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Technical Thoughts on brazed steel joints vs MIG welded?

Discussion in 'The Hokey Ass Message Board' started by Ziggster, Feb 10, 2020.

  1. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 2,954

    ekimneirbo
    Member
    from Brooks Ky

    One thing here that needs to be put to rest is that a brazed joint does NOT provide strength equivalent to a welded joint no matter whether it is furnace brazed or done by hand. It just ain't so !
    It may provide "sufficient" strength depending on application but the" total" or "maximum" strength is not equal.
    Most of the examples that are cited are some type of tube (round or square) that has thin walls and used in racing applications where they only have to hold up for a short time. Brazing does not melt the parent metal and become as one with it, it is a surface application .
    Skip to the 7 minute mark............
    .
    There is nothing wrong with using brazing in the correct situation. Building a frame for a car to be driven on public roads for thousands of miles is not that situation. There is a reason why its not the first choice in assembling aircraft that use tubing/fabric construction. Probably less than 1 in a thousand homebuilt tube airplanes ever used brazing as the main construction process. Given that brazing is so easy to do, you have to ask yourself why all those amatuer builders then struggle to learn how to weld instead. They have the same problems learning to weld that hot rodders do. At first it was O/A welding. Then Tig worked its way into the picture. Now there are even some planes constructed with Mig. They have to deal with not only trying to get penetration on thin metal tubing, but welding around curved surfaces......and trying not to burn thru the thin tubing. Still with all those concerns, they seldom ever revert to brazing. I can guarantee that many of those builders produce O/A welds that look like total crap.....yet they are still strong enough to hold together. Move over to an automotive frame and you have much thicker material with lots more mass. Penetration is easy with a Mig and even if your weld isn't beautiful, it will still be stronger than brazing.
     
    Last edited: Feb 11, 2020
    Ziggster likes this.
  2. deathrowdave
    Joined: May 27, 2014
    Posts: 2,939

    deathrowdave
    ALLIANCE MEMBER
    from NKy

    Brazing was old time work , let’s face it there are many better proven ways of bonding metal . Why not use the best and safest available . My bicycle frame was brazed , not my car frame .
     
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  3. Ziggster
    Joined: Aug 27, 2018
    Posts: 1,166

    Ziggster
    ALLIANCE MEMBER

    Still learning lots. Seems many space frames were bronze-welded in the UK like Lotus. Watched this vid on oxy welding which was very nice.



    Agree that brazing probably isn't the way to go as many have pointed out which is good to know. Now I'm intrigued by the results of the work in the video above. Over the next few weeks, I'm going to practice some more MIG welding, and give oxy-acetelyne welding a try. If I'm not up to the task, I'll see about getting a pro to do the welding.
     
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  4. gene-koning
    Joined: Oct 28, 2016
    Posts: 3,007

    gene-koning
    Member

    Just a note, I usually clean the lenses on my welding helmet every week. Its amazing how much stuff covers the lenses in such a short period of time. I take every thing apart and clean both sides of the clear lenses and both the inner and outer surface of the darkening lens with a clean damp cloth. When the clear lenses get scratched up, I replace them, cleaning the lenses with the damp cloth seems to prolong the clear lens life span. Now, if only I would have been smart enough to do the same thing with my prescription glasses, the lenses on them probably wouldn't be so scratched up.

    I also use an led light to light up the piece I'm welding on, I put the light above the piece I'm welding if possible. As long as the light isn't shining into the helmet light detectors, it usually won't effect the auto function of my helmet. Sometimes I need to adjust the position or the direction the light is facing. Gene
     
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  5. 6sally6
    Joined: Feb 16, 2014
    Posts: 1,999

    6sally6
    Member

    I vote to WELD it!! Then get a good grinder and make it look "finished"(slick)
    Is it 'possible' to braze a hot rod together?? Sure but.... would you really feel comfortable riding your grand kids down the road at 60+ mph in a hot rod that's brazed together? Go for maximum strength when people lives may be in play.
    Buy-a-grinder
    6sally6
     
  6. LM14
    Joined: Dec 18, 2009
    Posts: 1,937

    LM14
    Member Emeritus
    from Iowa

    Most sanctioning bodies won't allow any brazing on frames or roll cages. That should tell you something.

