Welding???

[Shutler1]

Tailgate on my 90 needs some welding. Would I use a mig welder for this job.??? Cheers all in advance. Dave.

[robertspark]

Mig will do it although what are you welding? Aluminium or the steel frame?

[Shutler1]

Not really sure of the general construction of it, but it's the outer frame that needs welding. I'm guessing its a steel frame and ally skins?? Is that rite?

[robertspark]

Yup steel frame and Ali skin is correct. Mig weld frame it no problem

[Shutler1]

Cheers that's great. It also needs the Centre bar replacing but I have found one on the net that you just rivet on. Cheers Robert.

[steve b]

.....the application of a magnet will tell you if it's steel or ally , tailgates are all ally as far as I know with a steel cap and maybe

inner galved steel liner ?

hope that's of use

Steveb

[Shutler1]

Cheers steve, used a magnet today and found out I won't be welding any of it my self. Cheers.

[steve b]

I'm sure you can find a local fabricating business that'll be able to TIG it up for you

If you put an approx. location on your ID someone on here may be able to sort it for you

cheers

Steveb

[robertspark]

In the interests of learning something..... if its aluminium can it not still be mig welded using argon shielding gas and an aluminium mig wire?

The question was cannot not be mig welded and I would still say yes, just with the right gas and wire

(this is a bit of a loaded question as I have a ESAB C200i, which will do up to 3mm aluminium / 6mm mild steel with the right wire (0.8mm mild steel, and 1.0mm aluminium, although I've not tried to use it on aluminium yet and cannot attest to it's weld quality)?

Don't shoot, always learning (tag at the bottom)

[steve b]

Yes , with Argon shield gas - the problems begin with running thin (0.6mm) wire usually with wire that thin a spool on the torch is needed . I've welded

3mm ally with mig and 0.8mm wire but for ultimate weld strength and neatness I'd say TIG for the matl thickness of tailgates

...or get creative with ally strengthening plates and some pop rivets

cheers

Steveb

[robertspark]

Is the problem with running 0.6mm and 0.8mm aluminium wire (besides the softness of the wire (if using 4043)) not also the wire feed speed that 1.0mm would not have so much of (don't forget I'm using an "idiot proof welder" (semi-synergic) .... had a clarke and me an it just did not understand each other ... more a testament to me than the welder...)

with the thin wire the feed speed must be really high to keep the weld pool from dropping and ending up chasing a hole.

Wire choice seems to be (most commonly available) 4043 or 5356, but I would not know which to choose for a tailgate ...

http://www.esabna.com/us/en/education/blog/should-i-use-4043-or-5356-filler-alloy.cfm

http://www.esabna.com/us/en/education/blog/filler-alloy-selection-for-aluminum-welding.cfm

http://www.advancedweldingsupply.com/documents/ALUMINUM%20Filler%20Selector%20Guide.pdf

[Shutler1]

Cheers, I only have a gas less mig welder just fir quick fixes of things at the yard, I know a fabricated that will sort it it's just a bit hard to get him to do anything, he like to work flexi time, but very good when you get it back. It was a very cheap tailgate so worth getting it done rite.

[steve b]

did you use a plastic torch liner Robert ? the steel std one will not work with alum wire .

Not sure what grade of wire I used as it was in the store cupboard in a plastic bag and acquired at a sale in a job lot ...

With ally MIG you do need more power than you would normally use for similar thickness steel and more of a spray transfer than dip ime

hence thinner wire to get a good spray

cheers

Steveb

[robertspark]

Steveb, yup had a teflon liner but still ended up with a birds nest at the roller end, 3 meter torch lead too (the 4 meter ones seem to sometimes be a no-no with aluminium I'm lead to believe because of the extra force required to push a soft aluminium wire, and I was more than likley using 4043 (which is soft)

.... there is a little more to the story too, I was trying to weld 5 bar treadplate / chequerplate (2mm), and the mig I was using was a clarke 100E, and dispite every effort I tried, the wire just bounced off of it and it would not weld even the smallest of spots ....

hence upgraded to something a little more powerful + more idiot proof....

(younger, more experienced, and one would hope I've learnt a lot since then.... (+ google and the forums are much better as that was 12 years ago... move on to ac/dc tig too for the task)

[steve b]

did you re-set the drive roller pressure ? the test is to load the wire , feed it thru the torch lead and holding the torch about 50mm from a hard (unearthed!) surface the drive wheel pressure should be low enough to slip when the wire feeds out and hits the surface perpendicularly .

Also use an A spec contact tip so for 0.8mm is 0.8A

Keeping the torch lead in as straight a run as poss is good too , and clean ,clean, clean matl too , but I'm pretty sure you will have done that

The rigid tube between the inner side of the euro torch socket and the drive rollers needs to be right up against the output side of the drive

rollers too

That's about all I can think of right now my brain is a bit fried after a long day deciphering badly drawn CAD drawings of building steels......I just love CAD

done by someone that has never been in a Fab shop...........50 odd steels total 8tonnes for del thurs next week........

cheers

Steveb

[robertspark]

Steveb

yes, did setup the roller pressure (suspect the issue was the liner position to the rollers on reflection for the birds nest (thanks very much for the pointer).

yes, the advice at the time I remember doing (and still do) is to keep a stainless steel wire brush just for scouring the aluminium just before welding i an effort to break the oxide layer. don't use the brush for anything else as it can contaminate the weld, same thing as tig.

the liner positioning could have been better I must admit to ensure that there is a very close to the roller lead in and out to provide as much support as possible to the wire.

