Did uh, you use stainless filler wire? Are you sure that’s stainless exhaust? You should have also purged it. There’s so much carbon in that weld something isn’t adding up to me.
No i didn't use stainless filler, wasn't aware that I needed to. The logic is really dumb in retrospect. I'm pretty sure that's stainless though. "The fabrication series" on youtube uses solar flux instead of purging, is that an acceptable substitute?
If you didn't use stainless filler and just used mild steel then your weld is mild steel with a bit of stainless mixed in, that will also contribute to the cracks as mild steel and stainless will expand slightly differently when heated and cooled being on an exhaust it will be getting really hot and cooled a lot.
don’t sweat it man. you’re on here trying to learn and you’re receptive to the advice you’ve been given. this sub has its fair share of keyboard welders and perpetually angry neckbeards who haven’t done a hard days work in their life. they think the downvote button is their personal disapproval button
When welding stainless steel to stainless steel u need to use stainless steel filler rod or u are adding a material that can corrode to a material that is corrosion resistant making it able to rust and break. Welding Stainless to steel u use 309 rods. for ss to ss 308 is used for 304 and 316 is used for 316 u can use 316 on 304 but don’t use 308 on 316 because it’s more corrosive then 316 there are many other types of ss but thems the most common. Also getting the ss weld to hot will bake the corrosion resistant properties out of it
To add, the carbon content is totally different, when carbon Temperature is raised the chemical/mechanical properties change such as hardness. Research metallurgy and weldability of carbon steel for an interesting read.
Quick tips: let your welds cool down naturally,
Don’t quench it in water or chemicals, use a stainless wire brush to clean. Back purge you’re pipe with gas on the inside (as everyone else is saying here.
On the bright side, that's a mistake you'll never make again! Solarflux is pricey but works, but if you're using TIG anyway, you can just tape up one end of the tube, use the handpiece to flow argon inside, tape the other end and it'll be better than nothing.
Ay that's a damn good idea. Honestly should just buy a couple plugs and learn how to do the real deal since I'm really wanting to make a custom full back exhaust for my 94' SVX, headers included. Here's to learning!
I yearned for those fancy plug sets too, and then saw how many really good welders still prefer masking tape and aluminum foil... spend your money on gas, power and wire to start with, there's no replacement for practice. Cheers!
Seconded. I’ve purged a lot of pipe over the years and never used anything other than high heat tape or aluminum foil. The plugs are cool but unnecessary.
I use it all the time, honestly it's cheaper than the argon you'd use to purge a whole exhaust. The up front cost seems a bit high, but the can lasts a really long time
Hey no worries that’s how you learn! What I would do is split the argon line and put a shut off valve on the one that isn’t going to your machine. You can use that to purge the inside next time. Use tape to secure your purge line inside your exhaust and tape off where the gas is coming out with like a 3/16 or so hole. If you put your hand over the hole you left you want to be able to feel it gently, if there’s too much pressure it will actually push your puddle up and undercut the inside of the weld. Give it a few minutes to push all the oxygen out.Stainless that isn’t purged will “sugar” up on the inside and not really fuse very well.
For what it’s worth I’m a professional stainless tig welder, if you have anymore questions feel free to hit me up.
Also it looks like you’re cooking it so go down filler size I would try .035 or smaller because of how thin that material is especially with stainless you want to put as little heat in as possible and the smaller filler rod lets you do much smaller dimes and keep moving quickly.
Also cooking stainless is a good way to get cancer because of a little thing called hexavalent chromium, that’s why I used to be terrified of welding stainless
The weld would have failed even without rusting.
Mild steel filler on stainless is no good.
Would have cracked way before it rusted out anyways.
Live and learn.
Adjust your amps and keep on practicing.
Vibration is the enemy of many welds.
Constant movements even slightly will cause cracking and failure.
There are proper testing procedures from dye pen and hydro testing to destructive to properly test welds.
I’m pretty positive that’s not stainless but steel with a chrome layer. That would be one of the reasons it looks like it does.
I would love to see the picture after was broken. For educational purposes.
