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What's wrong with my welding?

Posted: Thu Aug 01, 2013 2:12 pm
by rogerowen
I'm going to run this up as a new topic as it's more of a scream for help than a simple debate. What on Earth is wrong with my welding? The wire is melting and sticking to the new metal plates but it's not sticking to the old metal. I'm cleaning back to good metal but my welds always end up looking like rabbit droppings! All and any advise appreciated. :cry: Photos to follow.

Re: What's wrong with my welding?

Posted: Thu Aug 01, 2013 4:00 pm
by bmcecosse
More POWER - and faster wire feed... What size wire are you using? I found 0.6mm to be useless - 0.8 mm better and as before - the 0.9mm gasless much better......

Re: What's wrong with my welding?

Posted: Thu Aug 01, 2013 4:06 pm
by ian.mcdougall
have you looked at this website

http://www.mig-welding.co.uk/‎

Re: What's wrong with my welding?

Posted: Thu Aug 01, 2013 4:26 pm
by LouiseM
Here are the photos:[frame]Image[/frame][frame]Image[/frame]

Re: What's wrong with my welding?

Posted: Thu Aug 01, 2013 5:13 pm
by rogerowen
bmcecosse wrote:More POWER - and faster wire feed... What size wire are you using? I found 0.6mm to be useless - 0.8 mm better and as before - the 0.9mm gasless much better......
I got a reel of .8 Gasless, think you are right about more power, and having taken off my lousy first attempts - I've cut the bodywork back further to thicker stronger metal :roll: . I think I was Pussy-Footing here.

Re: What's wrong with my welding?

Posted: Thu Aug 01, 2013 5:14 pm
by rogerowen
ian.mcdougall wrote:have you looked at this website

http://www.mig-welding.co.uk/‎
Yes, I joined their forum too now. :D

Re: What's wrong with my welding?

Posted: Thu Aug 01, 2013 5:27 pm
by beero
Are you cleaning front and back on the old metal?

Re: What's wrong with my welding?

Posted: Thu Aug 01, 2013 5:40 pm
by rogerowen
beero wrote:Are you cleaning front and back on the old metal?
Can only access the front of the old metal as the back is inside a box section (MG Midget vertical bit just behind the seat back). I was overlaying a patch, but how I've hacked out further past the rust and will attempt to butt weld a new piece in. My new metal was going rusty - so I wiped it over the WD40, then I give it a brushing over with the grinder before welding. I'm also spraying masses of Jenolite inside the hole, and lots of weld-through primer in a hope to delay further rusting. I bought some rust encapsulator but I cant get to much of the internal box section.

Re: What's wrong with my welding?

Posted: Thu Aug 01, 2013 6:54 pm
by PaulTubby
rogerowen wrote:
beero wrote:Are you cleaning front and back on the old metal?
Can only access the front of the old metal as the back is inside a box section (MG Midget vertical bit just behind the seat back). I was overlaying a patch, but how I've hacked out further past the rust and will attempt to butt weld a new piece in. My new metal was going rusty - so I wiped it over the WD40, then I give it a brushing over with the grinder before welding. I'm also spraying masses of Jenolite inside the hole, and lots of weld-through primer in a hope to delay further rusting. I bought some rust encapsulator but I cant get to much of the internal box section.[/quote

DONT use wd40 to clean the metal! and do all the waxoyl -injecting after the welding, you will cause a fire in the box section if you weld near it! and to get to the internal box section, drill some holes and insert a prob and spray in then grommet over... when cars was new they did that back in the day with zeibarting etc... it works, but only do the cavitity and rust proofing AFTER the welding process! trust me :D

Re: What's wrong with my welding?

Posted: Thu Aug 01, 2013 6:59 pm
by rogerowen
PaulTubby wrote:
rogerowen wrote:
beero wrote:Are you cleaning front and back on the old metal?
Can only access the front of the old metal as the back is inside a box section (MG Midget vertical bit just behind the seat back). I was overlaying a patch, but how I've hacked out further past the rust and will attempt to butt weld a new piece in. My new metal was going rusty - so I wiped it over the WD40, then I give it a brushing over with the grinder before welding. I'm also spraying masses of Jenolite inside the hole, and lots of weld-through primer in a hope to delay further rusting. I bought some rust encapsulator but I cant get to much of the internal box section.[/quote

DONT use wd40 to clean the metal! and do all the waxoyl -injecting after the welding, you will cause a fire in the box section if you weld near it! and to get to the internal box section, drill some holes and insert a prob and spray in then grommet over... when cars was new they did that back in the day with zeibarting etc... it works, but only do the cavitity and rust proofing AFTER the welding process! trust me :D
Much wisdom, thanks.

