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Interesting results from a study on various Shellacs:

http://www.aiccm.org.au/docs/Bulletin19 ... o1and2.PDF

Which seems to suggest that;
Aging (at least artificial) increases the solubility of the film in various solvents.
Non heated Button (shellac) was of moderate hardness.
The hardest film was of Bleached Shellac, followed by flake Shellac.

That seems to contradict the thought that Button Shellac is harder than the processed types, although hardness is far from the only aspect of a Guitar finish that we should be concerned with. Unfortunately the test is not concerned with Human sweat and other real life Guitar playing wear.
I have heard it said from a few Violin restorers that certain Shellacs,over a long period of time, become insoluble in alcohol . Not what the test found but perhaps this insolubility occurs over a much longer aging process.
For our purposes we can ignore the heated samples. Other than the 1704 recipe I don't know of many makers who heat the Shellac/Ethanol solution.

Thanks for posting this. Interesting reading.

Interesting, thanks! Atm there is no turning back for me from buttonlac. I am sure it resists sweat better than the bleached and dewaxed stuff I used before. Sessions dry very fast consistently while some processed batches I had were dissolving slowly and drying even more slowly, I guess they were too old.
I didn't notice a softer film with button compared to processed , in practical terms.
I am dewaxing buttonlac with a coffee paper filter, there is a huge huge amount of wax in it. I might have missed this, but it doesn't seem to say they dewaxed their button. If they left the wax in that might explain the softness. It really has a lot.

Seedlac: this one has much much less wax than button, which is intriguing. I've used it less than button (because of the difficult color) and I won't comment on its properties during use but I appreciate that it dissolves and filters much faster than anything else.

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Unfortunately I've lost the link but I found another Shellac dedicated site which stated that Bleached Shellac finishes harder than any other. It also stated that it doesn't age quite as well as the others.
Good point on the wax content. It must be said that whenever I've tried to scratch one of the Buttons it seems very hard. It's not easy to get it to scratch with a fingernail and that's with the full wax content.
I use the Platina when I want little colour - mainly for sealing, the Blonde and Bysakhi when I wish to obtain Yellow/Brown. I also have some Kusmi #1 which I'm using at the moment. It's relatively light in colour for a button shellac.

My buttons are stamped "kusumi" which is probably an alternate spelling. The color is sort of caramel. After dissolving the solution looks like milk, while the dark seedlac is reasonably clear without filtering. Look at the amount of gunk left from less than 1 oz of button, that pool is almost 2" wide. Second picture is filtered. I like it that it is dark enough to give a warm color to spruce but with no risk of blotches.

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That looks a lighter (colour) grade of Button. Similar to the Kusmi#1 below. The buttons and the waxy stuff in the jar. Seedlac next to it for comparison:

Yes those are the same colors.

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As a note, hardness does not equal durability. The term hardness gets used to describe the durability of a coating because it is a term most will grip and understand. There are many factors that make a coating durable, actual film hardness is one. Flexibility is another. Flexibility is very important when finishing wood because wood moves. That is why lacquer tends to craze and check when the film builds get too high, it becomes less flexible and the film can't keep pace with the movement of the wood. Generally the harder he coating the thinner the finish film must be. For example, modern conversion varnishes have a max film build of about 5 mils. Applied at 3-4 mils they are some of the toughest, most durable coatings ever applied to wood, apply one at 6-7 mils and see how quick it comes undone. Many people also make the mistake of thinking an exterior finish such as spar-varnish is harder or tougher than an interior one when actually they are softer so they can deal with the increased expansion and contraction of the wood in an outdoor environment. As with everything else there is always a trade off.

I use only button-lac for my FP. It was used almost exclusively on all gym and ballroom floors prior to the invention of modern polyurethanes like gymseal and as such has a proven record as a highly durable wood finish. After all I don't dance on my guitar top. I also do not de-wax my shellac. The wax has a lot of benefit, it helps the coating stay flexible and actually helps prevent scratching and being worn away by making the coating a little softer. Most high quality paste furniture wax has a high percentage of wax that was actually removed from shellac in it because it is so good at absorbing abrasion and protecting the finish. The practice of de-waxing is a relatively modern one, began nearly as I can tell in the Victorian era. It was begun in response to one thing, the rise in popularity of iced cold drinks. Iced drinks sweat and as you may well know will leave a white ring on a shellaced table top, it was found that removing the wax lessened this tendency. I also do not place cold beverages on my guitar top. From what I have seen on antique furniture over the years, it also lessened the durability. I also believe that the wax adds to the sonic clarity of the finish, but of course that is an opinion and much as the debate over HHG can never be proven.

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Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

I don't see any flexibility issues with dewaxed buttonlac. I did have checking over purflings and rosette when adding sandarac and using walnut oil. Currently I am back to straight shellac and very very little olive oil, max 1 drop per session even 2 sessions, no checking.

I wonder if wax helps against sweat. I doubt it helps against heat. To me the only problem of shellac is not hardness (not my problem if the user bangs the guitar) but sweat and heat is not something that can be prevented. I'm going to finish one in dewaxed at some point....