    I was almost to the point of not welding anymore. I then stumbled across an article that some of the cheaper helmets had horrible optics in them. I went to a good welding supply store and looked at name brand helmets. Ended up with a Lincoln helmet, 1.5 magnifier lens and can see great now. Solved my problems. Also found as I age (I'll be 62 in a couple months) I need more light to see what I'm working on in certain situations.

    SPark
     
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  7. G-son
    Joined: Dec 19, 2012
    Posts: 1,045

    G-son
    Member
    from Sweden

    It can say lots of things. For example, it can say that they don't think they can teach enough people how to tell if it is supposed to look when done right so brazed items can be inspected. Hell, lots of people don't even know what brazing is today.
     
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  8. Ziggster
    Joined: Aug 27, 2018
    Posts: 1,166

    Ziggster
    ALLIANCE MEMBER

    Here's what I have as far as welding helmets. The one on the left came with the welder. No name, no auto darkening. After not liking it, I went back to the BOC store I purchased the welder at and they sold me the second one. It has a much larger field of view, but no auto darkening. After not liking that one either, I purchased the Linde helmet, as the store changed owners from BOC to Linde. It has a "sensitivity dial" and "time delay" dial inside the helmet and a outer "darkening" dial.
    The outer and inner lens are marred with light scratches for sure which on their own do obstruct the view somewhat. I find the Linde helmet cheap, as the head adjustment mechanism is not working properly, causing it to come loose easily as well. I think it is time for a proper helmet.
    image.jpeg
    The spec sheet on the Linde. It says a helmet for the "industrial" welder who welds "infrequently". Lol...

    image.png
    Here are the settings as they were while doing some recent welding on my crane project.
    image.jpeg
    image.jpeg

    Trust me, when it come to making my welds look "pretty" with a grinder, I'm a professional. Lol. Throw in some spot putty, and voila smooth as a baby's bottom.
    For a good tutorial about welding, and some really good laughs, watch this vid. This guy is hillarious.

     
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  9. wisdonm
    Joined: Jun 20, 2011
    Posts: 444

    wisdonm
    Member

    Yes, a lot of English stuff s brazed. I've done some on my race cars with not problems. But flux removal is a pain in the a$$.
     
  10. williebill
    Joined: Mar 1, 2004
    Posts: 3,012

    williebill
    Member

    If you're having problems seeing while you weld, then move your stuff outside. I can see much better to weld outside, even on a cloudy day, even when the sun has already almost gone down. The difference is dramatic for me. If you can't move it outside, follow the other advice about lighting. It will help.
    I do have several lights that I can arrange when welding, but outside in natural light is better for my work.
     
  11. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 2,954

    ekimneirbo
    Member
    from Brooks Ky

    You should be fine with the helmet you have. You said that you have trouble seeing ahead of your weld and getting off to the side of where you wanted to go. I think some type of auxilary light will clear that up. (I do that too).
    The other thing I'll mention is that people often start off with a decent weld and then it goes bad. When that happens to me, its because I tend to change the angle of the gun as I move along. Its a subtle thing that many don't even realize. Try to make a weld and as you move your hand, notice if you allow the gun angle to change so that the tip is at a different angle when you finish. Try doing it intentionally and watch the weld change. I have to tell myself not to let my hand do that every time I weld. The other thing is to check your reference chart for the correct setting before you weld. Again, being lazy I usually don't do that......I wait till my weld looks bad, then grind it off and look at the chart.
     
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  12. 36fordguy
    Joined: Feb 13, 2007
    Posts: 33

    36fordguy
    Member

    MIG welding is not universally approved as a structural welding procedure
     
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  13. Blues4U
    Joined: Oct 1, 2015
    Posts: 6,738

    Blues4U
    Member
    from So Cal

    Those freebie lights from Harbor Freight stuck to the chin area of a welding helmet will light up the work zone real well.
     
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  14. Blues4U
    Joined: Oct 1, 2015
    Posts: 6,738

    Blues4U
    Member
    from So Cal

    It wasn't too long ago when somebody here admitted that he had been having a lot of trouble seeing thru the lens of his welding hood, and then he found that the plastic scratch protection layer was still on the lens. He peeled it off and suddenly could see really well. He felt silly about it, but wanted to share in case anyone else was having the same problem. I wonder if the OP might have the same issue?
     
