Welding Methods for Chassis

[acra]

Hi guys, I've got another pre-pre-plan stage question. I'm set in the idea of taking on the challenge of welding my own chassis (cutting material and welding), and wondering what method would be best to use before I get started on a course.

Basically, from what I can gather there are two methods that would be in my price range: MIG and Stick.
TIG from what I can gather is too expensive for a single build, and brazing techniques are inadequate unless using bronze brazing (expensive).

Stick is something I can learn cheaper, as I have a relative who is willing to teach it, plus lend the welder.
MIG, from what I can gather is more reliable/easier to get a good penetration weld.

Is it still possible/safe etc to use Stick to weld a chassis?
Last thing I'd want is to have a weld destroy itself mid corner, but if it's just a matter of getting more training, I'm willing to spend the extra time to get it right.

Since I'm still in my apprenticeship, the actual build is potentially not happening for another two years, so that's potentially two years of practice welds and training to get on with!

[big_wasa]

Get hold of the best mig you can. You want around 150A and to be fan cooled.

MMA or stick welding is not easy for 1.5mm thick steel.

You can teach yourself with some offcuts and some practise. There are plenty on here and lcb that will give you pointers if you post the pics and some may even give you an hour or so of ther time and show you.

[acra]

Get hold of the best mig you can. You want around 150A and to be fan cooled.

MMA or stick welding is not easy for 1.5mm thick steel.

You can teach yourself with some offcuts and some practise. There are plenty on here and lcb that will give you pointers if you post the pics and some may even give you an hour or so of ther time and show you.

I thought that's probably the best way to go...
Only reason really I'd go Stick is that my Granddad is willing to teach me, and what with his experience I'd really gain from it - he was a Royal Engineer, then set up his own large fabrication business, so definitely one to learn from!

Though I've not actually asked yet if he could teach me MIG, so I may have to chat with him this weekend...

Apologies if posting links is frowned upon, I have no affiliations - but is this a recommended/suitable choice? This (http://www.screwfix.com/prods/30030/Power-Tools/Welding/Fan-Cooled-MIG-Welder-150A?cm_mmc=GoogleBase-_-Datafeed-_-Power%20Tools-_-Fan%20Cooled%20MIG%20Welder%20150A)

[Trif]

I cut and welded my chassis using a a metal cutting bandsaw and mig. I'd never used a mig before, but having talked to welder friends I was convinced that it wasn't too difficult to learn. I bought a 150A fan cooled machine and sat down one weekend with a pile of 1" box off cuts and by the end I'd cracked it. The one thing I found that helped more than anything else was an auto darken visor, it was worth every penny. The metal cutting band saw was from a previous project and made the cutting of the parts a doddle. Accurate angles and lengths made the assembly and tacking fairly straightforward. The finish welding caused a few backtracks but the finished chassis came out to the mm thanks to the excellent cutting list in the book.

[acra]

I cut and welded my chassis using a a metal cutting bandsaw and mig. I'd never used a mig before, but having talked to welder friends I was convinced that it wasn't too difficult to learn. I bought a 150A fan cooled machine and sat down one weekend with a pile of 1" box off cuts and by the end I'd cracked it. The one thing I found that helped more than anything else was an auto darken visor, it was worth every penny. The metal cutting band saw was from a previous project and made the cutting of the parts a doddle. Accurate angles and lengths made the assembly and tacking fairly straightforward. The finish welding caused a few backtracks but the finished chassis came out to the mm thanks to the excellent cutting list in the book.

I remember having a go with all the welding techniques in school - my favourite was TIG, I was pretty bad at the other two :(
But practice should help! And naturally I'm not gonna take on the task without being sure I'm good enough.

I used an autodarken mask, and a regular one (as well as one of them old style hand held ones (!)) and definitely loved the autodarken!

[Trif]

sounds like your starting from a better level than I was at, go for it, it's part of the fun!

