Type of Primer before raptor liner

[Cortez]

Hey Y’all,

I’ve been prepping, for paint and welding/patching my tub from all the holes drilled over fifty years...finally getting close . My plan is to raptor line the inside, with hytech thermal beads added to insulate and reduce noise. My tub is 50% bare metal and fully sanded. The paint shop recommended ppg black primer MP172 which states it’s ok for bare metal. It’s not an etch primer. Do I have to use an etch primer or will this bond with the raptor liner if I spray within the flash time?

Thanks for any input,
Dave

 

[rguest3]

I agree with the paint shop - PPG Epoxy Primer.

 

[68Broncoz]

I used epoxy primer on mine before raptor. On small sand thru spots I used the acid etch recomended by upol.

 

[Cortez]

I used epoxy primer on mine before raptor. On small sand thru spots I used the acid etch recomended by upol.

And I suppose that’s the real question...do I need acid etch on the bare spots or is epoxy primer sufficient. I have about 50% sand through because I scraped off three layers of paint.

 

[Cortez]

Guess I found the answer on their literature. Any of these can be used - urethane, epoxy, or etch primer ...so it sounds like it’s not a hard requirement for etch primer. I should be good to go.

 

[rjrobin2002]

Some primers are DTM "direct to metal" and some are not. This goes for epoxy, urethane, and etch. Just make sure your PPG epoxy says DTM on the can.

Also a big mistake on DTM primers is people dont sand the new patch panels before the primer, they think only the painted areas need sanded.

Run your DA sander over every surface with a 220 pad before the primer, degrease, prime, wait 1 hour, then shoot bed liner.

 

[Cortez]

Thanks RJ - this epoxy is DTM. And I just fit a new tunnel cover so I will be sure to sand it...would have missed that without your input.

 

[mtp71174]

I was told not to use epoxy primer (PPG dp brand) over etch primer by my painter/body man. It has something to do with the etch chemicals.

 

[rjrobin2002]

I was told not to use epoxy primer (PPG dp brand) over etch primer by my painter/body man. It has something to do with the etch chemicals.

No need to use an etch if your epoxy is DTM.