Braze welding

Discussion in 'Engineers' Talk' started by RK Joiner, Nov 5, 2008.

  1. RK Joiner

    RK Joiner New Member

    Would it be possible to braze weld a new steel wing onto a car instead of tack welding or using self tappers and if so could it be done with mapp gas or would it need to be oxy acetelene?

    If so would it be difficult?

    Never welded or brazed before but I'm competant in copper solder and circuitry soldering.

    Any advice appreciated as although I like doing things myself I get very annoyed when I arrrse it up!
     
  2. Bassrock

    Bassrock New Member

    Mmmm

    Yes, it is possible to braze weld panel but I doubt it can be done efficiently with MAPP, don't think this will generate required constant temp, due too large dissipation of heat through body work (I wouldn't even attempt it, especially if it's a quality finish your after . I've only ever used oxy in small (fiddly) areas and MIG gas for longer stretches. Oxy your holding torch in one hand a rod in other (does get sore after a while), MIG is two hands guiding, lot easier.

    Easiest route is MIG gas welding.
     
  3. Bassrock

    Bassrock New Member

    Mmmmm

    Forgot to mention, you will need a bit of practice !
     
  4. RK Joiner

    RK Joiner New Member

    mmm might leave this un alone... get the local body shop to fit the wing for me... think they have a tig pincer welding equipment,,, If I do want to learn to weld,, would gas be the best place to start?

    cheers guys
     
  5. Bassrock

    Bassrock New Member

    Mmmm

    Depends how you want to learn. If your buying kit youself then electric arc is the "easiest" (by easiest I mean all you need is £50 + other bits, http://www.screwfix.com/prods/53349/Power-Tools/Welding/Fan-Cooled-Arc-Welder-130A + rods, mask, gloves apron, suitable area etc..).

    I'd stay clear of NO-GAS mig welders, then it would be a Fan Cooled Mig welders etc.

    But prior to deciding I'd get down to your local TEC college, they normally run courses, better trying first in order to build up confidence, it does take time to learn to weld proficiently whether, arc, mig, tig etc..

    I learn't as an apprentice, the welding is only part of it, materials rod size, type of rod, weld type, joint type, etc....
     
  6. Bassrock

    Bassrock New Member

    Oh!

    Welding memories.

    Me Mother gave me a nylon boiler suit and I'd just bought a pair of doc martin boots.

    By the end of the first day arc welding I looked like a tetley tea bag and my boot's had a few punctures !!
     
  7. jasonb

    jasonb New Member

    Don't bother learning gas (oxy) welding if its for home use you will not be able to store the bottles at home as you need to notify your local fire officer and have all the proper hazchem signs, flammable storage etc.

    And technically there is no such thing as "braze welding" as brazing uses a filler rod with a lower melting point than the metals being joined and welding uses the same material.

    Jason
     
  8. malkie129

    malkie129 Screwfix Select

    Listen to Jason,he's dead right in what he says. Bassrock also has a good idea... Learn at your local "Tech". Welding, unfortunately, is something that you need to be constantly practicing to be proficient at. Over 30 years ago, I did a TIG course at BOC & could weld stainless tubing holding 3500 psi gas with no problem.... Now, my welding looks like chicken ****. :(
     
  9. Hitch.

    Hitch. New Member

    Mig is one of the most usefull ones. MMA is a bit harsh for automotive.
    Gas is old hat, and bit more difficult to master.

    If you want to learn a bit about it all, have a look here-

    http://www.mig-welding.co.uk/

    Theres tutorials, tips, and anything else you want to ask join us in the forum and ask away.
     
  10. RK Joiner

    RK Joiner New Member

    thanks for all the advice... the urgent requirement for the abillity to weld has gone (managed to beat the old wing back into shape so with a little catalloy and paint should be ok)

    I'm actually going to get a portable oxi setup soon as I want it for hard soldering.

    The tec course would be a good idea,,, might go for that in future.

    cheers guys
     
  11. jasonb

    jasonb New Member

    You don't really need oxy for hard (silver) soldering, I regularly silver solder parts for my model traction engine using a large burner on a 3.9kg calor propane bottle, though the boiler was professionally made using propane to warm it all up and oxy for local heating. Far cheaper than the hire costs of bottles from BOC or similar and regs re bottles still apply.