Re: What's wrong with my welding?

Posted: Thu Aug 01, 2013 9:54 pm
by les
Looking at the welds Roger, I'm thinking you're not 'pushing' the wire into the metal for long enough before moving along, and experiment with the wire speed you may be running too fast causing a build up.

Re: What's wrong with my welding?

Posted: Thu Aug 01, 2013 9:59 pm
by rogerowen
les wrote:Looking at the welds Roger, I'm thinking you're not 'pushing' the wire into the metal for long enough before moving along, and experiment with the wire speed you may be running too fast causing a build up.
This rings true! I think I'm so nervous about burning through that I'm moving a bit too fast. Gonna practice loads! Cheers :D

Re: What's wrong with my welding?

Posted: Thu Aug 01, 2013 10:15 pm
by les
I think most of us have been there Roger, you could get a spare similar thickness piece of metal and burn through on purpose, it may give you an indication of how long it takes, then bear that in mind when you do the real thing.

Re: What's wrong with my welding?

Posted: Thu Aug 01, 2013 10:19 pm
by rogerowen
les wrote:I think most of us have been there Roger, you could get a spare similar thickness piece of metal and burn through on purpose, it may give you an indication of how long it takes, then bear that in mind when you do the real thing.
Brilliant idea, thanks. Lot and lots of practice me thinks!

Re: What's wrong with my welding?

Posted: Thu Aug 01, 2013 11:00 pm
by drivewasher
are you useing gas? Co2 or argoshield. Those welds look like not enough shielding gas. Is the polarity right?

Re: What's wrong with my welding?

Posted: Thu Aug 01, 2013 11:16 pm
by bmcecosse
I didn't (couldn't easily ?) change the polarity for gasless use. Does it really matter? Has anyone done a direct comparison? What's the logic for changing the polarity??

Re: What's wrong with my welding?

Posted: Thu Aug 01, 2013 11:17 pm
by rogerowen
drivewasher wrote:are you useing gas? Co2 or argoshield. Those welds look like not enough shielding gas. Is the polarity right?
Argon mix till it ran out and then Co2. Polarity correct. Wondering if power was too low.

Re: What's wrong with my welding?

Posted: Thu Aug 01, 2013 11:23 pm
by Kinsley96
i use gasless as well, (only because i go for the cheap stuff), had the same problems today, and your welds look all too familiar.

when practicing my welding works a treat on 2 mm. however get to the car and it burns through the thinner (previously rusty) metal so had to build it back up. bloody pain!

i reversed polarity today and worked slightly better

meanwhile, I might invest in a quality welder. :roll:

Re: What's wrong with my welding?

Posted: Fri Aug 02, 2013 7:42 am
by kennatt
I use gassless,/gas and many times have just not bothered to change polarity never seen any difference in the weld.

Re: What's wrong with my welding?

Posted: Fri Aug 02, 2013 8:50 am
by rogerowen
Kinsley96 wrote:i use gasless as well, (only because i go for the cheap stuff), had the same problems today, and your welds look all too familiar.

when practicing my welding works a treat on 2 mm. however get to the car and it burns through the thinner (previously rusty) metal so had to build it back up. bloody pain!

i reversed polarity today and worked slightly better

meanwhile, I might invest in a quality welder. :roll:
I get the feeling that it's all down to getting the settings correct for the particular job in hand. If you are moving from 2mm to something much less, then the power will need to go down to avoid blowing holes. I think one of my problems is trying to weld where the metal is just TOO thin. I spent yesterday pulling off the plates I had welded to the car (disgusted with my work!), and they came off remarkably easily. I'm now cutting back further than where the rot just ends in the hope that I'm getting back to thicker metal and thereby be able to notch the power up a bit. Basically, I need to melt the old metal as well as the new plate and the wire. Will report back on progress.