Page 3 of 4 FirstFirst 1234 LastLast
Results 31 to 45 of 54

Thread: TIG welding SS

  1. #31
    Join Date
    Dec 2010
    Location
    Syd
    Posts
    492

    Default

    If you're going to use pulse, here's an article from a decade or more ago - going by the machine they're spruiking - which might help for a ballpark The settings are for slightly thicker material.

    https://www.millerwelds.com/resource...f-or-equipment

    Don't quite get why you'd use a 4, 5 or even a 6 nozzle for what you're doing at present, big is beautiful on SS.

  2. #32
    Join Date
    Jan 2016
    Location
    Wodonga Vic
    Age
    38
    Posts
    633

    Default

    I've done a little research and if the SS was used for splash backs or similar it might have a coating similar to this stuff Permanent Protection - Stainless Steel DIY Kit | Surface Protect - glass cleaning, glass protection and bath resurfacing, though I couldn't find any info about how to remove it

    I also found this bit of information about removing the glue residue on Australwright's website:

    Stripping & Cleaning

    • On occasions the film is left in place for too long. It may become very hard to strip, and may also leave a gummy or friable residue of degraded adhesive on the steel surface.
    • The residue is unsightly, and may also impair corrosion resistance by retaining atmospheric corrodents which settle on the steel surface.
    • Even if the film is stripped promptly, there may be small amounts of this residue left, although they may not be visible. It is prudent to clean the surface after stripping the film.
    • The adhesive residue can be cleaned from the surface of the steel with a solvent such as methyl ethyl ketone (MEK), eucalyptus oil or a similar solvent.
    • The surface should be swabbed with the solvent on a clean, soft, grit free cloth, left to soak in, then the solvent wiped off (and use elbow grease). The intent is to dissolve the adhesive into the solvent, then wipe off the solution. Hence the solvent chosen should not evaporate too rapidly. Consideration should also be given to the flashpoint and toxicity of the solvent.
    • Care should be taken to avoid marking the stainless – check a small area after the solvent has dried, as fine scratches may not be visible while the surface is wet.
    • Highly adherent films which have baked onto the steel may require an extended soaking period with the solvent, preferably after pulling away strips of film to allow access of the solvent to the adhesive.
    • The solvent may leave tide marks, which can usually be removed with an alkaline detergent and hot water, well rinsed. Allow the steel surface to dry naturally, blot dry with a clean rag, or blow dry with clean air.



    Ben

  3. #33
    Join Date
    Aug 2010
    Location
    Toorloo Arm, VIC
    Age
    39
    Posts
    1,270

    Default

    Quote Originally Posted by Michael G View Post
    Bearing in mind I'm welding 0.6mm stainless, are you suggesting that I should be running around 40A, when you would run 30A on a 0.8mm piece of MS? I would have thought that the reduced conductivity of SS and the thinner material would mean that more amps will just blow holes.

    With respect to a 2mm width, those beads are mostly 3mm wide (alright; +/- 0.1mm). In the second photo of post 22, that weld is without filler on 1mm material and the bead is 2mm wide.

    As to shiny, the only reason I'm chasing that is because I've had people tell me that SS welds should not need to be wire brushed post weld - they should come out clean/ shiny from the process.

    Michael
    More amps doesn't necessarily equal more holes - it depends on all the other factors. To give you an couple of examples here that hopefully helps illustrate the angle I'm coming from: When guys are welding repair sections (butt jointed in 0.8mm) into cars with a TIG, there are two ways to do it. One is to jump around and stitch it here and there using a bit of mig wire as filler, somewhere around 25-30A. Then take to it with the hammer and dolly and dress out the distortion that's been induced, which is usually quite a lot. The other way, used by the really talented guys, is to get a really tight fitup, and then they will run something like 65A, no filler, and run along the join absolutely flatout. The end result is a very slightly undercut weld bead, which is not an issue in this application, but more importantly, very little distortion occurs, and they need to spend much less time with the hammer and dolly correcting it. Although the amps are much higher, and the heat right at the tungsten is much more, the amount of heat put into the panel overall is much less, also thus cooling faster (and creating less shrinkage).

