Acoustic Guitar Construction in the small shop -- Kenneth Michael Guitars LLC

Information, ideas and help for those constructing scratch built acoustic guitars or acoustic guitar kits - © 2017
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 Post subject: Formby's Refinisher
PostPosted: Fri Nov 03, 2017 8:41 pm 
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Posts: 756
Location: Kalamazoo, MI
I acquired a 1920s Oscar Schmidt a few years ago. It had been "over sprayed" with a heavy coat or two of some sort of varnish, using a brush, complete with sags and runs. For that reason I paid pennies on the dollar, compared to what one with an intact original finish in just about any condition would cost.

That said, it was playable - 0.120" gap between the 12th fret and low E string and the saddle had been moved back to correct the intonation. And it featured the honky, growling bass that I expected from an old solid birch ladder braced guitar. And, of course, no buzzing, no matter how hard it was played.

But the finish was repulsive. Heavy, gooky, so soft it had an imprint from laying on a carpet too long at some time in its past. Stripping and hitting it with nitro did not seem like a good idea because I did that once on another 100 year old guitar that had been brushed, creating a sagged, and dripped "sunburst", no less, with matching sags and runs on the sides and back. This poor beast was "better" refinished as if new wood, but then what would not have been? So the Oscar Schmidt sat most of the time, just taken out on occasion to experience its great ladder braced sound, mellowed by a 100 years of whatever happens to a git in 100 years.

Eventually I began to contemplate the old Formby infomercials where he rubs his stuff in, using the old circular motion of course, then lays it off with a lighter circular touch. From the look on his rags it was clear some, if not quite a bit, of the finish came off. Yet some remained. While I would never apply Formby's to an old instrument with an intact original finish, doing it to the Oscar Schmidt seemed like a no-brainer. It could not look worse, and thinning out the heavy coat should not hurt the sound any and perhaps improve it.

Today I did the deed on just the top. I opted to remove most of the finish and would never coat what is left with any of Formby's finishing products. The wood emerged clearly sealed and finished, but with way less top coat than it had before. I could not be more pleased. It looks great. The original semi-sunburst, most likely hand applied to the bare wood, is now visible, no longer partially hidden by the dark-and-getting-darker varnish layers. The Formby's did not attack the basic staining, which is quite dark itself, even though applied to birch. Nor did it attack the plastic binding.

After it dried I sanded with 400, then 600 grit paper, wiped it clean with naphtha, then finished sanding with a 1500 grit micro mesh cushioned pad. It is evenly dull and consistent with a 100 year old instrument that was not glossy in the first place, but was not abused.

I am debating whether to apply shellac. As it is now, old faithful Dunlop 65 polish will remove "something" because the rag comes up red after applying it. If letting it all set for a few days does not resolve this nasty surprise, I probably will add a layer or two of cross linking shellac, such as Royal-Lac, then sand to a dull finish again.

I know trying out this process on a good sounding guitar might not suit the protocol of everyone, but happily enough, it seems to be working. And I also know, for some lovers of very old guitars and funky sounds, the uglier the instrument the better. However, when it gets as bad as it did for this one, apparently there are not enough such players to keep the price up.

Given the result, I will probably invest in some new tuners and fix the other problems that make it less playable, like do a slip-n-slide back adjustment to reset the neck angle. The back should come off anyway to fix the gaping crack that goes all the way from top to bottom. Of course, for the uglier-the-better crowd, I should probably enlarge the crack.

I'll post a pix later.

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 Post subject: Re: Formby's Refinisher
PostPosted: Sat Nov 04, 2017 1:15 am 
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Interesting approach, well-told. Thanks John look forward to pix.

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 Post subject: Re: Formby's Refinisher
PostPosted: Sat Nov 04, 2017 10:43 am 
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Joined: Fri Dec 23, 2011 8:33 pm
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Location: Seattle
I have seen the product but never looked into it. Is it a combo of a stripper of some sort combined with finishing oils. I will be interested to hear if the resultant finish does harden over time or if it needs an additional finish coat.

