Kwik
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| posted on 12/2/11 at 11:33 AM |
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brazing vs welding
reading "high speed low cost" Allan has explained the pros and cons of welding and brazing. and explained why he brazed the chassis
together as its more friendly for new comers to learn.
but, that was almost 50 years ago, i know MIG is now around but with only about 10 minutes using it am i better off brazing or welding a chassis
together? bearing in mind i start off with no equipment apart from a a couple of soldering irons 
chris
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David Jenkins
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| posted on 12/2/11 at 12:20 PM |
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Bronze brazing is good, but not ordinary brass brazing. However, it's a different construction method (the joints will be a different shape)
and you will need oxy-acetylene to do it properly.
If you have the gas welding equipment, and the skill to use it, then bronze brazing is something to consider. Otherwise - use MIG! 
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Triton
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| posted on 12/2/11 at 12:21 PM |
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I would opt for brazing if just making something for yourself. Mig is fine but you have less control. Then there is tig welding but the kit is
expensive but very similar to gas welding ie you create a molten pool and add filler rod.
My Daughter has taken over production of the damn fine Triton race seats and her contact email is emmatrs@live.co.uk.
www.tritonraceseats.com
www.hairyhedgehog.com
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big_wasa
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| posted on 12/2/11 at 12:35 PM |
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If you like the contole of brazing you will love Tig welding.
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designer
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| posted on 12/2/11 at 12:42 PM |
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I think that overall, brazing if not an option for a road chassis.
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dinosaurjuice
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| posted on 12/2/11 at 02:11 PM |
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quote:
Originally posted by designer
I think that overall, brazing if not an option for a road chassis.
the ariel atom is brazed. loads of those on the road.
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Kwik
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| posted on 12/2/11 at 02:17 PM |
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so, by the sounds of it brazing is easier and easier to reverse if you muck up, as your not melting the 2 parts just heating them up.
so what about price? whats cheaper, MIG or brazing?
TIG is out of the question due to price, and for brazing do i only need a torch and some brazing rod? or is their special equipment i need for a good
strong hold?
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David Jenkins
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| posted on 12/2/11 at 02:25 PM |
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Only an oxy-acetylene torch (maybe oxy-propane) will do the job - you won't do a chassis with a domestic/DIY/plumber's propane torch! I
can just about braze small parts in a hearth when using a propane torch, as you have to get the work up to a minimum temp of dull red, preferably to
orange.
A full kit of oxy-acetylene or oxy-propane is going to be similar in cost to MIG... plus you have the problems of safety, skill levels, storage, etc.
You will also have to pay for 2 bottle rentals + refills instead of 1.
As I said earlier - if you've already got the gas welding kit and know how to use it then it's an option... otherwise... no.
Bronze-brazing rods & the correct flux can also be quite expensive.
[Edited on 12/2/11 by David Jenkins]
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Canada EH!
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| posted on 12/2/11 at 04:43 PM |
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Being of the "Old School" of racing, I have used both ozy-acetylene and mig, I still have both.
That said the mig is easier for the beginner, the Nicol-bronze type of brazing that was used in the 50's and 60's takes a lot of practice
because of temperature control.
This type of brazing was used mostly with 4130 alloy (chromoly tubing) it can be used on mild steel. all of the suspension on my Datsun racecar was
nicol-bronze brazed.
My Locost is mig welded.
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minitici
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| posted on 12/2/11 at 04:59 PM |
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9% Nickel Bronze rods are not cheap (£70 per Kg)
Linky
As mentioned Oxy-Acetylene is really needed to get the parts hot enough (I now use Oxy-Mapp Gas as I don't have Acetylene anymore).
Joint fit needs to be good and really clean metal.
Flux is used and is a pain to clean off afterwards.
As a lot of heat is input, there can be a fair bit of distortion.
Mig is now the best DIY option for chassis work (Allan did not have the luxury of cheap Mig welders back in the 60's).
I still use a little nickel-bronze 'welding' when working on old racing chassis.
[Edited on 12/2/11 by minitici]
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MikeR
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| posted on 12/2/11 at 06:03 PM |
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How accurate at you? MIG works well with small gaps - therefore if you're not 100% accurate MIG is fantastic. Brazing needs very accurate
joints, studious cleaning before and after (i believe - could be wrong here). This also means MIG will be faster to assemble as you get damned close
with the metal, quick rub, weld it, and your done.
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Bare
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| posted on 12/2/11 at 06:09 PM |
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Mig IS easier no question. But Brazing is how Caterhams are made... to this day I believe.
Lotus had Brazed chassis in their earlier F1 cars. No question as to it's strength.
But it is harder than pulling a trigger while the gun head is pointing in the general direction of the intended weld.
TIG is nice but a decent kit is half way to buying A Caterham kit... and it's painfully tedious/slow as well as needing genuine aquired skill
to do decent welds.
