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snow cat body fabrication

battdad

Member
I am currently in the process of building a cab for a snowcat project i acquired last year. The main frame of the body is made of steel square tubing. My plan was to sheet the outside of the body with aluminum sheeting. I am almost to that stage of the build and until now, hadn't put much thought into how i was going to attach the sheeting. All along i had been thinking"Ill just throw some rivits in to hold everything together". Now lately I have been hearing about corrosion caused by dissimilar metals in contact with each other, so I went to the thought of using stainless rivits through aluminum into steel tubing. can anyone tell me the proper way to fasten aluminum sheeting to steel tubing? in the matter of a snow cat cab. I also thought that the proper way would be to paint the tubing before hanging the sheeting and then putting a coat of paint over the whole outside.
any help would be appreciated.
 

redsqwrl

Bronze Member
GOLD Site Supporter
valid concerns, I see old (40+ years old) distressed thiokols that some reaction to the aluminum and steel contact.
How old are you....... If you are twelve I would paint the steel and rivet away.

I have used 3M adhesive to glue a new rear quarter onto a rally car. it held together and that adhesive was tough. (fitment and clamping were key)
 

teamster

New member
I'm in the process of doing the same thing right now. The first picture is of a trailer I built in 2003. I painted that trailer with plastic paint (Endura) and the aluminum sheeting is powder baked aluminum. To prevent corrosion of the aluminum, I used poyalocan tape, used on pipe, to separate the 2 metals. Then I used self tapping stainless steel screws to hold the sheeting on. The self tapping stainless screws are a pain because they twist off before the tighten up and the sheeting warps over the years. The second picture is of the trailer I built in 2015. Same paint, but I used the commercial 2 sided 3m tape that is used to hold the siding on the new cargo trailers. If you go on You Tube and look up 3M tape, there's a video that shows how the riveted trailers warp and the 3M tape doesn't. Also you can't remove a panel without wrecking it, the tape holds that well. My Tucker that I'm building, (100 Mile Tucker thread) is going to be paneled the same way.
 

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Blackfoot Tucker

Well-known member
GOLD Site Supporter
Now lately I have been hearing about corrosion caused by dissimilar metals in contact with each other, so I went to the thought of using stainless rivits through aluminum into steel tubing. can anyone tell me the proper way to fasten aluminum sheeting to steel tubing? in the matter of a snow cat cab. I also thought that the proper way would be to paint the tubing before hanging the sheeting and then putting a coat of paint over the whole outside.
any help would be appreciated.

Battdad,

What you're describing is called galvanic corrosion. A few years ago I started a thread about it on Tuckers:

http://www.forumsforums.com/3_9/showthread.php?t=44452&highlight=galvanic+corrosion

That thread also talked about rust issues with Tuckers, but as far as preventing galvanic corrosion, you need to do something to "break the bond" between the dissimilar metals. The 1979 and 1980 Tuckers I've owned all use raw aluminum sheet metal riveted to the raw steel frame for the roof and doors. Those year Tuckers use a clam shell style hood and the center portion of the aluminum hood halves are riveted to the steel hinge. The floors are also aluminum, and they are screwed to the steel frame.

My snowcat buddy and I drill out all the rivets, sand the steel frames to remove all rust and corrosion, and then spray them with a couple coats of primer. The rivets Tucker used were steel blind rivets (they're basically POP rivets) but this is also a problem area. The rivets have a mandrel that when pulled on by the rivet gun, compresses the rivet and eventually breaks off. The portion that remains in the rivet can (and does) fall out. That leaves a nice hole in the center of the rivet. Water can then enter the support frame. We have replaced door frame sections that were distorted by water intrusion. Enough water filled those steel square tubes that when it froze, it expanded the steel to the point it was rounded and split the tubing.

In reassembling the machines we use an auto body seam sealer on top of the painted frames (which also helps prevent a bond) and closed-end stainless steel blind rivets on the hood, roof and doors. The ends of these have no hole and the mandrel's remains can't fall out the back of the rivet. These rivets can be a bit difficult to find, but they are out there. If you go with rivets, I'd also suggest getting a pneumatic rivet gun. Steel and stainless steel rivets that are 3/16" in diameter take a lot more force to compress than an aluminum POP rivet. Using a hand powered rivet gun you'll get sore fast and/or have forearms like Popeye when you're done.

I think Teamster's method is excellent, but in our case we would have literally hundreds of holes in the aluminum and the steel frame to weld closed.
 
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