Can anyone offer words of experience for pounding out dents and rough spots in thin brass pieces such as this headlight bonnet? I know the brass must be annealed, however, can it be done without putting the torch to it? Can one use the wife's oven (yes, I have permission!) and heat it to 550 deg F for 30 minutes and get the same effect as 1200 F for a few seconds?
You might consider checking around your area for a store that handles musical instruments - they can usually refer a brass repair person.
No, the temperature is not cumulative.
Straightening brass is easy but I would practice on something less valuable til you get the hang of it. Annealing can be done with a propane torch.
I had some success with a small hammer, hardwood rounded dowel with a backup wood piece. I did mine cold on a set of Victor 2s. Took it easy and used light file with polishing wheel to finish off. I will be interested in other suggestions. Worked for me.
Rich, pieces with curves like lamp tops are the easiest to work on. Flat stuff is way more difficult. I cab see no need for annealing to work on that chimney. Use a wood block as a backing buck and a small hammer to beat out the dents. I have used a damaged plastic handled screwdriver, beating on the tip end, as a dent driver. Check your progress often by lightly filing. This will reveal low spots which require more work. Then I finish filing with a fine wet n dry paper glued to a flat stick.
Hope this helps.
Allan from down under.
I had the exact same looking dented chimneys when I did my lights. I felt a lot more comfortable annealing those dented ares before pushing them out--would have hated to see a crack show up. A fine file and then fine sandpaper then buffing finished them up perfect.
Used to be a guy on south Harvard Ave that worked on brass instruments and also would do brass for car parts. (Around 17th Street)
I find making a rounded tool that is polished so you can put pressure on the back side of each dent while rubbing often times works best. Using only hand pressure, keep rubbing the tool while pressing on the dent. Many times, you can remove small dents in thin brass. Once the dent is pushed/rubbed out, use a fine file/sand paper followed by a buffing wheel.
Hammering can stretch the metal which sometimes makes the repaired area even look worse vice leaving a small dent in place. Having a small dent or two leaves the impression that the lamp is original vice a re-production.
If the brass is work/age hardened, annealing makes it much easier to push out dents.
Gilbert sheet metal in El Monte ( Los Angeles, Calif.) makes re-production Model T brass lights,generators ect. Ask for Wayne.
What temperature is required to anneal? One doesn't need it "dead soft" but not hard either.
The suggested temperature for annealing general sheet brass is 2 seconds after the Sharpie mark disappears
Then hold it for two seconds admiring it and then plunge it into water...if it sizzles as it settles you did it right...if it snorts and splatters you heated it too much but that is ok as you still have a long way to go on brass before you burn it through or make it do quirky stuff...
An old tradesman showed me an easy way to tell if the brass has been softened enough.
Rub a soap bar on the area ( no need for fancy perfumed soap we have one here called Sunlight soap its an old plain soap my mother used with her scrubbing board) , heat it, when the soap turns black that's enough.
I restored a triple twist horn using Les V's method, had to make a couple of steel rods bent into the shape of the curve and a few times used it to back the brass as I used a small wooden mallet on a deep dent. soft blows, you can always hit it again, lay into it with a hammer and you will get into trouble.
As Steve said, when I was in high school they
brutalized tuba's trombones and such. All I know
they were sent out as needed and came back
perfectly and they were bent up with their'brass
If the brass is thin enough I have had luck by simply putting the piece on a hard piece of wood or a flat polished piece of metal (no scratches nicks or debris on surface that could harm the soft brass surface) and rubbing the high points with a rounded piece of smooth hard wood such as a cut off broom stick. Run it over the high points while applying downward pressure. On thicker brass you may need to tap it slightly. Do not use steel. Use anything that is softer than the brass but not anything that is harder. Do not use a soft wood as a backing or you could cause the dent to go in the other direction. On really thin brass, I have been able to remove dents by the same methodology just by using my thumb nail. Jim Patrick
On some odd places I was able to get at some nooks by polishing the head of a carriage bolt with no markings on it, and bending the shaft of the bolt to reach inside to push the dent out.
I have used Brass Instrument repair people to straighten Horns and all brass parts. One caution. If you call around to find someone to work on Brass, don't tell them exactly what is to be repaired. Go in and show them. Apparently other old car people have been pains in the past.
After watching this video:
it would seem anything can be done.