Technical Thoughts on brazed steel joints vs MIG welded?

I'd suggest that you stick / arc weld a frame before o-a. For thicker steel you would need bigger than usual tips and big bottles, compared with typical o-a use.

 

https://www.locostbuilders.co.uk/viewthread.php?tid=151252
http://www.fsae.com/forums/archive/index.php/t-10986.html?s=2f4ac3793225a1cc9fb6f05198249449
here is some discussion on the subject

https://www.rowanhick.com/2012/10/09/brazing-complete
This type of chassis is different than a typical ladder hot rod chassis.
I think it could work but wouldn't attempt until I became educated on the process

 

How not to bronze weld / fillet braze, by non other than the late, great Tom Jobe.



All welded structures are subjected to loading of some kind.
The loading on the welds depends completely on the structure's geometry.
Note the Surfers' frame design put the side rail triangulating diagonals in almost pure tension or compression which is the most efficient (potentially lowest weight and greatest strength).
Designs that try to bend the tube really require larger diameter tubes, more sophisticated joinery, etc.
https://weldtalk.hobartwelders.com/...lding-questions/50248-i-get-a-call#post657168

Note the Surfers' bronze welding failure really was a surface prep failure.
Although some types of welding, and weld electrodes tolerate contamination better than other surface prep is always important.

 

With all the requirements needed to braze a tube frame well the concept of welding makes too much sense. If I had my d'ruthers about a welded frame vs brazed as I launched a 3000lb car at 4000 RPM, well I'd be in that long line wanting a weld. Not to say braze won't work, but I think the skill and alloy selection and all the other intagibles makes it a really selective choice. And for the "...not building a race car..." thought? Ok, fuckin eh. Now the foundation is subjected to all manner of stresses every mile driven on roads. Never see too many potholes or RR tracks at the speedways or drag strips, do ya? My .02...

 

Thanks for the encouragement. I'm not giving up by a long shot. I tell my girls exactly the same thing. We are only limited by our imagination and determination.
Looking at a few more vids, etc, it seems my wire feed was way too low for the thickness of material I was welding which was 3/16" - 1/4". This probably explains why it was sputtering and stopping. Recommended feed rate was 80-100 and I think I was at 50 and lower. Lol. Lesson learned - read the damn chart on the machine first.
I picked up some new outer lens as mine were scratched which I found out really diffuses the light from the arc. I also purchased a much better head band that will keep my helmet from slipping off and moving. I also found yet a fourth helmet. Holy $hit batman. So yes, no new helmets. Got some better gloves, and a set of thinner ones as well for better feel of the gun. It really is also about position and comfort which I tend to shrug off as I just want to get er done.

 

Not sure if it’s been mentioned but Caterham chassis were 100% brazed until recently. Allowed bent chassis members to be replaced easily.


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Sorry to have been so brash, but its usually just some simple things that drive you nuts. My welder was working fine a few months back and all of a sudden everything went to pot. It looked like the weld wasn't getting gas to surround it. Tried all the usual adjustments then tried higher gas and lower gas flows. Removed the tank and replaced it with another tank to see if I had bad gas. Put a different regulator on the tank. Couldn't figure it out..........
Took my welder to a repair shop and in ten minutes he found the problem. Apparently I had stepped on/stumbled over my wire cable and caused it to to pull down slightly from its seat in the machine. My gas flow was exiting before it entered into the cable. Simply pushed it up in place slightly so it sealed again and machine was good to go.
Told me I didn't owe him anything. I insisted that I should pay him something for his trouble. He said go inside and tell the guy to charge me for 1/2 hour ($30). Went in and paid. As I got back to my truck he was loading the welder. I gave him another $10 told him to buy his lunch.
Most of the time its the little things that frustrate us. I think you have learned a little and you will get better. You just need to systematically work thru problems. Using the reference is a good start. Try a few of the other things I mentioned so you see how things change when you intentionally have too many or too few amps. Like I said, I catch myself changing my hand angle as a weld progresses and I have to tell myself to keep the torch more vertical. Try turning your gas off and welding. Then you will know what a weld looks like when you have a gas problem. Its obvious...... When your wire feed is too slow you have popping and spurting.....you recognize that now. See what happens when you turn the wire speed up way too fast. Then try real high amps.
The soft deerskin gloves give a much better control than the heavier leather gloves. Once you use them you will like them.

 

Just a thought, remove the paint and rust, then weld ???


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Lately, I have been watching Michael Waller on "Britania Motorcycles" on YouTube. Being British, he explained the terminology of brazing and bronze welding and while I am confused, he does have a valid point that it provides a strong joint so I whipped out a brazing rod and went to work on my bicycle.