Refurbishment of Antique Aneroid Barometer

I am planning to refurbish an Antique Aneroid Barometer which is contained in a polished brass case. The case is lacquered but the lacquer is worn through in places and needs to be redone. What is the best media to remove the lacquer without damaging the brass and then what lacquer would be suitable to recoat it with? Any useful info gratefully received.

Dave

Hold on now... you want to use....

Lacquer Thinner!!

Any paint store.

Pete

Thanks Pete, obvious really, I must engage my brain more often, any suggestions for a brand of lacquer to recoat with that will give a good durable finish.

Dave

Hi Dave,

I know there are specialist lacquers for brass but I can't think of a name right now. I have a spray can but the label has fallen off long ago.... it is a true lacquer; it has that unique, powerful, lacquer smell. All of the lacquer work I've done recently has been wood. Restoration of old finishes.

Pete

If it's shellac based acetone/nail varnish remover will get it off.

As Neil implies first identify your lacquer.

Antique is unlikely to be the same as modern formulations. Using the wrong one might create a horrible sticky mess that will neither scrape off any sense or dry in reasonable time. One such mess I heard about allegedly took about 6 months to harden off enough for mechanical removal after various nostrums had been tried.

Clive.

If this is an old piece of equipment then it was likely hot laquered. Then possibly done with a concoction called, 'Dragons blood'. This gave the instrument a nice reddy tinge much nicer than bright brass.

The formulea for dragons blood has been lost as I have searched for a long time for it but it entails mixing a red dye with a clear laquer. Hot laquering was done with a clear laquer called, 'Frigiline' by heating the item and brushing it on and never going back on a brush stroke, very skilled action.

Removal of the old laquer is best physical with going down to the base metal and doing what is called, 'Graining'. If it a round item then just put it in a lathe and use emery sticks to cut the old varnish away., de-grease afterwards and make sure you leave no fingerprints!

i've found a good coating for brass is 'incralac' - i did some piano brass about 30 years ago, it still looks good. not subject to much handling of course.

Before you start I would think very carefully. You cannot patch up lacquering, it is an all or nothing operation. I used to do up clocks and getting the old lacquer off was sometimes easy(ish) but most often it was the very devil of a job especially on not so antique not so good items. Often only hard work on the polisher would do it. This approach is not so good if the original finish was grained. Or see the emery stick approach above.

So try a small area with your chosen remover, you may be lucky.

Also, putting shellac lacquer on by hand is not so easy. The usual advice is to warm up the work, use your best sable brush and don't go over the work again. If you leave any places it will dull and look bad later on. If you go too slowly it will dry as you go and drag.

Thanks all for your inputs, the item I will be restoring is fairly old, I think latter part of the 19th century so unsure about type of lacquer, possibly Dragon's Blood as suggested by Clive. I think that I will try various solvents first, perhaps cellulose thinners, acetone and possibly synthetic thinners but on an area on the back of the case which is always against the wall and therefore if I really screw it up then it will be hidden. Yes Clive it is circular so will be able to be rotated on the lathe if necessary, although I will need to fixture it because larger diameter than my chucks. I will post a photo of the barometer if I can master how to post photos on this website. Once the case is sorted I need to focus on the dial, it appears to be silvered, but is very tarnished, so maybe just needs a careful clean to remove the tarnish then treat with lacquer. In respect of lacquer I have had some success with the spray cans of lacquer that are used by car paint systems, the final topcoat of lacquer applied after paint has been applied, have used the Halfords brand in the past but mainly on wood, works well on oak, gives a nice durable finish, so maybe trial on the rear of the case to see how it comes up.

Dave

Hi

Dragons blood

**LINK**

Also
**LINK**

It appears to be available, I guess purity is an issue. and cost!
**LINK**

Regards
John

Hi All, have managed to transfer photos of the barometer to my albums folder so at least image is available, not yet mastered how to include it on a posting, will get there eventually.

Dave

Hi John, thanks for the dragon's blood references, plenty to choose from but I think I will give mercury sulfide a miss, a bit too toxic methinks.

Dave

It dissolves in both, but acetone is quicker and easier to use.

I saw a recipe in an old ME once, not sure if it's 'correct', of course.

Neil

Your Barometer case looks similar to mine, I'v decided to leave it as is.

Ian S C

Hi Ian, yes appears similar but the face on yours is much more readable than mine, the silvering on the face of mine is very tarnished and will need some restoration to render it legible. I am still of the opinion that the brass outer case does ned to be stripped and repolished then re-lacquered, it all depends how easily the old lacquer is to remove.

Dave

My wife & I collect & restore vintage oil lamps and mechanical calculators. ( What don't we collect ) We use Acetone to remove old laquer and recoat with Rustins metal laquer. Never had any problems using either.

Meths safer though, and easier to buy in larger quantity?