old nitrocellulose finish on a guitar

[astrid]

I,m a bit confused here guys, I always thought that the finis in australia in the 20's thru 60's was a nitro cellulose, it certainly disolves with meths in a crusty sort of way. I strip it with meths alone, quite quickly and it give a musty sort of smell
Are we talking the same finish here?
old nc was sprayed on and was discontinued in general manufacturing here and in europe because of its highly flammable nature, (workers burned to a crisp) or so i have been told.
Best ask how old is the guitar and where was it made (guessing the US)
before we start giving advise on how to patch it up.
wasnt old film made from NC and dolls and records?

Astrid

[MacS]

Now, were going all over the place.

If you can use Shellac and Lacquer together, then they are COMPATIBLE.

Nail Poilish, is not made with Nitrocellulose, its made from Acrylics resins. Acetone, is the nail polish remover.

Nitrocellulose, will amber over time, whereas, Acrylics will stay water clear.

Bob Flexner, is not an industrial chemist, but he knows a lot about chemistry and wood finishing. he has a book worth reading on finishing.

Shellac, is a softer coating then Lacquer, because lacquer has been modified to be harder. Shellac takes too long to harden in comparision to lacquer, that's why lacquer is used in production finishing.

Custom woodworkers who use Shellac on their work, do not have to worry about their pieces being abused, these pieces are high end, and well taking care off, no lacquer off the gun can reproduce the look of french polishing, there is a place for both of these coatings in finishing.

[astrid]

My husband is a collector of vintage guitars and he this to say:

"If it's crazed then it's definitely nitro, modern laquers don't craze. If it's nitro it's probably 1960's, early '70's at the latest, nitro hasn't been used on guitars anywhere since around 1969 although Maton might have kept it for longer - I don't really know because I'm not a specialist in Maton.

Since it's 1960's, it's definitely valuable. I just checked and can see quite ordinary Maton's from that era going for around the $1300 mark and up - a price I can quite believe as Maton is a highly regarded brand and the price of even the junkiest 60's instruments have skyrocketed in the last 5 years. Maton is not junk.

Given that, any work on the finish will only devalue the instrument (and possibly the sound as well). Crazing doesn't affect value at all as most of these old instruments suffer from it. A few dings and scratches are immatterial. They just don't make guitars like they used to (I won't go into details, but the differences between old and new are real), and the demand for the old is very strong.

Secondly, in a past life I used to be a chemical engineer working with solvents. I can definitely confirm other comments here that shellac is incompatible with nitro. Application of shellac to nitro will mess it up. Further (guitar hat on again) the comment re. nitro being transparent finishes and shellac being opaque is dead on the money.

Speaking as a collector, I wouldn't touch it. I have quite a number of old guitars some of which have finishes in pretty ugly condition and it doesn't affect their value much at all. The only time finish is an issue is when you have a really top notch mint example. And mint means mint in this market - right down to every screw and wire being present, original and untouched. From the sounds of it he doesn't have one of them, and all that will be achieved by trying to tart it up is to reduce its value"

Credits to HWMNBO (except in this instance)

Astrid

[MacS]

I am no chemical engineer, but I was a field salesman for a company that sold finishing materials for over 30 years. I have serviced many thousands of finishing shops, and I have to disagree with you, Shellac and Lacquer do work together, I personally have been doing this for a long, long time, I mention this to customers all the time, if there is a problem it caused by the finishers and not the coatings.

If fact, I use this finish all the time same now, I write some finishing articles and do my own photos. I use the Shellac for the sealer coats, because shellac is an excellent sealer, but it has a high gloss sheen, so I have to use lacquer to reduce the sheen for the photos, so I do not get and flash back from the gloss.

You mentioned, that nitro being transparent finishes and shellac being opaque is dead on the money.

Were, you referring to both of them being in containers, where the clear shellac is milky white, and the lacquer is a clear amber, you do not mean when once they are applied as coatings?

Do they sell Shellac aerosol cans in OZ.?

