Carbon heat shrinking attachment for mig welder

[Chickenjohn]

Hi All,
One of the instructors on the restoration course I'm on said its possible to convert a mig welder to a heat shrinker- this has a carbon tip and you draw an arc in a swirl pattern to heat shrink stretched areas of sheet steel bodywork. Does anyone know of such an adapter that is available commercially or has anyone made one up on a lathe??

 

[fingers99]

Never heard of these for MIG, seen pics of them for arc.

 

[Dusty]

When I lernt Vehicle body restoration at mid kent colledge, quite a few years ago now tho'. we learnt to do this with the Oxy kit and handfuls of papermache mix, then w were shown it's possible to do a similar trick with a humble stick welder (arc) using a brazing torch attachment.

Use one carbon rod to make a Hot spot or more to tighten the pannel.
watch out for arch flash and dont hold it too long!!!

Practice on scrap first ! not on that rare pannel !

Dusty

Never herd of for a mig set up, Anyone?

 

[wyn]

Could try a shrinking disc. never used one myself though.
They are a stainless steel disc that fit on a grinder. Run it over the high spot and cool with water.

 

[Chickenjohn]

When I lernt Vehicle body restoration at mid kent colledge, quite a few years ago now tho'. we learnt to do this with the Oxy kit and handfuls of papermache mix, then w were shown it's possible to do a similar trick with a humble stick welder (arc) using a brazing torch attachment.

Use one carbon rod to make a Hot spot or more to tighten the pannel.
watch out for arch flash and dont hold it too long!!!

Practice on scrap first ! not on that rare pannel !

Dusty

Never herd of for a mig set up, Anyone?

The Mid kent college course is the one I'm on (advanced student now)- we have used oxy acet to heat to red hot, then tap the high spot to a dolly and cool quickly. Or, the bit of kit they have which is a spot welder with a shrinking attachment that holds a carbon tip. So yes it is effectively an arc welding attachment. I have used this bit of kit many times, and its very useful, could do with one at home too. Brilliant course, BTW. I re-built my traveller before going on the course, wish I had been on the course first.

YOU may remember Brian, the older chap, brilliant metal worker, he told us that you can make an adapter to hold a carbon shrinking tip to screw onto a mig swan kneck up from brass. I've made a few drawings and before I scavenge some brass rods and lathe a piece up, I was wondering if such a piece is commercially available??

Is the mig tip thread a standard metric thread?? looks like M3 or M4 to me, anyone know? If not I will measure one tonight.

 

[RSOHC]

A MIG shrinking attachment is offered at www.usaweld.com. The product code is 15003. The price is about $18 plus shipping in the year 2012. The phone number is 1-800-872-9353. Call and they will let you know if your MIG can accept this tool.

 

[Sean]

Is the mig tip thread a standard metric thread?? looks like M3 or M4 to me, anyone know? If not I will measure one tonight.

M5 on hobby, M6 on pro

 

[Chickenjohn]

Funnily enough, I finally got hold of some carbon electrode rods and made one of these heat shrinker attatchments last week. I used a lump of brass from a broken regulator and it works a treat.

Why buy one when you can make it for pennies???

No thread matching needed now.

 

[Chickenjohn]

Take your lump of brass and drill a 10mm hole to accept the carbon electrode and (I think) a 5mm hole to accept the Mig tip. Also drill two more holes at right angles to these holes and tap them to accept small machine screws. These screws gently clamp onto carbon electrode and copper mig tip.

Could improve the design by using a bigger bit of brass and grub screws, with internal hex.

Takes seconds to fit the shrinker attachment, just unscrew mig shroud, screw on the attachment, switch off the gas and disable the wire feed. Set the welder to minimum, pull the trigger making spiral "snail shell" shapes over the stretched metal, cool with damp cloth or blow gun and the metal magically shrinks back down!

Cost nothing and less than an hour to make and does the job on a Morris Minor door.

 

[Chickenjohn]

American one, but how much after shipping and VAT etc??

BTW the design is not exactly my own- courtesy of Doug Barrow and Brian Dunmall of Mid-Kent College vehicle body restoration course. If I were to make one again, i would use a pillar drill as it is tricky drilling into brass and keeping the drill running straight.

Prefer my free one!

 

[paul_f]

Where did you get the carbon electrodes from?

 

[Chickenjohn]

Ahh, well that is the bit I did have to buy. It was about £17 plus VAT for a pack of three from Kent Body and Paint in Chilham. The guy there is very helpful!

However, as I have three full length electrodes and I only really need a few inches, guess I could cut a bit off for you.