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 Post subject: Re: Formby's Refinisher
PostPosted: Sat Nov 04, 2017 4:02 pm 
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Joined: Tue Nov 27, 2012 8:01 pm
Posts: 756
Location: Kalamazoo, MI
After 24+ hours of drying time, the result from simply applying and removing the Formby's is still susceptible to attack from the Dunlop 65 polish. A test section I did on the back, in which I added two wipe-on-wipe-off coats of Royal Lac shellac is much less susceptible, but still slightly so. My guess is there is not enough shellac to fully seal. I will try a couple more of these very thin coats and see what I get. In any case, it is apparent the Formby's by itself does not fully seal the surface and something must be put on top of it to accomplish this important goal. I would also think it should be fully sealed before squirting with any kind of lacquer, but then, maybe not. This is a blues voiced instrument and there are a lot of liberties one can take, given the tradition of the blues and its use of bottom shelf guitars. Keni Lee Burgess, for instance, uses cigar box instruments in addition to his collection of old gits, to the profit of his music and the way he looks will making it.

Michi Matsuda, a very refined maker with a great sense of adventure and originality, uses gunpowder to scorch the tops of some of his instruments. They are not "ugly" - to my eye at least - but they do take some getting used to. The explosion from igniting the gunpowder tends to blow out some of the soft grain, introducing an early washboard effect which he addresses by filling the furrows via traditional French Polish and pumice. I find scorching especially relevant to the aesthetic of a new guitar voiced for the blues, but not necessarily carried to the extreme of French Polish. You can see one of his scorched top guitars played here:

https://youtu.be/WZczvhqN-iU

He says he prefers these tops finished matte, which I agree with completely and wonder how he manages that with French Polish or if he uses some other method. The top of the instrument in the video is matte, while the body appears glossy.

I thought I had a "before" picture of my Oscar Schmidt project but can't find it. However, I shot its current state today and must say I am quite happy with the "look". Todd Cambio of Fraulini Guitars has been doing some interesting work with hand applied stains and sunbursts, and I have seen at least one demo of the same thing done on a mandolin. Hand staining is a different twist compared to the spray approach for adding color and I like it a lot, though for some, it too may take some getting used to. The Formby's method certainly has preserved the hand done look of my 100 year old instrument, pictured below.

Attachment:
File comment: Oscar Schmidt Guitar
Best.JPG
Best.JPG [ 194.77 KiB | Viewed 164 times ]

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 Post subject: Re: Formby's Refinisher
PostPosted: Sat Nov 04, 2017 8:43 pm 
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I really like that look, John.

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 Post subject: Re: Formby's Refinisher
PostPosted: Sat Nov 04, 2017 9:56 pm 
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Joined: Tue Nov 27, 2012 8:01 pm
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Location: Kalamazoo, MI
The third coat of ultra thin Royal Lac shellac sealed the test area on the back from Dunlop 65 polish. Probably the reason the first two did not entirely succeed is I sanded them to dull them. In any case, it is pretty clear the Formby's Refinisher does not leave a perfectly sealed surface. The instructions on the can are clear that it is to be followed up with one of their topcoats.

I thought you might like the look, Dave.

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 Post subject: Re: Formby's Refinisher
PostPosted: Mon Nov 06, 2017 3:40 am 
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Location: Kalamazoo, MI
For those who are interested in restoration, I will add an update to this project.

I removed the back and made some observations. The instrument, even though bottom shelf (it was given away if you purchased mail order music lessons), is a poster child for building light, with some impressive characteristics. The spruce bracing is thin and tall, made from fine grained quarter sawed spruce. The birch top and back are both slab cut, .110" thick. Sides are same, only .070" thick. The back is very responsive to tapping, and is quite brittle.

The hide glue joints were all intact, though I have questions about the prognosis of staying so for much longer. They were easy to break. That fact was helpful so that I could pop the back off the waist brace, leaving it to maintain the alignment of the sides for re-gluing the repaired back. Of course, there was quite a bit of slop, as it typical of many lower priced guitars, but it too popped off easily.

Some work had been done in the past that was thoughtful (as opposed to the overbrushing of the finish). A couple of cracks had been cleated, a maple Popsicle brace was added, and the bridge plate was reinforced with a small piece of maple to protect it from tear out by the ball ends of the strings.

