Je ne sais pas si quelqu'un a déjà donné ce lien :

http://www.finishing.com/229/90.shtml

Et celui-ci :

http://www.guitarseminars.com/ubb/Forum1/HTML/006634.html

Il semblerait bien que la naphtaline soit la clé du problème...

Voici un passage intéressant extrait du lien que vient de proposer Wlud:




bdeivert
Member

Posts: 187
From: Karlstad, Sweden
Registered: Aug 2004 posted 09-22-2004 01:59 Click Here to See the Profile for bdeivert Click Here to Email bdeivert Edit/Delete Message Reply w/Quote Len,

please post some pics of the finished results of the DUCO finish??? I am sure everyone is interested!

cheers
BERT (longing for my new Style O)




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Bob Brozman
Member

Posts: 2590
From: Brozmanistan, Earth
Registered: Nov 1999 posted 09-22-2004 09:07 Click Here to See the Profile for Bob Brozman Click Here to Email Bob Brozman Edit/Delete Message Reply w/Quote Some years ago a National collector who was also a chemist, sent me a 1/2" thick stack of patent papers for these finishes. All of them fall between 1929-34, so typical of Dopyera to use the latest cutting-edge materials!

Altering the various components changes the amount of crystallizing and also the "depth" of same. Must be done in a still room. Also The crystal "flowers" are started by lightly touching the wet paint with the tip of a nail in different places.

Too bad these finishes are illegal in Calif, but how about in Houston Texas? It' "Anything goes" there, pollution-wise!

While we are on the subject, have you ever noticed that rolled f-hole triolians of a certain period have visible wrinkling in the metal near the bass side f-hole? Something inconsistent wth the die.




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Mike D
Member


Posts: 1393
From: Phx, Az
Registered: Dec 2000 posted 09-22-2004 10:02 Click Here to See the Profile for Mike D Click Here to Email Mike D Edit/Delete Message Reply w/Quote Nitro can be sprayed in California, you just need the right EPA-Ok'd booth and re-claim set up similar to what Fender uses. Bigger bucks I'm sure than what National R-P and most other builders can swing.
Maricopa county where I live has essentially the same air quality laws that Cali. has so I can't buy nitro here, but I can in other parts of AZ, as well as most of the country, not just Texas.

.............

Un autre lien intéressant sur le sujet :

http://www.jessedeanefreeman.com/nationalinfo.html

Citation:

If it's a metal bodied single cone - it's either a Duolian, Triolian, Don, Style N or Style O. Duolians are steel bodied (although you can't tell by looking at them unless they're rusty) and either have a weird "crystalline", semi-transparent painted finish (1931-1937) which ranges from green-ish to brown-ish to gold-ish depending on how they've dried. There has long been debate as to what this finish actually was but it is now believed to be a mixture of Naphthalene (a mothball ingredient) and Shellac - several people have made good replicas with this recipe although I believe it is prohibited for commercial manufacture in the U.S. by environmental and health laws. The later models (1938-1940) have a quite realistic wood-grain paint job. Also it says "Duolian" on the headstock!

_________________
Cogito, ergo meus caput capitis sino..

Pour documenter un peu plus la chose, voici un lien explicatif vers le "shellac" : http://en.wikipedia.org/wiki/Shellac

Le vernis de shellac se trouve en france :

http://kremer-pigmente.de/shopint/index.php?cat=0604&lang=FRA&product=60453&sidCE829F4273D84D0B9E28A8641D82C087=0f1d3f6eff08713038c4f7861ac143de

on l'appelle plus communemént "gomme laque" et il se présente sous la forme de cristaux à diluer :

http://cgi.befr.ebay.be/SHELLAC-Gomme-laque-orange-extra-pure-1-4-kilo_W0QQitemZ300232836415QQihZ020QQcategoryZ7798QQcmdZViewItem

Après, il ne reste plus qu'à trouver le taux de mélange avec la naphtaline et faire des essais..

avantage caché donc, d'une vielle National
tu la met dans le placard, fini les Mites !!

tutututt...focus sur le sujet, 'ttention au dérapage

Hé bien Dobro, puisque tu le dis publiquement, je te réponds publiquement que si tu n'es pas content, tu te barres !!

revenons à nos moutons
ici:
http://elderly.com/new_instruments/names/national-frosted-duco-delphi-and-case--NGFDD.htm

il y a des photos des differentes finitions "frosted duco" que propose National sur ses Delphi à l'heure actuelle
j'ai l'impression que même eux n'ont pas le "vrai truc" si?