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  15. OP's in Canada no Harbor Freight up here.
     
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  16. Little known, less cared about fact - my Lincoln 110 MIG welder bit the dust so I branched out and bought a Hobart. Nice machine, a few features better than my old Lincoln but a part broke so I contacted Hobart for a replacement. Turns out that Hobart is just a division of Miller Welders! Part even came in Miller packaging. Hobarts just don't have all the fancy electronic bells and whistles that Millers do.
     
  17. Ziggster
    Joined: Aug 27, 2018
    Posts: 1,166

    Ziggster
    ALLIANCE MEMBER

    Agree with all the advice here. Thanks. Yes, I can generally see way better when I weld outside my garage. Lighting in the garage sucks for sure. I'll be looking into auxillary lighting for sure.
    Yeh, I remember that post about the film, and wondered if I had done the same, but luckily no film on mine. Lol.
    My Hobart hasn't skipped a beat in over 10 years of mild abuse. Actually, I'm really surprised I haven't had to replace anything on it yet.
     
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  18. rooman
    Joined: Sep 20, 2006
    Posts: 4,052

    rooman
    Member

    If you need to grind a weld to make it look nice you need to get better at welding or have somebody with more skills do it for you. Any worthwhile racing sanctioning group will fail a car in tech if the welds show signs of grinding.
    I recently saw an extremely nice 55 Chevy hardtop that was absolutely show quality (paint, chrome, upholstery etc) but the frame had failed where the brackets for the rear suspension were attached because the welds had been ground down to make everything smooth and slick.

    Roo
     
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  19. 6sally6
    Joined: Feb 16, 2014
    Posts: 1,999

    6sally6
    Member

    I have been guilty of hanging plenty of 'gorilla-welds' (ugly and strong)..that required grinding a booger off occasionally.
    Like anything........ye gotta know when to stop grinding! IF you grind down into the base metal its gonna weaken the weld.
    Its amazing how strong just a little dab of weld is!
    Most of us are prolly guilty of over welding stuff cause we don't want it to fail but......just because you pile 3/4" of weld on a 1/4" material is NOT gonna make it any stronger than the base material.
    I have found you can really make a weld look slick by buzzing over it with a TIG torch.
    Not practical in many situations though. Jus say'in
    6sally6
     
  20. nochop
    Joined: Nov 13, 2005
    Posts: 2,834

    nochop
    Member
    from norcal

    Your a F’n genius....(I had to use spell check btw)
     
  21. Ziggster
    Joined: Aug 27, 2018
    Posts: 1,166

    Ziggster
    ALLIANCE MEMBER

    I'm not at home, but when I do get home, I'll send some pics of my recent welds on my crane project. I'm not ashamed to share my handywork or lack there of.
     
  22. Ziggster
    Joined: Aug 27, 2018
    Posts: 1,166

    Ziggster
    ALLIANCE MEMBER

    I did sixty of these 2" long stitch welds every 6"-7"on my transverse beam for my overhead crane. Probably way too many for what I needed, but it felt safer. I did quite a bit of weld prep to make sure I had bare metal, and cleaned everything with brake cleaner, but I still had some issues as you can see. I have the argon CO2 tank and not the flux core wire. The outer pieces were 1/4" thick angle irion, and the center section was a thin walled box section, perhaps 0.100". In a couple spots I actually burned through the box section, and had to go back and carefully close up the holes. On the second pic you can see my weld wander off the joint a bit. This was welded in my garage with the door closed, do ageism lighting was not optimal.
    image.jpeg
    image.jpeg
     