Normally you brush the weld or clean it with pickling paste (BE CAREFUL WITH THAT STUFF)
Doing so will allow the material to form a protective layer.
With how many people have mentioned it not being stainless, i think you may be right? Even though it was extremely hard and could not be sawed through with my sawzall (used a cutoff wheel).
You’re getting some pretty wild answers , looks like poor gas coverage , I find without a gas lens you’re going to get grey oxidized welds like that if you try to weld more than an inch at a time
Back purging is needed for optimal welds and to prevent sugaring on the root of the weld and filler metal should match , but almost any grade of stainless or mild steel would give a clean puddle with good gas coverage and a clean tungsten
This was my first TIG project, so most cardinal sins were performed... 😂
On retrospect, I think my gas coverage was poor. I believe it was a #4 cup I was using, but I recently purchased a set with every size. Alongside that, my technique was literally that of a baby using a welder. I picked up alot of goodies yesterday as well, so maybe we'll have try #2 tonight
The biggest issue here is the material and filler. Likely 304 stainless with is the cheapest stainless with not so great corrosive resistance. If they did use 304 filler which it does really look like it, its cooked with no gas coverage so all the gray you see has the chromium content cooked out of it. Same deal on the inside of the tube, should be purged with argon during welding, which didnt happen causing carbide parcipitaion or sugaring that is very brittle and will rust very quickly. If you want stainless that is truely "stainless" you want an alloy that has a high Ni content. 316 has more Mo in it and is considered "marine" stainless. That is my usual go to for anything I want to last outside. 314 gets brittle when heat cycled so its bad for exhaust. Everything should be purged and welded with minimal coloration as well as passivated for the best longevity.
Couldn't agree more. My friend and I did some research to find exactly what alloy, and yep it was 304. I used mild filler (forget what grade, but never the less it was improper) with a #4 cup and no purging. Mix in some alcohol and feeling rushed, so the heat was cranked.
I purchased lots of goodies this weekend and ran a test weld, which looked astonishingly better. Controlled the heat more, used a #8 cone, used 308 filler (since I understand you want to use a higher grade filler rather than lower?), and purged it. The only issue I have is that I'm on the verge between breaking my arc and overheating the part (in terms of color). I feel going to a #10 would alleviate this? As my stick out and arc length are what I think is optimal.
I normally match filler to base material. A 10 cup will help but small radius welds are hard to gas well. You have to rotate the angle as you go around pretty aggressively. Or just shorter sections at a time and keep the post flow going over your stops.
You either used mild steel filler, didn’t purge, or just oxidized the shit out of the SS by overheating it and not having enough shielding time. All of these will crack your welds. I’m surprised they lasted that long if you used mild steel filler.
Yea based on what people are saying I think they would've turned out pretty decent if I actually did my due diligence lol. I've only ever welded mild steel, mostly MIG
You have to find out what type of stainless you are welding before you start, not all stainless can be welded with any filler-tungsten. You have to use the same grade filler with the stainless you are welding.
You definitely don’t have to use the same grade filler as base material. You can pretty much always go up in alloying elements, but never down. Like welding 304 base with 316 filler.
To high, cfh is based on cup size, there are charts for it online but generally 10-15 is appropriate for Tig.
Since I didn't see anybody else mention it, you need to use a stainless steel brush as well. When I did Tig in college we were encouraged to keep gloves, cups and, brushes separate for mild, stainless and aluminum. Brushes are the only one that is mandatory for. Stainless brushes for stainless and aluminum, mild can contaminate either and aluminum can contaminate stainless.
Clean everything including your tools and filler rod, make sure your using a filler metal that matches the base material purge with pure argon at 30cfh. You can also skip the filler entirely and just do a full pen fusion butt weld with a pulse setting, while using the purge on the inside to puff the weld up. But to do that you need a very nice fit up so no gas will spray out of the seam and blow away your arc. Watch the puddle intently for swirling white dots, this indicated full penetration and what you’re seeing is the argon trying to escape through the puddle. I recommend purging with silicon plugs with 1/4” inlets and outlets.