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Peteff
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| posted on 12/2/11 at 09:36 PM |
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Arch used to bronze weld chassis for Caterham but they are now built by Caged using CAD process and robot welded since 2005. The old way depends on
you being deadly accurate with your cuts and cleaning all your ends up. I brazed and gas welded but once I discovered mig it got left for heating
stuck bolts. Unless you want it for bragging rights just use the simple quick and cost effective method. Even Caterham have caught up with new
technology now.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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Kwik
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| posted on 12/2/11 at 10:21 PM |
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ok, seems like MIG is the best choice.
now next sub question is what amperage should i get (tight budget) and should i get the gasless ones as i will be welding outside in a garden, and i
think the gas from a gas welder will just blow away in the wind...
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britishtrident
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| posted on 12/2/11 at 10:27 PM |
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quote:
Originally posted by designer
I think that overall, brazing if not an option for a road chassis.
Lotus/Caterham used bronze welding for decades I think the likes of Chapman knew a teeny bit more about chassis design than the designer (!?) of
Robin Hood.
Bronze welding is good because provided the surface prep is good it is actually quite difficult to make a bad joint.
MIG is popular because it is the cheapest easiest DIY method of producing a sound weld that is fit for purpose.
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Steve Hignett
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| posted on 12/2/11 at 10:44 PM |
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quote:
Originally posted by designer
I think that overall, brazing if not an option for a road chassis.
So all those Atoms and Caterhams are falling to bits on the road are they???
quote:
Originally posted by peteff
Arch used to bronze weld chassis for Caterham but they are now built by Caged using CAD process and robot welded since 2005. The old way depends on
you being deadly accurate with your cuts and cleaning all your ends up. I brazed and gas welded but once I discovered mig it got left for heating
stuck bolts. Unless you want it for bragging rights just use the simple quick and cost effective method. Even Caterham have caught up with new
technology now.
Arch are still doing Caterham chassis. Well they were when I went for an extensive tour round their factory a few weeks ago... I guess they could have
changed back in the last few weeks, but I doubt it!
And they are stillbronze welded...
To the OP - In my experience, if you don't have brazing/welding experience then what I would do is:- design the chassis, make friends with a
local fabrication firm, buy steel from them etc, cut all the tubes to length, hire a MIG, tack weld the chassis tubes together, take the chassis to
them to be welded (whichever way they choose when they see your cuct/shut lines.
It will prob be cheaper in the long run and although I/you can't guarantee better results, I would imagine they would be better, but also there
would be the confidence in your welds versus the confidence of their welded chassis.
Anyway, hope I didn't cause offence above, but some posts don't always ontain acurate, or maybe up to date is more polite, facts. And to
the OP, this is just my 2 penneth worth...
ATB
Steve
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Kwik
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| posted on 12/2/11 at 11:08 PM |
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thats perfectly fine and i think thats a good idea tacking it up and tacking it to someone who can weld !!
the chassis has been designed, its the terrapin chassis so not an awful lot needs doing.
will probably mean ill need a roof rack for the mini to carry it places but even so it shouldn't be too difficult
i know a local workshop that mends lorries maybe they can give it a go with a bit of money thrown their way.... i know they are aloud to do their own
projects, but maybe not a whole car though...
either way i do it, i need to finish reading the book first 
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Peteff
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| posted on 13/2/11 at 10:24 AM |
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Sorry yes, Caged are doing the roll cages for the Superlight. There's a
nice picture of the chassis here with the roll cage in progress.
Here's a bit on their Caterham contract with a few videos of the
equipment further down. It's not exactly blokes in sheds any more 
[Edited on 13/2/11 by Peteff]
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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Steve Hignett
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| posted on 13/2/11 at 03:23 PM |
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quote:
Originally posted by Peteff
Sorry yes, Caged are doing the roll cages for the Superlight. There's a
nice picture of the chassis here with the roll cage in progress.
Here's a bit on their Caterham contract with a few videos of the
equipment further down. It's not exactly blokes in sheds any more
[Edited on 13/2/11 by Peteff]
Have you ever been to Arch?
That is EXACTLY what it is!!!!!!!!!!!
Albeit, a very large workforce and several very large sheds, all adjoining maze like with each area of constructiona nd preperation in different
"sheds"!
If you look in the News sections, you'll notice that the Caterham stuff is over 5 years old, and it's Arch nowadays!
To be fair Pete, I thought Caged had a lot to do with it, until I was at Arch just recently to pick up Caterham parts, was given a tour and saw all
the Caterham chassis' in various stages of production, the Atom chassis' the same, the Chevrolet the same, and then a couple of secret
projects that I'm not allowed to talk about...
[Edited on 13/2/11 by Steve Hignett]
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CNHSS1
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| posted on 13/2/11 at 05:45 PM |
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the likes of Chapman and the original Lotus were brazed but thats not to say that if MIG technology had been around then as it is today they wouldnt
have used it. I suspect a lot of what is considered 'de riguer' now, was just needs must back then. some old Lotus F1 cars used Imp style
rubber donuts on the driveshafts for christ sake!
"Racing is life, everything else, before or after, is just waiting"---Steve McQueen
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