Welding 0.8mm 304

[smokie]

Hi Im new to this welding type and any help to get me started would greatfully recieved. I have a Giant TIG200 HF start invertor. I want to fuse weld 0.8mm 304 but I understand the purging and I have the rig to do it. What rod will I need just in case I blow through? What amperage and travel speed should I be looking at? I have added a post elsewhere loking for a manual for this machine too.

Regards Smokie

 

[Shox Dr]

I've welded miles of .8mm 304. knowing what you are doing would help

 

[smokie]

Well Im trying to weld 0.8mm sheet rolled into cones Its not surgical or anything like that. What I have read would 1mm tungsten, 4lpm torch and 2lpm purge, 20amps and 50mm per min sound about right?. Not sure on the grade of rod though.

 

[hotrodder]

What Shox is saying is that calling out amperages and travel speeds is almost meaningless when talking about 0.8mm stainless and someone completely new to TIG. If you read the TIG tutorial again (i'm guessing that's where you got the suggestion of 20A?) at the top of the page it'll suggest beginning with 2 or 3mm material. It does this for a reason...

To give you a very rough idea of the sort of control needed to get neat (and airtight) results grab a pen, paper and a small thin washer. With the pen nib in the centre hole move the washer along the paper without marking the paper or slipping out of the washer- this exercise is about 1000 times easier than actually welding as there's no weldpool or filler wire to worry about and the paper isn't hot. That's the kind of control needed with respect to arc length. Arc length and travel speed have an impact on heat input (amps needed) and with thin materials (especially heat sensitive ones like stainless) there ain't much margin for error

FWIW the filler wire you want for 304 stainless is 308L although 316L will also work fine. For 0.8mm base material you'd want 0.8 or at a push 1mm wire. If you blow a hole you'll really struggle to fill it without totally trashing the part. Tacking the thing together will be hard enough at first as stainless will disort like you wouldn't believe given the chance. If you're determined to make life hard and dive straight into thin stainless i'd suggest getting a length of ally or copper to clamp to the back of the joint, at least while tacking up

 

[FranV8]

Wow - I'm off to find a pen, a washer and some paper! One to do while Mrs FranV8 is watching something I'm not a fan of (like Glee...) on the box!

 

[Shox Dr]

As usual Hotrodder has put it far better than I could have, and given you an insight into the difficulties in welding .8 SS.

I thought I could weld before I started work for a local Co who built Custom Canopies for commercial kitchens, oh how wrong I could have been, in my time working there we are constantly advertising for TIG welders, they would come take one look at the Tokens we had tacked up, for them to weld, some would have a go, but most would turn tail and walk out with out trying, and these were guys that had codes coming out their ears. That's how hard it is.

I did learn though, you need to grind the tungsten to a needle sharp point, a gas lens will make a big difference as well. we only had 1.6mm rod and we only used 316l; the weld cannot be seen when polished or blended in on brushed finish.

Good fitup cannot be stressed enough, if the two edges do not fit perfectly you will run into trouble.
as for Ampage, an outside corner 20amps, lap joint 30-40. Most of the time we used no rod at all, but some times the fit up was bad with gaps greater than a 2.6mm rod wouldn't span. Oh the fun

Plenty of tacks, get comfy.

 

[Drains]

Nice. Shox, do you fill in between those stitches? I assume you must as you'd surely not leave those corners hanging loose.

Also, are those things purged? (again, I assume not, but do correct me...)

 

[Shox Dr]

They are mounting brackets for the top of canopies. Pictures show finished part. No purge. If you move fast enough you'll get full pen' with no sugaring on the back.

Pictures 1 and 2 the corner is just nipped together in one hand and fused, the three laps in picture 3 are clamped together with a small C clamp. Full part takes less than a minute to weld

 

[busastars]

Hey smokie,

I have a Giant 200A Tig and I am guessing welding cones you are doing 2T pipes. I've only done Mild Steel 2T pipes but I find the gauge on my Giant tig a bit out, on 0.8mm I can run upto 40 amps, always start with the filler first, strike away from the point and once I have an arc move over to the filler/joint, only dab a little filler here and there.

Think I am on about 1mm or 1.2mm tungstern and keep 2.4mm for other work. I never run under 8lpm and upto 12lpm on larger stuff.

 

[BRODTuning]

i must say, some fantastic work there shox