BXProject

[Bx Bandit]

Right, as always the job gets bigger the more you poke. I welded this up 2 yrs ago but surface rust was showing so I investigated. To cut a long story short I have two patches to make up out of 1mm galv sheet. But, how is it best to patch up?

Butt weld - more tricky perhaps but I've done ok-ish in the past. The biggest problem being smoothing the weld off to a decent finish only to end up with wafer thin tin that rusts in two years!

Overlap - in which case should the galv patch lie on top/in front or behind the original? And what's the best to treat from inside the sill once the welding is done to prevent the damn rust from bust my dumb ass again?

[docchevron132]

what you do is lap the joint.
Get a former to put a kink in the overlap, then weld it, grinf back. Lots of metal behind the joint to take the weld so assuming you get good penetration it'll be stronger than new!

[Philhod]

Yep if you cut the hole first, then put the joggle in all round, you can measure your patch to fit, then as Doc said you are welding over thicker stuff.

It's that long since I did a sill I don't know what they cost now.
They used to be so cheap it wasn't worth patching up. I bought the complete sill, cleaned and
removed all the rot, rustproofed, then stichwelded the new one right over the old.
Drilled a lot of 6 mm holes in it, pop riveted it on then filled and dressed the welds.

[Bx Bandit]

So Doc joggles the patch and Phill joggles the 'hole'? Either way I'm a biy a stuffed as I don't have a joggler. Am giving up caring what the fucking thing looks like TBH - I need to repair a foot long section on the rear of same sill - and I still blow holes in the fucking shit Bad day.........grumble grumble

On the plus side, the welder seems good and it's nice to actually use the thing!

[docchevron132]

I can lend you a joggler if you wish.

[Philhod]

Pair of mole grips and some flat bar, piece of wood, a hammer and cold chisel will do the job pretty good.
In the absence of said tool.
Clamp the end of the cut between the 2 pieces of bar (6x10), with the mole grips. Jamb a piece of wood between the grips/bar and the inner sill. run along behind the bar with the cold chisel to bend it down.
Then just pull up on the grips and release. jobbed.

[Bx Bandit]

Thanks for the offer Doc, I've decided to just do it even if it looks crap - I'm beginning to wish I had a modern car I need to picture what you describe Phil - which for some reason I find hard to do right now. Maybe the galvanised fumes are fucking with my head - what are the symptoms?

It's official though, despite some expert tuition, I'm crap at welding! On a nice flat plate I'm A ok but turn me upside down and swap flat plate for rusty BX and it all goes wrong. Having said that, the last 5 minutes I seemed to be doing reasonably well - bit fucking late in the day though. Arse planks

[Philhod]

Serves you right for using Galve. I can't weld well with that stuff it's shite.
For sills I use ordinary 2mm MS sheet, paint the inside except for the bit where I'm welding,
squirt waxoyl in and prime and paint the outer after.
It will last as long as you will ever need, so fuck that poisonous crap off.

[Bx Bandit]

Well I seemed ok in the end mate but it's odd shit when you weld it aint it? First yellow shite and then spider web fluff everywhere!

You're probably right mate but I have no 2mm m/s and at least the galve is 1mm which stops any further complications due to thickness mismatch (which for my ability will result in car meltdown!)

[Bx Bandit]

Right then. I went back to basics and consulted the Mig welding forum and the two things I didn't actually set right on the welder were wire feed tension and the reel tension. I probably had both a tad tight. Hey presto - much better welding. I also learnt that co2 is ok for thick stuff but struggles on the thin stuff. BUT, I managed fairly nicely today. I was getting good penetration without blowing holes!

I did have two observations though which I'll gladly take advice on:
1) When welding into a corner - the welder did a lot of popping, fairly regular
2) At times the weld had the appearance of pummice stone. It was as if it was too hot but at other times the weld looked good (with the same settings)

I'll also add that I spent my Xmas money finally on an auto darkening helmet! Very pleased. I can't say it would be warranted if all I did was 'bench welding' but when I'm on my side trying to hold the piece and tack it it ends up a million miles away. It just makes life a cajillion times better! Very pleased.

Sadly, the more I fit the more holes I discover. Am I to assume that a hole in the rear chassis leg (adjacent to the oval bump stop that's bolted to the chassis) is an MOT failure?!

Also, is grease 'leaking' from a non split CV gaitor a failure too? I either put too much grease in or didn't get the ligarex tight enough or even both! Is it supposed to 1 of those sachets of grease per joint? I put nearly 2 in!

[docchevron132]

erm... need to see piccies of the weld really, although TBH I'm a shit welder so I'm not the best person to comment!

Yes, a hole in the chassis leg will be an MoT failure, unless you take the car for MoT where Smiffy Mot's his!

Erm, unless the joint is entirely void of any grease at all on assembly then I've only ever used one sachet....
You could just hoik the outer end off, scoop a bit out then slap a new ligarex on the bitch?
They might or might nor fail it for that actually. I've had cars pass with weeping CV grease but no hole/tear in the boot... Others have failed..

Wow, I've been really fucking helpful there huh!

[jayw]

I did have two observations though which I'll gladly take advice on:

1) When welding into a corner - the welder did a lot of popping, fairly regular
2) At times the weld had the appearance of pummice stone. It was as if it was too hot but at other times the weld looked good (with the same settings)

Also, is grease 'leaking' from a non split CV gaitor a failure too? I either put too much grease in or didn't get the ligarex tight enough or even both! Is it supposed to 1 of those sachets of grease per joint? I put nearly 2 in!

The most likely causes of:

1.
When welding into corners (particularly at awkward angles) the torch is too far from the workpiece, the wire burns on contact and isn't fed in fast enough to create a bead. Although is has to be said that turning up the feed won't help as you'd also need to increase the power, and in turn the gas shroud to compensate.

