Stick Welding Exhaust Pipe? - Your Methods And Theories

[doo doo]

Oh goody, my turn. Purging in tig welding is necessary on stainless ONLY and it's sole purpose is too prevent the backside of the weld from being contaminated by atmosphere. Also called cauliflowering it looks like a really bad fungal disease and the weld will eventually break if subjected to heat and stress over time eg on a heatshield. If you are using thick enough steel and you don't achieve full penetration (behave!) with your weld and no purging then you will not have contaminated the weld, but less penetration means relatively weaker weld also. Which may well suffice for a given application like cooler piping. I back purge my own stainless exhaust in the interests of longevity and I back-purge all my own stainless coz i can and I think the result is going to be much more reliable and last longer. And yes it uses the argon quicker but so what, I won't have to make it again. You can also protect the back of your stainless welds with a copper backing bar for flat stuff and you can even machine a channel in it and put the weld over the channel and run argon through it to protect the back of the weld.

Yep, when it comes to paying someone to do it for you, remember if you can't afford to do it right, can you afford to do it twice.

(A spin off of my favourite quote- We didn't have time to do it right but we found time to do it twice)

Hey I've got some spare welding books (one by robert finch and the other is an american aeronautical welding standards book)- I was sent 6 of one and 4 of another (talk about misreading an order)- first in with their postal addresses get their choice, i'll foot the postage.

[rb26s13]

I would say thet the 0.5% of customers who would be happy to pay the extra for a purged exhaust system, all of them wouldnt want it done in stainless, when inconel or titanium are available.

have you looked into the price of inconel or titanium recently.. and yes in the case of using those materials obviously no expense spared purging isnt goin to make f**k all diff to the price

And Im sure they woulnt be intrested in paying extra for inconel or titanium as well as the extra cost of welding in a atmosphere of inert gas it also depends on the application (race or street) I know we cant use either of the alloys in our cat of racing, but when you look at the cost of a full race spec exhaust (around $16,000 is what it cost for us) that small amount of extra gas used for purgeing is neither here or there.

for someone like me who does this work from home as a hobby to help mates out the extra expense isnt worth it to me.. its not the gas that gets me its another bottle rental, reg, fittings and wat not to go over the end of the pipes in all different sizes as i work with anything from 3/4inch up to 4inch .. perhaps you could show me a few pictures of the setup you use

[The BOP]

Oh goody, my turn. Purging in tig welding is necessary on stainless ONLY and it's sole purpose is too prevent the backside of the weld from being contaminated by atmosphere. Also called cauliflowering it looks like a really bad fungal disease and the weld will eventually break if subjected to heat and stress over time eg on a heatshield. If you are using thick enough steel and you don't achieve full penetration (behave!) with your weld and no purging then you will not have contaminated the weld, but less penetration means relatively weaker weld also. Which may well suffice for a given application like cooler piping. I back purge my own stainless exhaust in the interests of longevity and I back-purge all my own stainless coz i can and I think the result is going to be much more reliable and last longer. And yes it uses the argon quicker but so what, I won't have to make it again. You can also protect the back of your stainless welds with a copper backing bar for flat stuff and you can even machine a channel in it and put the weld over the channel and run argon through it to protect the back of the weld.

Yep, when it comes to paying someone to do it for you, remember if you can't afford to do it right, can you afford to do it twice.

(A spin off of my favourite quote- We didn't have time to do it right but we found time to do it twice)

Hey I've got some spare welding books (one by robert finch and the other is an american aeronautical welding standards book)- I was sent 6 of one and 4 of another (talk about misreading an order)- first in with their postal addresses get their choice, i'll foot the postage.

Hey mate I'm keen always more you can learn pm me and I'll give you the address (both books if poss) cheers

[The BOP]

have you looked into the price of inconel or titanium recently.. and yes in the case of using those materials obviously no expense spared purging isnt goin to make f**k all diff to the price

for someone like me who does this work from home as a hobby to help mates out the extra expense isnt worth it to me.. its not the gas that gets me its another bottle rental, reg, fittings and wat not to go over the end of the pipes in all different sizes as i work with anything from 3/4inch up to 4inch .. perhaps you could show me a few pictures of the setup you use

Hey mate sorry I can't take photo's at work against team policy, but with all the ends of the pipes you can get away with just useing tape you could go that extra step and have machined bunges made but you only need that when your welding right near the end of the pipe and yeah you will have wear the extra cost of a reg. Also put a small hole (in the end cap or tape) in the opposite end of the tube your welding so the gas flows and doesnt put to much pressure against your weld trust me it will blow the weld out if trust me it happens.