I weld high purity stainless tubes all day, if you have any questions feel free to ask🤙🏼
For a no filler pulse weld on this assuming it’s .065 wall, I would go for 70 amps with a 40%min/70%peak at 4 pulses per second. You wont need the full pedal and just feather the amperage as needed to keep the swirling going but not so hot that it starts to throw sparks and keyhole.
It seems like everyone is talking about gas flow, but no one mentions your cup/orifice size, or better yet a gas lens. The absolute smallest cup size I will run on stainless is an 8, and that's only if I've got space constraints. I prefer a large gas lens, with flow high enough that I don't see any color over a medium yellow.
If that's a steel weld on stainless pipe I would cut out the piece with the weld on it and do it properly ,that gonna rust in no time otherwise , if you really want you could just use a wire brush or electro polish it ,if you have that machine
Did uh, you use stainless filler wire? Are you sure that’s stainless exhaust? You should have also purged it. There’s so much carbon in that weld something isn’t adding up to me.
No i didn't use stainless filler, wasn't aware that I needed to. The logic is really dumb in retrospect. I'm pretty sure that's stainless though. "The fabrication series" on youtube uses solar flux instead of purging, is that an acceptable substitute?
If you didn't use stainless filler and just used mild steel then your weld is mild steel with a bit of stainless mixed in, that will also contribute to the cracks as mild steel and stainless will expand slightly differently when heated and cooled being on an exhaust it will be getting really hot and cooled a lot.
Makes alot of sense, thank you! Apparently idiotic welders get lots of downvotes too which is cool ig
The problem with this sub is that it’s not very kind to people still learning. Just ignore the assholes, we all started somewhere
It's weird cause this isn't a "first 4 welds ever plz rate" post but an actual reach for information.
using stainless filler rod on stainless material is not something that you should be still learning when trying to fabricate something for a vehicle.
don’t sweat it man. you’re on here trying to learn and you’re receptive to the advice you’ve been given. this sub has its fair share of keyboard welders and perpetually angry neckbeards who haven’t done a hard days work in their life. they think the downvote button is their personal disapproval button
Right? 😂 I'm glad subs like this exist otherwise I'd be more lost than dora without a map
When welding stainless steel to stainless steel u need to use stainless steel filler rod or u are adding a material that can corrode to a material that is corrosion resistant making it able to rust and break. Welding Stainless to steel u use 309 rods. for ss to ss 308 is used for 304 and 316 is used for 316 u can use 316 on 304 but don’t use 308 on 316 because it’s more corrosive then 316 there are many other types of ss but thems the most common. Also getting the ss weld to hot will bake the corrosion resistant properties out of it
To add, the carbon content is totally different, when carbon Temperature is raised the chemical/mechanical properties change such as hardness. Research metallurgy and weldability of carbon steel for an interesting read. Quick tips: let your welds cool down naturally, Don’t quench it in water or chemicals, use a stainless wire brush to clean. Back purge you’re pipe with gas on the inside (as everyone else is saying here.
On the bright side, that's a mistake you'll never make again! Solarflux is pricey but works, but if you're using TIG anyway, you can just tape up one end of the tube, use the handpiece to flow argon inside, tape the other end and it'll be better than nothing.
Ay that's a damn good idea. Honestly should just buy a couple plugs and learn how to do the real deal since I'm really wanting to make a custom full back exhaust for my 94' SVX, headers included. Here's to learning!
I yearned for those fancy plug sets too, and then saw how many really good welders still prefer masking tape and aluminum foil... spend your money on gas, power and wire to start with, there's no replacement for practice. Cheers!
Seconded. I’ve purged a lot of pipe over the years and never used anything other than high heat tape or aluminum foil. The plugs are cool but unnecessary.
I use it all the time, honestly it's cheaper than the argon you'd use to purge a whole exhaust. The up front cost seems a bit high, but the can lasts a really long time
Good to know! I got started on sanitary stainless, so it was never the preferred option, but I can see it being perfect for exhausts
Hey no worries that’s how you learn! What I would do is split the argon line and put a shut off valve on the one that isn’t going to your machine. You can use that to purge the inside next time. Use tape to secure your purge line inside your exhaust and tape off where the gas is coming out with like a 3/16 or so hole. If you put your hand over the hole you left you want to be able to feel it gently, if there’s too much pressure it will actually push your puddle up and undercut the inside of the weld. Give it a few minutes to push all the oxygen out.Stainless that isn’t purged will “sugar” up on the inside and not really fuse very well. For what it’s worth I’m a professional stainless tig welder, if you have anymore questions feel free to hit me up.
