Thinning rubber based ink

Mineral spirits will indeed thin the ink, but it will not print well at all.
Use printer’s varnish. Available where you buy ink and paper. It may not be in stock and will have to be ordered.

I can’t find much info on printers varnish other than applying varnish after the print. Can you point me in the right direction?

I use rubber base a lot and to thin it i use tack reducer. Dick G.

My supplier carries a product called Sterling Varnish. It is high quality linseed oil. Check with your ink supplier - if they don’t have Sterling Varnish they should have tack reducer like DickG uses.

Thanks for all the help guys. I’m using linseed oil and it’s working wonderful. Much appreciated.