My personal machine is a kempi ac/dc 200 amp with foot control and pulse function with standerd reg and flow meter, my work machines are lincon a whole bunch of them

[doo doo]

the BOP- got your PM, am looking for the books, will get back to you asap.

As for setup, agreeing you just need a back purge regulator to hook up to your bottle reg (they're about 60 bucks) and extra line- masking tape is the (cheap) go for blocking off tubes, you can get pretty close before it burns, heat takes quite a bit longer to travel through stainless than mild, it's why you use a lesser amp, the heat piles up. And YES, you definitely need to punch a hole for argon to exit, make it the same size as the inlet and run 20cfm through it for a minute (depending on the amount of space to fill) then back it off to 10- you want to flush all atmosphere out. Pressure behind the weld that is greater than what you're running through the torch will push the weld back out toward the end of the weld. Another tip if you don't already do so is to wipe the areas to be welded with acetone, including the rod just prior to welding. Don't leave the open bottle next to the welding area. You should take LOTS of care that no flammables are in the area anyway. Don't use mild steel rod on stainless welds, and don't use that copper coated crap either. Copper contaminates the weld. (If it's all you can find for mild steel welds then use a bench grinder to take the copper coating off.) Use stainless rod for stainless and I usually pay the extra for 316 grade rod. (mind you if it's for me I usually buy 316 pipe to start with) I also use a belt sander for the tungsten (using a drill or similar to get a really nice conical tip) and I have a 400grit belt I use ONLY for tungsten tips- other metals remaining in sandpaper will contaminate the tungsten. I also try to have the direction of the sandpaper run lengthwise down the tungsten rather than around as this helps the arc track to the tip, which i also very lightly touch to the sander to slightly round the sharp point. If you don't have a high frequency start use a copper strip clamped to the work to strike the tungsten on as copper won't stick to the tip and contaminate the tungsten. Take the time and the care, keep it CLEAN and free from contamination (ie re-grind the tip when you accidentally touch the weld) and you're welds will not omly look good, they'll be sound and last. Hope this might be useful to anyone, sorry of it's fairly standard.

Anyone can feel free to add (or subtract!) tips they might have picked up, I'm always looking to learn more.

[The BOP]

the BOP- got your PM, am looking for the books, will get back to you asap.

As for setup, agreeing you just need a back purge regulator to hook up to your bottle reg (they're about 60 bucks) and extra line- masking tape is the (cheap) go for blocking off tubes, you can get pretty close before it burns, heat takes quite a bit longer to travel through stainless than mild, it's why you use a lesser amp, the heat piles up. And YES, you definitely need to punch a hole for argon to exit, make it the same size as the inlet and run 20cfm through it for a minute (depending on the amount of space to fill) then back it off to 10- you want to flush all atmosphere out. Pressure behind the weld that is greater than what you're running through the torch will push the weld back out toward the end of the weld. Another tip if you don't already do so is to wipe the areas to be welded with acetone, including the rod just prior to welding. Don't leave the open bottle next to the welding area. You should take LOTS of care that no flammables are in the area anyway. Don't use mild steel rod on stainless welds, and don't use that copper coated crap either. Copper contaminates the weld. (If it's all you can find for mild steel welds then use a bench grinder to take the copper coating off.) Use stainless rod for stainless and I usually pay the extra for 316 grade rod. (mind you if it's for me I usually buy 316 pipe to start with) I also use a belt sander for the tungsten (using a drill or similar to get a really nice conical tip) and I have a 400grit belt I use ONLY for tungsten tips- other metals remaining in sandpaper will contaminate the tungsten. I also try to have the direction of the sandpaper run lengthwise down the tungsten rather than around as this helps the arc track to the tip, which i also very lightly touch to the sander to slightly round the sharp point. If you don't have a high frequency start use a copper strip clamped to the work to strike the tungsten on as copper won't stick to the tip and contaminate the tungsten. Take the time and the care, keep it CLEAN and free from contamination (ie re-grind the tip when you accidentally touch the weld) and you're welds will not omly look good, they'll be sound and last. Hope this might be useful to anyone, sorry of it's fairly standard.

