Technical Thoughts on brazed steel joints vs MIG welded?

Just a question
Could you fit the xmbers inside the rails(or over) and rivet line the factory.
Looks cool.
OEs recommend bronze butt joints on many section locations.
Sheetmetal only.
You could fab a sleeve and spot weld with a mig. Then braze the joint for looks.
Just a suggestion.

 

What do you mean by “without the requisite skills and knowledge”? Are you referring to specific observed procedures that looked really sketchy or perhaps a perceived lack of formal instruction in those skills/knowledge? If one comes from an authoritarian ‘jurisdiction’ where most human activity is strictly regulated, I can see why that seems so strange.

But, remarkably, even in the USA where that has increasingly been adopted, working on one’s automotive creations is still a relatively free pursuit. To be sure, we have all seen poorly assembled, potentially unsafe rigs at car gatherings, but such mechanical builds are not often self destructing and wreaking havoc on the public. And sanctioned motor events usually have self policing rules and tech inspections to rein in the marginal players.

My observation has been that there are a lot of quite capable builders in various mechanical hobbies and it would seem they possess some combination of innate ability, self education and good judgement about what works. Given what I believe to be a pretty enviable safety history, I hope it’s a long time before we are further encumbered by ‘bureaucrats’.

Ray

 

If your going through the effort of brazing the pieces together, substitute steel welding rod for the brazing rod and gas weld it. Don't use coat hangers, use real steel welding rod. Modern hangers are nothing like the hangers of the 50s and 60s. It might be pretty hard to actually find real steel hangers anymore, most that look like steel and a really cheap alloy and they don't weld worth a darn. Gene

 

So you can't see the weld puddle and and can't mig weld so you're thinking that all of a sudden changing to tig or brazing will solve all your problems.
Start by getting a eye test and find out if you need glasses or something like cataract surgery.
You can also get cheater lenses that magnify the weld so it's easier to see.
You really need to take a class where someone can start with the basics and show you how to set up a mig welder properly. How to set wire tension, wire speed, gas flow, change the liner, change the tip, wire stick out, travel speed, proper gas, and the importance of a good ground.
A professional can watch you weld for a few minutes and point out what you're doing wrong and how to improve your welding.

 

This is probably most of your problem. Your profile doesn't list your age. How long are your arms reading the newspaper? Even with reading glasses I found a cheater lens in the hood helped even more. They have lights that attach to the torch, I usually put a good light over my shoulder.

 

Also curious to know what kind of helmet you're using. Modern welding helmet technology is truly amazing and not too terribly expensive.

 

I think many people have a problem seeing the weld and don't realize it. They kinda see it and think what they are seeing is correct........but they aren't seeing everything as well as needed.
First you HAVE to use a helmet that has a sufficiently light adjustment . Some helmets are too dark. Use something that gets down to a 9, and then put a helmet light on it. Next go to whatever kind of discount store Canada has. We call them various names like "The Dollar Store" . They sell reading glasses for about $3/5. Get a pair that puts things in focus about 15 inches from your face.
If your welder doesn't have a "chart" on it, let me know and I'll send you one. The chart will tell you what speed and amp to set your welder at. If you only have a 110/120 volt welder .......sell it and get a 220/240. Some of the newer welders come with "Auto-set". You put the dial on your wire size and the other dial on the thickness of the metal......and the machine sets the amps and speed for you. I recommend a Miller 212. They aren't cheap, but you will love it.
Once you are set up properly just practice a little and you will find your welds get better. My son got a 212 when stationed in Arizona and called me. He got help over the phone and was soon doing well. Does he ever get bad welds.......yes, and so do I.
Did you know you can braze with a tig ?

 

If you use braze and then for some reason need to weld to that area later, you are going to have all kinds of problems with contamination. You're better off welding everything.

 

That wasn't "brazed" it was gas welded which he clearly explained in the article. Basically "aircraft welded" a lot of small plane frames are gas welded to this day.
I agree 100% with those who say if your mig welding isn't up to par PRACTICE until it is. Get some metal and build something for the shop or build your wife, significant other or your mom or aunt a plant stand. I have a plant stand out here that I bought 40 years ago from my friend's son because his mom already had the ones her older brother's made when they were in Ag shop and couldn't afford it. Those gals don't care if the welding is a bit sloppy as long as the stand holds plants up. Need a work bench for the shop get some metal and weld it up. Anything for practice and making something you can use beats the hell out of running a bead on scrap and then throwing it back in the scrap pile even though that has merit too.

