I have a '72 and am in the process of replacing some rusted metal. I have read of the possibilty of bonding the under-hatch (above tail lights) repair panel using one of the high-tec body adhesives. Has anyone done this? I thought about using this method along with spot welds on the braces coming off the rear panel above the tag. Seems like this would eliminate the possibility of rust after welding in hard to treat areas. Any thoughts? Does anyone have one of these panels made by Nissan they would like to sell? Thanks!

I've used a body adhesive instead of using roset (sp?) welds on a truck bed panel and it has held for the last 7 years no problem. FYI spot welds are made with two panels roset (sp?) welds are the ones when you drill a hole and weld, and with a little paint look like spot welds. The truck had 86 spot welds that I would need to roset weld, so the adhesive looked like a good idea.

I don't know if it would be a good idea to weld metal with the adhesive in the middle. You would damage the adhesive bond and contaminate the welds making poor bonding on two accounts. On my 240z the have seem sealer along the seems in this area and that kept it from rusting from below. I have the rust in the corner from the top it got a little thin and pin-holed so I'm replacing and will have it spot welded and put on new seam sealer. However if I was not going for an original, or I was replace this panel, but was not stripping the car to a shell I'd consider using these automotive bonding adhesives. It is easy just get a whole bunch of clamps, and you won't need seem sealer.

Sorry I have been away on a motorcycle cross country trip up into Canada for the last five days....

No you need to remove the old metal piece first, I plug welded mine back were the old spot welds were. As for metal treatment I removed as much rust as I could then used rust converter in the hard to reach places, all metal was stripped bare than coated with weld thru primer. after welding seam sealer (out of a caulking tube) was used between the new part and adjoining panels, this was how it was originally installed at the factory. hope this helps clarify.

Edited July 27, 201014 yr by grantf

Alright!...another motorcycle guy. Never been into Canada...just a lot of trips to East Tennessee and NC mountains. Anyway, back to the subject. I'll be bonding the new panel in. I finished removing the old on last night from a fairly rustfree 240 and there's a ton of surface rust on the remaining panel. There's a couple of inches of metal overlap where these panels meet which will give a good bond. And it will be permanently sealed from water. There are 4 spotwelds for the extra braces above the tag, which I will weld. Thanks for the input, guys.

Installed the replacement panel with 3m panel adhesive...worked great and solid as a rock. And water can't get to it at all...serves as it own seem sealer.

(Reviving this topic)

I'm about to install a rear hatch replacement panel on my '72 and have been asking myself how to attach it.   

As I see it, the options are

1)  Perform plug (i.e. "Rosetta") welds

2) Using a portable spot welder

3) using 3M Body Panel Adhesive. 

Since the last comment eight years ago,  are there any more current points of view on this topic?  What am I missing?

(I'm leaning toward either 2 or 3 as I think the end result will be a lot less work and more likely top produce a good looking result.)

Edited August 3, 20186 yr by Jughead
Typos

When I do this I use method #1. Some predrilled or punched holes. Puddle them in, a little grinding, good as new...

1 hour ago, Patcon said:

When I do this I use method #1. Some predrilled or punched holes. Puddle them in, a little grinding, good as new...

This ^

Hey @Jughead curious how you did on the panel. I had to remove the entire top layer of the hatch area on mine as it was all compromised and I was tempted to try and build in more rigidity using the patch panel on top (it has those pressed grooves which make it much stiffer than my underlying patch.) Did the plug welds do the trick?

Also, anyone have any bright ideas on how I can attempt to recreate the small weatherstripping lip?

 

Edited October 1, 20186 yr by Unicorn Z

Are you trying to recreate the top panel, that is available, or the panel underneath it? It's not quite clear?

I attempted to recreate the panel underneath first. While it is passable, it's not very strong.

I have the prefabbed top panel ready to go on and it feels much stiffer. I was wondering if Jughead had taken your advice and how satisfied he was with the sturdiness of the plug welds.

 

1 hour ago, Unicorn Z said:

I attempted to recreate the panel underneath first. While it is passable, it's not very strong.

I have the prefabbed top panel ready to go on and it feels much stiffer. I was wondering if Jughead had taken your advice and how satisfied he was with the sturdiness of the plug welds.

 

To make the lip you were asking about earlier, you really need a metal brake. Then you brake the edge up for the seal lip and it stiffens the panel. You can weld a lip on, but it's tedious and easily warped. If I were going to weld one on. I would make it oversized and then cut it down to the right size along a scribed line, so it's straight

I fabbed the cover piece once. The problem with bending the 1/2" rear lip down is that neither long edge is straight. Not much of a radius but it's there. I ended up using a 6" vice to coax the bend in short sections then hammers and dollies to clean it up. It came out better much than I expected.