[locostkiwi]

ive been a welder for the past 20 years
im welding my chassis 25x25 shs 1.6 thickness, using a 170 amp single phase mig, gas im running will be carbon dioxide, ( use plenty of anti splatter spray ).
For all my front and rear end suspension parts, ill use mig to tack them up but over here in New Zealand all final welding of suspension parts MUST be tig welded up then crack tested.
Also we arent allow to weld the steering shaft MUST be splined and pinched bolted to the universals.
hope this helps

[acra]

ive been a welder for the past 20 years
im welding my chassis 25x25 shs 1.6 thickness, using a 170 amp single phase mig, gas im running will be carbon dioxide, ( use plenty of anti splatter spray ).
For all my front and rear end suspension parts, ill use mig to tack them up but over here in New Zealand all final welding of suspension parts MUST be tig welded up then crack tested.
Also we arent allow to weld the steering shaft MUST be splined and pinched bolted to the universals.
hope this helps

That does help mate, it's interesting the regulations you have for welding, but a good idea I think. What level of crack testing do you have to conform to? I can do surface crack detection (dye-penetrant Non-destructive testing) but unless I get my hands on some of the fancy gadgets I can't do sub-surface myself, and we don't test for cracks to my knowledge.

Out of interest, would you reckon that Tig produces a better weld, if suspension has to be Tig?

[locostkiwi]

for non destructive testing i will get my A arms etc.. X-rayed,
cost is about NZD$40/item.
My personal opinon is that TIG welding does do a better weld than MIG, but i have seen people TIG weld and it looks like s**t, by the way I,m getting my arms etc.. TIG welded by a real pro at it. im not that good at TIG welding so will leave it to experts..:D

[7even]

Hi all :)

so this wont be any good then ??

http://www.aldi.co.uk/uk/html/offers/special_buys3_15678.htm

I have built a GBS Zero and enjoyed it sooo much...

Now I want another challenge :D

Many thanks Mike

[frankieboy]

Have a look on www.mig-welding.co.uk ,i found this very helpful :)

[acra]

7even, I'd be dubious about that welder you've found - from Aldi with what looks like too good to be true...
I'd replace the mask anyways, I've had a tiny bit of experience with hand-held, regular head fit and auto-darken, and found auto-darken to lead the field by a huge amount!

To everyone else - has anyone actually welded the chassis with Arc/Stick? I'm expecting to spend a year and a half training before I can actually afford the donor etc, so it'll be about that long before I start the chassis, so I will definitely have ample training.

If it's possible to use stick, just easier to Mig/Tig, that doesn't matter too much as I'm having top-notch training...

[acra]

Hi guys, just resurrecting my old thread! I've still not yet got down to getting a welder and learning a technique due to other commitments.

I'd be interested in hearing if anyone here has actually used MMA to weld their chassis? I'm still tempted to go down that route, mainly for cost reasons but as mentioned previously in this thread I have relatives with experience willing to tutor me!

The book doesn't really mention much on MMA welding, but has anyone tried it on their roadster??

Many thanks!

[MarkB]

If you are new to welding then using a stick welder will prove a real "challenge".
By far the easiest method especially for beginners is Mig welding. But practise making something less critical first.

[acra]

Don't worry, whichever technique I use will have many, many practice pieces made up and tested prior to chassis building :)

I'm just thinking that being taught MMA (arguably more tricky from my research) by a decent welder would produce better welds than self-learning MIG welding.
So far I've only found one builder who used MMA, which is surprising to me considering the price of the welder!
(one thread I remember reading somebody recommending a £700 welder - something that might be a little overkill!!)

[MarkB]

There is no reason why you can't use stick to weld the chassis, there are few joints that would be easier done with stick anyway as once you pointed the mig torch into the joint you can't see what the hell you are doing, stick will make these joints a breeze.

Go for it but you will use heaps of rods:)

[misty]

i have been a welder all my working life either tig mig arc gas, the easy way i did my chassis was arc welding. welding with mig, yes there are places you cannot see to weld that is why i used the rod. a piece of advice for you and if you think about it it works strike it like a match and let the rod do the work and it does work .if you go down the line of arc welding then use 2.5 rods and 1.5 rods for tacking

[acra]

Thanks for the feedback - it's great to hear it's possible, I'll have to try and find a load of scrap of the right gauge etc I can practice on!

