Old French Bass full Restoration

[charangohabsburg]

Hi Matthew, I'm glad to see your epic restoring project going on!

That black liquid you were stripping off is reminding much more of a car repair than of a musical instrument restoration!

Was that originally an oil varnish? (I'm just saying it because I ignore if luthiers used to use something else than just that). Do you have an idea why it had tuned like this?

What kind of solvent did you use to clean off that terrible remains of deteriorated varnish? Just alcohol?

Cheers,

[matthew]

originally the varnish would have been a transparent red-brown spirit varnish ie shellac and other resins and colourants.

over the years and due to heat (the instrument was found in an attic) the colourants have oxidised and the finish has crazed, melted and clumped and probably encapsulated a fair amount of dirt and tannin from the wood too.

So yes, just using spirits of wine to remove the treacle. I might keep some of it in a jar - may help with matching new wood colour undr varnish later.

[charangohabsburg]

Thank you Matthew.
When you say "spirit varnish" do you think of another than an oil based varnish (just spirit, shellac, resins and colourants)?
If so, was this typical for french violin-family instruments?

[matthew]

Thank you Matthew.
When you say "spirit varnish" do you think of another than an oil based varnish (just spirit, shellac, resins and colourants)?
If so, was this typical for french violin-family instruments?

spirit varnishes are simply things dissolved in alcohol. When the alcohol dries off, the lac, resin, colours are left.

oil varnishes are things dissolved in an oil and other solvents that dry off, polymerise and form an impermeable layer with the additives.

both are used. Different resins dissolve in different solvents. Spirit varnishes are easier to make and dry quickly. they are commonly used on cheap instruments and are typically less durable than oil varnishes. But they dry fast and can look great. Spirit varnishes are also most commonly used for retouching even good oil varnish, because they are fast drying, easy to make and colour, removable (important in restoration work - all work has to be reversable) and stick to everything. Matching and applying an oil varnish to match an oil finish is much harder, slower, and you'd better not screw up.

But finishing an instrument in an oil varnish can give a more durable finish, and because it is much slower to dry, is easier to apply - you can brush and brush till the layers and colours are how you like. with a spirit varnish you have one, maybe two brush strokes and that's it, wait to dry between coats and work quickly. you can easily pull a previous colour layer off again if you're not careful.

retouching is I think one of the hardest skills to learn and i am far from a master at it yet. very satisfying though when it works.

[matthew]

More

[auscab]

Hi Matthew ,
Nice to see more of this great restoration project.
I was wondering how you were going to tackle that finish.

I could probably list here thirty questions about spirit varnish, I have do deal with it all the time with furniture restoration, and its a bugger .

Do you know of any ways to revive a dull or lightly scratched and marked spirit varnish finish ? and does that come under what you mean by re touching ?

The spirit varnish I have to deal with ,from what I know so far , is a mixture of shellac and Rosin and I was told the Rosin is first dissolved in pure turps and that solution is mixed in with the shellac. the more Rosin the more hard the finish and I think the more of a pain it is to refinish years later. French polishers I have asked about it have just told me a thin dry rubber of shellac. That's fine if the original finish was mostly shellac.
I have tried the rosin pure turps / shellac mix in a rubber to revive an old finish thick with rosin it did shine up well ,but did not stay that way long. I think that maybe that is the way to approach it ? What do you think ?

[Nick]

Absolute craftsmanship in every sense of the word Matthew. I'm loving watching this restoration & glad you have picked up the baton & ran with it again. Thanks for posting progress

[matthew]

yes simplest way to revive spirit varnish is just to FP over the top of it.

[christian]

Absolutely amazing restore Mathew !!!
your meticulous attention to detail and craftsmanship will see this instrument improved substantially in every way.
hats off to you!!! I certainly wouldn't know even where to start on something like this.
can't wait to see the next installment.
Cheers,

Christian.

[Lando]

Mathew please please update this resto...i started reading and became hooked.

its so cool and that bass will look amazing when its done

cheers


Lando

[Dubass]

Hello Matthew,

very inspiring work on that Bass!