Anyone can feel free to add (or subtract!) tips they might have picked up, I'm always looking to learn more.

+ 1 for the acetone I clean all surfaces and filler rods with the stainless rule of thumb is use at least the same or higher grade stainless filler, and with all stainless work (and ali) always use inox grinding and sanding disc's never use anything that has ground mild steel touch your work to prevent contamination and directly connect the earth to the job as close to the weld area as poss this will stop arcing and get better current flow. Try to put a sheet of the same materialon your bench when working also to prevent contamination.

Almost all the work I do is either CrMo, SS (309-316-321) and ali I try to use the closest filler I can get my hand on for the ali work I use 5% mag, stainless the same grade as material and CrMo filler wire for the moly (you can use mild steel but if you do use low hydrogin mig wire's not to bad) just remember the weld is only going to be as good as your prep work I hand file all joints and debur and clean everything before I tack up and then I will clean it again just before welding it out.

Back to the ali when grinding sanding or whatever use bee's wax as a lube and when your drilling use kero or WD40 ( I prefere kero myself) and if your going to polish the job after pre polish all of the ends were your going to weld this way you can leave your welds looking lnice and not half sanded of after polishing (if you like to leave your welds exposed I think it looks trick myself)

you would do this for stainless also.

[Ki_spirit]

Appreciate all the feedback guys.

Thanks.

[doo doo]

+ 1 for the acetone I clean all surfaces and filler rods with the stainless rule of thumb is use at least the same or higher grade stainless filler, and with all stainless work (and ali) always use inox grinding and sanding disc's never use anything that has ground mild steel touch your work to prevent contamination and directly connect the earth to the job as close to the weld area as poss this will stop arcing and get better current flow. Try to put a sheet of the same materialon your bench when working also to prevent contamination.

Almost all the work I do is either CrMo, SS (309-316-321) and ali I try to use the closest filler I can get my hand on for the ali work I use 5% mag, stainless the same grade as material and CrMo filler wire for the moly (you can use mild steel but if you do use low hydrogin mig wire's not to bad) just remember the weld is only going to be as good as your prep work I hand file all joints and debur and clean everything before I tack up and then I will clean it again just before welding it out.

Back to the ali when grinding sanding or whatever use bee's wax as a lube and when your drilling use kero or WD40 ( I prefere kero myself) and if your going to polish the job after pre polish all of the ends were your going to weld this way you can leave your welds looking lnice and not half sanded of after polishing (if you like to leave your welds exposed I think it looks trick myself)

you would do this for stainless also.

Yep sounds familiar! Good stuff, do you get vacumm melted MC grade CrMo filler and where from? And does your work ever have a seconds sale? One of those lincolns would prob look good in my setup.... still onto those books for ya, and i reckon you'd like carroll smith- he ran racing teams in the state for 30 years (after being a racer himself) and was an independant design consultant for half the open wheel categories- look up 'engineer to win- understanding race car dynamics" in amazon or something, should be copies in oz

[The BOP]

Yep sounds familiar! Good stuff, do you get vacumm melted MC grade CrMo filler and where from? And does your work ever have a seconds sale? One of those lincolns would prob look good in my setup.... still onto those books for ya, and i reckon you'd like carroll smith- he ran racing teams in the state for 30 years (after being a racer himself) and was an independant design consultant for half the open wheel categories- look up 'engineer to win- understanding race car dynamics" in amazon or something, should be copies in oz

All the machines are supplied by sponsors but if we change sponsors at the end of the year and still have them you might be in with a chance were strictly a racing team no sales unless you want to buy a car or select parts!

All consumables are supplied by the sponsors too unless there a emergancy and we run out then we get it from however has some, i'll have a look round for Carroll Smith when work slows down a bit so prob around xmas! ha ha thanks again for the books if your ever down Melbourne give me a call i'll show you some of the stuff we make cheers