ive been in the garage trying to weld 5mm plate onto 3mm box section. I failed miserably...

The welder is a 135amp mig from machine mart. I blew two fuses whilst running it on full power, which is what caused me to give up finally, but i also had a complete lack of penentration. To the extent that, with 4 tack welds, i undid the clamp and the plate dropped off! So i got the blow torch on it to preheat it, which made a significant amount of difference. One side looks firmly fixed now, though its a damned messy weld as ive lent my mask to a friend the blink technique isnt ideal.

Would degreasing or derusting the metal make much difference. Obviously it would be a good idea and good practice, but im terribly unmotivated at the min

I dont really know why im posting to be honest Maybe just to tell people that clark 135s are no good for big metals, or to mention how much difference preheating it does.

I guess i really need to get that new welder i was on about. Im torn between a more powerful mig, for cheapness, or a tig. Trouble with tig is id have to learn how to use it first...

Anyone interested in a group buy on a circa £6-800 tig?

You really need to grind back to clean metal to use MIG, TIG or ARC if you want to join dirty metal use gas. Preparation is 90% of just about everything and good welds by electric means are included. Also you could bypass the fuse in the 13A plug, if you're garage is properly wired you are still backed up by a 30a fuse and you should have a pretty thick cable back to the plug, but I didn't tell you that neither will I be responsible if you use such wreckless information!!
Caber

Is it safer to run a heavy duty extension lead out of a cooker point? , aren't they 45a?.......

I run my mig off cooker socket, Its 185 amp exstension lead gets a tad warm when its flat out only problem is weld on a sunday no roast

Buy a proper welder not a mickey mouse machine mart effort and all will be well

The welder you are using is great for car body panels - I borrowed on a few months ago when I put a pair of cover sills on the Metro for MOT. It was great, not like the big b**ger we have, in the workshop, which we used to make the benches. It is good for thick metals but blows holes in car bodywork. The old saying "horses for courses" rings true here. Best of luck - don't give up, just get the right gear for the job and you'll be OK.
Pete

ive had problems with my 150 amp like that before .i now put down a a row of tacks all over lapping each other and it looks like a tig weld a welding article in ppc said the same thing.ive got a cheap dc inverter but you need the foot pedal to make really pretty welds but you can make a really tidy job of thin stainless with it!

silly question, have you re-setup your welder? I was curising one night, never occured to me it was about 10 degrees colder than when i last used the welder.

next night, set the damned thing up properly before i started and it ran like a dream.

Stop mucking about Joel. Go spend some money.

Paul G
Rescued attachment mickey-mouse.jpg

hmmm, the wleding thickness stated is total i.e. includes both pieces. 150 A is about 4 mm; you are welding 8 mm; ain't gonna work.

use pop rivets

I connect my MIG to the cooker otherwise it trips the garage circuit breaker.

If you use an extension, make sure it is uncoiled and loose.

[Edited on 2/12/05 by 02GF74]

Along the same lines as MikeR's reply. Cold metal makes a hell of a difference to the quality of weld. Just leave two pieces of 3mm outside on a frosty night bring them in and try to weld them. If your garage is cold as mine is at the moment getting good results from a small mig will be difficult. The options are to warm the garage up or as you suggested to heat the area before welding. However I think you may still have problems welding 3mm to 5mm with a cheap 135 amp mig. Having said that I have used a Cebora pocket mig turbo which is a 130amp mig on the whole of my chassis and have found it coped admirably but I have used co2 rather than argon/co2 mix. co2 generally gives a messier finish but better penetration and it is cheaper if you have a pub type co2 bottle and know a friendly fire extinguisher company. Hope this helps.

[Edited on 2/12/05 by Locost?]

Get your mask back so you can see what you're doing. Point and squirt welding might look like tig to some but it is nothing like tig or mig, learn to adjust your welder and put a run down. The blowtorch probably burned some crap off so the weld worked better, preheating shouldn't be needed for mig on steel if your arc is good. If you get a tig and are welding 3mm to 5mm you could use it as a normal arc welder, much cheaper.

quote:

---

Originally posted by Peteff
preheating shouldn't be needed for mig on steel if your arc is good.

---

quote:

---

Originally posted by JoelP
Maybe just to tell people that clark 135s are no good for big metals,

---

All i'm saying is it made a difference for me!

quote:

---

Originally posted by 02GF74
hmmm, the wleding thickness stated is total i.e. includes both pieces. 150 A is about 4 mm; you are welding 8 mm; ain't gonna work.

---

I had an old oil cooled 140amp arc welder given to me by a local shop along with about 1cwt of rods of varying type and size which are in the airing cupboard now. It's ages since I did any stick welding but I can put a run on 2mm steel with it without burning through. It's easier to use the mig though, erfi 170 which will cope with 6mm on full power and still blow a hole if you hang about. The biggest offender I find is not cleaning where you are working including under the earth clamp.