Joining aluminium bar/rod

- G
- Gav
  
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posted
18 years ago

Tue, May 10, 2005 8:09 AM

I am wanting to make a model car based on a space frame chassis and was thinking of using aluminium rod/bar. I have not attempted anything like this before so its a bit of a learning curve. I am thinking of brazing the pieces together but am unsure of what I will need to do this. I have a small butane torch, pen type that I mainly use with a soldering attachment, will this be sufficient to braze rods of up to 6mm thick? I'm open to suggestions on the best way forward from you experienced people.

By the way, I went to the show in Harrogate. I was very impressed by the quality of workmanship in the models. Got me motivated to finish a few projects that I have had lingering around for ages, can't wait for the Pickering show.

thanks

Gav

- A
- Alan Marshall
  
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posted
18 years ago

Tue, May 10, 2005 4:43 PM

You will not braze aluminium ...... brazing is a term usually given to a brass based process.

However you can join aluminium with low melting point alloy and there are kits about that provide you with the necessary bits and instructions. The rod melts about ordinary solder temperature I think so your butane torch may be OK if the parent material is not very large. The secret of joining aluminium is breaking down the oxide layer that forms during the heating process and the kits provide a stainless wire brush for preliminary cleaning and a stainless rod for breaking the oxide layer whilst the melt is running in the joint.

The kits are often demonstrated and on sale at model exhibitions.

- T
- Tim Christian
  
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posted
18 years ago

Wed, May 11, 2005 7:29 AM

Both Lumiweld and Technoweld are very good - but require quite a high temperature. The only snag is that, due to the temperature, the aluminium around the joint softens. It can be work hardened again, but that is tricky without distortion.

Using the same method - scraping, ss brush, etc - a good joint can be made using plumbers' lead-free solder at a lower temperature. There was an article about this in ME Workshop a few years ago. The joints aren't as strong, but strong enough if the joint area isn't too small.