Hot Lacquering Brass

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Hot Lacquering Brass

This topic has 5 replies, 4 voices, and was last updated 1 September 2015 at 21:29 by Clive Hartland.

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1 September 2015 at 11:15 #202780
Garry Walton
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@garrywalton84951
Approximately 40 years ago I worked in a small company (as a young boy!) that built and repaired balances for the scientific community and precious metals industry. The brass components were often hot lacquered which resulted in warm dark finish. I am now interested in restoring some early assay balances and would like to use hot lacquering. Despite searching the internet I have not found any details of this process. Has anybody experience or knowledge of hot lacquering. I recall the person who did it used a spirit burner (clean gentle flame) and a solution which I assume contained shellac?

Thank You

Garry
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1 September 2015 at 11:15 #32558
Garry Walton
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@garrywalton84951
1 September 2015 at 13:26 #202811
john carruthers
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@johncarruthers46255
I don't know the traditional method but I recently re-finished a brass microscope and have done telescope parts in the past. Indian shellac, alcohol and a little curry powder (for colour) 5% shellac, 95% alcohol, colour to taste. Blend well in a jar with a few marbles run it through a filter paper, then dip or spray the piece. Then using either a strong hair dryer or hot air gun warm the piece evenly to drive off the volatiles, you can watch the colour change gradually, it also gives a more even coating.

Edited By john carruthers on 01/09/2015 13:28:07
1 September 2015 at 14:44 #202835
Clive Hartland
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@clivehartland94829
I think the mixture you are looking for is, 'Dragons Blood'. If you search for that you may find what the mixture is.

Hot laquaring is easy to do by gently warming the part and then using a Sable brush go all over and do not go back on a stroke. The curry powder mix sounds a bit sensational.

Clive

PS. see Google as it is well described and also Wicki.

Edited By Clive Hartland on 01/09/2015 14:46:33
1 September 2015 at 18:00 #202853
Ajohnw
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@ajohnw51620
I thought that Nitrocellulose lacquers were used from around 1920 or so. It did get rather thin on the ground but does seem to be around again. I believe heat is sometime used with it but I think it's more associated with drying. The problem was probably that it's one step away from explosives.

I have seen mention of shellac based with a mix of things like turmeric being used. Eg this one

**LINK**

There are also epoxy type things around that are mostly used on musical instruments

**LINK**

I have a slight interest in restoring a brass microscope. Looking around nitrocellulose seems to be used most often but if pre circa 1920 that probably isn't authentic.

John

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1 September 2015 at 21:29 #202880
Clive Hartland
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@clivehartland94829
I do remember using a product called, 'Frigiline', Again I think it was cellulose based and dried to a clear coating but was told that it could be coloured by a pigment thus becoming , 'Dragons Blood' , The colour of this varnish enhances the brass tubes of old instruments. The last Company that I know used this method was, Cambridge Instruments, but that was before the late 60's. Enquiries to people who worked there told that it was no longer used.

I long sought this item but gave up trying, I see that 50gms of pigment cost about £30. The art is now lost and modern finishes have taken over.
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