Disolving wood filler?

[Kudzu]

Long shot, but I have a BUNCH of bronze screws I have removed from my Sea Skiff. 99% of them where covered with filler and it is hard. I ground a screwdriver down and chiseled enough filler out to remove them.

I hate for them to go to the scrapper so just curious if there is anything I could soak them in to soften the filler? I know it is a long shot but...

Lot of uses for them above the water lines and you know the cost of bronze.

[Peerie Maa]

Heat should soften the resin.
Battery said should remove corrosion products, and any residual crud.

[Kudzu]

.....
Battery said should remove corrosion products, and any residual crud.

Not sure I follow this?

[jonboy]

If the filler is cement, plaster, or gesso base then muriatic acid should work... do a couple in a glass to see if the bronze is affected, but Id be surprised.

[P.I. Stazzer-Newt]

Battery said should remove corrosion products, and any residual crud.

Not sure I follow this?

That smells of autocorrect - I suspect he meant "acid"

That said - without knowing the nature of the filler, all we can do is guess.

Strong non polar solvents - acetone/ kerosene/trichlorethylene - will attack some fillers

Sulphuric acid will attack others but leave plaster/cement based fillers untouched

Hydrochloric acid (muriatic/spirits of salt for the archaic or Brick Cleaner for the practical) will dissolve calcium based fillers

Still others will fall to hot caustic soda.....

[Gib Etheridge]

Maybe if you boil them then put them on a wire wheel hot.

[jonboy]

PISN's right there..unless you know the nature of the filler or you know it's a modern acrylic base, its almost certainly Gilder's whiting or gesso, plaster of paris, portland cement even, lime based, acid degradable. ,
with rabbit skin glue and white lead. former water soluble, latter almost insoluble, Acrylics yield to heat and alcohol , methanol ,ethanol , but even the most complex fillers will succumb to a strong commercial paint remover. Nitromors I remember as a brand name moons ago in UK, maybe still available. But first hydrochloric, rinse well then a strong alkali , caustic soda- One at a time though or there will be a backyard etna old geyser scenario.

[Peerie Maa]

That smells of autocorrect - I suspect he meant "acid"

That said - without knowing the nature of the filler, all we can do is guess.

Strong non polar solvents - acetone/ kerosene/trichlorethylene - will attack some fillers

Sulphuric acid will attack others but leave plaster/cement based fillers untouched

Hydrochloric acid (muriatic/spirits of salt for the archaic or Brick Cleaner for the practical) will dissolve calcium based fillers

Still others will fall to hot caustic soda.....

Copper/silver smiths use sulphuric acid (Battery acid) to clean copper silver and copper alloys after heating to anneal or silver solder, so it will also remove ordinary oxides.

[Kudzu]

No idea what the filler was. 1963 Chris Craft if that helps. All I can tell you is it is gray, quite hard and a little brittle Literally have to take a hammer and my ground screwdriver to chisel it out.

I was thinking about trying the solvents I had in the shop. Just thought someone might now what it was and something that would work.

[jonboy]

I have some old windows with glazier's putty. white lead and linseed oil and some chalk base, lime maybe. Old school painters and decorators used it, and still do here.

This thread got me exercised, and I went out and dug some lumps out of the old frames and tried every thing suggested here, my ideas too, and nothing had any worthwhile effect.

It's going to be attrition. clamp each screw and a fine flat file or dremel to physically grind out the filler. or similar.