Cleaning corners is very hard! Contamination (sealant, paint etc) causes poor contact and "popping".

2.
The "dry" appearance of the weld is attributed to overheating but this can be caused by the varying speeds at which you apply the bead (the slower you move, the more heat you put into the weld), also the thickness of the steel you're welding to will affect the heat (welding over 3 layer seams will allow it to handle more heat than a single layer). Your gas flow will also be a factor, too small a shroud will worsen overheating, whereas too much gas will overcool and cause "popping". First port of call really is to reduce the power slightly, or apply a little more gas.

TBH, as a novice, if you can lay down good enough welds to pass a genuine MOT i would consider yourself very successful. Welding isn't easy to master, it took me a couple of years to get it right first time, every time. And welding the tin foil you're doing is some of the hardest out there!

As for the CV grease, it'll only fail if it's actually pissing out at the time of the test, a little "seepage" is allowed as long as it's not contaminating it's surroundings (brakes etc.). If you're worried, just squeeze some out or take it for a good run using full-lock frequently to squeeze out the excess.

[Bx Bandit]

Thank you both - you've both been helpful! Blimey!v

I need to digest what you said about the welding Jay - think I'll write it down and put it into practice.
When, generally, we talk about turning the power down, are we talking wire feed (amps) or powah (volts)

Think I'll stick some cable ties on the CV boot, perhaps akin to swearing but I find ligarex fidly and I never seem to get it tight enough.

I have a rear chassis leg to weld then. Ideally it'd benefit from dropping the rear subframe............sigh

[docchevron132]

dropping the subframe is easy enough mate TBH..
Especially since if it's only one leg then you can just slacken off the nuts on t'other side and only drop one side down..
Thats how I did Groliffe in under an hour.
Easist way to weld: buy a bus. Much easier welding 6-15 MM plate than poxy car shit!

[jayw]

When, generally, we talk about turning the power down, are we talking wire feed (amps) or powah (volts)

Think I'll stick some cable ties on the CV boot, perhaps akin to swearing but I find ligarex fidly and I never seem to get it tight enough.

What welder are you using? Most domestic migs have only got controls for Wire Feed (which controls the speed of the feed) and control of Amperage (generally termed) "Power". Oh, and gas feed via a bottle regulator...

Just bear in mind that if there's too much grease in that joint it will just squirt everywhere once it compresses!

Easist way to weld: buy a bus. Much easier welding 6-15 MM plate than poxy car shit!

I agree completely! I try and avoid welding wherever possible these days, too many scars...

And i'd love to buy a coach & convert it into a touring home so i can fuck off onto the continent for a couple of years!!!

[Philhod]

The pumice effect on the weld Bandit, is down to insufficient gas shroud and is termed porosity.

When you weld in areas where you need to pull the shroud back from the weld, to see what you are doing, Raise the flow to 15 L/min if you are inside or it's a calm day. 20 if you're outside and it's windy.
This will allow you to pull back up to 40 mm

[Bx Bandit]

Ah thank you Phil. I don't have a flow meter - just a pressure gauge (2 gauges 1 for bottle pressure and 1 for 'outlet' or 'nozzle' pressure). I'll turn it up a notch it has been a bit breezy today. I have to say though it's better than a week or so ago so quite happy with progress.

Jay it's a clarke 160T. Wire feed 1-10 and 'power' 1-2-3 (hi & lo). It's hard to turn the power down a 'bit' as it's obviously in steps. I thought Power selected the voltage and the wire feed in effect selected the current. Or have I got that horribly arse over teet?!

[jayw]

Ah thank you Phil. I don't have a flow meter - just a pressure gauge (2 gauges 1 for bottle pressure and 1 for 'outlet' or 'nozzle' pressure). I'll turn it up a notch it has been a bit breezy today. I have to say though it's better than a week or so ago so quite happy with progress.

Jay it's a clarke 160T. Wire feed 1-10 and 'power' 1-2-3 (hi & lo). It's hard to turn the power down a 'bit' as it's obviously in steps. I thought Power selected the voltage and the wire feed in effect selected the current. Or have I got that horribly arse over teet?!

UIVMM, Domestic MIGs are fixed voltage, the wire feed simply changes the speed of the wire delivery, nothing else. Your power switch adjusts the current and therefore it's power intensity. As you said, fine tuning is somewhat limited by the 3 stage power you have.

Getting technical (some boffin correct me if i'm wrong) the only voltage variance happens at the tip of the wire, as the arc is created the voltage varies depending on how close the wire is to the workpiece. The voltage is lower in a short arc and higher in a long arc...

[mat_the_cat]

Or have I got that horribly arse over teet?!

Kind of! The power setting controls the weld current (actually, with voltage and current being linked it may do this by controlling the voltage) and the wire feed controls the…erm…wire feed speed. The power setting does also change the wire speed into a different band, so you don't have to change the wire speed just because you've changed the power.
I've got almost the same welder as you, the 151 Turbo - I think you have the ability to use (expensive, but better if it's windy) flux cored wire whereas I don't. I tend to use setting 2 low most of the time on car stuff, going up to 2 high if I don't get enough penetration, and down to 1 high if I'm blowing through. Another thing I've noticed is that I may start on a slightly higher setting for tacking things in place, and then find I need to drop it down a bit once I start seam welding and the heat gets into the metal.

[Bx Bandit]

Flux cored stuff?? Not sure mate, that may be the 'TE', mine is just a 'T' I probably wouldn't bother even if it could mind mate. It's not a bad set as it goes, despite it being in the hobby range and hobby sets getting bad press. Quite pleased with it really. I made even more progress welding wise this evening so I'm starting to bond with my welder!!!