I have two SD Tactical homebuilt suppressors with titanium tubes and I used Plastikote's Ultra High Temp Hot Paint on both of them and it has held up really well, it is rated to 1500 deg. If yours already have paint on them I recommend you bead blast them clean. Wipe them down two or three times with a solvent (I used naptha) and don't handle with your bare hands. The paint needs to be cured according to directions on the can to hold up properly, three stages of heating and cooling which can be done in your home oven (preferably when your wife is NOT home!) The last stage calls for something like 600 deg. but home ovens don't go that high. I just set mine on max and left the stuff in there for an extra 30 minutes, seems to have worked pretty good.
Another option that has worked really well is Cerakote's air dry coatings. It takes a week or so to fully cure but is very resistant to high temps.