I didn't know that there was a different profile tip .... an "A" tip?? What's the difference? Thought it was just a bore issue (make sure you use the one that has the same bore as the wire you're feeding through it).

Is the "V" and "U" shaped roller actually an issue, or can you run a V shape without too much issue?

On the CAD side, the problem is consultants require degrees today and the focus is getting the university piece of paper IMHO and not so much on doing something like a stretch in a fab shop (first or during the degree) understanding that it's a bit more than calcs, numbers and lines on a drawing (sorry if I offend anyone (not looking for a slanging match), but there is no substitute to doing a bit of something physical before putting lines on paper, to understand and view it from the welders, fitters or turners perspective) ... yup I am a consultant, but started on the tools first, and still try to keep my hand in and take advice from the man actually doing the task on site.

Rob

[steve b]

I didn't use u rollers and haven't since on other Al MIG welds , but can see the point

A tips relate to the rate of expansion of Al to steel at arc temp - roughly 4x more iirc for the tip temp - a 0.8A tip is nearly 1.0 dia in reality

as for design and manufacture , hohum will it ever be integrated ??

patience is a virtue/frustration depending on if I've had enough or too much coffee ,

I'd keep trying Al MIG as when you do get a nice weld it sure does feel satisfying , you do need much more power than you would for the same given size in clean steel , another good tip is for thinner section's to have a good heatsink behind the weld such as a lump of brass plate , yeah I know who has that under the bench

.. a chunk of steel with a thin layer of brass on it will work too

the main thing with Al MIG is practice , it can be fruitful

cheers

Steveb

[Cynic-al]

I've done Ali with a mig and it was structurally sound but really not pretty! I used 1mm wire so had to get a new roller and tip, changed to a plastic liner as the steel one became clogged, had a pig of a time getting the roller to work as it either slipped and shaved it or crushed it and the Ali was so soft it went straight through. I decided there's no way I could do body work so ended up bonding my bobtail... which has failed from impacts so at some point I'm going to have another go with the mindset of if I can get it strong with weld I can get it pretty with filler.

[Lewis]

They use a combination of bonding and mig on ambulance bodies. I've seen them come back for repair after fairly serious impact and the adhesive holds fine. Perhaps a better glue would last longer for your application Al?

[robertspark]

The lotus elise use to be (not sure about the newer body shape, but original one) aluminium panels pot riveted together with a special heat cured adhesive but the problem was (from long time ago research + memory) that the adhesive needed to cure at a high temperature and atmospheric pressure so they need an pressure vessel like I've seen used for carbon fibre manufacture but it had to take most of the chassis in one go.

I believe the adhesive was from somewhere like holland or denmark from some specialist glue manufacturer (all of this came off an extensive search of the internet and putting info together from various companies, never worked in the industry so happy to be corrected).

[Cynic-al]

They also glue planes, range rovers and minis so I hope they're better at it than I am

The panels were quite damaged to start with, I can't remember what I used to be honest, it held for quite a while but I think as the panels have bent it's sort of torn. The edge of the roof has suffered where I was sliding along a tree which dented it until I got to a tree where it caught on the join and now it leaks in the rain :/

The best way to have done the rear panels would've been to take the steel corner off and make a jig to reform the lip that the steel corner bolts to but you live and learn

[robertspark]

Steveb

Thanks very much, you've defiantly enlightened and motivated me to have another go at it (after the plasma cnc project is complete [other thread])

I've got a roll of 5356 1.0, just need to look for the 1.0A tips and a new telflon liner for the MB15 torch plus another stainless brush (can't be sure if I kept the current one only for aluminium and I'll defiantly have a go at trying out the "Qset" aluminium function of the ESAB C200i and see how it pans out + post some pictures on some scrap 5 bar treadplate I've got lying about.

Got a bottle of argon for the Tig, but I must admit although I like the Tig for its ability to weld anything and control the weld very closely, it's the speed of the process that disappoints me and where the mig wins through (cba over the stack of dimes look myself, just want A jointed to B most of the time). If it welds aluminium and stainless as well as it does mild steel, I'd consider getting shot of the tig.

Rob

[steve b]

It's definitely worth the time to practice it , you should find stainless MIG pretty easy , not much different to steel

I'll try and remember to take some pics over the next few weeks of any stainless or Al MIG and share

cheers

Steveb

[Bingy]

Have you thought about using a spool gun and attatching it to the mig welder?

If it is a gassless machine maybe a slight adaptation on the pipe to the spool gun with a bottle and regulator?

[FridgeFreezer]

From what I've observed of Ali welding it needs to be surgically clean, free from any contamination, oxidisation, etc. or it will go badly. Clean wire brush & abrasive pads are your friends.

And for bonding panels, if you get it clean & de-greased and have a reasonable surface area, stuff like Sikaflex or tiger seal will stick so hard you'll tear the ali trying to unstick it. For LR panels (which are not structural) it should be plenty strong enough - the difference with the Lotus was they glued the chassis together, not just sticking body panels on. Airbus glue the wings on the A380 but it's not a 1" bead of pritt stick round the edge, there's a LOT of surface area.