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After stripping the varnish from my ziricote a 4th time (long story... will post in my build later) i give up and am going to slop a sealer coat of Shellac on the sides. (Back hardened fine) ... hoping that that will seal in whatever oils are preventing the sides from drying.

The question:

Is canned shellac fine for a sealer or do i need to go out and get the flakes and brew my own? Seems i see a few posts about how shellac is only good for a few months to a year once mixed. Old luthiers' tale??

Does the canned stuff have all sorts of stabilizers and stuff that will defeat my purpose? I don't know if the canned stuff is dewaxed, but i am assuming i will need dewaxed for the sealer coat. I don't want anything in there that is going to force me to do this a 5th time. I am getting close to my tolerance....

Home depot is pretty close to woodcraft, so i will probably get both and check this forum before i start.

I don't know if everclear is available here or not - never drink the stuff so i'll find out shortly. If that's not available what else can be used? I have some 50 year old scotch on the shelf that i might be conviced to try... (one for me.... one for the finish... two for me, one for the finish).

What a dang hobby!

I used to mix my own shellac for seal coats but switched to the Zinser seal coat product and have never had a problem using it over several types of epoxy before spraying Nitro lacquer for finish coats.

Fred

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I get my flakes from shellac shack, blonde dewaxed , dewaxed orange , and garnet w/wax shellac as I can control the mixture, For FP and a wide variety of tasks.If I bought from HD I would want to know the date it was manufactured

You are creating your own problems by not testing first. It's pretty easy to test a finish on a very small piece of an off cut, assuming you have kept some of the Ziricote.
Just think how much time that would have saved. . .
Pre mixed Shellac does have a shelf life(not sure about the Zinser). Some much longer than others. Poor drying/remaing soft is a tell tale sign. Waxy button lac seems to have a much longer shelf life than the more refined types. Dry waxy shellac (ssedlac and button) I've had for near two decades and it still dissolves and works to this day. Mixing your own from dry ingredients at least tells you WHEN it was mixed. It's one less factor to be concerned over. The refined types (dry flakes) have a shorter shelf life but even that should last several years at the very least. Of course one can never tell how long the stuff has sat with the importer/retailer. As such it's probably best to buy from places that you think have a healthey turnover.
You certainly can use waxy Shellac as a seal coat but that might depend on what is going on top. Shellac on shellac is fine.

Thanks... I saw the zinger products on the website. I'll chat whit the folk at woodcraft when I get there.

Micheal... I hear what you are saying, and it's appreciated but I don't know how accurate that is. The back is the same wood and has dried fine with no finish issues except that the first coat a bit longer. The sides have been a pain. I suppose the sides can be from a different tree with different amounts of oils, but no I do not have leftovers from those.

Also... I am using murdochs uralkyd 500 floor varnish over the shellac. The finish pros there said it will work fine over shellac, though they were surprised I am having issues.

Thanks for the replies!

Shellac usually dries fine on top of oily woods. At least I've never come across a piece of wood that seriously retarded the drying of Shellac.
Putting an Oil varnish directly on top of oily wood is another matter. You really have to seriously blast it with UV to get it to dry. I've yet to find an Oil varnish that won't dry but I haven't tried all types of wood. Perhaps that is why you are having problems: Oil varnish direct on wood/not enough UV to dry it.

Isopropyl alcohol works with Shellac but you need the strong stuff. Over here it's given as being 99% pure, presumably ABV.

Thanks Michael.... I actually tried a couple of UV bulbs but i am sure they are not powerful enough. I had them on for 4 days but to no effect. Not seriously, but i wondered if it would have been better to put a dry cleaning bag over the thing and rent an O2 bottle fron a hospital supply... my understanding is that the UV generates Ozone breaking down to O2 which the varnish uses to cure. Overkill for sure, but it beat taking the thing to a tanning bed....

I eneded up getting the Zinser Per Fred's suggestion and will see if that solves my problem.

While the canned stuff will probably work, there is always a risk buying shellac off the shelf. If you have access to Woodcraft and home Depot, then you have access to denatured alcohol and shellac flakes. Everclear smells better than hardware store denatured alcohol, but hardware store grade will dissolve shellac flakes just fine. I would mix my own, particularly if I had already experienced setbacks.

No risk with Zinser it lasts several years after opening and from Woodcraft it is now on hand great lengths of time. I have a can that is 3 years open that I use for non finish things and it still dries like when new. Mixing is a pain in the butt as I always mixed fresh batches for each use so you need to be aware of the need. I have done 25 guitars with Zinser between epoxy and lacquer with never any issues. Heed the advice on testing finish products before trying a new one.

Fred

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I had similar problems with the Murdock's varnish not drying on the edges of the fingerboard of my harp guitar. I tried everything I could think of, including UV. At one point I scraped off the soft finish, wiped the Macassar ebony down with acetone until the rag came away clean, and sealed it with two coats of fresh shellac padded on. Still no joy. The shellac hardened fine, but the varnish over it didn't. In the end, I just removed the soft varnish and padded shellac on. I never saw the beat of it....