 

This frame, and fork, is 4130 Chromoly tubing. It was brazed together in 1967. It was flogged hard in '67,'68 and '69. Then again 40 years later. In all that time, it has had no joints let go.

 

We built this frame the same way, in 1970. It was laid down at speed 3 times (didn't handle worth a shit) but the frame is still intact, needing no repairs.

 

As they say, the mind is the first thing to go. I dug out the March ‘71 R&C and @Mr48chev is right, Cotton used gas welding.

 

Brazing is good for some things but it’s a bit of an art to do it strongly, have a look at brazed steel bicycle or MC frames. Would need nice joins and fillets. Anyone can braze not anyone can do it well. Go with a mig. Example of a fillet brazed bike frame attached.

 

For the life of me I cannot understand why anybody would want anything less than the best welding on their car frame. I had 3 years of high school shop classes and the last semester I was assistant instructor. We taught kids how to braze first and then how to gas weld and arc weld. We'd test their work with hammer and vice. A good bead of brass on clean metal is strong but not near as strong as steel.
I wouldn't settle for second [or third] best unless there was a helluva good reason for it.

 

I would say NO to brazing. Get a good MIG machine from a reputable welding supply company. I have several for different purposes and get the most use out of a small 180 Miller but do use a larger machine when needed. I am just a hobbiest now and don't build frames every day but have been doing it for more than 50 years. Started out gas welding with coat hangers and using a homemade buzzbox made from light ballasts. You can get a decent auto darkening helmet from Princess Auto in Ottawa without breaking the bank. They put them on sale all the time. I always wear the same reading glasses that I would use for looking at a computer monitor and take the time to ensure you have enough light directed on your work. I use a small fan to move air away from the area. Preparation is key and practice directly correlates with results. Most machines come with the necessary charts to get you dialed in. Takes time to learn the machine and hone your skills. It's a lifelong learning thing for me. Good luck!

 

Welding stick, mig, tig, & brazing since 1951----Mig it!!!

 

Bike frames and motorcycle frames are furnace brazed. They are clamped together, and a brass alloy paste is applied to the joint(s) and the frame is heated in a furnace to the melting point of the brass, and it then flows into the joint and around the outside leaving a nice clean joint. It is stronger, neater, and faster than brazing, or welding each joint one at a time.

 

Thanks for all the advice. That's why I thought I would ask. I'm no expert at welding by any means. I have a Hobart Handler 180 which is 220V, so the machine is capable of 1/4" mild steel.
I have no issues with my eyes, and thank the heavens I don't need reading glasses. I can see the puddle for sure, but I can't really see the joint half the time in front of puddle so I "wander". I have 2 or 3 "cheap" helmets with the auto darkening, and one without which came with the machine. I think I was welding better with original helmet quite frankly. I'm "tuning" up my machine, with new wire, tips, nozzle, and will see about a welding helmet light or other light. I do most of my welding in my garage which really isn't that well lite, even with two 150W bulbs (approx. 200 sq ft).
All the feedback is good, and I'll look at perhaps riveting as an option. I like the idea of testing joints, and I'll see about local welding shops and what they might charge. I had the local blacksmith, yes we have one, weld some recovery lugs on my ARB bumper a while back, and I wasn't completely satisfied. I think just that was $100. I did this because there was no way I would trust those joints with my small machine, and indeed those recovery lugs have been used in tough off-road recovery situations without issue.
Even with MIG welding, and for that matter, any type of joint, one can calculate the strength of that in theory from first principles. Those calcs assume the weld etc. is perfect without issues. My point is that even if you are good at welding, fabricating, etc., you don't know how strong that joint is unless you calculate it or test it. You may have a gut feeling based on experience, however nobody but nobody will do those calcs as hobbyists. We've all seen questionable stuff people have done to their rides, and it goes with the territory, as many of us think we are better than we really are, and some others are fine with "looks good enough". Rest assured, whatever I decide to do, it will be better than "good enough" because of the engineer in me. Lol.