[Bonzo]

If I were given the choice of using either a low power/budget hoby MIG or half decent hoby MMA welder, personaly I would go for using the good ole stick.

I would use 2mm thick chassis tubes, most importantly, use the right electrode for the job ( Some are better suited than others )
Go to a welding supplier that knows what they are talking about & ask them to recommend a good general purpose Rutile welding electrode for the welding of thin material ;)

If the fancy took me, I would use a stick welder in the blink of an eye, that said, I have been trained to do so :)

[Enoch]

I did mine entirely with sticks. I don't really know why I went down that route. Oh hang on, I remember, it's cos I got a welder for 20 quid:D
That welder turned out to be crap though so I bought one of the Chinese inverter welders off ebay for about 150 quid. Best money I ever spent. I also bought a decent auto darkening helmet and good quality rods that I keep indoors in the airing cupboard until I need them, they work best when totally dry. My welder is very easily controllable and with practice it gives fantastic results with very deep penetration. I used 2.5mm rods for just about everything except the 1mm thick curved side panels. My welder goes up to about 200 amps from memory, which was plenty big enough to do the rear uprights with ease. Hope that helps.
Enoch.

[TheArf]

Definatley agree with you, £700 for a set that will only used once in a while. The only thing i would say is to buy the best you can afford, which ever route you take, stick or mig, good luck with your build

Arfon

[acra]

I did mine entirely with sticks. I don't really know why I went down that route. Oh hang on, I remember, it's cos I got a welder for 20 quid:D
That welder turned out to be crap though so I bought one of the Chinese inverter welders off ebay for about 150 quid. Best money I ever spent. I also bought a decent auto darkening helmet and good quality rods that I keep indoors in the airing cupboard until I need them, they work best when totally dry. My welder is very easily controllable and with practice it gives fantastic results with very deep penetration. I used 2.5mm rods for just about everything except the 1mm thick curved side panels. My welder goes up to about 200 amps from memory, which was plenty big enough to do the rear uprights with ease. Hope that helps.
Enoch.

Ah you were the builder who's diary I'd read :)
What kind of ampage were you using on the whole - just as a general idea?

Again thanks to all the guys giving feedback - I really love the community here!

[Enoch]

Hi Acra, I found between 90 and 120 amps suited most jobs - that was what it showed on my dial anyway, not sure how accurate that is. I went up to about 130-140 for the rear uprights, I never got anywhere near the limit of my welder. Incidentally my one is also a TIG welder but I have never used it as such.
Enoch (Dave)

[Wynand]

Hi Acra, I found between 90 and 120 amps suited most jobs - that was what it showed on my dial anyway, not sure how accurate that is. I went up to about 130-140 for the rear uprights,.... (Dave)

Actually, the electrode size determine the current to be used.
A rule of thumb method is to multiply the diameter of the electrode with 40 example; 2.5mm (12#) x 40 = 100amps or lets say 3.15mm (10#) x 40 = 125amps.
If you weld vertically, it is best to drop the amperage a bit or use broken arc technique (my preference).

The above method is only applicable to AC or DC arc welding and not mig/tig.

[acra]

Just looking around, seems that screwfix do a reasonable one for £56 that goes up to 130A, or one that does that little bit more at £71 for 160A - the next level up is £128 for a 250A so that's a bit of a step, but worth it if I'll use it!

Seems from what you guys have said that the 160A should be ample for all the tasks I'll need :D

Have you had any experience with Autodarken Masks? I know I'm looking at a response time as low as possible, with a range of darknesses of 9-13 or something, and Amazon do some for around £50 that look reasonable...

As usual, cheers for the info so far guys!

[baz-r]

here is how i see it yes the chassis could be sticked up by arc and there is no reason why not but note there would be meny positonal welds that would be tricky for a novice
a mig could equaly be used easy in practice

if you want to go down the stick/arc route a 150a dc inverter would be your best bet with a quality positonal rod. much more than 120 and you will be pushed for a 13a supply if you go for a transformer type set

if you go for mig then mixed gas with a .8 good qulaty wire and a mig 130-180a with the best duty cycle you can find in your budget have a look round for a s/h one