Rust repair/body tub questions

[ljense8]

So, I work a swing shift job, and this week it is my turn on 3rd shift(12am-8am). During this shift, things are pretty slow and my sleep deprived brain has lots of time to come up with crazy ideas.

The idea I have been toying with the last couple nights/mornings is building a custom body tub for my '91 K5 with diamond plate aluminum instead of using replacement panels from somewhere like Classic Industries. I would still like to keep the exterior panels factory, although they will need to be replaced/patched in the process as well. The two main ideas behind this being potential weight savings, and it would look cool. The thing I am wondering about is what gauge of aluminum would it take to provide sufficient structural rigidity? If I could use .125" or .063" sheet, that would save me some weight but if I have to go thicker, it wouldn't be worth it, in terms of both weight and money. Also, I have never welded aluminum, so I would have to find a welder in the area who could do this for me, but that shouldn't be too hard, since I know a few people who are pretty good. The alternative to welding that I sort of thought of and half dismissed at the same time would be to build a sort of frame for the tub out of angle aluminum and either rivet or bolt the diamond plate panels to that. This method seems like it may not be as structurally rigid and could provide ample opportunity for lots of squeaks.

Or, this whole thing may be a bad idea. What do you guys think? Any feedback or ideas are welcome, even if you say it's the dumbest idea you have ever heard.

 

[diesel4me]

You will likely run into electrolosis problems ,with aluminum on steel....I have a refidgerated truck body that has diamond plate aluminum floor panels that are attached to the steel channel iron skeleton/frame ,and where every screw they put in it to hold it to the steel is,the aluminum has a large hole about 3" around the screws,it disintegrated from the two dissimilar metals creating an electric current....I think if you did your truck that way,it would look great for a few years,then you'd be facing this problem....especially if it sees any road salt...

 

[ljense8]

Road salt here is a major issue. I still like the diamond plate idea, but with what you said, I may look into steel and see what kind of investment it would be. If it's going to be too much I will just do what I originally planned and just order replacement panels. Thanks for the feedback.

 

[454Sub]

Yes, electrolysis is the real deal. Im a union sheet metal worker by trade, and its amazing how much metal will rot other metal just by being close to it. Copper is a big one. We constantly have people wanting to replace damaged copper downspouts with aluminum, and then they argue with us that copper wont rot aluminum, copper rots concrete. lol But since the customer is always right we have to do it, and then go back in a year or two to find the elbows rotted clean off the aluminum.

That being said, you would be better off just using steel as its much more durable and crack resistant. 1/8in would probably be good, as Im not certain of the body tub thickness, cant imagine its much thicker/thinner than that.

 

[ljense8]

I know about electrolysis, I work with a lot of metal piping and such at my job, but for some reason I never put 2 and 2 together . Could be the combination of switching shifts and bad sleep I get every time I'm on this shift... This isn't a project I will be tearing into right away, I have a couple other things to get straightened out first, but every time I see my K5 with it's saggy midsection it makes me sad and gets me pondering repair ideas. The passenger side is still fairly straight, but on the driver's side the rocker is completely gone along with about 2" of floorpan along the bottom of the door and the rear fender is separated from the body support right behind the door. Also, the bottom mount of the driver's seat belt was only held in by the little piece of carpet trim right there. I made a pretty crappy support for the driver's seat and seat belt mount out of some fairly sturdy steel tubing I had laying around just to get me through the upcoming winter, but the sooner I can start repairing it, the happier I will be. The two main limiting factors are budget and having a way to get to work. I only live 1.5 miles from work, so I think late spring/summer will be a good time to pull it all apart. That way I can just ride my bike to work, and I can do my work outside for the most part, since my garage is barely big enough to hold the Blazer.

Needless to say, I have a pretty big project ahead of me, so why not just go all out and go with diamond plate right? Now i just need to get my wife to agree

BTW: As far as steel goes, I have no doubt that 1/8" would be plenty, as long as it's built at least halfway decent. The more I think about it, the more I like the idea of building a frame out of square tubing and angle iron to bolt or weld the panels of diamond plate to. I feel it would provide much more body stiffness while making installation of the panels much easier and cleaner looking. I could also incorporate reinforced sections for a roll cage. I live fairly close to Silver Lake and would like to bring my kids along for the ride when I head out that way. I have a few ideas for the cage as well, but that's a conversation that can wait for now. I need to stop getting so far ahead of myself and focus on a few other trouble items I have first.

 

[rampage]

How about stainless steel or using a sacrificial anode?

 

[ljense8]

It's almost like you were reading my mind rampage. The sacrificial anode idea did cross my mind, but I think I will be going with steel, preferably stainless for the diamond plate. The "basket" frame will likely just be regular steel with a good coating of roll on bed liner. Being that the "basket" for the body panels will be insulated, I will run a couple grounds to the actual frame.

 

[diesel4me]

You might search this site for ideas,I know one member here did his entire floor on his K5 with diamond plate,"Jauhlinger" I think was his screen name,I probably spelled it wrong though!...if it took 20 years to rot away the original sheet metal,I'd think 1/8" diamond plate steel would last double that,especially if treated with paint or bedliner or other protectants...