I use shellac when I need a gloss finish, it works best for me as it flows into the fretwork that I cut.

I have a new (to me) issue. I just finished a name plate for a friend of a friend, and when I applied the finial coats of rattle can shellac the finish pulled away from the sides, but not the top or bottom.

Any ideas what went wrong and how to prevent this in the future?

Arr, I had to use my phone to get a good zoomed picture of the issue:

Edited May 22May 22 by Wichman3

That last picture helped me understand what you were describing. Honestly I have no idea what caused that, but I think I would take a cloth soaked in DNA and try to rub the shellac back into that edge area. If it did the same thing on the back, you might try it there (just in case) to see if it works. Maybe someone else will have a better idea.

Shellac is supposed to be a good sealer and is often used to prevent such occurrences in other finishes. That is unusual and something I have never seen before,

Entire finishing schedule:

superglue as a light coating to stabilize stress fractured, brittle wood.

sanded the piece down to bare wood, superglue impregnated wood .

dipped in 50/50 diluted shellac, sanded with 200 grit.

I couldn't get the finish as smooth as I wanted so I bought a fresh can of spray shellac.

Several coats of spray shellac, the finish looked good with no pulling away from the edges. After allowing to dry in the sun for several hours I brought the piece into the house, finish still looked good.

Placed the piece above a furnace vent, several more hours until I turned up the furnace for the night. In the morning I could see the finish pulled away from the edges.

I have used the furnace technique many times in the past without any issues, the warm air fully cures the shellac to a very hard state. I have used a non-contact thermometer to check the temp of the finish, it gets to be about 92*, but no higher.

Put a sizing on it.

To make sizing...Mix up a 50/50 woodworkers glue and water. Mix well. Use a brush and apply to the edges. Let bone dry. Lightly sand with 220. Then silly shellac over it.

Do a sample first. When you're happy do the real thing.

It looks to me like he effectively sized it with superglue before he put the shellac on. It's puzzling that the shellac did that, it pretty much sticks to everything.

Edited May 22May 22 by Fred W. Hargis Jr

Shellac is famous for its "stick to almost anything" reputation, but it specifically struggles to adhere to contaminated, greasy, oily, or waxed surfaces.

Here is a breakdown of what shellac does not adhere well to:

• Contaminated Surfaces: It will not adhere to surfaces with silicone (furniture polish), oil, grease, or wax.

• Oily Exotic Woods: Shellac may not bond properly to very oily or resinous woods, such as teak.

• Non-Dewaxed Shellac: If you are trying to apply a topcoat, standard (waxed) shellac does not allow water-based finishes and some urethanes to adhere well to it.

• Uncured Finishes: It will not stick to oil-based products (like Boiled Linseed Oil) if they have not fully cured.

• Dirty/Unprepared Surfaces: It can fail to stick if applied over dirt, or if applied in extremely cold or humid environments.

• Thick Coats: Thick layers of shellac do not adhere well to the substrate or to each other; it should be applied in thin coats.

That's actually not been my experience. Except for dirt, uncured BLO, and natural shellac (not dewaxed) I've used it on all the contaminated surfaces mentioned just to overcome adhesion problem. As for the thick coats, I've never applied it that way, but shellac does melt into itself effectively making several coats just one.I have seen thick shellac, but that was well after it's shelf life was over. That melting process is also part of the problem with putting dewaxed on top of natural. The melting process can (and often does) bring the wax back into the new applied shellac, effectively making it waxy.

I just made a table to match another using the same stain. The first one has also been blonde shellacked. Much to my surprise I then realized the one I just made is slightly darker then the first one. So I'm thinking I could add another coat of the water based dye stain on the first one to match this newest one. The concern is that I would be adding the dye over top of the shellac. Would there be an issue doing this? Anyone have experience with this?

Edited May 23May 23 by MrRick

I have not. But since dyes penetrate the wood, and the shellac has sealed it my guess is it isn't going to do anything. Because dyes don't have a binder in them, it will won't stick to the shellac, just wipe off when putting something on top of it. .You could try using a stain as a glaze, but personally I've never much cared for doing that. But like i said, I'm just guessing.

Edited May 23May 23 by Fred W. Hargis Jr

Another thought. What you may need is called a toner. I'm hardly knowledgeable about using them, other than the theory. But I think it's normally a tinted rattle can lacquer that you spray lightly over the surface attempting to get the wood tone to what you want. It's probably a tricky process, but @kmealy does a fair amount of this, he may have some suggestions (and corrections to what I typed above). I suspect picking the right shade of toner is just as important as applying it correctly.

Just tried warm water only and a sponge. Counted my strokes on all faces of each piece so lightening the dye by removal would be as close as possible.

Worked very well.

I mix my shellac so not versed on spray can. One possible is that the CA interfered with adhesion. I have seen something like this when edges are sharp but cannot give a solution or cure. As to curing shellac I think you are going to extremes. If shellac is fresh it will cure to a hard finish inn15 minutes or less. This also depends on how heavy the application is .

@MrRick I have applied alcohol based stain over shellac . BUT the stain must be sprayed and the hard coat also sprayed. It is verrry easy to mess up the finish doing this. I do not use oil stain so not sure how that would do.

@Gerald I never use oil based stain. Only water based as well.

sorry to get in late to this, I've been out of town for events for the last 9 days.

I am not sure what happened as I don't use a lot of aerosol can shellac. When I refinish, I use a sprayer in light coats, when needed, as an initial coat. This serves well to isolate silicone oil (e.g., Pledge) contamination. Is there a chance that you stopped spraying before starting or ending the pass?

Aerosol toners I've used extensively in touch up & repair work. They are lacquer with an added color (dye or pigment) They are applied in light coats to adjust/restore color. If put on too thick, they run. And you have to be careful as they go from "almost there" to "too much color" very quickly. Experience helps.