Tig welding stainless manifold help

[johnny99]

you gonna give a good reason why or just leave it open ended as i'm curious.

Aluminium is always used by us. It's lighter, easier to port. Stainless steel will cause condensation, water droplets in the inlet, and icing problems on the inlet tract, it can also be difficult to start in cold weather, as the fuel can fall out of suspension in the airstream.

John

 

[Pete.]

It'll just take a bit longer to come up to temperature that's all. Once it's warmed up it will work as well as an ally one.

 

[smithy1851]

hi all,

the tig welding caught my eye, so thought id just add my few pence worth,

with regards to tig welding the manifold, i would advise you to use alot less heat and take it easy, spreading the heat throughout the manifold piece would even out the heat within the job.anything like this should always be clamped or tacked to a backing strip to try and hold the piece as true as possible...
I would also suggest putting alot more filler wire into the fillet weld as there is alot of undercut on this weld.
with thin wall pipe of this diameter, you could afford the weld this on considerably less amps, around 75-85amp would be more than enough.
check the pin holes, and add more down slope , mayb also add alittle more gas shield as the welds arent very clean,
with regards to a back purge, always worth taping up the pipes n putting a purge on, makes the job so much easier...and if correct would give you a perfect route on the inside..rememeber to make a vent in the pipes to allow the air out n put on around 8-12 litres a m..

stainless can be manipulated to get it right and with good results,

chris

 

[Autolupus]

hi all,

the tig welding caught my eye, so thought id just add my few pence worth,

with regards to tig welding the manifold, i would advise you to use alot less heat and take it easy, spreading the heat throughout the manifold piece would even out the heat within the job.anything like this should always be clamped or tacked to a backing strip to try and hold the piece as true as possible...
I would also suggest putting alot more filler wire into the fillet weld as there is alot of undercut on this weld.
with thin wall pipe of this diameter, you could afford the weld this on considerably less amps, around 75-85amp would be more than enough.
check the pin holes, and add more down slope , mayb also add alittle more gas shield as the welds arent very clean,
with regards to a back purge, always worth taping up the pipes n putting a purge on, makes the job so much easier...and if correct would give you a perfect route on the inside..rememeber to make a vent in the pipes to allow the air out n put on around 8-12 litres a m..

stainless can be manipulated to get it right and with good results,

chris

8-12 litres a m.. is too much, 2-3 lpm after purge is established will be more than adequate and 75-85 amp is going to be too low as the 10mm flange will soon suck the heat out in that range.

 

[smithy1851]

hi,
i would bare in mind that you are dealing with thin wall tube and a base plate that will heat up very quickly, everyone welds differently but keep your amps down to a manageable amount..you can always come up alittle if needed by a couple of amps...try it on some scrap.
a nice fine sharp tungsten will give you a real nice weld around these tubes,
with regards to the purge, depending on the size of vent u are using a reasonble flow of gas wont hurt..if you can tape up these ports tightly then drop your purge flow..leave on high 4 a couple of mins then drop n try it...see how you go..

 

[Phataz1]

Cheers for all your input guys

I've just got hold of some more gas and given this a go with the 1.6 tungsten, 110 amps and trying out a shorter arc length. I think the results speak for themselves, weld is smaller and neater. I realise there is still an undercut and pinholes in places which I will now work towards, but I am pleased I have got the arc length somewhere near right.

You can see the comparison between the last attempts on the right and the new attempt on the left. I think beforehand I was scared of touching down with the tungsten and kept arc length too large to prevent it.

 

[langy]

Getting better but still have a wide weld, You need to get the tungsten closer, i would also try going back up to 120 amps but move a bit quicker and also push a bit more rod in. hope this helps

Cheers for all your input guys

I've just got hold of some more gas and given this a go with the 1.6 tungsten, 110 amps and trying out a shorter arc length. I think the results speak for themselves, weld is smaller and neater. I realise there is still an undercut and pinholes in places which I will now work towards, but I am pleased I have got the arc length somewhere near right.

You can see the comparison between the last attempts on the right and the new attempt on the left. I think beforehand I was scared of touching down with the tungsten and kept arc length too large to prevent it.