 

In my experience MIG welding near brass is the next thing to fireworks. IIRC brass melts at around 500*, MIG welding goes over 1000*.

I found that marking the joint with a soapstone helps with that. Also as mentioned before, lots of light is needed.

 

You mean gas welding in place of tig welding correct? You are not talking using bronze rod, correct?

I have welded car and bike frames up with an oxy-acetylene torch, a brazing tip and steel filler. When I was learning to weld we had to be able to weld with a gas torch before we could move to electric. Anyway it works for me. I cannot say if it will work for you or not.

 

Boy that sounds familiar. I too flipped up my hood and discovered what I thought was a good bead was 1/4" off the seam. It's hard to admit your eyes are going, but you can get readers at the Dollar store, try some +1 or 1.25. You can get your nose closer to the work then get a good light. I've used a quartz, haven't tried a LED yet.

 

If your eyes are good and you can see the puddle but not the joint, then I’ll bet your lenses are filthy or your hood lens is too dark.
The only way you’re gonna know is comparing to another hood or get someone to try your hood.

When you’re windshield is all jacked up with road spray you can see the headlights, the street lights, the gas station lights but you can’t see the road or read a street signs. Maybe you can even make it to the store to refill the washer bottle but it ain’t fun.

 

Brazing is plenty strong if done right with the correct rod. Regular brass is not what you want, but rather nickel bronze. Just about all British tube chassis race cars from the 50's and 60's were were nickel brazed and when done correctly the weld is at least as strong as the tubing. As Dean Lowe noted it will hold up as well as a TIG welded structure if done correctly. A long time ago a friend of mine in Australia went off the strip in his mild steel, nickel bronze welded rear engine dragster and ran over a big rock which ripped through all of the lower cross members in the frame, cutting some of them in half but every weld held up.
That said, there is a bit of an art to getting it right with the correct amount of heat to make the filler flow and bond without getting the tubing too hot. I have also seen plenty of MIG welded frames where the welds had little penetration due to lack of operator skill along with TIG welded junctions with severe undercuts, an excessive HAZ or porosity so some level of operator skill is paramount..

Roo

 

This or like many do you work right under the light you have so it shines in the back of your helmet and produces a glare on the inside of the lens. Try moving so the light is infront of you and not above you or get a cover for the back of your helmet to keep the light out.

 

Seems the local college is now only offering full-time welding courses which last 42 weeks! Found someone on kijiji (Canada's version of Craig's List) for ONLY $350 for two days. Lol...


This what the local welding shop told me to use. Have not yet checked to see what this actually is.



I think my issue is either the helmet or lighting, of a combination of both. I have the darkness dialled down to 9. I sometimes position my dual halogen work light on what is I'm welding, but them typically the helmet will darken as I get ready which is a royal pain. I'll try a few things this weekend, and will look into a helmet light.

 

A guy named Colin Chapman from England built cars named Lotus that were brazed together square tube.

 

If I were you I would make my frame connections overlap so you can install bolts or better yet, rivets at each joint like the old Ford frames. Nothing gives peace of mind like redundancy. I personally feel that you are overthinking the whole deal after all it's a Speedster not the Golden Gate Bridge but better to overthink than to not think I guess.
What was it Clint Eastwood said? "A man's got to know his limitations"

 

They did have some round section tube as well. And he was not alone--Cooper, Lola, Brabham, McLaren etc. all brazed their cars in that era.

Roo

 

A guy named Lloyd Taylor built a number of engines this way. The one you will recognize was named Crosley. It was later switched to a casting for production and water leakage problems.

 

I think hot riveting is out. Lol. Three man team, and look at the equipment!



The wooden framed GN JAP is basic and has worked for 10 years in numerous racing events and extended road trips to France and back to the UK. I think it weighed in around at just over 1,000 lbs. The difference is that engine probably weighed no more than 200 lbs. You just have to love Richard Scaldwell's craftsmanship and attention to detail. He and a few other prewar guys in the UK are in a league of their own. He and his daughter thrash that thing on the track.