paint removal Green River fish

[FossilDAWG]

Hey all,

 

I have a Green River fish I purchased many years ago.  The bones mostly seem well preserved, but the fins at least (and likely all of it) was painted a dark brown and then some sort of a sealant was applied.  The matrix is different from the usual split fish material, it is more like a hard sandstone (much more sturdy than the split fish layer) and it is a brownish color.  Likely the fish was painted to "improve" contrast with the dark matrix.  I would like to remove the paint and restore the fish to its natural condition.  I have soaked it in acetone for hours (in a fume hood of course) and that removed the sealant but the paint is almost untouched.  Does anyone know what kind of paint commercial dealers use (or used to use 30 years ago) and how to remove it?

 

Don

[Thecosmilia Trichitoma]

Most restorers use acrylic paint, which will not be affected by a solvent. However, I do not know how to remove it.

[Auspex]

Try methylene chloride, judiciously. Be aware that it is extremely toxic. A little dab'l do ya'.

[snolly50]

If that is an 18" layer fish (sounds like, and it is possibly oil shale matrix*) it may be that the color is natural. Examine the piece under magnification. It is "impossible" to paint something small without "going out of the lines." If you see no paint mischief under magnification, it is probably natural coloration.

 

*break off a small bit of matrix, grind it up. Does it smell like the underside of a '58 Buick?

[rfarrar]

Over the many years that Green River fishes have been collected, many products have been used on them. Acrylic paint is a good bet, but color has been added to fish using colored pencils, stove black, and various types of mineral pigments dissolved or suspended in various binding agents like shellacs, Glyptal, varnishes, and polyurethanes. Some are removable with organic solvents, others are not. I suspect you will need some solvent assistance, but most likely best results will be mechanical removal with the piece under magnification.

 

Bob

[Ptychodus04]

On 7/27/2019 at 10:40 AM, snolly50 said:

If that is an 18" layer fish (sounds like, and it is possibly oil shale matrix*) it may be that the color is natural. Examine the piece under magnification. It is "impossible" to paint something small without "going out of the lines." If you see no paint mischief under magnification, it is probably natural coloration.

 

*break off a small bit of matrix, grind it up. Does it smell like the underside of a '58 Buick?

 

It could also be from the bottom cap. It is extremely hard and will be brown or gray with dark brown to black fossils. It also smells like the belly of a muscle car.