I am working on a similar French Bass, here are some pics.
It took me a few weeks to get the former "restorations" undone and clean it. Will absolutely try to use some of your techniques in my restoration.

Look at the way the cracks in the front are filled up from the outside with little chips of wood dipped in white glue.

Pics in File (hope it works, dont know how to get pics in the message)

I am searching for an old set of French Tuners, in any condition, will pay a good price and/or can give very old German tuners as an extra.

[matthew]

That crack fillers technique is interesting ... how are you going to get all that white glue out?

And ... are you in Australia or are you ... "rest of the world"?

[Dubass]

Most of the glue is out. I used water, heat and a lot of patience with a little knife.

I am in doubt wether I should fit the cracks back together or carve large strips of spruce that fit in the cracks as to keep the form. One crack is aprox 5 mm.

The body and back are in bad shape as well. lots of strange repairs, two additional bars were installed, which is not very french.

I am in Europe, otherwise I would gladly visit you for some expertise.

[matthew]

As the cracks have already been "repaired" once before I doubt whether you will be able to pull them back together. You might be better off cleaning up the sides of the cracks and replacing with new wood splints as you said. Sometimes it is easier to break open the whole crack end to end, clean it up, and re-join. It will be difficult to keep the arch intact and the edges flat. Think about shaping some cross-bars from pine that match the arching across at several points. You can tack-glue these to the top, then trim off the pine flush with the bottom edges of the plate so you have a temporary internal frame that will sit on a flat surface and keep the arch intact. Then fit your splints. Jim Hamm invented a technique where the splints are rolled/compressed between a steel roller bearing and a hard surface, particularly at the thin ends. these are then glued in with hide glue and as they are wet, they expand to fit the crack. I haven't done this though yet.

Good luck! That thing looks to be a bit of a mess!

[Dubass]

Thank you, that's a big help!

I will let you know if and how it works.
I am in no hurry, still looking for matching Tuners.

thanks again and greetings from The Netherlands,

Martin

[charangohabsburg]

Jim Hamm invented a technique where the splints are rolled/compressed between a steel roller bearing and a hard surface, particularly at the thin ends. these are then glued in with hide glue and as they are wet, they expand to fit the crack. I haven't done this though yet.

Here: http://www.thestrad.com/pdfs/HamTradeSecrets.pdf

I have used James Ham's technique, but on much smaller instruments than double basses. It works like a charm. Of course you need "a gap which holds its shape", and this is where I guess the temporary frame Matthew suggests will shine too.

[Mark McLean]

Thanks for that link Markus. That is a very clear and well illustrated guide to a useful technique.
Mark

[simso]

Dubass, Ive never seen someone fill cracks like that method you have shown, would love to see the finished repair prior to colouring if you could.

Steve

[matthew]

Dubass, Ive never seen someone fill cracks like that method you have shown, would love to see the finished repair prior to colouring if you could.

I've been assuming that is NOT Martin's repair technique

[Dubass]

No, no, that would never be my repair technique!

I once had the idea of making the inside of a Bass a kind of "Magic Box", where you can look through the endpin-hole and shine a light through the F-Holes.
The "woodchip" repair (which was there when I bought the Bass) would make a nice Big City Skyline


I will go and try to go with the Hamm technique, the cracks are much longer and wider than in the example.
42 cm, 40 cm an one of 67 cm!

Oh, and did I mention that I found little holes drilled on either side of the previous repairs. I believe they have used the method of pulling wire through those to pull the crack close till the glue was dry.
Mostly used as een ouside repair thechnique in guitars.

[matthew]

finished.

[matthew]

image.jpg (38.34 KiB) Viewed 20919 times

[kiwigeo]

The Bassmeister returns! Thanks for the update on the restoration project Matthew.

[needsmorecowbel]

WOOO!

[Allen]

What a journey that one has been. Thanks for the update pictures.

Just amazing attention to detail.