New TIG HF add-on unit and crystalline looking welds on stainless

[tombardier]

Hi all. I've been doing some practicing with my new SMP Strike1 as described here:

http://www.mig-welding.co.uk/forum/threads/smp-strike1-hf-add-on-unit.59532/#post-734221

I've been welding stainless 1mm and 1.5mm sheet because that's basically all I've got so far. I've also been using stainless 1mm mig wire as that's all I've got at the moment too! I'm using 1.6mm thoriated tungsten, sharpened lengthways to a sharp point (it hurts to poke my finger with it!), pure argon of course (been experimenting with different flows, anything from 5 to 15lpm), and I've been using a variety of amperages from my R-Tech MIG180 which I'm using as the power plant. I'm wondering why I'm getting such crystalline looking welds on my stainless as per the photo below. If it's a case of the mig wire being unsuitable then fair enough I'd much rather have nice shiny rainbow beads hehe I'm also wondering about my arc going out at low amperages. I'm having to up my amps to around 50 minimum to maintain an arc otherwise it keeps going out and I see the HF lightning! Should I get some 1mm tungsten?

Thanks all.

 

[Shox Dr]

Too hot

 

[tombardier]

Cheers. I literally can't go any colder and maintain the arc so perhaps I need 1mm tungstens?

 

[Tom Orrow L]

For 1.5mm you're best using 1.6mm 2% thoriated or 2% lanthanated tungsten @ around 50 amps with maybe a no 6 cup.
It looks like your machine is running too hot on those welds.

 

[Maker]

Too long arc length?

I was going to suggest that, the beads look too wide.

 

[Shox Dr]

what amps have you set it at, you should be able to write your name in that sheet, just using the torch. As said arc length is paramount

 

[Tinbasherdan]

Too hot or too slow travel speed, also quite looks a large arc length. Wants to be 40-50amps , 7lpm gas, nice tight arc. 1.6 tungsten should be ok, with a nice long needle point to it.

 

[Richard.]

Combination of shox (too hot) and pdg (arc length) . Doesn't help that You'r practicing on tiny bits of it either. I would not say a change of tungsten is gonna help a lot tbh. Just sharpen the 1.6 to a nice fine point 2-3 times as long as it's diameter and see how that carrys your current.

 

[Richard.]

I was surmising that the need for higher amps to keep the arc alight was due to excess arc length.

In all honesty I didn't think for a second I may have been close to something near right, it just sounded like a good theory in my head

Makes sense to me. A longer arc length has lots of bad effect on a tig weld such a wider transfer, contamination and as you rightly say the arc can be unstable and wonder which in effect as you say can encourage you to turn up the juice. In this case more juice is the last thing needed. Id suggest a decent narrow prep on the electrode, a tight arc and bring the current down

 

[Richard.]

Hi all. I've been doing some practicing with my new SMP Strike1 as described here:

http://www.mig-welding.co.uk/forum/threads/smp-strike1-hf-add-on-unit.59532/#post-734221

I've been welding stainless 1mm and 1.5mm sheet because that's basically all I've got so far. I've also been using stainless 1mm mig wire as that's all I've got at the moment too! I'm using 1.6mm thoriated tungsten, sharpened lengthways to a sharp point (it hurts to poke my finger with it!), pure argon of course (been experimenting with different flows, anything from 5 to 15lpm), and I've been using a variety of amperages from my R-Tech MIG180 which I'm using as the power plant. I'm wondering why I'm getting such crystalline looking welds on my stainless as per the photo below. If it's a case of the mig wire being unsuitable then fair enough I'd much rather have nice shiny rainbow beads hehe I'm also wondering about my arc going out at low amperages. I'm having to up my amps to around 50 minimum to maintain an arc otherwise it keeps going out and I see the HF lightning! Should I get some 1mm tungsten?

Thanks all.

I've just read this properly which I should of done to start with. You say the arc goes out completely below 50 amps? That's a different problem that I'm not clued up to answer but I do have a question though. Why the hf ad on? The Rtech is a multiprocess machine inverter with 1 amp incremental steps. Surely your going to get wonderful looking runs hooking up a lift arc torch straight to that and having all the current adjustment you need. Personally that's what I would do. 50amps minimum current is quite useless unless you plan on only welding thick gage.

 

[tombardier]

I've just read this properly which I should of done to start with. You say the arc goes out completely below 50 amps? That's a different problem that I'm not clued up to answer but I do have a question though. Why the hf ad on? The Rtech is a multiprocess machine inverter with 1 amp incremental steps. Surely your going to get wonderful looking runs hooking up a lift arc torch straight to that and having all the current adjustment you need. Personally that's what I would do. 50amps minimum current is quite useless unless you plan on only welding thick gage.

Thanks everyone. I bought the HF add-on box because it was £50, and that included the torch. It seemed a cheap way for me to try my hand at TIG and see how I get on with it before considering getting a decent, fully featured machine. I'd also like to plug it in to my Oxford Bantam and try some AC on ally. Pretty sure my r-tech mig is (and mma140 inverter stick welder too) are infinitely variable, but I think they'll only do scratch start, not lift? I'd also have to have a gas tap on the torch too? The guys at R-tech said that SMP make really good quality kit. I'd like to see how I can get on with this.

Yes, the arc does keep going out when I'm below 50 amps. It'll do the same on thicker metal at higher amps, so I was thinking that I just perhaps , and lengthening the arc actually goes some way to keeping it a bit more stable. Keeping a really tight arc seems to not be possible as it'll just go out, and I'm definitely not dipping it. It just goes out and then the HF lightning starts arcing across the gap. As you may see from my previous thread, I was getting some better looking welds (if a bit wobbly) on a thick piece of 304 that I messed up on my milling machine!

