LocostUSA.com

Noticed this video on the DonkaDonka company and a surprising amount of their chassis on display, thought that side of it may be of interest here...

http://www.youtube.com/watch?v=vcU4jKuMbFc

Very good video. Did you notice that he was bronze welding with the mig? I know the process is possible but never seen it done.
Bruce

You made me go to my favorite MIG welding site to investigate this.

MIG brazing is low heat meant for thin gage metals for less disortion apparently. They mention the DonkaDonka tubes were 1mm/0.040" thick so I guess that's the reason.

Apparently a pulse MIG is best for the process.

I was surprised to see they use 25mm/1" tube and also surprised at the thin gage they use.

A benefit for us of using the brazing wire would be you could take an assembly apart with a torch if you decide to redo something.

It doesn't it would be as strong if you can just heat it up and melt it with a torch.

Marcus, It doesn't matter what we build with; an oxygen acetylene torch will take it apart.

Tom

Very cool, thanks for posting it Cheapy! The bonnet buck/bonnet forming was very very helpful, if i were ever to build another Seven.

Not sure that heating to several hundred degrees is inside of the design parameters of my frame tho. Everything fails if you try to make it do things it wasn't designed to do, right?

Since the brazing doesn't melt the base metal, when you heat the joint and take it apart the tubes are not really damaged. It's not a perfect situation but you could remove something with less damage.

I don't know if it's easier to do this method. The wire costs more, but it's probably not a big deal overall.

It's not that easy to melt a brazed joint without heating the whole joint to the brazing material melting point at once, which will be rather hot. The main reason for brazing this chassis is because of the thin walled material and the fact that the brazed joints will be stronger than welded. 1mm is getting pretty thin and you can bet that the steel will be better quality than the mild steel that we are using. Now I don't want to start a war re square versus round but my opinion is that they use square because it is easier to work with, difference in strength is negligible and (in my opinion) joint strength is greater. I can't produce any mathmatical evidence for this it is just my opinion, but with square you have four distinct corners which are the strongest part of the tube so that when you make a tee section for example you have to flat planes on either side which creates a stiff strong joint.
Bruce

The wire feed brazing process is much faster in a production type situation. The process typically still need a fair amount of post cleaning to remove the flux before E-coat or paint. The new Viper frame is using this same process for all of the thin gauge tubes and MIG for the heavier gauge tubes. Dave W

the length of the joint on square tube is longer and therefore the joint is stronger when using braising.

what i noticed was a distinced lack of tubes,

The poor TV recording mixing engineers- they could only afford a sound room that was next door to some rock drummer practice session....

Gawd that video was annoying, Unbelievable, some of you guys voluntarily watch that cr^p?

but yeah, mig brazing has interested me since it was mentioned when they first started bring Smart cars into Canada and I was working at a dealership. They called it out as one of the best ways to fix the high streength pressings used in that vehicle.
But, really is it not pretty common to TIG using silicon bronze rod? I see it on a lot of headers, and even a bit on Pirate4x4 in offroad buggy fabrication, and in Hot Rod magazine in roll cage additions. Different method but same idea.

No, I live in China and some soldiers tied me to a chair and stuck toothpicks under my eyes forcing me to watch it all and then forced me to link it here by hammering bamboo under my fingernails to subliminally convert you Western Dogs to see Red as the only true way.

HTHs.

I was shot by a sniper with a mind altering drug that made me paralized,except my index finger luckily thats all I need on my smart phone...the voices in my head said "watch it" so I did..cant imagine what would have happened if I didnt.ps..i kind of liked the music.