    It's a little bit like if you try and heat a 20c piece sized area in the centre of a piece of 3mm steel plate (say 500mm square?) to red hot, first with a MAPP torch and then with a O/A set. Both will get make that 20c sized area red hot, but by the time the MAPP torch gets that centre area red hot, you won't be able to hang on to the edges of the plate, whereas the oxy will do it in a matter of seconds, and you could most likely hold the piece of plate in your hand while doing it.

    That's what I mean when I keep mentioning overall heat.

    The quicker you can get the metal right at the weld pool to melt, the less heat soak you'll get in the surrounding areas, and the quicker it will cool with the argon flowing over it, and my guess is you'll see the shiny colours come as a result of that. You are 100% correct that SS welds should come out shiny, but that is if the bead has been laid down correctly! That's why my approach is to lay down a bead, then look at it very critically - is it undercut? Has it sunk into the plate? Has the filler wet in properly to the parent metal, or is it sitting on top? Is the bead a consistent width, and if not, why? Did I speed up, slow down, change the rate of filler depostion? Did my workpiece get heat soaked as I went (particularly common with aluminium!)

    You mentioned your second photo - notice that it has various colours showing in it, and hasn't sunk into the plate. The HAZ around it is also quite close in, being roughly the width of the bead either side. It's pretty close for a baseline, but possibly still a little low on amps by the time you add filler (cools the puddle a bit). Then have a look at the HAZ on your other beads, its twice the size - much more heat in the area around the weld. And while your beads may be only 3mm wide, they've also cut deep into the plate - running a faster travel speed will reduce this depth, and reduce the overall heat input.

    And finally, with respect to the actual value of amps - no idea what your machine is, mines a chunking great big old transformer Kemppi. It's very likely that while my readout might say 40A, yours needs to say 50A (or 30A) to get the same result. It doesn't matter, what is important is to figure out what amps YOUR machine needs to say for you to get the desired result, and that comes back to self analysis of the bead you just laid, and the experience/experimentation to know which way to adjust it.

  4. #34
    Join Date
    Feb 2010
    Location
    Ballina, NSW
    Posts
    900

    Default

    Quote Originally Posted by Michael G View Post
    Bearing in mind I'm welding 0.6mm stainless, are you suggesting that I should be running around 40A, when you would run 30A on a 0.8mm piece of MS? I would have thought that the reduced conductivity of SS and the thinner material would mean that more amps will just blow holes.

    With respect to a 2mm width, those beads are mostly 3mm wide (alright; +/- 0.1mm). In the second photo of post 22, that weld is without filler on 1mm material and the bead is 2mm wide.

    As to shiny, the only reason I'm chasing that is because I've had people tell me that SS welds should not need to be wire brushed post weld - they should come out clean/ shiny from the process.

    Michael
    It's a bummer you're stilling having hassles with this Michael. I think J&H has got a few good tips listed above. My feeling also is that it's combination of being too cold and traveling too slow, but it's so hard to tell without watching. SS is funny because it is sensitive not only to too high amps, but also to being exposed to high temps for too long. So a balance between slow/cool and fast/hot needs to be found. In any case, some of those last welds are sort of looking better.
    Trying a quick spot weld is another approach. Torch vertical and tungsten 2mm from the work, set the amps so that it takes about 2 seconds from startup to get a puddle 2mm wide. No filler. Stop the arc and keep the post flow on for a few seconds. You should have a shiny little pimple. Do the same again, but this time add just one dab of clean filler and stop the arc as soon as that dab has fully melted into the puddle. Should be shiny with no wire brushing. The idea of just one dab is to eliminate any issues with filler oxidisation, torch movement, etc.
    I would definitely clamp this stuff tight to a aluminium or similar heat sink/backing block while trying to sort out issues.
    If you can't get someone local to have a go with your material, then it could be worth sticking a bit of the thin SS sheet in the post to a fellow member. I'm in northern NSW, but PM me if you don't don't get any better offers.
    Cheers
    - Mick

  5. #35
    Join Date
    Aug 2008
    Location
    Adelaide
    Age
    68
    Posts
    1,373

    Default

    Quote Originally Posted by WelderMick View Post
    If you can't get someone local to have a go with your material, then it could be worth sticking a bit of the thin SS sheet in the post to a fellow member. I'm in northern NSW, but PM me if you don't don't get any better offers.
    Cheers
    - Mick
    Michael G

    If you want to try a different machine you are welcome to bring some test pieces to my place and use mine - Aberfoyle Park.