 

[Phataz1]

Cheers langy, I'll give that a go!

 

[Seventynine]

looking really good arun, definately on the right track

 

[Freshfabrications]

Hi looking good and thin tube to thick plate can be tough to achive good results if you have little experience.

for my 10 pence worth I'd like to add two small sugestions.

1 If you have a larger ceramic say size 8 or 9 you will ne able to use it like a pipe welders "Walking The Cup" tecnique, this is where you set your tungsten to stick out of the cup so its just clear of where the weld material that you deposit will be when the ceramic cup is sitting in the valley of the fillet weld, ie the ceramic cup is resting on both the tube and plate at the same time, ergo it cant get any closer.

You must still maintain the same travel angles and you will have to rock the torch the tinyest amount to the plate and then the tube repetedly whilst applying a little forward presure, its a steady very slight motion, at the same time you lay the wire in the valley of the joint and weld over it. this produces a very consistent bead profile and weld once mastered and helps keep that short arc length you need.

2 Use a backstepand skip method to limit heat input, eg do one short string of weld on one inlet then move to the next inlet, also each time you go back to an inlet thats previously been welded, start the nect weld on the opposite side to limit the distortion.

Back step welding means to start ahead of ths last weld and weld back towards it.

this may sound a liitle confusing to start but once you fugure it out and apply it its amazing how well it works.

One example was when I hadto weld two 1400mm wide flat of 18 guage stainless steel sheets together to make a 6000mm wide kitchen top and combined splash back. It still distorted a little for sure but nothing that wasnt sorted in about hald an hour with a hamme and dolly.

 

[hotrodder]

As Langy arc length is still erractic, it's going to take time and practice especially with tube/pipe as the angles of attack (torch and filler wire) are constantly changing. End of the filler wire needs to be kept within the gas shield too, pull it back too far and it'll oxidise only for those oxides to be dunked in the weld pool next dip. Too close and/or angles of attack wrong and the end of the wire will melt and ball from the heat of the arc

If you haven't already then checkout the Miller TIG resources

Personally i would be leaving techniques like 'walking the cup' alone until you can freehand consistantly. It is a useful technique but there's not always room to walk it so you need to be able to freehand too

 

[Freshfabrications]

A fair point about the free hand and it's true that it takes practice, any element of tig requires patience, my sugestion is that he should start to learn the tecniques, in time he may well need to walk the cup if he does alot of these headers or other projects.

My second sugestion is the order in which you weld will help limit distortion along with clamping, chills and purging, also by welding in small sections you can learn more, review what you have achived and make adjustment.
It's very daunting trying to go around most of pipe joint in one pass and also could be bad practice for distortion controll.

I'd be very interested in seeing how you tackled your purge setup for this job (photos ?) I'm finding I have to turn up plugs and heat sinks for my bicycle frame on the lathe at the moment, also can you sugestion a good lpm flow rate for thin wall tube?

Thanks

 

[Phataz1]

Great advice guys thanks! I have seen loads of videos on 'walking the cup' and it seems like a helpful technique. I think my main problem right now is getting comfortable enough to be able to steadily move the torch. At the moment I am trying to weld with the peice too high (almost the same level as my head when sat down) and it results in quite jerky movements. I'm trying to make a lower bench to make it more comfortable as I know it will help!

Sorry I don't have any pics of the back purge system, but its not worth taking pics of lol. I basically just hooked up a small disposable argon bottle up with a peice of copper tube to direct it into the bottom of the tube, then block off the top with a peice of aluminium. I turn it on and leave it a minute or so before I start welding.

Does this look any better? This afternoon I tried sitting on a higher stool and getting the arc length even shorter...

