Question: WTF and dyes....

[David DeCristoforo]

One thing I like about finishing with lacquer is that alcohol based dyes can be "burned in" to the dried lacquer. This is done with a "rubber" in a manner similar to French polishing and allows a great deal of control over the color, especially when fading one color into another. JK has discussed the ability to tint WTF with alcohol based dyes so we know this can be done. Does anyone know if it is possible to "burn in" color after the finish is dry?

[Rick Markham]

Interesting David, In my extensive finishing schenanigans I did tint the WTF, and it works well like that. I haven't tried burnishing the dye into a dried coat. Explain the process to me, I've gotten some small straight grained cherry for coloring experiments, and will be coloring a piece in the next day or two, I will gladly try it and see... Lord knows if it doesn't work, I am no stranger to starting over again and again and again :D "I ain't skeered"

[Bill Hensley]

Sorry, I know nothing about this technique but I am interested to hear more about it.

My question is when would this technique be ideal vs doing the dye treatment prior to applying the finish top coat?

[Prashun Patel]

This is just speculation: WTF is a varnish. As such, the resin should irreversibly cure, meaning you build layers. Lacquer and shellac don't cure. Subsequent layers burn into the existing layer, creating a single layer. As long as the dye uses a compatible solvent, it too will burn in.

With any type of varnish, the first few layers may be thin enough and uncured enough that you get some amount of lifting and redisolving. However, this is far different from burning in, which allows you the kind of control yr looking for. In fact, I bet the opposite happens; your results will be highly UNcontrollable, likely resulting in unevenness and streaking.

Correct me if I'm wrong, JK.

[David DeCristoforo]

"...the resin should irreversibly cure, meaning you build layers. Lacquer and shellac don't cure..."

That's not exactly correct. Lacquer does cure. But, since lacquer is essentially it's own solvent, additional coats will "burn in" to the previous ones, even after several years.

"Explain the process to me..."

Simply stated, take a rag (tee shirt material works great) and dampen it with DNA. Apply a drop or two of alcohol based dye. Then rub it into the lacquer with a circular motion. (Anyone who was ever in the military and had to "spit shine" shoes will know this process well.) The amount of alcohol and dye will vary as will the pressure needed to burn it in but this will become very clear when you try it.

[John Keeton]

I haven't tried it, but for the reasons stated by Prashun, I doubt it would work. Once cured, which begins to happen pretty rapidly with WTF, it will not dissolve in a solvent - even itself. One would have to use a chemical stripper of some sort and that would make for a HUGE MESS!

Rick has airbrushed WTF, as have others, and I suspect one may be able to get a fade by doing that atop a previous coat. Just not sure of the effect. Might be interesting to try, though!

The fades that I have done were with the dye and/or acrylic paint and/or tinted shellac PRIOR to the application of the WTF.

[Prashun Patel]

I am a little out of my league, but I thought 'curing' is different from 'drying' in that drying just means the solvent evaporates; curing means a chemical reaction takes place that is irreversible. I thought there are different types of lacquers, some that are strictly evaporative, and some that actually cure. I thought burning in is only possible on drying type finishes - at least reliably.

What type of lacquer do you use David?

I defer to yr experience, but I didn't think that lacquer is its own solvent. I thought every finish consists of a solvent, and a 'resin'; I thought the solvent in lacquer is a blend of solvents known generically as lacquer thinner...?

[David DeCristoforo]

Oh crap... terminology....

OK. Let's see if we can clarify. Lacquer "dries" by the evaproation of the volatile solvents. This will occur rather quickly varying on the conditions, temperature, humidity, etc. But there are still solvents remaining in the material and these will not dissipate for several days to several weeks during which time, the finish is considered to be "green" (still somewhat soft). This process is called "curing". Many of the newer finishes neither "dry" nor "cure" in the "traditional" sense of the words. Rather they "set" via a chemical reaction. Or if they are catalyzed finishes, they "catalyze" in much the same manner as epoxy. Once this reaction has occurred, it is, as you have stated" permanent and irreversible.

When we say that lacquer is it's own solvent, what we are saying is that "raw" lacquer contains solvents that, if applied to fully cured lacquer, will desolve or soften it, allowing a fresh coat of material to bond with (or "burn in to") the existing coating.

My question about how alcohol based dyes will (or will not) react with WTF that has set (or dried or cured or whatever you wish to call it) is based upon my total ignorance of this material and how it handles. But if it becomes "impenetrable" and resistant to any other materials being laid down on top of it, my beloved process of "burning in" color after applying several coats of finish would not be possible. I plan to try this finish soon and will be able to make my own determination. But my enthusiasm will be seriously diminished if this technique is precluded. Of course, it might be possible to substitute shellac for the first few coats and burn the dyes into that. Apparently WTF is perfectly happy to lay down over shellac.

[Prashun Patel]

I read an articly by Jeff Jewitt that said that many waterbased finishes are strictly drying-type finishes, which might mean that they can be redissolved... I'm curious to hear yr findings too.

[John Keeton]

David, here is another term for your consideration - polymerization. Don't know much about it, but apparently most varnish resin finishes/oil finishes rely on this chemical change and it is not easily "undone".

As to burning in dye with the shellac, that would no doubt work so long as it is dewaxed shellac. WTF is very much compatible with the shellac base.

[David DeCristoforo]

"...here is another term for your consideration - polymerization..."

Oh there's lots more... dryerization, setupification, curify just to name a few...

[Rick Markham]

Ok, in my extensive botching of this current piece, I will relay some observations I have made with WTF. First it does dry quick, but it doesn't "cure" quick. When heavy layers are applied, especially rapidly, there is a point in which the lower layers are softened by the current layer. I have my suspicions that using the French polishing/boot polishing method of burning in a color will work, but only if you do it within a several hour period of the previous coat. I "think" it might work in all honesty. Maybe it's the bottom half of my can that has lost some of it's volatile solvents that I see this occuring hard to say at this point. I'm willing to give it the old "college try" and see if I can get it to work. I've got some new cans of this stuff so maybe an old can vs. new can test is in order. This stuff really doesn't "cure" right away, which explains the observations of many of us that the finish improves over the next day or two. Honestly, from my experience so far, this stuff is really in a league of it's own, and doesn't compare very well with how other types of finishes behave. Yes it dries exceptionally rapidly allowing quick coats, but the finish continues to shrink as it cures, and this takes a day or two to complete (depending on how thick you've built the layers up)

I will turn a piece this evening, or tomorrow, and get started on trying this for you David, I'm interested to see what happens. JK's point is excellent too, if it doesn't work, some experimentation with shooting tinted WTF in a fade pattern, might just be the ticket!