  6. #36
    Join Date
    Oct 2015
    Location
    melbourne
    Posts
    473

    Default

    To eliminate shielding issues could you try welding inside a box flooded with argon? There's a name for that, but I can't recall it. Would eliminate one variable.

    -russ

  7. #37
    Join Date
    Sep 2010
    Location
    Lebrina
    Posts
    1,910

    Default

    Among all the possible parameters that could be making life difficult for you, the weldability of the material must be taken into account also. Ferritic stainless in thinner thicknesses is not always a particularly weldable beast. Precisely what grade is the stainless you have? It will be a 400 series number. Has this material been sourced in brand new sheets or from a scrap metal dealer? Given the common uses for 400 series stainless in sheet form, it could be coated with anything. For example, stainless steel fridges would typically be made from one of the 400 series alloys and in order to prevent endless finger marks from showing, they are coated with a clear finish. This would play merry hell with any welding process and give similar appearance to what you were getting in your uncleaned parent material welds. 400 series are also typically lower in Chromium than the 300 series alloys while Nickel content is much lower, possibly even described as negligible in many cases. Depending on the exact grade, corrosion resistance may not be all that great either.
    As others have posted, a tight arc length is imperative. I suggest you adjust your tungsten stick out so that the shroud rests on the parent metal, thus eliminating the inevitable wobble that all humans get while trying to hold a super short arc. I find that tungsten diameter is less important than its sharpness and filler metal thickness - for example, 1.6mm filler is nearly 3 times the thickness of your parent material and can be prone to sticking and adds a heck of a lot of filler relative to the parent metal. .6 to .9mm filler would possibly be a more ideal match.
    If your machine has pulse capability, you will find it advantageous, although possibly not so much for tacking. Pulse has the effect of slowing the whole process down, giving you more time to add filler and be less stressed. 130Hz was my sweet spot on the Miller Tig that I spent quite some time on. Typically amperage would be set higher when using pulse.
    .6 is thin in anyones book and combined with some potential surface coating and the 400 grade material, you have set yourself quite a task I feel. Best advice I can give is to firstly identify the material, (if it is offcuts/over run from a factory stamping components and has some type of clear coat, then I would rate it as unsuitable for purpose), next is to experiment by changing only one thing at a time so as to accurately assess the effects of various parameter changes, thirdly I would really take the time to sharpen your tungsten to a perfect needle point and to check that you have good gas flow and to set your post flow erring on the side of excessive. Yes I know it may waste a bit of gas, but you really need to maintain that nice clean tungsten. Once you can maintain a clean tungsten, then you can gradually cut your post flow back until you find the optimum level. Set your amperage by the seat of your pants, as in, set the amperage to give the welding performance you want, not on an arbitrary amperage figure (traditional wisdom suggests 40A per mm by the way, so .6 would come in near 24A) no two welders are exactly the same in their output and no two operators weld the same. Keep your headshield scrupulously clean. If you can't see, you can't weld. Finally, go back to basics and start running beads on your material. This will eliminate any fit up issues and allow you to dial in your setting more easily, back purging your welds may well help as well. Stainless that is back purged welds much easier than that which is not.
    While you may have issues with your technique, I strongly suspect that the material may be as much to blame and is thus complicating matters.
    What are you actually fabricating by the way?

  8. #38
    Join Date
    Oct 2011
    Location
    Norwood-ish, Adelaide
    Age
    59
    Posts
    6,540

    Default

    Thanks for the offer Gavin; I'll have another play but the equipment as such I don't think is a problem - it's more to do with technique or as Karl suggests, material.

    The material came from a scrap yard and was a series of sheets around 1m by 600mm. Because of the number of them I suspect that they were offcuts from a commercial kitchen fit out. They are varnished but I can clean that off with a disc sander. It takes the finish from brushed to slightly matt but I can live with it. The job itself is a toolbox/ chest for some of my measuring and test equipment I use when working rather than a cardboard box and assorted plastic bags. I chose stainless because I could be going into food prep areas and so needed to avoid flaking paint while being able to wipe things down with caustic. In hindsight I have a material that is more difficult than it needs to be but sometimes that can't be helped. The welds I need to do are only small - corner seams for drawers etc, so I don't mind if it takes a little longer to do but I approach jobs like this as a learning opportunity, hence the questions/ photos.