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The wax content of Shellac has a reputation of less resistance to water. . . . . which isn't quite the same as sweat though. I guess it depends on it's resistance to something slightly acidic, as in sweat.
Somewhere I have one of my very early Guitar attempts that I distinctly remember finishing with the dark button lac. It must be near 30 years ago. It's had virtually no playing time. I'll see if I can dig it out and do a few tests on it. The only problem is that I don't have the type of sweat that strips Shellac off Guitars.
IIRC it does give a slightly softer sheen, as you would expect with a high wax content. Personally I don't find that a bad thing. I'm just not a fan of that glass like glare.

Sorry I'm late to this discussion but it is a good one, and shellac discussions are so few & far between.
Brian, do you not remove any of the wax from your buttonlac? How does the included wax affect the application?

I use Kusmi seedlac mainly (thus far) and I simply decant from bottle to bottle until the shellac is mostly clear of visible clouding.
To make a good waxy trial batch, should I only remove the bugs & wood particles, usually the first decant or filtering, and use the remainder?

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Anybody spraying, or all you all FP?

I use shellac only as an undercoat to other finishes, all WB acrylic lacquers to this point and I've often wondered if wax-in shellac would cause adhesion problems. Any experience with that?

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Last couple I sprayed.
Quite pleased!

David,

How long does it take for you to decant? I noticed it takes at least 2-3 days to get a clear half inch out 2-3 inches of bottle, seems awful slow when I can do it in 1h with a filter. Other than this, I never found any wood, dirt or bug in my button, it is quite clean. When they make buttons, they melt seedlac and force it through a cloth or something, that filters the debris.
I did some application tests with waxy, works ok and much of the wax seems to get caught in the cloth, as a result it seems to ask for changing more often. If I read it well, when dissolved in alcohol only the resin is in solution while the wax is just floating around like a debris. Perhaps not much of it is left in the film.

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I think he's referring to Seedlac rather than buttons. Try filtering but using a bigger mesh filter, one that allows the wax through but not the debris. I think the debris usually settle long before the wax, so you might be able to decant after a day or so - hopefully ending up with a waxy Seedlac.

Another benefit of using waxed shellac is that I do not need to add any lubricant such as olive oil. The wax provides enough lube to keep the pad from sticking, although it does not slip and glide as with oil so it also makes you press a little harder which packs the shellac tighter. Also there is nothing but shellac involved, no oil to remove between sessions and no oil trapped in the film. Personally I do not believe you ever get all the oil back out and I think that oil trapped in the film is a cause of poor durability in some finishes.



Yes, I simply strain mine through a disposable paint strainer and keep it well mixed while working with it.

A few other points, If I am using shellac as a sealer or bond coat I only use de-waxed. The wax can cause adhesion problems with other coatings, especially water based. If I spray shellac it is only as a seal or bond coat under a hand applied finish such as a natural varnish, not as a complete finish. I find shellac has lousy flow characteristics when sprayed and requires too much work to level sand and buff and I do not believe the coating is as dense when sprayed as compared to FP.

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Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

When I make up a new batch of seedlac, I set the bottle outside in the sun to heat up the contents, it quickly dissolves & I pour off the "more clear" shellac and leave the trash behind. Then I leave the decanted shellac in the sun a while longer and the wax settles to the bottom, and I decant that.
Pretty much ready in an hour on a warm day, though I may forget it for a few hours.
I use bottles that are shaped like flasks, with a shoulder & neck, to make decanting much easier.

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Alan,
Are you using it as a topcoat or as a sealer?
Using waxed shellac under waterborne is asking for trouble. I used yellow lid rattle can Zinsser and when I was removing finish for the bridge, the whole section just peeled off like a static cling sticker. Not so with dewaxed from flake made fresh...

Here's a very quick, rough and ready test with the full wax button shellac. 6 brushed on coats done yesterday, all rubbed down and buffed today (I said it was quick).
Perhaps a little more glossy than the photo suggests. Looks a touch softer looking than a dewaxed finish but I don't think there is a huge amount in it. Viewing angle changes things a lot.

Meddling,
I used a 1 lb. cut,
f.p. on the first 4 coats,
then sprayed the last however many I put on,
and 320 grit when necessary.
I didn't go crazy with the polishing.

Thanks Alan,

Michael, that looks fantastic! When you say buffed, are you buffing by hand or using a powered buffer?

I think I went 800G, 1200G & 1500G, wet. Then hand buffed using burnishing cream. Never used a power buffer but then again I'm not concerned with obtaining a super, super gloss finish. If I was I would probably switch to one.
Over time that finish will sink back and look a lot less flat. It will sort of take on some texture of the wood. That's the problem (perhaps not) of cutting back so soon after applying the finish.

Ime with using rottenstone to buff, it works better if you wait 1 week and very well after 2-3 weeks. But that sinking occurs more slowly, 2-3 months maybe. I really love the look on the soundboard revealing the spruce texture.

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