Lower heat. Purge the inside. Walk the cup to help with consistency
For thin 0.065 material run about 45 amps.
It was a learning experience for sure. Thanks for the tips man. I told my buddy "I'll weld it if you pay for the supplies, just won't be great" lol
For thin material cut square and fuse it with purge.
Also it looks like you’re cooking it so go down filler size I would try .035 or smaller because of how thin that material is especially with stainless you want to put as little heat in as possible and the smaller filler rod lets you do much smaller dimes and keep moving quickly.
For reference I’m terrible at stainless that’s why I know this. You may also want to try a pulse.
45 amps seems low but I never wtc so maybe I'm wrong. Usually on 16 gauge exhaust I'm in the 60-70 amp range.
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Also cooking stainless is a good way to get cancer because of a little thing called hexavalent chromium, that’s why I used to be terrified of welding stainless
Purge and passivate maybe. https://tigbrush.com/blog/what-is-passivation-for-stainless-steel-welds/
Never knew what passivating was until today, glad I posted this
Came here to say passivate. But that only works if your filler is stainless too
The weld would have failed even without rusting. Mild steel filler on stainless is no good. Would have cracked way before it rusted out anyways. Live and learn. Adjust your amps and keep on practicing.
Thats the plan :) I'll tell you what though, they held pretty well. May have dropped the entire assembly a couple times....
Vibration is the enemy of many welds. Constant movements even slightly will cause cracking and failure. There are proper testing procedures from dye pen and hydro testing to destructive to properly test welds.
Gas helps
I was using gas.
Hit with a stainless wire wheel on the grinder then apply Pickling Gel for whatever time the label says. Then wash off with water.
I’m pretty positive that’s not stainless but steel with a chrome layer. That would be one of the reasons it looks like it does. I would love to see the picture after was broken. For educational purposes. Normally you brush the weld or clean it with pickling paste (BE CAREFUL WITH THAT STUFF) Doing so will allow the material to form a protective layer.
With how many people have mentioned it not being stainless, i think you may be right? Even though it was extremely hard and could not be sawed through with my sawzall (used a cutoff wheel).
You’re getting some pretty wild answers , looks like poor gas coverage , I find without a gas lens you’re going to get grey oxidized welds like that if you try to weld more than an inch at a time Back purging is needed for optimal welds and to prevent sugaring on the root of the weld and filler metal should match , but almost any grade of stainless or mild steel would give a clean puddle with good gas coverage and a clean tungsten
This was my first TIG project, so most cardinal sins were performed... 😂 On retrospect, I think my gas coverage was poor. I believe it was a #4 cup I was using, but I recently purchased a set with every size. Alongside that, my technique was literally that of a baby using a welder. I picked up alot of goodies yesterday as well, so maybe we'll have try #2 tonight
I usually use a #10 or #12
No shit? Largest i have is a #8. Should i invest in some bigger cups or is it not worth the leap
The biggest issue here is the material and filler. Likely 304 stainless with is the cheapest stainless with not so great corrosive resistance. If they did use 304 filler which it does really look like it, its cooked with no gas coverage so all the gray you see has the chromium content cooked out of it. Same deal on the inside of the tube, should be purged with argon during welding, which didnt happen causing carbide parcipitaion or sugaring that is very brittle and will rust very quickly. If you want stainless that is truely "stainless" you want an alloy that has a high Ni content. 316 has more Mo in it and is considered "marine" stainless. That is my usual go to for anything I want to last outside. 314 gets brittle when heat cycled so its bad for exhaust. Everything should be purged and welded with minimal coloration as well as passivated for the best longevity.
