Stainless Problems

Hi all,

First of all I must congratulate you all on what a good thing you have got going here.

At work yesterday someone asked me to do a little homework job, to weld up a couple of lugs on a stainless steel battery box (trike project) I think. The stainless was about 1.6mm thick and the lugs were the same. But boy did I struggle, first I was blowing holes everywhere then when I turned down the amps the weld bead was high and just didn't look nice, if you know what I mean. It was going to be on show so I wanted it to look half tidy.

The tig welder I was using was a Murex Transtig AC/DC 252 big industrial jobby using pureshield argon. I use this machine quite a lot to do aluminium and mild, normally with quite good results. I have never been trained as a welder so I was wondering whether there was something I was missing with this sheet stainless thingy, I normally do heavier work than this,

Oh i forgot to mention the warping and the twisting like you wouldn't believe, I felt embarrassed giving it back to the bloke.

Any advice would be much appreciated. Many Thanks

Oops. Tungsten and filler too big?

Pics are always a great add when looking for advice, secondly the parameters you have the machine set at as well as gas flow, tungsten type, size and filler material with size are a plus.

I would tend to agree that the filler wire was probably too small for the job...

lorenzo said:

Pics are always a great add when looking for advice, secondly the parameters you have the machine set at as well as gas flow, tungsten type, size and filler material with size are a plus.

I would tend to agree that the filler wire was probably too small for the job...

Click to expand...

Id go for that, ceramics and gas are very important for stainless more so than ally.

snowcat said:

Id go for that, ceramics and gas are very important for stainless more so than ally.

Click to expand...

snowcat m8, can you explain a bit more, only i have been playing with tig for the the first time over the last week or so, i had a pack of mixed filler rods to play with using them on mild steel

the steel filler rods give quit a reasonable weld, cant get any were near like it with the stainless ones (316) kind of looks all grey mess, wont bead even though i am dipping the filler rod in the same as i did with the steel filler rods

tungsten is 1.6 mm, filler rods are both 2 mm, wp 17 torch, ceramic says 6 on it
any advise would be great.

also sorry didn't mean to hijack thread




sheps

no hijack away, well for starters your need a bit more heat into the stainless to get a decent weld, you have a red grey or green tungsten i take it. pleanty of pre flow on the gas followed by post but on the welded joint not around it, BOC special stainless mixes are very good but pricey, A gas lens is a good addition to the ceramic as this helps a linner flow of gas, with ally it can be flowing all over the plate it wont make a jot of diffrence, tungstens sizes are not that important as long as the tungsten can handle the amount of current you are welding at, The filler rod as a rule of thumb should never be any bigger than what you are welding, amp settings well as iv said before i dont use em i always drive on the foot pedal, and stainless will always tend to darken when welded so expect to polish for a perfect job. Sorry to be a bit breif and rushed but mrs cat is waiting to go out!!

thanks m8

i have the red tungstens, and post gas, i will have a play with that to see if that makes it any better don't think i have post gas, or its the other way round ER i haven't actually read the destruction book, cant say i ever do (slaps hand) thermal arc 220 gms 220 amp inverter lift tig
should be picking up ac/dc next week with foot control

i haven't come across a gas lens yet, well i don't think i have

i tried upping the amps it got more messy and shrunk my tig gloves rapidly
ive been practicing on 3mm mild steel and above

BOC special stainless mixes..... do you mean the filler rods or gas ???
im using pure argon

just another quickie i brought about 40 kg of stainless filler rod off flea bay the other day, (£65) so as to have plenty to practice with
problem is i don't understand the codes, 316 and 309 are easy but the others i don't understand and there at my workshop at the mo is there a place i can reference the numbers to

have a good night out, drink as much as this fella



sheps

Sheps, don't know if this'll be any help, but it's worth bookmarking. I've found it useful - Miller tig calculator

Si

er... found this lot...






that was all here
lost more written info there too.

this might be useful too.

Or try other wire manufacturers sites. Sif, for a start.

Si

thanks Si

never knew there were so many types, much easier in bolts a2, a4

will have to sit down and have a proper read on the miller site, got to get to grips with the tig so far i love it.

cant wait for hf start and foot pedal, its got to be better than sticking tungsten and having to keep turning around to adjust amps




sheps

I went and had me first play with stainless on the tig tonight. Tbh, no probs at all. Still not so neat as i've hardly don an hour altogether - other things to do. But it's great being able to take your time and work on the small scale. Funny how mig's great for bangin out the welds, but mma and tig are so much nicer to do, imo.

A welder pal of mine was quite scathing about hf/lift, cos he does lots of site work with a standard inverter. Reckons it's easy doing scratch. I'd like to prove him right! (I'm stuck with what I've got so i'll have to)

A bit like learning vertical downs on a buzzbox with 6013's! It can be done!

