Help welding car chassis

[Sneekyparrot]

Afternoon,
I came across this forum when i was searching mig welding help. Basically i am rebuilding a track car with the addition of some more roll cage and stitch welding the rest of the chassis so i read thru all your items and got myself some steel etc to practice on before starting anything.

I did have a 150T clarke unit for years that i used when i was building bike stuff and never had a problem until i lent it out and it got wrecked guy supplied me with a draper 13002T unit that i have had a while but never used up till now.

So i started practicing and all was going well. With .8 wire and the unit wound up to max i was able to weld up the cage sections fine.

now the problems started when i dropped down to .6 wire for the chassis, basically i cant get a decent weld, the welds are all over the shop and i just don't know if its me or the welder?? i have been up and down the settings / wire speed for hrs. Back to my practice metal and it seems fine, a little distortion but its only practice. Back to the car and i might get 1 half decent weld out of 10 and just when i think i have got one weld i move 25mm up and the next just produces a ball of fuzzing weld wire no penetration which then drops off the end of the gun onto the floor.

Practice:

Weld on Car:

so i have to grind the kak welds back down and try again. 1 seconds its like i dont have enough wire speed then it wont penetrate and looks like a worm on top or a mixture of both with a horrid stalk of weld wire as though its to fast.

chassis has had the seam sealer removed and metal ground clean with a angle grinder / wire brush, and the earth it attached to the panel i am welding.

i was just about to go for broke and get a new welder but if everyone thinks its me and the setting then i reckon i will pay a local welder for some tuition on the car ??

cheers

Paul

 

[Exuptoy]

There's a thread on here confirming hey are a pain to set up on thin stuff. Other than that I have no experience. Good luck.

http://www.mig-welding.co.uk/forum/showthread.php?t=20907

 

[rkde]

What condition is the wire in? if its been a while it could be all rusted up. I presume that you have take the wire speed back a little from where it was for 0.8? I do like a 0.8 on thin car work but recently have been using 0.6 on the beetle.

Silly question but have you changed all the wire feed rollers over to 0.6 so your not seeing any slipping.

Can hardly see the photos but what gas are you using? also what sort of bottle?

 

[Sneekyparrot]

What condition is the wire in? if its been a while it could be all rusted up. I presume that you have take the wire speed back a little from where it was for 0.8? I do like a 0.8 on thin car work but recently have been using 0.6 on the beetle.

Silly question but have you changed all the wire feed rollers over to 0.6 so your not seeing any slipping.

Can hardly see the photos but what gas are you using? also what sort of bottle?

Hi,
New wire, had the wire speed down at 2 and upto 6 trying to find sweet spot.
Rollers swapped over to .6 that caught me out when i first installed it
gas is a 110ltr new bottle of argon/co2 from machine mart.

doing my head in

 

[Exuptoy]

Recently saw a vid where the guy turned his set right down then positioned his hand then fired the trigger and increased the speed until it sounded right. Tried that myself and surprisingly it does put you in the ball park. Have you checked the tension on the reel and the wire feeder? Not too tight?

 

[mike 109444]

Have you replaced the 0.8 tip for a 0.6 Basic I know but easly over looked.

 

[CKJDJK]

Have the same welder for a while now. Always was better on 0.8 wire and welding thicker metal. More recently I fitted a steel wire liner ,a Clark cut down item, which has made a big differance to 0.6 wire. I have the wire spool brake almost off using 5kg reel. I set the feed tension so that wire just slips if gripped with pliers at the torch end. Use good 0.6 tips and keep them clean. I need to keep the shroud clean and use about 8l/min of CO2 although Argon/CO2 would be better. The torch is less sensitive to bending the lead now but it still affects the weld if too tight a radius. On 0.6mm wire I find I need to keep the torch angle almost vertical to the weld and about 10mm from it which makes seeing the weld pool difficult but a good auto mask and plenty of light help. the parent metal needs to be very clean especially on the thinner stuff. The sweet spot can be hard to find but perservere as the welder is quite tough, mine has been hammered being carried up and down ladders and dragged over rough ground then being kept in a wet shed and it still come back for more.
Just finished welding mild steel patches to a stainless exhaust system on a winter hack bike using 0.6 wire, CO2, outside, and rust from previous owners weld attempts which the welder did very well considering (only got to last a couple of months or so).

 

[Sneekyparrot]

Have you replaced the 0.8 tip for a 0.6 Basic I know but easly over looked.

yep on a .6 tip.

thx

 

[Wozzaaah]

Why did you go down to 0.6mm wire?
0.8 would be better for chassis thickness.

 

[Sneekyparrot]

thx for the help guys, will give it another go tomz but if its that fine a line setting up for the thinner car panels and seeing as i have the whole chassis to stich i may just plump for a newer better welder

cheers
P

 

[Sneekyparrot]

Why did you go down to 0.6mm wire?
0.8 would be better for chassis thickness.

Tbh I thought I was Having to turn up the power to much and increasing the risk I would just blow thru but I may try a switch back to .8

P.

 

[SiPMerlin150]

Hi there,

As probably mentioned, the wire feed speed also controls current, the higher the wire speed the more power is transferred. A fast wire speed will build up weld quickly, but will give a bigger chance of burn through.

In my jobs at work welding up rotten ford ka's and old nissan micras and the like, the worst enemy of the MIG welder is rust, grease, underseal, water, and road salt/dirt. Even the dust from the grinding process causes problems. The metal has to be bright and shiny, and the shielding gas must be covering the weld area to prevent porosity where the wire will blob up and drops off like you mention (We call them 'weld bombs' painful if they catch you up the sleeve of your overalls... I have the scars!