    I was going to try to find some smaller filler rod, so I'll do that today and play with the pulse. While I can understand the theory behind a high speed, no filler, weld at high current, the lengths of weld are not long enough or straight enough to make that viable (at least at my skill levels)

    Michael

  9. #39
    Join Date
    Aug 2008
    Location
    Adelaide
    Age
    68
    Posts
    1,373

    Default

    Or take another tack (no pun intended) and try TIG brazing it with Silicon Bronze instead. I can give you some rods to play with as a test if you want to go down that route.

  10. #40
    Join Date
    Jun 2012
    Location
    melbourne
    Posts
    341

    Default

    I have an interest in micro tig for jewellery for some years but the welders were usd5k. I see some things on ebay just recently for $200 that I’m wondering what they they would do Jewelry laser welding machine mini Gold Silver Spot Welder 220V 300W | eBay. Capacitor discharge with argon coverage. Where do you get 0.1mm tungstens from though?

    Anyway, I just came across this while I was looking
    https://www.youtube.com/watch?v=q0pCir2hmhk Someone is tig’ing 0.6mm 304 ss here.
    He’s advertising a fancy torch but if you jump to 2:50 you can see how he got shielding on the back, then jump to about 4:30 and you can see him weld. 1.6mm tungsten at 20 amps no filler if I hear him right. Gives you an idea of how it should all look. You don’t really see his welds but it might help to get an idea of speed and gap.

  11. #41
    Join Date
    Jun 2012
    Location
    melbourne
    Posts
    341

    Default

    I didn't think the penetration in the video looked very even on the outside and you can't see his weld on the inside at all. I looked up the welder and he gets slagged off a lot by real welders who i recognized as producing stunning looking welds on some forums. The tinfoil/dam thing is useful to see and I still think seeing someone else do a weld at all on that gauge is useful to get you going.

  12. #42
    Join Date
    Sep 2010
    Location
    Lebrina
    Posts
    1,910

    Default

    Quote Originally Posted by sossity View Post
    I didn't think the penetration in the video looked very even on the outside and you can't see his weld on the inside at all. I looked up the welder and he gets slagged off a lot by real welders who i recognized as producing stunning looking welds on some forums. The tinfoil/dam thing is useful to see and I still think seeing someone else do a weld at all on that gauge is useful to get you going.
    Youtube is full of "experts", both posting and commenting on videos. Having watched a few Youtube welding clips, I've come to realise a few things. Firstly, the Americans have a very different approach to welding than we do down under, techniques, consumables and machine choices are vastly different. Secondly, more than a few idiots seem to be able to get sponsorship from welding companies and become instant experts. ChuckeE2009 absolutely rubs me the wrong way and his fabrication work is often rough as guts. Mr TIG has some good moments, but seems like more of a spruiker for his online store, (not that self advertising is all bad, but you do need to sift through the hype a little), while Jody from welding tips and tricks really seems to know his stuff and his method of presentation really gels with me. Thankfully none of them are as bad as the truly awful Bunnings how to weld videos!
    You can draw some useful information from Mr TIG's .6mm wall tube welding video. Tight, gapless fitup, correct amperage for a controllable weld puddle (remember, he may not be a TIG God and probably has a pile of tube in the corner with holes blown etc while getting his party trick perfect), welding between slightly downhill to flat (stacking the deck in your favour), sharp tungsten, back purging and holding a nice close and consistent arc.
    No matter how good you are, or think you are, there is always someone better. I had the priviledge of learning from 2 masters of their craft. One was an absolute MIG God and I doubt a robot could have welded any more consistently. He could hold his own with stick, TIG and Oxy as well, holding pressure certificates for all processes mentioned. The second was the Yoda of the TIG torch. If he could not do it, then it could not be done in my opinion. I would love to see that pair with their own Youtube channel, they could wipe the floor with most of the experts.