  23. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 2,954

    ekimneirbo
    Member
    from Brooks Ky

    Two questions: Did you weld the beam on the ground or overhead? How fast do you move your hand side to side. The reason I ask the second question is because I was showing a friend of mine how to mig weld, he weaved his hand back and forth "extremely fast".........so fast that he didn't really have control. My hand completes a back/forth motion about every second. I would guess he was going 5 times what I do. Another way to do it is with a short push/pull.......like you are just pushing a little metal forward and back. Very short strokes.
    Get two thick pieces and practice on them. At least 1/4" thick. Have someone "slowly" rotate the amp control "while" you weld. Then do the same with the "wire feed". Watch your weld change as they do it and try to find the best setting. You need thick metal so you have sufficient range for adjusting.
    When welding thick to thinner, point the gun more toward the thick material and put most of your heat into it. Kinda like you are putting almost all the heat in it and the thinner metal is drawing heat from the thick side. Then quickly move the gun to the thin metal and back to the thick again.
    One other thing you might do just to do it........multiple spot welds spaced closely together so they overlap and look like a single weld. Turn the amp up a little to get penetration. You can make a pretty strong weld that looks decent. Anyway give it a try,.......
     
    Last edited: Feb 12, 2020
  24. SilverJimmy
    Joined: Dec 2, 2008
    Posts: 417

    SilverJimmy
    ALLIANCE MEMBER

    I just got chills when you said you cleaned it with “brake cleaner”!!!!!!
    Please do us all a favor and make sure you know what a deadly hazard that could be!
     
  25. SilverJimmy
    Joined: Dec 2, 2008
    Posts: 417

    SilverJimmy
    ALLIANCE MEMBER

  26. After seeing those pictures, my suggestion is find a buddy who IS A GOOD welder and have him show you how to set YOUR welder up(heat range, wire speed, etc). Then watch and listen as he shows you the proper way to lay a bead. Let him watch you do it, and listen when he tells you you're screwing up. Once you get the basics down, all you'll need is practice. YouTube shit is good if you're gonna weld with your phone, but out in the real world, hands-on is still the best teacher.
     
  27. Ziggster
    Joined: Aug 27, 2018
    Posts: 1,166

    Ziggster
    ALLIANCE MEMBER

    Thanks for the tip about the brake cleaner. I know all about phosgene gas as I used to manage most of Canada's military supply of CBRN equipment. The stuff I use is non-chlorinnated, and I make sure the metal is completely dry as I wait 5-10 mins after applying, but still good to no if Inhappen to pick up a can from somewhere else. On it's own it is just nasty stuff, and I should treat it with more respect from a PPE a perspective.
    Unfortunately, no friends know how to weld, and I'm the go to guy in the extended family and with friends.
    I welded the beam in the horiztal position at waist height, so welding position was ideal. I do make small "Cs" when welding, but if the tip is not in the "ideal" position, things tend to go south. I'll double check the recommended settings, but I tend to ignore them and play with it until I find the "right" combination. For sure, I need more practice, and a few pointers from a pro would likely go a long way.
    I think the thread has deviated a bit from the original question, and that is my fault entirely, but it touches on the fact that I don't really have the skills to weld a car frame together, or at least I wouldn't be comfortable with my work, hence the brazing question. Now that brazing is out of the question, I'm going to have to look at the following:

    1. Oxy-aceteylene gas welding
    2. Bronze welding
    3. MIG welding
    4. TIG welding

    It's too bad the ad for private welding classes I posted is so expensive, as well as being an hour and a half away. Perhaps I'll give him a call anyways.
    Now that my welding skills have been established
     
  28. I have noticed that the panels on cars they use silicone bronze for the joints not brass. They are a rose color not yellow like brass.
     
  29. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 2,954

    ekimneirbo
    Member
    from Brooks Ky

    Quit saying that shit! Probably half the people on the HAMB don't weld any better than you do. If your wire speed is correct and your amp range is correct you should get decent welds. Its really not that hard, but it gets ten times harder when you make too big a deal out of it. Its like your first time driving a vehicle. How hard was that? Nowadays people are driving their cars as an after thought while they fiddle with everything else in the world. Quit looking for alternatives and just practice. Turn the amps way up and see what happens. Turn the amps down and see how it looks. But quit saying you don't have the skill............I'm telling you that you do have the skill but you have to practice a little.
    Contact that welding instructor and see what he would take to come to your shop and spend two hours with you. Or bite the bullet and go take his class. If you think you are proud of your crane, I guarantee when you get comfortable welding it will be one of the most rewarding things you ever did......and you will realize you can do anything.
    You can do it if you just make up your mind to do it !:D:D:D

    One last thing, try holding your gun more vertical and start welding.....then start leaning it and watch the weld change.
     
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