Need help with this HACK job

[bradleyheathhays]

96 XJ here and I'm rebuilding what was once a huge hole in one of my rocker panels. I've riveted in 1/8" diamond plate aluminum for the backer support and now I've got 2 good coats of bondo on there. I'll end up going over the 1/4" thickness limit for bondo, oh well.


So my question is...how do I go from where I am now on the left side of the pic to building and smoothing this out so that it's paint ready and in the shape of the rocker panel on the left.


I've got a can of color matched red and high build primer on the way.

 

[Anak]

Aluminum diamond plate is a really bad choice.

Look up electrolysis.

I would take the aluminum out of there. It is going to create more problems than it solves.

Cut out the cancer and put some steel in its place. Cut the steel to the shape you need, fit it, and then take it out and at least put on a couple good coats of primer. Then install it. Ideally you would weld it in, but I am going to guess you don't have that capacity. If nothing else, install it with JB Weld (Yes, I know, that is not the right way to do it, but it is going to be a step up over aluminum diamond plate and the havoc that will create down the road. Just trying to work with what looks like the tools available). You could use screws to hold the steel in place while the JB Weld cures, then remove the screws and start in with the Bondo.

If you can weld then there are several much better ways to go.

 

[clean96XJ]

HomeDepot rent welders. pretty cheap too
Helmet they give is garbage. (cant see shit with it)
Uses Flux weld

Buy a good helmet (seeing is important) and gloves.
watch some YT videos. Practice on some scrap metal.

 

[Rob Mayercik]

The 3M body panel adhesive (a 2-part epoxy) would be another no-weld option that works well (I rebuilt part of my driver's side door sills using that stuff and self-drilling screws, and it looks to be very solidly stuck together).

 

[tjmotter]

Agreed, you absolutely need to get that rust out of there or it will continue to eat everything around and behind it.


The thing is, you don't really need to be able to weld with this type of repair, just tack and that is pretty simple. True "Welding" is all about puddle/heat management to get a good, strong bond. That isn't what you do with bodywork. Watch a couple of episodes of "Iron Resurrection" and you will see the proper way of doing this which is place the piece (use a magnet to hold it), tack the point where the two pieces meet with a short (1 second) burst of your welder then stop and let the area cool. While that spot is cooling, you can tack the opposite corner. Let it cool again and now tack the other two corners. Moving around like this helps keep both pieces of metal from warping but the cool down is the key thing because if the metal is still hot, your next tack will create a big hole.



Again, when you weld, you try to create a solid seam that bonds the two pieces of metal together. You simply can't do this with sheet metal because it is too thin so tack welding is the norm. There are some people who will invest in expensive TIG welders and who will have the skills to "dial in" the heat to the point where they can actually weld this stuff but that is far from the norm. You can see examples of this in TV shows like "Bitchin Rides" where some of their guys have mad skills but again, 99% of the shops that do this work tack weld with MIG.


I know you are on a budget but if it were me, I would also invest in a cheap blasting tool like this to try to knock out as much of the rust as possible. Despite what people think when they hear the words "sand blasting", most work isn't done with sand, it is done with ground walnut shells, aluminum oxide, soda or even glass. Once you have the rust knocked out, you can clean up the mess, tack in new metal and then prime/finish.



https://www.amazon.com/dp/B01M0CRUU...g&sr=1-1-a094db1c-5033-42c6-82a2-587d01f975e8

Aluminum diamond plate is a really bad choice.

Look up electrolysis.

I would take the aluminum out of there. It is going to create more problems than it solves.

Cut out the cancer and put some steel in its place. Cut the steel to the shape you need, fit it, and then take it out and at least put on a couple good coats of primer. Then install it. Ideally you would weld it in, but I am going to guess you don't have that capacity. If nothing else, install it with JB Weld (Yes, I know, that is not the right way to do it, but it is going to be a step up over aluminum diamond plate and the havoc that will create down the road. Just trying to work with what looks like the tools available). You could use screws to hold the steel in place while the JB Weld cures, then remove the screws and start in with the Bondo.

If you can weld then there are several much better ways to go.

 

[Tim_MN]

Remove rusty metal, replace with stamped steel XJ rust repair panels, use uni-body adhesive.

Pink bondo attracts and holds moisture, the green fiberglass bondo does not.

 

[tjmotter]

Remove rusty metal, replace with stamped steel XJ rust repair panels, use uni-body adhesive.

Pink bondo attracts and holds moisture, the green fiberglass bondo does not.

Maybe the cheap pink stuff does (I don't know) but the good stuff doesn't. I have never had this issue (retaining moisture) when using this Rage Gold (like this stuff):


https://www.summitracing.com/parts/fge-112


Note that the green reinforced filler is very good and 3M's version is known as the best but it is an absolute bear to sand. This stuff gets so darn hard that it will triple the repair time in sanding alone.

 

[Tim_MN]

A coarse wood rasp or a DA sander with 80 grit makes short work of any body filler. The green Bondo Glass from walmart or the farm and fleet store works just fine.