Working with aluminum?

Thinking about how to build the body for my next speedster

Debating on skinning a steel tube frame with alum sheeting instead of steel sheet. I assume I would have to rivet it to the frame right? Are there any rivets that look better than pop-rivets but are still easy to install?

How hard is it to weld aluminium? Could I build the frame out of alum tubing and then weld the alum sheet to it? Does alumin tubing bend in a pipe bending or is it too brittle?

Lots of thoughts, lemme know what yall think!

check out rivetsinstock.com

If you do decide to go with bucked rivets, there are more than one style. The typical domed head that most people are familiar with. There is a pan head rivet, the head is lower and a slight dome shape to it, and a flush rivet head that sits flush with the outer skin. But the flush rivet has to sit in a recessed area, and that recess is formed with a dimple die. So your kind of doing the job twice with flush rivets. Google aircraft rivets or bucking and installing aircraft rivets and you should find a lot on the subject as well as required tools that will be out of the ordinary, but necessary.

BigIrish said:

How hard is it to weld aluminium? Could I build the frame out of alum tubing and then weld the alum sheet to it? Does alumin tubing bend in a pipe bending or is it too brittle?
Lots of thoughts, lemme know what yall think!

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Pretty big undertaking, but the answer is yes, anything can be done. There are several different kinds of aluminum and some can be bent, some break, some have memory, and go back into the shape they started. If it was me I would do a steel frame. As far as welding, I am guessing TIG is what you are thinking. Just like all welding, it takes practice, and clean aluminum. Use a stainless steel brush to prep your work, and don't use that brush for anything else. Same as your tungston, keep it clean, and when sharpening use a stone you don't use for anything else.

Sounds like a great project.

This is one of my old rock buggies. Steel tube and aluminum panels.

Thanks for the good info everyone.

Bonehead - do you have any info/pics on how you attached the panels to the steel frame?

I used the large pop rivet, around here they are called a snowmobile rivet, but they are in the speedway catalog as well. 3/16 steel rivet with a large head. I just measured out the distance betwwen them to make them look a little better. It would work for a car but bucked rivets are more old school.

My main motivation would be so I don't have to paint it and I want it to look cool.

So that means brass or copper bucked rivets, which would look awesome...but how hard are those to install by yourself? I assume typically you would need a man on each side of the rivet with an air tool.

I saw a tool online that looks like it can be operated by one man and squeezes it from both sides. Anyone ever use this?

I'm slowly talking myself out of this...but can't let it go just yet!

aluminum welding is not for a guy who has never done it, if ya Mig it it is a lot eaiser than Tig but with Tig you can fuse it and do a way better job ,also get a cleaner after ya brush it anykind will do the trick,if ya need any pointers just ask i have welder for a longgggggggggggggg time and will help you

waldos_1 said:

aluminum welding is not for a guy who has never done it,

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I know what you mean, but that kind of makes it hard for anyone to ever learn it.

Hey just try on some scrap till ya fell you can do it ,might take a bit of even go online and do a search but hey if ya mig it ,thats the easiest way, just dont try to carry to much metal at one time

I prefer AC TIG on aluminum using a lanthanated tungsten, more bead control and more amperage control.

Aluminum requires more amperage. I use around 200 - 280 on 3/16" material.

In either case, MIG or TIG, keep in mind that your travel speed needs to be faster after you have established your puddle.

It is really not that hard with a little practice. Cleaning is king here, stainless wire brush or scotchbrite pad. After brushing or scotch brite, wipe down the area to be welded with denatured alcohol. Also clean the area you plan to weld and 1/2 inch either side of the joint.

OK I really cannot let this aluminum body thing go. I would like to figure out how to skin a steel tube structure with aluminum sheet without using pop rivets. The goal is to end up with a smooth skin that I can leave unpainted.

I've come up with this (see pic). Steel tube structure, bolt or rivet thin wall aluminum angle to it, which I will have to pie-cut around the curved areas. This will give me a flat aluminum surface (the alum angle) that I can puddle weld the aluminum sheet to. Will this work?

I know you can drill a hole in sheet steel and then puddle weld it to a steel surface below. Can you weld aluminum sheet to underlying aluminum surface this way?

We call it plug welding around here. Yes it will work, but in that configuration, I think you will get cracks in the angle iron. It looks like too much flex between where it is welded and where it is attached to the tube.

Sorry, yeah i meant plug weld. Still an amatuer here

OK I see what you mean. My next idea is to use pop rivets but then fill the little holes in the rivet with a aluminum-based body filler. I just don't like the hole in the middle of pop rivets, but if I could fill them to make them look more like bucked rivets I would be happy.

Thoughts??

OK I finally figured out a solution. Apparently they make a pop rivet that when finished looks just like an old school solid rivet. Used for reparing Airstreams, old truck cabs etc that were orig assembled using solid rivets. You have to buy a tool that shaves the head nicely after installation, but seems like it will look good when done. So this is what I plan on using:

http://www.vintagetrailersupply.com/Olympic_Rivets_p/vts-179.htm

Stay tuned!

just remember that if you skin aluminum over steel it will eventually corrode do to the dissimilar metals touching.

aluminum also work hardens meaning the more you hammer, stretch or bend it the stiffer it becomes until it cracks. you can aleveate some of this with annealling

jfg455 said:

just remember that if you skin aluminum over steel it will eventually corrode do to the dissimilar metals touching.

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One way around that is to paint the area that will be touching the steel with a bitumastic paint (almost like a black rubber). It's nasty stuff to work with but it should keep the disimlar metals from corroding or atleast slow it down. We always have to paint any aluminum angle being embedded in concrete with it at work.

pistolpete said:

One way around that is to paint the area that will be touching the steel with a bitumastic paint (almost like a black rubber). It's nasty stuff to work with but it should keep the disimlar metals from corroding or atleast slow it down. We always have to paint any aluminum angle being embedded in concrete with it at work.

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Interesting, never thought about that. I was planning on painting the steel structure before attaching the aluminum. I was also considering putting down a layer of rubber tape or duct tape in between the two, more to keep it from rattling/buzzing than anything, but now I think I will definitely do something like that.

What about building your framework out of steel as you mentioned, but attach the aluminum panels with Dzus fasteners. Sections of aluminum panels could be buck riveted together to make larger panels, or some of the more complex compound curved panels. Check into some aircraft construction techniques for some ideas, lots of possibilities. The cool thing about Dzus fasteners is they can be removed easily and the panel taken off to work on what ever is behind it.