I'd just like to note that I've been following best practice with regards to electrode sharpening and length etc. Also, I've been trying different arc lengths. Welding on this thin stuff, I might have had thinner beads on different bits of metal (of which I've gone through a lot), but they've all had this crystalline look. The picture is simply one that I've chosen at random I'll see what I can come up with later and see if I get anywhere!

Thanks for the help everyone!

 

[Richard.]

If you can't keep a tight arc your wasting your time and results will always be poor. Scratch or lift it doesn't matter too much they are both usable processes and you'll get lovely results if done right. 50 amps on 1-1.5mm stainless is too hot to get a decent profiled shiny run. I'd suggest half that for the 1mm and 35-40 for the 1.5mm. You'll be more interested in getting yourself dedicated tig kit if the results your getting now are coming out nice. Valved torches are cheap (30-40 quid) will suffice something decent. I had a member over last weekend for a little help with getting started and one of the units he owned and bought over was a migatronic 150 amp stick welder with a scratch start valved wp9. A little point in the right direction and some lovely runs were been chucked out on stainless flat with this thing. The hf box with torch was cheap and worth a punt but it's preventing you gaining talent IMO. I would choose decent low current and arc stability any day over hf striking.

 

[Richard.]

Been able to control current at thinner gages is pretty essential and 5 amps difference on the scale of things is a big % when talking low currents and below you can see this.
I tried to replicate what your doing but I also did this with lift start ignite. All runs were performed without a gas lens so that you can see what can be done with limited stuff.
Plate is 1mm.
Bead 1 is 40 amps and even with a tight arc and travel speed up it didn't go well. Profile is sunk, it's too wide and in need of a good clean.

Bead 2 went better. 35 amps. It's acceptable. A little duller in the middle and was gaining a little width as I went on but tbh I could of rectified this and kept control with travel and filling. Only 5 amps less than above but a massive difference.
Bead 3 was set at 30 amps which is ideal for 1 mm stainless. I didn't feel I was having to race along or plough in the fill to keep it controlled. No extravagant cups or flow rates it was all done with basic equipment. Every kept the same apart from current.
. Once you start applying to joints you'll tune in your current even more so depending on which one.
Ditch the hf limiting your current and lay down some good welds.
EDIT just to add I did all these with a well prepared 2.4 tungsten and 1mm 308 filler. A 1.6 would of been preferred but again I wanted to show it is only your lack of current control holding you back. So I selected things based on a worse case scenario.

 

[Mr shiney]

I love it when you do demos like this!

 

[tombardier]

Thank you very much Yes, number 3 is what I'm after of course! I wonder if there's something wrong with the HF start box. I'd be interested to see someone with some skills have a go on it and see whether it's me, something else I've done (or I'm using), or perhaps it is just the HF unit. My r-tech might be telling me that it's pumping out 50 amps, but I've no idea what's actually coming out of the HF box, there could be significant loss in current? I'm not sure! I'm going to have to soldier on with it until after Christmas now, so I won't be buying anything else apart from maybe some proper stainless filler etc. I'll try and work with some thicker stuff too I do like this TIG stuff, so perhaps I'll invest in an r-tech tig unit in the new year

One thing I should note is that when the arc dies and HF's, I see the warning light on my MIG come on whilst the HF lightning is sparking, and go off again when the arc reestablishes. I think that's just the same as when you've got your stick welding rod stuck. Also, when I turn the unit on with the HF plugged in, the warning light stays on for 3-4 seconds, then the green light comes on on the HF unit indicating it's powered on. I've been thinking that it's just powering up a capacitor for HF or something, but I don't pretend to know for sure!

 

[Tom Orrow L]

I believe the r tech machine is an inverter based unit.
IIRC most HF add on boxes are supposed to be used with transformer machines.

I used to have an old BOC HF box and attempting to run it in my parweld 161 DV was nigh on impossible

 

[Richard.]

If you cannot keep a tight arc and the unit won't allow you to go any Lower on the current than what you put in the pics without the arc going out then there is no doubt the setup is causing the issue. Whether it be the hf box, the power source or combination of the two not been compatible it's almost certainly causing the problem. I've shown what can happen with current too high in semi competent hands so I personally wouldn't struggle on with it till you can get round to sorting out the kit. You said in one of your posts that even at higher current levels you were unable to tighten the arc length without it shutting out? This simply isn't a case of unskilled use. I cannot tig weld very well with a long arc either. Pack it all away and get a valved torch when the time is right then simply practice off the inverter without the add on. I'll bet you see a huge improvement.

 

[Shox Dr]

What is the lowest amperage the set your are using to drive the addon with?

 

[DecK]

Does the r-tech have to be switched between mag and smaw. I use a newarc viper off an inverter and the power source has to be set to smaw and the power turned up to the max for it to work right. If I use the HF box with the power source set to mag the hf and the arc stability go weird. Might be the same for your set

 

[tombardier]

Well, I was doing OK on some thicker metal at 80 amps I could maintain a tight arc, it's just if the amps were lower, I would have the arc going out again (but the amps were still higher than they were when it was doing the same thing on the thinner metal). Below is a piccy of the stuff I did on the (much) thicker material. Still shockingly sloppy welds, but I think the finish is nicer!

What is the lowest amperage the set your are using to drive the addon with?

I just checked. I had assumed 30 because the mig side is 30, but it's actually 15!

Does the r-tech have to be switched between mag and smaw. I use a newarc viper off an inverter and the power source has to be set to smaw and the power turned up to the max for it to work right. If I use the HF box with the power source set to mag the hf and the arc stability go weird. Might be the same for your set

It's definitely on mma mode. I can't adjust the power on the HF box itself, so I have to do it on the MIG