 

[smithy1851]

hi,

welds are certainly improving, still needs more filler wire as you can see the undercut and the uneveness of the weld,
with practice you should be able to put a nice fillet weld evenly around these pots, no undercut and without any pin holes, remmember to make sure you keep the tungsten moving when you come to stop, i tend to move to the side of the weld as the downslope takes hold....this will also improve with more wire in the weld...

walking the cup around these would make a nice finish but takes practice to keep the torch at the correct angle n the wire flowing inside the gas shield..would tend to concentrate on freehanding this, practice makes perfect...

with regards to purge pots,

over the years we have made a vareity of pots, plugs and suchlike to bung up pipes etc for purging..
ive rubber bungs made up for different setups, for welding pipes, and also mouses, for purging butts within a pipe, so that your only purging the weld and not the hole pipe length.

these sort of headers are arkward because they r so short, id tend to make up alittle set of pots that slip tightly into these with my hose connected..
again we tend to use air push fittings, in either 6mm or 8mm. easy to change and set up each time.... i'll take a couple of pics for you and post when ive a minute, give you an idea...

chris

 

[langy]

Definite improvement but the tungsten is still a fair way from the surface and still need more rod, Keep plugging away and it will come.

If you keep the tungsten nice and tight this is what your aiming for, This is 8mm to 3mm

Great advice guys thanks! I have seen loads of videos on 'walking the cup' and it seems like a helpful technique. I think my main problem right now is getting comfortable enough to be able to steadily move the torch. At the moment I am trying to weld with the peice too high (almost the same level as my head when sat down) and it results in quite jerky movements. I'm trying to make a lower bench to make it more comfortable as I know it will help!

Sorry I don't have any pics of the back purge system, but its not worth taking pics of lol. I basically just hooked up a small disposable argon bottle up with a peice of copper tube to direct it into the bottom of the tube, then block off the top with a peice of aluminium. I turn it on and leave it a minute or so before I start welding.

Does this look any better? This afternoon I tried sitting on a higher stool and getting the arc length even shorter...

 

[Phataz1]

hi,
we tend to use air push fittings, in either 6mm or 8mm. easy to change and set up each time.... i'll take a couple of pics for you and post when ive a minute, give you an idea...

chris

Thats a good idea Yeah a photo would be great! Thanks!


Langy, beautiful welds! Well done sir Definitely something for me to aim for, maybe in years to come lol

 

[Freshfabrications]

Photos please and purge rates in Lpm!

Phataz1 it looks like you have nowhere to rest your hand or elbow to steady your self when welding. Is this correct?

I have only seen a couple of welders who got good results welding with nothing to support there arm or hand, and thoes guys were both pipe welders, and pipe welders walk the cup which is a way of supporting the torch!!

Remember your whole body is moving constantly to keep you upright, this transfers to the torch!

One great tip for comfort is to make sure you do a dummy run on each weld and make sure you feel comfortable and steady, especially at the end where things are getting hotter and less easy to controll, I call supporting your hand/arm anchoring and it really helps, try it, I use the little finger or the side of my hand or if nothing else my elbow!

Let me know if this helps

 

[Rick]

You don't want to walk the cup on that weld. I'd be welding with my cup touching the runner, so the tungsten is angled about 60 degree's from the flange. Using 1.6mm rod, welder set to about 110 amp's, probably welding at 90-100 using the pedal.

Bolt the flange down rather than using clamps.

However, I wouldn't be making a manifold in that order.

Langy, what are you using to polish the pipe with? I never do mirror polished, but i'm always open to new methods.

 

[Phataz1]

Photos please and purge rates in Lpm!

Phataz1 it looks like you have nowhere to rest your hand or elbow to steady your self when welding. Is this correct?

Correct It is also a little bit high when I'm sat down which makes it more difficult. I have started to do dummy runs like you say and that does help!

But I think I will make a stand for this peice of box section I'm using as a bench, to lower it down so I can move more comfortably


Rick, in what order would you make the manifold?

 

[ironmonger]

Manifold

Nice progress on the manifold.

I was wondering if there was a reason that you haven't placed the welds on the other side of the flange?

Since you already had to make holes that matched the barrels, i would think that the tube could have slipped completely through the flange and be welded on the 'head' side of the flange. That would give you a nice bead inside that could likely be accomplished by a fusion weld, (no filler) and if need be you could also weld the 'outside' as well.

The advantage of a weld on both sides is to even out the heat distortion by balancing the stress on both sides of the flange.

Is this for a motorcycle?

paul
Waukesha, WI USA