Coating backside of panel

[7t3 TA]

Check out the pic below. The rear tail panel was hit at some point. It was drilled and slide hammered out, then bondo'd about 1/4" thick. I found it after sandblasting and decided to cut it out and weld in a new piece. This part is not reproduced anywhere so I formed my own.

The question I have is how do I get to the backside to coat it after welding in the new piece? I can only get to a small portion of the welds from little factory holes but nowhere near complete coverage.

Anybody got any ideas?:help!: I'm at a stand still.

https://static1.pt-content.com/images/pt/2008/08/IMG_1249-1.jpg

It's a 73 Trans Am upside down on a rotisserie.
Gary

[Motown 454]

My car is being done at mikescustomcars.com and he strips all the EDP primer off everything. Then he primes it with weld through epoxie primer so he can weld the parts on. He also undercoats the back before he puts them on, accept where the weld is going. Check out his site you can learn a lot from his build photos.
Wayne

[200horse]

you can use simple restoleom in a can and brush it on cheap and it works very simple know one sees it.

[Roadbuster]

A tip I read somewhere (but have not tried) is to use one of those straw tips (like on a can of WD40) on a spray can of weld thru primer.

[7t3 TA]

Thanks guys, I'll be butt welding this piece in. Does the weld-thru primer burn off with the weld or does it kind of "mix" in with the new bead?
:hammer:

I may get some weld thru primer and try a sample first to see how it reacts .

Gary

[Denvervet]

It seems to do both ...mix in and burn off around the area welded from what I've seen. I have done as above mentioned painting all with epoxy primer or rust bullet, etc except the strip to be welded and spray those areas with weld thru primer. After that in an area that can't be reached you are stuck with either leaving it and knowing most of that area won't see moisture if seam sealed around that panel. If you really are concerned you'll have to cut a small hole and spray the cavity type waxes and plug the hole with one of the plastic plugs....which if done in inconspicuous spot won't like be much of a blemish. Good question because most of us have had the same issue. Remember the factory didn't do as much as all that and took many years of abuse to rust our hot rods won't likely see.

[7t3 TA]

Thanks DenverVet,

This area could see a lot of moisture. If you look to the left of the area I cut out you can see a factory square hole. There are more like it. Then in the middle of the panel you can see a "divet" or recess in the factory red primer. That appears to be a drain hole where the two panels are opened to allow water out. That's what it looks like anyway. You can see the surface rust around it. Not really bad at all after all these years (35yrs).

I may just drill some openings so I can coat the welded area. Then plug them up.

I used those little plugs on a thunderbird front poly bumper that I removed the license plate frame from. Stuck them in the bolt holes and coated with touch up paint. No one ever noticed.

Gary