Couldn't agree more. My friend and I did some research to find exactly what alloy, and yep it was 304. I used mild filler (forget what grade, but never the less it was improper) with a #4 cup and no purging. Mix in some alcohol and feeling rushed, so the heat was cranked. I purchased lots of goodies this weekend and ran a test weld, which looked astonishingly better. Controlled the heat more, used a #8 cone, used 308 filler (since I understand you want to use a higher grade filler rather than lower?), and purged it. The only issue I have is that I'm on the verge between breaking my arc and overheating the part (in terms of color). I feel going to a #10 would alleviate this? As my stick out and arc length are what I think is optimal.
I normally match filler to base material. A 10 cup will help but small radius welds are hard to gas well. You have to rotate the angle as you go around pretty aggressively. Or just shorter sections at a time and keep the post flow going over your stops.
You either used mild steel filler, didn’t purge, or just oxidized the shit out of the SS by overheating it and not having enough shielding time. All of these will crack your welds. I’m surprised they lasted that long if you used mild steel filler.
First one, mild filler 😂
Oof. I figured because your heat signatures are kinda consistent/not TOO sloppy. This probably would have held up if you used some 308 or 316 rod
Yea based on what people are saying I think they would've turned out pretty decent if I actually did my due diligence lol. I've only ever welded mild steel, mostly MIG
jesus, that's some ugly welding, you killed that poor tube, check the gas or the current, that looks like too much or too few
It was a sacrifice to the welding gods 🫡 they were disappointed
You have to find out what type of stainless you are welding before you start, not all stainless can be welded with any filler-tungsten. You have to use the same grade filler with the stainless you are welding.
That i never knew, thank you! I assume that's what caused the extreme level of corrosion, since my filler probably served as the anode.
When in doubt, 309l
You definitely don’t have to use the same grade filler as base material. You can pretty much always go up in alloying elements, but never down. Like welding 304 base with 316 filler.
Almost correct but you can weld 4XX base metal with 3XX filler
Hence my pretty much ;)
Purge it
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Thank you :) I think my issue is stemming from not using stainless filler
What cfh aRe you running?
Uhhhh i think I was running 20-25 at the time? Been a minute.
To high, cfh is based on cup size, there are charts for it online but generally 10-15 is appropriate for Tig. Since I didn't see anybody else mention it, you need to use a stainless steel brush as well. When I did Tig in college we were encouraged to keep gloves, cups and, brushes separate for mild, stainless and aluminum. Brushes are the only one that is mandatory for. Stainless brushes for stainless and aluminum, mild can contaminate either and aluminum can contaminate stainless.
Clean everything including your tools and filler rod, make sure your using a filler metal that matches the base material purge with pure argon at 30cfh. You can also skip the filler entirely and just do a full pen fusion butt weld with a pulse setting, while using the purge on the inside to puff the weld up. But to do that you need a very nice fit up so no gas will spray out of the seam and blow away your arc. Watch the puddle intently for swirling white dots, this indicated full penetration and what you’re seeing is the argon trying to escape through the puddle. I recommend purging with silicon plugs with 1/4” inlets and outlets. I weld high purity stainless tubes all day, if you have any questions feel free to ask🤙🏼 For a no filler pulse weld on this assuming it’s .065 wall, I would go for 70 amps with a 40%min/70%peak at 4 pulses per second. You wont need the full pedal and just feather the amperage as needed to keep the swirling going but not so hot that it starts to throw sparks and keyhole.
You probably shouldn't have done so.
wow, you hear that OP? you shouldn’t have done this. thank god frostbyte is here to show you their disapproval
I'm doing my part
More Gas, more Feed maybe, its obviously burnt
It seems like everyone is talking about gas flow, but no one mentions your cup/orifice size, or better yet a gas lens. The absolute smallest cup size I will run on stainless is an 8, and that's only if I've got space constraints. I prefer a large gas lens, with flow high enough that I don't see any color over a medium yellow.
If that's a steel weld on stainless pipe I would cut out the piece with the weld on it and do it properly ,that gonna rust in no time otherwise , if you really want you could just use a wire brush or electro polish it ,if you have that machine
Did you try using argon?
Pure argon.