    Jason
     
  12. malkie129

    malkie129 Screwfix Select

    Jason's right again..How I hate a smartarse ;) I've never needed oxy for silver soldering. A propane torch is quite adequate, because normally, you heat the whole item up & let the solder run. Don't get suckered into paying a deposit for a Calor cylinder (which you never get back) as most plant hire places will let you have one (Easiflo or similar)for just the price of the gas.
     
  13. RK Joiner

    RK Joiner New Member

    will propane/butune mix be good enough for lead soldering as well and also... I watched a video on youtube of an american guy trying to hard solder using mapp (hotter than propane?) and it took him 16 mins to bell joint 2 bits of copper 15mm to 22 or something like that.

    I know you can often get away with using propane but for some things that I may be wanting to attempt in the future... I might want the benefits of using an oxygen rich flame. so...

    just to sumarise... best getting some lessons... best start with electricly heated welding... If I insist on playing with oxy acetelene,,, I have to notify fire brigade where I'm keeping it stored,,, and I'm best to find somewhere that will give me the cannisters for the price of the contents!

    Cheers guys
     
  14. jasonb

    jasonb New Member

    Do you mean lead soldering or lead burning (welding)?

    Lead soldering will be like soft soldering but most solders are now lead free, mapp or propane will be ok for this although if you are thinking of using lead as a filler on car bodywork then oxy is more commonly used as garages tend to have oxy available.

    Lead buring or welding needs oxy as lower temp flames will take too long to heat the metal causing oxidation and will heat the whole sheet making it all melt rather than the small localised heat you get from oxy.

    Can you post a link to the youtube video, I would think he was using too small a nozzel/burner to get sufficient heat into the work, this will exhaust the flux making it harder to get the silver solder to flow and the prolonged heating will also cause oxidation which again stops the solder flowing. Another problem may be he had too big a gap between the two surfaces as silver solder will not fill gaps, couple of thou' is what it needs to flow.

    What exactly are you thinking of joining and then we can suggest bthe best method.

    Jason
     
  15. RK Joiner

    RK Joiner New Member

    http://uk.youtube.com/watch?v=wGOQkTlL1OI

    Well I have a multitude of desired skills invloving metal work/welding:

    I would like to be able to tack repair/whole panels in place on cars, in the case of repair panels I would like to be able to blend the repair back into existing sound surface.

    I would like to be able to burn/weld lead for the purpose of repairs to lead gutters etc.

    I would like to be able to braze dissimilar metals toogether though a practical use for this I cannot think of!
     
  16. RK Joiner

    RK Joiner New Member

    I've now had time to properly look through the mig welding link... I think thats exactly what I'm looking for so thanks for that!
     
  17. jasonb

    jasonb New Member

    I would say MIG for the car work, OXY for the lead burning.

    You won't have much choice of metals with brazing as it will tend to be very close to the melting point of copper & brass and won't work with ally so that leaves you with steel. Have you been looking at American sites as they use the term "silver brazing" for what we know as silver soldering" Silver soldering will with the right flux and solder work with brass, copper, steel, stainless steel and even cast iron. Propane will be best for this.

    Jason
     
  18. jasonb

    jasonb New Member

    Few comments on the video

    1. he's silver soldering not brazing as we know it
    2. Silver solder needs a couple of thou gap he had a couple of mm
    3. No sign of flux on the joint, may have been coated rod that mapp sell but the joint should be fluxed
    4. too small a nozzel for size of pipe
    5. holding the nozzel too close to pipe therfore not using the hottest part of the flame.

    Having said all that mapp gas is not suitable for that size work.

    Jason
     
  19. malkie129

    malkie129 Screwfix Select

    Hi Blokes. I watched the link too. As Jason has said, no mention of flux. There is no indication of how long the length of pipe was , so could have been a massive heat sink. The most apparent fault was that there was no attempt to "muffle"the joint, ie, no fire bricks or similar to build a heat retaining hearth & was he trying to braze (bronze weld) or silver solder? I must admit I have no experience of MAPP, but with a suitable temporary hearth,I'm sure that I could have silver soldered that joint using propane, or even a praffin blowlamp. ;)
     
  20. malkie129

    malkie129 Screwfix Select

    Sorry, I meant paraffin :^O
     

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