Panel bond adhesive to POR-15?
 

I have a rusty inner rocker on my 85, the outer is still solid. The rust was in an early enough stage that it was just soft in the middle and I cut that part out. The upper lip and lower lip are still there and I'm planning on cutting and trimming a flat piece of steel to overlap those areas and attach with panel bond instead of welding them in. And I would like to put down POR while I have access to it all to seal it up. Will panel bond adhere to POR? I don't have to use it in the areas that I'll be using panel bond, but if they adhere well then I may as well put down a liberal coat while I can.

Re: Panel bond adhesive to POR-15?
 

You may want to check the instructions of the panel bond, but most require bare, prepped steel. Part two of your question, not much of anything sticks to POR15. Part three, the rocker areas tend to become a collection point for condensation that occurs on the inside of the roof. The water runs down the A and B pillars and deposits inside the rockers. Any overlapping is sure to be another collection point for water and where you’ll find the next rust-through to occur.

The best way to fix a rocker is to replace it in its entirety and spot weld as the factory did to minimize weld distortion.

Re: Panel bond adhesive to POR-15?
 

Your questions have been answered well. But let me throw this out there on the panel bond to Por-15. Think about the "weakest link" idea, why use the panel bond when the Por-15 is what is holding the whole thing together?
'
NO, you don't want to do that.

Brian

Re: Panel bond adhesive to POR-15?
 

Well, shoot. Yeah, I know, but doesn't hurt to ask right? I haven't replaced an inner rocker or tackled a job like that so I was hoping for a patch. I would not cover the drain holes. Alright. Brothers has the inner rockers for $12. I'm not sure if they'll work on a K5, but they did have a vid on how to RR them. I'll check it out...

Thanks guys.

Re: Panel bond adhesive to POR-15?
 

Not familiar with your year of truck but if your inner rocker is bad your outer rocker probably is not far behind it and can it be easily replaced with out removing the outer rocker ??

Re: Panel bond adhesive to POR-15?
 

The outer is solid.

Re: Panel bond adhesive to POR-15?
 

my suggestion is to cut out all the cancer, shine up the good metal that's left, then paint all the metal the patch will attach to with panel bond adhesive. This will get rid of the rust, seal and chemical weld the patch on. If you're wanting to fix like a 6 inch area and not wanting to do major surgery on inners and outers, this would be a good solid fix. I would come back after the panel bond adhesive is cured and plug weld 3 spot welds on each side for piece of mind, then por-15 the whole patch on the side you can see. I would doubt water or anything would get in and it should last as long as the rest of the truck.

I'd like to hear opinions on my suggestion from anyone seeing any loopholes in this method....

Re: Panel bond adhesive to POR-15?
 

Brian is a better source for info on the adhesive, but I believe if you come back afterward with plug welds, the heat is going to cause the adhesive to release in the area of the heat.

If the panel is abraded properly, Epoxy primer would be a better choice over POR products, as the epoxy is far better at preventing rust creep than any other paint substrate. POR type paints (moisture cured urethane) were originally formulated as a paint for bridges, and there (as well as on vehicles) the MCU's are far from a permanent rust solution and don't match up to the sales hype.

Re: Panel bond adhesive to POR-15?
 

This makes perfect sense, thanks. Another point is POR15 doesn't adhere as well to perfectly clean metal as far as the patch is concerned. A 2K epoxy primer would be ideal. In my mind, I was assuming he would be brushing on POR15 in area's with surface rust in the hard to reach area's anyway. If only there was a 2K epoxy primer with built in rust encapsulator and while were dreaming....in a rattle can....

Re: Panel bond adhesive to POR-15?
 

You sound very knowledgeable, so ive got a question. If you took 2 pieces of 2 inch x 2 inch sheet metal and applied panel bond adhesive to all 4 sides, pressed them together, and left them out in the rain and weather (but not in direct UV) for 50 years...would you expect there to be rust 50 years later? My understanding is they would never come apart because it's as strong as a weld and the panel bond adhesive has built in seam sealer. Thoughts?

Re: Panel bond adhesive to POR-15?
 

Another question ive been wondering is when they panel bond new cars together at the factory, are they putting glue over a dipped rust inhibitor coating? I also wonder if it's a 3M 8115 type pba or something stronger?

Re: Panel bond adhesive to POR-15?
 

m2d...heres a experiment Brian did with panel adhesive...http://67-72chevytrucks.com/vboard/s...highlight=bond

Re: Panel bond adhesive to POR-15?
 

Wow! Thanks! Im forever a fan of pba now! To add to what was said on that link about shaved doors, i recently had a door panel off of a professionally custom tacoma. I found pba was used to patch door handle openings. I saw the glue from the inside. I know the truck was painted in 2009 and the paint and body had zero blemishes where they shaved them. All the door slamming and flexing from 10 years of use and no cracks.

Re: Panel bond adhesive to POR-15?
 

Just like anything else, there is a place and time for it. You need to exercise caution using it in the middle of a panel, as the seam doesn't always play nice and may come back and wave at you... The adhesive requires a flanged seam, which gives you one thickness of metal next to two thicknesses. Two thicknesses will heat up and cool slower than the single thickness next to it. Given the differing expansion and contraction rates over long enough time, you will see the exact location of the seam, through filler and paint.

This is a tailgate on a wagon that had the lower skin fixed with a flanged seam. The ghost line just up from the bottom shows exactly where the repair was made.


https://www.youtube.com/watch?v=OGhFEfVqxb0


So where the panel adhesive has it's uses, it should not be used anywhere on a panel if you expect an invisible repair. The factories use the stuff every day, but you don't see them using it down through the middle of a panel..

Re: Panel bond adhesive to POR-15?
 

Thanks. Ive used it with floor patches so far and feel good about the durability. I may never use it on exterior panels that get painted...but that's great info to know.

Re: Panel bond adhesive to POR-15?
 

:chevy:

Re: Panel bond adhesive to POR-15?
 

Just to throw something else out there, I'm a firm believer in setting up welders on practice pieces before tackling that expensive quarter panel. By the same token, a floor patch is a good opportunity to hone your welding skills for when it is needed where it does count. So my thoughts are tight gaps, radiused corners, and BUTT welded.


On another note, I had a prospective customer come by the shop this weekend wanting a 1970 Suburban lift gate rebuilt due to rust and stress cracks, similar to our repairs on the 55 wagon liftgate. (that repair thread starts here: http://www.67-72chevytrucks.com/vboa...=564201&page=3 ) I asked him if he needed his quarter panel fixed as well, as I looked at it from 40' away.

"no, it's already been fixed"

Sad thing was I could pick out every spot where repairs had been made, yes, from 40' away, and yes, he said the replacements/patches had been installed using flange repairs..