I had assumed the neck joint was a dovetail. Wrong. At least I cannot imagine there is a dovetail inside the smallish headblock. I wonder if it is butt glued? Anyone have an opinion? M and T? In any case it is tight. But for the sake of prudence, I will put a couple of screws through the block into the heel to make it even tighter, since it is open and easy to access. I also plan to remove a section of the Popsicle brace and run a block of wood between the head block and first horizontal brace, to further protect against top collapse from string pressure. I've read at least one theory that even a Popsicle brace impedes sound, but most think preventing collapse is more important. Somogyi and others go so far as to build the head block so that it extends to the first brace. His guitars do not appear to suffer from this reinforcement.

My hope to adjust the action by slipping the back forward over the top edge then trimming the overhang should work well. There is plenty of flex with the back off to accommodate the necessary movement.

The back needs extensive work. The main crack must have started out small, as the bottom end is glued with Titebond and cleated. That did not stop it from advancing all the way to the top. I plan to pop that whole piece from the braces and reglue it up tight against the other side, then reinforce the joint as if it were a center seam. I also think it might be wise to glue thin strips of veneer in between the braces across the grain to mediate against future cracking.

Once the major work is complete, I plan to coat the inside of the top, sides, and back with a wash coat of shellac to mediate the transfer of moisture in and out of the wood, thus reducing the rate of expansion and contraction and hopefully reduce their susceptibility to cracking. Then I will introduce thin CA into all the joints. The trade off is is the CA will reduce the likelihood of them failing in the future, but will make it harder to fix them if they do. I don't understand the rationale that expects a $1,000 guitar to last indefinitely when a $35,000 car doesn't go much beyond 10 years. So making it harder, or even impossible to fix in the future does not trouble me.

One of the surprise advantages of the Formby's Refinisher is that, after the repairs are made and the instrument reassembled, using it on the remaining finish should reduce the visibility of the repairs, especially if i wind up adding wood somewhere. It should redistribute the color in a way that brings the look back together, cracks, splices, and all.

Pix below.

Attachment:
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Attachment:
Back.JPG
Back.JPG [ 190.96 KiB | Viewed 146 times ]

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 Post subject: Re: Formby's Refinisher
PostPosted: Mon Nov 06, 2017 3:50 am 
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Joined: Sun Dec 30, 2012 1:20 pm
Posts: 1019
Location: Arnhem area, the Netherlands
That looks good John, I like the story too.
Herman

That is an awful lot of work.
You did not pay a 1000, or did ya?


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 Post subject: Re: Formby's Refinisher
PostPosted: Mon Nov 06, 2017 2:23 pm 
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Joined: Tue Nov 27, 2012 8:01 pm
Posts: 756
Location: Kalamazoo, MI
Herman: $1000 is what one with an intact original finish and in playable condition would be worth, more or less. This one was playable (with issues) so I paid $125. Yes it will be a lot of work, but it is the kind of challenge I enjoy. The sound is remarkable, which also increases my interest. Because it will not have an intact original finish, I don't think the result will ever sell for $1000, but who knows? It will be much more playable than when I got it, with a flat fingerboard, new frets, closer action that can be adjusted to preference, tuners that work perfectly, and so on. Would I make much of living doing such projects? No way. But there is more to it than money.

It is also upping my interest in building new ladder braced instruments. There are at least a billion X-braced instruments made each year but just a fraction of that number of the ladder braced. Yet there are a lot of casual players who dig the blues and might like the way they sound with ladder bracing. A new build could emphasize simple, clean design coupled with thin, matte finish, smallish size, and light construction, all stuff that I admire. I've got a couple sets of very nice "flamed" birch that are calling ...

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 Post subject: Re: Formby's Refinisher
PostPosted: Mon Nov 06, 2017 2:27 pm 
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I'm sold on the ladder-braces also, for the reasons you point out. The ones I've built have all had a good-to-very good bluesy sound that really gets one's attention. And as you said, the matte finish and simple appointments look nice and are appealing.

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