Safe way to open up concretion blobs?

[pcolaboy]

I've got several large blobs of encrusted and rust locked debris obtained from some scattered shipwrecks. Several of these have copper nails poking out but they are locked into this concretion material. I'm really wondering what else may be locked inside these blobs but don't want to risk damaging something by breaking apart with a hammer and chisel.

Does anyone know of a good method for loosening up this concretion material to release the objects within?

Thanks,

Pcolaboy

[Functional]

I'm not sure how big your blob is, or what other types of encrustations are holding it together. Those in the ShipWrecks forum might have a better idea of how to deal with that problem. If it was me, I'd consider using dilute muriatic acid, (which is diluted hydrochloric acid), a little at a time. It will eat rust and is used to etch glass, so be ready to rinse it off and use only in a plastic tub or other plastic container, in a well ventilated area, (don't breathe the fumes). Once you get down to bare metal, rinse and apply oil to the exposed surface, as it will start to rust almost immediately. Electrolysis is also a potential method, but your copper would likely disappear first.

I'd ask in that ShipWrecks forum first though.

F.