[astrid]

What HWMNBO was refering to (I think) is that when shellac was used on a sunburst,
it was coloured so as to give a more solid colour finish,
not that the material itself is opaque. I think that, as in most cases, you can put shellac under NC, but not the other way round, i also think that 50's NC was made up different than it is today.
vintage guitar finishes are a trade in themself and not a generalist area.

astrid

[durwood]

Astrid,
You arn't confused pretty well spot on.

N/C lacquers are a product of the first world war. It appeared in the early 1920's and was a big break through as the old finshes were slow drying varnishes. Suddenly there was a finish that could be applied in a day and not weeks. It was a especially taken on by the automobile industry and is commonly refered to as "Duco" which is actually a brand name.

It was used up until 1960 on cars ( all Holdens were finished in it) when it was replaced by Acrylic lacquer. Duco was a so so product, some colours were good some were terrible. Black N/C was fantastic so much so it performed far better than acrylic lacquer blacks which only became reasonable 10 years later. White duco was hopeless ( it went yellow) and colours that were reasonable performers were pastel colours. It was rare to see a bright red car that didn't go pink quickly and maroon was even worse.

Acrylic Lacquer was far superior, it was not affected by the UV light and colours stayed the same, white stayed white and other colours stayed the same. The biggest breakthrough was with metallics which up until then were not possible. Now it was possible to have silvers and golds.

When A/L became the paint on Holdens and the baked enamel cars were repaired with A/L Duco was fazed out not because people were being burnt to death but because it was inferior. ( acrylic lacquer is even more inflammable)

It still was the base material in the primers and putties for A/L (still is) as it dries so fast compared to Acrylic materials and is the the easiest paint to use of any.

BUT the clear is lousy in sunlight as UV rays destroy it fast and its been reduced to the furniture/interior market and is still widely used for numerous products as its is easy to apply drys fast and requires not much in the way of equipment ( in its hay days it was sprayed in factories with little or no resourses such as booths just somewhere where it could be sprayed on and allowed to dry for a few minutes before being moved on.

Its also been relegated into obscurity by polyurethanes in the piano industry so its becoming less used all round but there still are a lot of users who use it as it fits their requirements. It has a place its just a smaller one these days.

[astrid]

Thanks durwood,
Re the guitar in question, would we be right in assuming that a 60's sunburst would be "decorated" in coloured shellac, ie the sunburst, and then finished in NC.
you can put shellac on under a lot of finishes but not over, as its too soft and will move the sub finish.?

Astrid

[MacS]

Shellac can be used over or under nitrocellulose, there are situations when it is used both ways.

Shellac, is also used under Varnish as the seal coat.

Shellac, is also used under water base coatings to seal the wood, other wise if the water base sealer or coating is used, they will raise the grains of the wood.

How "nitrocellulose" can about was after the war, there was millions of shells with gun cotton an actvator in the shell casings being stored, the goverment wanted to get rid of all these shells, it was Dupont that came up with the nitrocellulose lacquer by dissolving the gun cotton. Duco was a trade name for Dupont, and that was the beginning of the lacquers.

[Different]

Shellac can be used over or under nitrocellulose, there are situations when it is used both ways.

Shellac, is also used under Varnish as the seal coat.

Shellac, is also used under water base coatings to seal the wood, other wise if the water base sealer or coating is used, they will raise the grains of the wood.

How "nitrocellulose" can about was after the war, there was millions of shells with gun cotton an actvator in the shell casings being stored, the goverment wanted to get rid of all these shells, it was Dupont that came up with the nitrocellulose lacquer by dissolving the gun cotton. Duco was a trade name for Dupont, and that was the beginning of the lacquers.

Right on
Cotton (cellulose) reacted with Nitric Acid (Nitro) created as said Gun Cotton which when disolved with Ether and extruded in thin strips and dried forms Smokeless or Nitro Cellulose gun powder. Just happens to be my favorite invention too !!!

Rgds

Ross

[kiwigeo]

Best ask how old is the guitar and where was it made (guessing the US)
before we start giving advise on how to patch it up.
wasnt old film made from NC and dolls and records?

Astrid

Matons are made right here in Australia......

For good advice on finish repairs try here:

http://www.frets.com/FRETSPages/pagelist.html

Cheers Martin