what reducer to use with the 2k mar-hyde primer. i've got about a half gallon and it is thick.

It will thin down when you activate it but if at that point you still want to reduce it, you can use any urethane reducer.

I use to use that primer, it's the thickest stuff out there.
I thinned it a lot, up to 100%,(probably too much), but never had a problem.
But that's probably due to me letting it cure 48 hours or more
before top-coating.
It did have a problem settleing out in my gun when thinned.
I used the DeVilbiss bag system and would lay the gun on its side beteen
coats, or else it would clog the gravity feed gun when thinned a lot.
Good primer though, I used a lot of it and it did great.
sure is thick though.