Ugh.... not feeling warm and fuzzy now...

Al, I did the same with a freash can of Murdochs'... Wiped the sides down with acetone. They never really came clean as there was so much oil in in them but it went from black to light brown, that was about 3 sessions of wiping. AFter that, the first two ultra thin coats of murdochs seemed to dry nicely but then the next layer took a couple of days and the 4th never dried. The guy at woodcraft thought that by wiping with acetone it dried the wood but then it acted as a wick for oils deeper in the wood. I dunno. it's one theory i guess...

Well, We'll see whether the Zinser works on this....

excellent tutorial here by Michael Dale Payne which I followed, having a background in chemistry (not necessary) never having done it before with a successful outcome.
Tanks Michael.

viewtopic.php?f=10117&t=25507

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I like to mix my own. But just because I like home brew. Even the alcohol is home brew....benefits of living in the hills of TN if ya know what I mean.


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I mix from the flake, small batches. I buy from, and endorse the advice from the folks at - shellac.net

The first attempt was a failure. I wiped on 3 coats of the zinser shellac sealer (allowing each to dry) and then wiped on a coat of varnish. Two days later the varnish was still waxy. Sooo... for the 5th time it was stripped back to the wood. I am actually getting pretty fast at that so it wasn't as painful this time. *sigh*

This time I brushed-on 5 coats of shellac sealer. It was to the point where i was wondering if it wouldn't be better to strip the back too and just finish it all in shellac only... it was so easy and didn't look bad (move to towards the liiiiiight!...) but i decided for one more try and went with the varnish. It seems to have worked. The varnish is hard and dry just a measly 24 hours after putting it on. it's only been a month and a half....

My next guitar will be french polished using only a rock whist blindfolded... should be quicker.

No doubt about it, finishing sucks.

Only if you pore fill and go for the super gloss. Sand to a high grit, forget pore filling and wipe a dozen or so very quick 'coats' of Shellac and it's a breeze. Looks pretty good too. Finished in one hours work.

If I ever do another ziricote I'd probably go that route. The only reason I ddin't this time was I was worried about the durability of shellac.

A couple of thing I learned doing this...

Varnish seems to darken the wood a bit more than shellac. On the ziricote, the difference in colors Light browns vs. Black became less differentiated whereas with the shellac I think the brightness of the wood was preserved a bit better.

Watch the humidity!! Raising the temp to try to dry the varnish will cause the humidity to plummet. I'm not a fine woodworker so the amount of difference it made was amazing to me and unfortunate to the tune of 3 cracks in the back. Stoopid wood.

FWIW dealing with shellac flakes is not much of a problem especially if you grind it fine with a coffee grinder. Let it sit over night and it's ready to go. I keep mine in a glass Ball canning jar. IT seems to thicken up over time but adding a bit of alcohol seems to revive it.

Most varnishes have an index of refraction that's closer to that of wood than the IR of shellac or nitro. You get more 'light' with a varnish finish: the wood reflects more, and the color saturation is higher. By comparison shellac or nitro can look 'veiled'. That's why you either have to have a good undercoat of shellac, with no sand-throughs, or else sand all the way back to wood if you use shellac sealer under a fill coat. Nothing looks worse than a spotty undercoat with a different IR than the finish.

You can add cocobolo and pao ferro (aka morado, bolivian rosewood) to the list that's problematic for oil varnish.

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Well... perhaps i spoke too soon. The back, which i thought was fine with the pure varnish, i noticed today has some tiny bubbles along the grain lines in and around the sapwood... i'll try to post some pix later as i decide whether i am going to scrape down the whole back and seal with varnish. It has worked nicely for the sides.

Now, where did I put my sanding hammer???

Bummer dues, lots of grief.

You might want to think of trying home brew dewaxed shellac. I use my hide glue pot to heat up the alcohol, and have a batch completely ready in about 40 minutes, using 99% isopropyl alcohol (no everclear in Canada).

I wonder if vinyl sealer would be appropriate?

The best way to mix shellac is the 'teabag method'. Tie the flakes up in a fine cloth bag: T-shirt material works well. Suspend it near the top of a jar with a wire, and put in enough alcohol to reach the bottom of the bag. The shellac will dissolve, and settle to the bottom, pushing the alcohol up to the top. The resulting circulation does a great job of mixing the stuff all by itself, and you don't have to heat it. An added bonus is that the wax particles in seedlac are too big to go through the cloth easily, and the wax, along with the bark, dirt, and bug parts, stays in the bag so long as you don't squeeze it. Dissolved and filtered in one go, with no work. I've had a solution that would work for FP in an hour or less this way, by using extra shellac, although it takes longer for all the shellac to dissolve.

Interesting...