wire build up no penetration

[steae92]

hi all

i am probably going to sound like a bit of an idiot but im new to this and skint until next week but im in a rush to get my car ready for its mot.

basically i have just bought an old sip migmate and i mean its really old lol. im not sure the exact model but its red and it goes from 35amp to 100amp the wire feed is on the bottom left of the machine with 4 switches on the bottom right that say low, medium, max and a black switch that says range 1 range 2.

what i am trying to do is weld my exhaust but i can't get my hands on any gas until next week. i have read that it is possible to weld mild steel with no gas on normal wire? just that the welds will be ugly and they will oxidize or something? well ive tried and tried on all settings and all that happens is that it just balls up on the surface with wire all other the place and splatter. i did get one neat bead but it did no penetrate. it just sat on the surface.

the workpiece is clean. i am using 0.6mm wire (normal gas wire). i have tried holding the gun over the workpiece in the same spot to make a pool and when i lift my mask up i just find a pile of weld. im thinking i am going to have to wait for gas? unless someone can advise me otherwise.

many thanks

 

[redwine300]

Well I am no expert, but as I understand it, to gas-less weld you would need to use some kind of flux filled wire. Secondly, the polarity will need to be changed over for gas-less, (that's if your kit is capable of this)
Hopefully one of the more knowledgeable members will be able to explain in more detail.

 

[cumbriasteve]

You are on a looser really, attempting to weld without gas and normal wire is never going to turn out any good.

I may be able to help if it's not a massive amount of welding, if you are local (Whitehaven) and the exhaust is off the car, my days of lying under cars with hot lumps burning my vitals are long gone.

 

[Wozzaaah]

Easy answer....get gas!

The other thing probably hampering you is the aluminised coating on the exhaust, it's horrible to weld to and needs to be ground off to give you a reasonable chance of success, even with gas.

 

[steae92]

well its ground down. i dont know about polarity is that swapping earth clamp and torch lead around? i will see if its possible. ill just hang fire then and see if i can get some gas next week. do i need some sort of certificate to get gas from boc? i keep getting told i do and that i have to rent the bottles. i dint really want to rent bottles as i doubt ill use it that much unless my welds end up neat enough. is there any way of getting a bigish bottle and just get it filled when i need to?

and cumbriasteve im in barrow-in-furness.

cheers

 

[Wozzaaah]

If there's no obvious way of swapping polarity, i.e swappable cables then your machine will be gas only BUT....it may still work with gasless wire, especially as what you're trying to do is non-critical. I'd suggest get a roll and try it, you'll also need the appropriate size contact tip.

 

[Robotstar5]

ill just hang fire then and see if i can get some gas next week. do i need some sort of certificate to get gas from boc? i keep getting told i do and that i have to rent the bottles. i dint really want to rent bottles as i doubt ill use it that much unless my welds end up neat enough. is there any way of getting a bigish bottle and just get it filled when i need to?

If you just need to do a quick job cheaply, pick up a disposable bottle from local motor factors or Halfrauds for about £15, they don't last long (about 10 mins arc on time) but will get you going while looking for a decent big bottle (check out the shielding gas section)

 

[steae92]

cheers guys ill get a small bottle then. i should really anyway to test the welder as it an old machine lol. hope i can get the hang of it as im used to stick welding i find the pool on stick welders easier to see than the mig. i want one of them self darkening masks but that can wait for now. ive got a very unsteady hand which doesn't help but i find a couple of pints makes my hand steady for some reason so i think a few beers before jumping on the mig will help lol.

 

[Tiggy_dorset]

Do a search for rent-free bottles, there are companies who allow you to pay a one off deposit for a bottle then just pay for gas refills when you need it. Search the forums, there are a lot of posts regarding rent-free bottles and where ypu can get them from.

 

[cumbriasteve]

Think I found a gas supplier at Barrow when I was looking but can't remember the name, Inngas at Workington does a pub bottle of CO2 for £12 a year rent and £11 a refill, they also do a full range of CO2 /Argon a lot cheaper than BOC, my full size bottle is £30 a year rent and £30 refill.

 

[steae92]

i think i will try inngas out next month then as ive got mot and tax to sort this month. they do sound quite reasonable. i think ive decided just to see me threw this month to get some flux cored wire. i know its not the best option but i dont think my budget will stretch any further this payday. will the flux cored be strong enough to hold the exhaust without developing cracks in the welds? this is what im worried about as ive welded my exhaust in the past with a stick welder and the welds just snapped after 20mins. although im guessing thats the welders fault as the burn through was too much.

 

[Chickenjohn]

Get some gas! Your old SIP is probably not designed to use flux core wire and the polarity will be wrong.