So to try and restore brass Tilley Pl53, Bialaddin and Vapalux hoods I have usually spent hours on the buffing wheel, starting with a course scouring wheel then working my way with soap to a final finish, it seems to take hours and I end up just trying to buff scratches out. Looking at alternative (easier) options I have gone down the citric acid route, 25g per 500ml of hot water. After around 5 minutes the black crud starts to fall off with the persuasion of a tooth brush (I must remember to put that back in the bathroom) but I then end up with an orange hood..., however a little light buffing brings the brass up, not perfectly bling but I think it’s acceptable. Comments welcome please as this the first time I have tried this.
@Gary Waller I use a similar method and it works well for me. However I limit the time in the warm to hot dilute citric acid to about 20 minutes for brass, shorter for anything nickel plated. The citric acid solution will erode nickel plating if left in too long. I use the citric acid that's used for cooking bought from the supermakets. Cheers Pete
I either use GSR that I make myself using the recipe on the stove site or I have a bath of vinegar which does the same thing. As you say, a toothbrush makes a great tool for getting rid of the orange bloom. GSR = George's Stove Restorer which is citric acid in wallpaper paste - incredible stuff!
@AussiePete @ColinG cheers guys that’s useful info. Interesting with the wallpaper paste so you can apply it to specific areas rather than a full immersion. I have a brown Vapalux 300 to tackle so I will try it on there, just trying to source a suitable shade of brown.
There's a Rustoleum spray can colour called 'Chestnut' that I used on an early Bialaddin. The good thing about GSR is that it clings to the surface which is very handy!
I assume that you also stop the acid proces with a soda solution and wash carefully. After this you can use clear lacquer to preserve the shine. But for a lantern to use it is all gone after lighting.
The mechanical means are usually the safest. But sometimes, as we all know, can be seriously tedious. Elbow grease that is. So next, the acid treatment. I guess the most common for our purpose would be citric and acetic(vinegar) acids. Or any specific products that contain these. These are not strong acids and much favoured for use on our delicate pieces. Its advisable that traces of acid should be thoroughly rinsed off with clean, flowing water. Better, it should be neutralized with carbonate or bicarbonate of soda or even a weak caustic soda solution. The final rinse off with clean water is still crucial after the neutralization. Personally, I've used stronger acids or mixtures that could completely remove all kinds oxidations and tarnish very quickly (or rather, too quick for comfort) but they are not recommended here for both user safety reasons and possible over-etching/damage risks on the base metal.
Oups sorry, it's 200cl of hot water and 50cl vinegar !!! You can see the result here: Lampes à pression à pétrole, à essence, à alcool - Topic "Optimus 930"
When I've been faced with severe surface corrosion on brass, mechanical methods can be hit and miss. Using chemical means has the advantage that the corrosion is happening all over the piece, not just the easily reached areas. I get rid of the stubborn black layer with vinegar and then use my buffing wheel to add the final shine. I wash the piece with soapy water when the brass first comes out of the vinegar or GSR. Sometimes you're faced with small, dark spots of corrosion that won't budge and I sometimes use wire wool or fine wet and dry paper on these.
I’m still on the citric acid mix... Vapalux 300 hood, I wish I had taken a pic before because this was absolutely black as coal. It needed a good 20 minutes soak then a fettle on the buffing wheel.