Hey Shep.... The dull gray color of the weld may be linked to several things but too much heat may be more of the problem, contamination,and what I mean by this is from the underside of the plate being welded. Thin material will pull junk into the weld from beneath it. Clean material is also a key part of it.... I wipe all my parts with some sort of a cleaner prior to welding.... even use a stainless brush as well. Hope this helps.... give some pics if you can.

Chris your ahead of me was just thinking that grey = contamination, brake cleaner works well as it evaporates and leaves no residue, but there are acids on the market avalible for the job but nasty stuff the other problem can be carbon cross over, ie useing a cuting grinding or flap disc from an lcms job, there are also grinding cuting and flap discs designed for the prep of stainless but keeping a set just for stainless will help, the same applys with alumunum, stainshield as i said helps has a little hydrogen in it for pentration, there are also methods for double sheilding getting the gas on the underside of the work pluging etc but they tend to be complex and time consumeing, with a no.6 ceramic flow rates of 4-6lpm the higher the amps the more pre and post flow of gas that will be needed. but try the gas lens as well i found a marked improvement with em.

the plot thickens

i have been practicing on just bits of scrap that i had lying around, at first i didn't clean any of it, IE the hot rolled slag didn't seem to matter for the mild steel filler rods, plus i weld in 1.2 mm mig wire and that burns thru all so thought the tig would do the same.

i thought i had read about using 10-14 lpm of argon so i set my flow meter to 10 ??? perhaps to much

when i did use a grinder i just used the cutting disk that was on it at the time, i also just ripped out a doggey weld and went back over that, i have had the tungsten welded to the job and being lift tig once its stuck I'm ******** i have to snap it of. i have just welded over it, makes a bit of a hissy sound as i do it

i have now started to hold the tungsten a little higher, i get a tiny gas flare is this good, by tiny I'm talking about a 2/3 mm flare

i also seem to find it harder with the tungsten at a needle point, when i have had it stuck and managed to wiggle it out i just carry on

should i resharpen it every time this happens, if i do i will have to buy new 10" grinding wheels

I'm starting to think my slap happy approach is not acceptable with tiging must be my miging attitude where you can get away with a lot more, (unless structural).

Snowcat where does the gas lens go m8

and just to say guys a big thanks for taking the time to reply with your wealth of knowledge

i think i will shoot over to the unit and take some pics, just to embarrass myself



sheps

Ok sheps get some pics should help us with a bit of diagnostics,
but il try me best with these questons first,
Sounds like your flow rates are a tad high, each ceramic size has its own recomendation so theres no set volume.
Too much argon on the plate does not matter with alumumun but with stainless you want it at your weld and knowhere else, theres some vids on this with uv dyes in the gas kind of intersting if you like that sort thing.
Another thing is how far is your tungsten in relation to the end of the ceramic?
I take it your scratching not hf start so once you have the arc a resonable distance should be kept from the workpeace.
You need a needle point to keep your arc controled as soon as you touch the work it will contaminate this causes a porius unsigltly weld, I dont think your need to worry about contamination from your stones too much, a good tip is to grind both ends and a few tunstens, burn out or contamination is then a 2 second job to change,
gas lenes fit at the top of your ceramic collet end.
And yes its a diffrent job to mig or arc prep is everything i did an alumunum bike stand on friday for someone, it required about 4" of weld in total but was an hour's set up.

Sheps,

The grinding wheel should be reserved to tungsten grinding ONLY! Do not use it to grind anything thing else. When you grind the point the grinding lines should run length-wise with the tungsten and not ground in a radial direction. You can put a small flat spot at the tip, getting rid of the point. I don't do this myself, I tend to like a nice sharp tungsten. For SS and steel, even aluminum at times I'll use a red tungsten... 2% thoriated. The Gas lens will replace the difuser and you will need to use a different type of cup. The point of the gas lens is to provide a better coverage of gas across the weld. I use acetone to clen material, but make sure you move it out of the area before welding as it is extremely flamable.

There are many things that can effect the weld so without seeng any pics it is hard to try and give any specific advice. Also..... on the mild steel...... get rid of the mill scale and you will see a huge difference in weld appearance.

These 2 pic are steel.....

LOL..... Snowcat, seems you and I are in tune with this thread.

Oh yeah Sheps.... using a gas lens will allow you to extend the tungsten out beyond the cup further than a conventional difuser body will.

Il change me comment on the stones then!!! Chris lol, Iv never cross contaminated this way but then I only tend to sharpen tungstens on that wheel anyway.

Don't change it on my account....... I too have used wheels that have had different materials ground on them but as a rule I try to use a wheel to sharpen with. This is one of those do as I say and not as I do lessons..LOL

Oh yes i have pleanty of those rules