Another newbie from Ivybridge

[Damian]

Hi folks,

Firstly, what a fantastic site with so much info, vids and pictures.

I recently bought a 1989 Mini which requires a new wing and A panel, I was lent a Rockworth AR90 mig welder to carry out my task, at first I had no idea between the 2 different types, with Gas and Gasless.

I have a Gasless one which (fingers crossed) will be ok for the job in hand.
I am trying to Spot weld or should I say Plug weld, I have read loads of info from this site, but being a novice I am still scratching my head more times than I care for.

I have loads of questions to ask as you would imagine from a novice, but my first one would be....I have 2 settings for Amps, 45A and 90A, and the wire feed controller. I am practising on an old door skin off the car, I am grinding all paint and crap away, drilling a 7mm hole through the top piece and laying that tight on top of the other, I just don't know what is the best settings to start with, none of the welds seem to penetrate and hold together.

Is there a rule of thumb for how strong a Plug weld should be?
I'm using 0.8mm fluxed cored wire.

If anybody has any experience with this type of welder, you help would be very much appreciated.
I want to do a welding course in Plymouth, but the next one is not until June!!!!

I know I haven't given you guys much to go on, I'm kinda confusing myself by typing it

Thanks in advance guys and girls

Damian

 

[Wendelspanswick]

If you have a 90 amp welder you will want the highest setting, try not to have the wire speed too high, the wire shouldn't be pushing you hand away. A constant crackle is want you want, think of bacon hitting a hot frying pan!

 

[Damian]

Brilliant, thank you for your reply. I was under the impression you had to go with the lowest setting, at least you have pointed me in the right direction so I can practise. Thanks again mate.

Can I ask another question....if I was to plug weld 2 pieces together with 1 plug weld.....what sort of pressure should it take to seperate the pieces. Im worried that it may look ok but when I take it out on the road and go over one of the uk's pot holes.....I might over take my front wing?? Not just that , I would be gutted if I thought I done a good job but it fails the mot.

Thanks

Damian

 

[Wendelspanswick]

To test your plug welds rip a sample apart, the metal surrounding the plug should tear. If the plug separates without tearing it's not hot enough.
If you are struggling to get a good bond try drilling a 3mm hole through both sheets when clamped together and then carefully enlarge the near side hole with an 8mm drill bit, have the drill on a low speed as it will try to pull through both sheets.
Hold the torch at a slight angle as you start the plug and then bring it up to vertical as the arc starts.
The best thing to do is practice and play about with the settings/hole size/angle until you get consistently strong welds.
Good luck.

 

[Damian]

Thanks again my friend, very helpful. When you come to welding new panels on to old.........do the old panels have to look like new ones, if that makes sense. Would I be wasting my time setting up to weld new to old, reason I ask is where do you stop taking old stuff off. Some flanges etc are thinner due to grinding back surface rust and I'm worried all I would do is blow holes in the old panels.

I take it I use 90A for plug weld and turn down to 45A for seam weld, else I would distort the hell out of the panels.

Thanks

Damian

I'm a Plasterer by trade so metals have never been my strong point