either a gel stain or transfast dye and then shellac.

[Patrick McCarthy]

Others here are much more knowledgeable than me, but I had a similar situation with glazing. I am thinking the solvent in the shellac is "hot" enough to dissolve the transtint. With the shellac I think you might want to use the varnish brushing technique: brush only one direction and not go back over it, ie lay it on, don't brush it "into" the wood. . . at east not on the first coat.

As I said, others here know a lot more than me, so take it with a grain or thee of salt. Good luck, Patrick

[glenn bradley]

Sam's got it. Transtint is made to use with water or alcohol as the vehicle; your results are what I would expect. One solution is to seal the dye prior to the next product's application. Spraying dewaxed shellac is most common because it sticks to almost everything and almost everything sticks to it without causing finishing issues. If you don't have a spray rig (I got rid of mine as I used to so little) you can pick up a Preval kit for about $5. I hit Zinsser's Seal Coat 1:1 with denatured alcohol and spray it with the Preval to seal between coats in such situations.

[Mike Henderson]

Yeah, you really need to spray and not brush.

Mike

[Kent A Bathurst]

I had the same problem with Transtint. There is much, much less "lift" of the dye by using the Transfast powder. Waterborne. I let it sit overnight, and then apply shellac - couple thin coats of 3/4# - 1#, using a padding cloth.

Both products are, AFAIK, soluble in either water or alcohol.

MIke is correct that the spray finesses the issue entirely [Zinsser aerosol is dewaxed 1#, IIRC]. But - I've never had a problem once I switched to the Transfast.

[Kent A Bathurst]

With the shellac I think you might want to use the varnish brushing technique: brush only one direction and not go back over it......

Absolutely correct. Never go back over shellac. Put down thin coats, and any imperfections will be handled with subsequent coats.

And remember - the best shellac finish is the one with the minimum possible film thickness.

[Prashun Patel]

Dick-

Transtint is indeed alcohol soluble.

What is your final topcoat? If it is oil-based, there's no reason to use a barrier coat of shellac; you can go straight to the topcoat.

Can you post pix of how your piece looks now? Depending on how far gone you are, your easiest solution may be to use a dna-soaked rag to blend out the shellac and dye now.

Do you have the ability to spray?



What is your final topcoat?

[Dick Holt]

Thanks for all your answers guys. I have never used alcohol with dye and I had forgetten that it is also a solvent for Transtint. I guess from now on I will swith to Transfast dye. I used the amber shellac for two reasons. The cupboard is made out of knotty pine (plywood and solid) and I wasn't sure if I needed to seal the knots. The other reason is that my daughter liked the color combination of the medium brown dye with amber shellac. The final finish will be a wipe-on varnish (type to be determined). If the final finish is to be varnish, is it even necessary to seal the knots with shellac? Prashun, I would post a picture if I knew how. I don't have a clue where to even start. Unfortunately, I am not very computer savy. Thanks again for all your replies. I now know what my options are. I just have to decide which way to go.

Dick

[Dick Holt]

Glen, I bought a Preval kit recently, but haven't used it yet. I actually considered using it to spray the shellac. The directions did not mention using shellac at all. Have you used it to spray shellac? If so, did you get good results.

Dick

[Kent A Bathurst]

Dick -

using alcohol as the carrier can make it difficult to avoid lap marks when not spraying......the alcohol flashes off fast, and the dye is set, before you can complete the job. Just be sure to try it out before you commit on the finished piece.

On the shellac - that are definitely combinations where you don't need the shellac as an interim step. On the other hand, I am not aware of any instance where the shellac is a bad thing. I just do it all the time, as a matter of habit - plus, I don't have to sweat the details of "when" and "when not". Always have some in a mason jar, takes almost no time to put it down, so I just do it routinely.

[Scott Holmes]

Dick,

Poly is going to give you fits, trying to put it over shellac that still has the wax! Zinzzer Amber is NOT dewaxed. Better solution would be a non-poly varnish.

[Kent A Bathurst]

Dick,

Poly is going to give you fits, trying to put it over shellac that still has the wax! Zinzzer Amber is NOT dewaxed. Better solution would be a non-poly varnish.

I see an omission in my previous post. I only use dewaxed shellac.

[Dick Holt]

I did use dewaxed shellac. Thanks for the heads up though.

Dick