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lungovw
16-Mar-2009, 14:31
A couple of weeks ago I posted a DIY about re-lacquering brass lenses. That was using modern epoxi resin, the one applied to brass musical instruments.

GPS and Pete Watkins gave then some tips about the way lens manufacturers used to do it in former times. That was using shellac as a basis.

Well, I tried it out too. That is what I want to share with you today.

http://www.lungov.com/wagner/DIYBrassLensReLacqueringOldWay.html

Thanks GPS and Pete.


Rgds



Wagner

Ernest Purdum
16-Mar-2009, 16:26
Regarding colorants, I have heard of people extracting them from "magic markers".

I am sure methods differed from one maker to another, but at least one mounted the barrel in a lathe turning slowly while the lacquer was applied.

For what it's worth, the prettiest lacquering I've seen was not on a lens, but on the brass parts of a Gandolfi "Universal" dating back to Louis's time. The color is gorgeous, more red than most.

sun of sand
16-Mar-2009, 17:04
It's cool what you're doing

I like the satin epoxy resin look better than this tinted shellac sugarcoat
too yellow for me
But then I like the appearance of highly polished brass/metal itself and would never varnish
I'd simply keep polishing ..as I do with brass hardware around the home

However
I have my first brass lens showing up soon and it appears to need a major polishing effort.
I do polish away "all" imperfections
and this time only
WILL do multiple coats of shellac -by brush-
will also wax over the shellac

Archphoto
16-Mar-2009, 17:19
Muito Bom !!!!

This looks realy great, thanks for sharing this with us, this looks so good.
I have a restauration project like that in Holland: this will be my gideline for shure !

Where are you living in Brazil ? I am in Goi‚nia.

Greetings,
Peter

Pete Watkins
17-Mar-2009, 02:15
Wagner,
That looks great. The colour is fine as well. It will last for years.
Sun of Sand(?) you cannot do multiple coats of shellac, it involves heating the brass up and this would make a mess of the existing coat. This type of laquering cannot be repaired either, it's a case of strip it and start from scratch. Waxing over the shellac would be a pretty pointless excersize. The coat of shellac will give the brass sufficient protection for years to come. Contstantly polishing brass items gradually wears the brass away, all these polishes are abrasive to some degree. If you just want shining brass get some cellulose laquer from your local vehicle components shop and spray it on. It won't last long, multiple coats and waxing are possible with cellulose laquers if you want to go down a non traditional route. Your choice!
Restoring / cleaning up the brass prior to laquering was done in several ways. We turned the round parts in a lathe and used the finest grades of emery / polishing paper to shine them up. Clock components often needed years of dirt and old laquer removing, many industrial clocks had been placed near gas lamps for years (many of our rural railway stations didn't have electricity, even in the late '60's) and suffered from verdigrease (similar to rust on steel). We stripped the clocks down, carried out the repairs and placed the components in a hot mixture of soft soap and ammonia. I am not recommending this, it stinks and can't really be a lot of good for your lungs etc. After a few hours, when the solution was cool, we would scrub the parts with fine pumice powder using long bristle brushes. This would put a fine grain onto the brass. We would then wash the parts in a spirit (unleaded petrol (gasoline)) allow them to dry making sure that there were no stains on the brass, then heat it up and laquer it.
Ernest, the red hue was down to the additives that had been used as colourants. I assume that the Dragons Blood (never seen the stuff myself) could have been the component that gave the laquer the reddish hue.
Thanks for the praise Wagner, keep up the good work.
Pete.

GPS
17-Mar-2009, 11:09
Great job, indeed, Wagner. I like the rich yellow colour. And what a rich country you live in if you can get all those exotic ingredients "in a shop"..!

goamules
17-Mar-2009, 13:52
Wagner, thanks for this excellent instruction site. I think the color matches the original 1800s lacquer much more closely, as can be seen on this Darlot (http://www.largeformatphotography.info/forum/attachment.php?attachmentid=23862&d=1237001229) with period laq. It's probably from about 1900.

I should know the answer to this, but what is the difference between lacquer and shellac? I know the former is discussed more for use on metal, and I use it to varnish tintypes. My recipe is sandarac, a tree gum.

But your results look very good.

lungovw
17-Mar-2009, 16:55
goamules,

The Wikipedia says: In a general sense, lacquer is a clear or coloured varnish that dries by solvent evaporation and often a curing process as well that produces a hard, durable finish, in any sheen level from ultra matte to high gloss and that can be further polished as required.

That is also what I deduced from other readings: Lacquer is a generic name and Shellac is an specific ingredient to make lacquer.

It is interesting that you mentioned Sandarac. Talking to a artisan that makes acoustic guitars, he told me that by adding 5%, in weight, of Sandarac taking as a 100% the weight employed Shellac, lacquer's hardness and overall resistance to scratches, that is already very good, improves even more. He said also that it takes several weeks till its total cure.

Those are very interesting and effective natural ingredients. After using the epoxi resin with all the care that it takes, I was surprised by the friendliness of this lacquer, it smells so good, it smells food actually. Good for the user, for the environment and for those old brass lenses!!

Regards,

WL

Steve Barber
17-Mar-2009, 23:25
Good information, thank you for posting it.

Aesthetically, I prefer the "polished brass" look without the coloring. On my monitor, the photo of the finished piece makes me think of "anodized aluminum".

sun of sand
18-Mar-2009, 21:17
I got that same info from some clock repair site that night
I tried doing a french polish type technique on a brass push plate and didn't work well
but then maybe the shiny metal just highlights mistakes
Tried brushing it on and no matter how thin it always "rippled" to the point I couldn't knock it down level to recoat without going through to metal
I've tried heating shellac before to cure it only to have to strip the shellac -with alcohol same as for diluting it, in case- and begin again
I don't know if there is any need to help the curing of shellac, anyway

I always wax over shellac on wood so I figured it would work on brass, too
doesn't matter anymore. Probably doesn't do anything.

I keep shine up with simichrome. Probably take me 40 years to strip away enough brass so I don't worry about it

I polished up the lens to a mirror finish and I like it. I'm not putting anything on it
some wax.


I think the thing making this homemade lacquer job not look the same as original finish is just the fact that the original brass wasn't mirrored. It was left at satin and that kills the depth of reflection ..color does look pretty right on.
too yellow for me still