  13. #43
    Join Date
    Oct 2011
    Location
    Norwood-ish, Adelaide
    Age
    59
    Posts
    6,540

    Default

    I went back today and tried with lower amps - I settled on 24A eventually. As several people suggested, a needle sharp tungsten helped. Previously I've been putting a small flat on the end because that's what the book says... I could not get filler rod under 1mm (and that was $144 for a whole tube) so I'm using 0.9mm MIG wire, hand 'straightened'. Backing blocks were used in most places but I could not get them in the corners so just had to be careful. I also found that 'lift-arc' worked a little better than HF start
    This is a photo of one of the welds I was producing - I still have some colour in there but it's better than it was. I might have to try going lower again perhaps or work out how to get pulse working for me. A variation on the backstepping technique mentioned in the Miller article was useful too.
    (The photo is one of the outside corners between the base and the side)
    P1030842.JPG
    So here is the box so far after dressing back the welds. The two sides are separate from the base so have been welded around the contact edges, as has the front cross bar. The inner part is currently held in with skin pins but will eventually be riveted in once the slides are made and fitted. A couple of spots that need to be rewelded and dressed back but nothing too bad. I'll get some more welding practice making the drawers and lid.
    P1030844.JPG
    Michael

  14. #44
    Join Date
    Jun 2012
    Location
    melbourne
    Posts
    341

    Default

    It's pretty difficult to use filler and produce a 2mm bead like that, on 0.6mm ss. You're probably better than me already and how good you get is just practice now. The problem I find is, I lose the skill I pick up during each project. its always worth setting up practice on the same material before you start for real I reckon.
    I tried to weld 0.6mm stainless just there but had a go at autogenous welds with perfect fit up as the pros said. It was dead easy, very little distortion because you can keep the haz so small. I cut the pieces with tin snips but used the factory cut edge for the welds so the fit was perfect. With all the talk of big amps and the fact the aluminium angle was about 5mm thick, I thought I'd go for 30 amps but immediately blew a hole (starting at the right) I went back to my instinct which was 20 amps (no pedal, I don’t like using pedal for small welds).
    20170218_171248.jpg
    The first weld from the right going left was about 1cm to get the feel, then another 1cm. I wanted to keep the haz really low so I was trying to do short welds but that means I’m even more messy. At school the teachers thought I was being difficult because my handwriting is so bad, but I just can’t do really neat stuff for some reason.
    Because for the short welds the haz remained so narrow, I tried the next one at 4cm. The haz remained small but in the middle of that weld I went wrong and my accuracy drifted off so the flame was onto the sheet facing you and not on the edge. The last 4cm weld I tried to go fast but that meant my arc was not as tight to get more heat and I think what happened was the longer arc causes more heat round the weld also, because you can see the haz has gone to pot. I think its purple instead of gold because I was going faster and the weld would come out the gas sooner. For me, controlling the arc is more important than just speed.
    I did a destruct test and flattened it with a hammer. It all held up so would be ideal for boxes.
    20170218_172100.jpg
    I’d definitely recommend to give it a go for your box. It’s so easy to do these autogenous welds in comparison to using filler, plus keeps distortion down.
    20170218_172159.jpg
    This was with a 2.4mm tungsten sharpened so it can jag into you easy. In fact, it needs grinding again in this picture, this was after I finished. I didn’t dip, but the tip deteriorates quite quickly because its so fine, even at 20 amps. If you don’t keep it dead shiny and clean, the arc won’t go tight and you get a much bigger haz. That might also be what was wrong with that last weld actually. For scale, the bead is about 1mm.

  15. #45
    Join Date
    Sep 2008
    Location
    N/A
    Posts
    535

    Default

    Quote Originally Posted by Michael G View Post
    I also found that 'lift-arc' worked a little better than HF start
    Maybe the start arc parameters are too high? I know with my machine it's set to 2.4mm tungsten by default, with appropriate settings for that diameter. If I were using something way outside normal 2.4mm range I could set it to another diameter's defaults or fully customise all the parameters.

Page 3 of 4 FirstFirst 1234 LastLast

Similar Threads

  1. Welding through POR 15
    By simso in forum WELDING
    Replies: 3
    Last Post: 18th Oct 2016, 08:37 PM
  2. CO2 with TIG Welding????
    By iron bark in forum WELDING
    Replies: 3
    Last Post: 26th Mar 2013, 06:47 PM
  3. Welding 5mm SS rod for BBQ with Oxy
    By Paddy in forum WELDING
    Replies: 4
    Last Post: 2nd Feb 2012, 09:43 PM
  4. new to welding.
    By Bluegum in forum WELDING
    Replies: 8
    Last Post: 24th Oct 2006, 09:22 PM
  5. welding tip
    By mako in forum WELDING
    Replies: 4
    Last Post: 7th Jul 2006, 04:59 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •