Welding Tips and Tricks

I've been working with stainless a bit more lately, even picked up a few more pieces at the scrap yard today and it's been hitting me all the things I didn't even realize I didn't know. I've found roloc scotchbrite discs to potentially be a great way to clean at least thin pieces of stainless prior to welding in my limited experience, I've destroyed bimetal sawzall blades attempting to cut stainless. And today I realized not only was it unlikely that my scrap finds were all the same alloy, but I had no real practical way of telling the difference.

So does anyone have some wisdom to share about stainless that perhaps isn't covered so often in popular videos or information sources? Can anyone confirm my roloc experience or refute it due to disc longevity or other issues? Any decent alloy identification tips or even just stories realizing a certain kind of stainless wasn't what was assumed? Things along those lines.

Stainless steel destroys cutting tools because the heat builds up locally and can't get away. It traps heat more than mild steel. Use an inox labeled 1mm cutting disc to cut. If you have to drill, use a good quality drilling lube and a slow speed with constant firm pressure.

Your scrap is most likely 304 and 316. If you are just practicing use 308 rods or wire, if it's a really and truly weld use 316.

If a magnet sticks to it, it's most likely 4 series stainless. 416 is the most likely. This stuff will rust. Some variants can be hardened, though not nearly as much as typical hardenable carbon steels.

If a magnet doesn't stick, it's most likely 3 series. 304 being the most common.

PH Stainless (Precipitation hardening) also is ferrous (a magnet sticks). Examples would be 15-5, 17-4, 18-8... This stuff can be hardened, welded, and machines beautifully in the annealed state. It also is dimensionally stable in heat treat. Full hardness can be achieved at 900F in the case of 17-4 for instance. With so little heat it just doesn't warp very much.

It's hard to convey just how slow a blade needs to go in order to cut stainless without wrecking a blade. When I'm cutting it in my bandsaw, (metal cutting saw), you can read the info on the blade as it passes by. Guessing here but let's say 2-3" per second. Very slow. That's also with constant coolant running on the blade. Even at that, blades don't last forever. Especially so in thin cross sections, they rip teeth out like they're free.

Whatever the slowest speed a saw will provide, that's what you need with stainless. Might not be slow enough, but don't even consider using 2 on the 1-10 scale.

I use Walter Stainless Cut fluid and aerosol when cutting or machining stainless of all grades. It is difficult to convey how damn good that stuff is, but I can use a can for more than 6 months easily and never lose a tooth on a bandsaw or chop saw.

Welding stainless is all about clean and atmosphere control. More gas coverage, more post flow, even bump your preflow is you have that control. On machines that don't, I bump the pedal with the tungsten pointed away, then rotate over the welding area. Then ignite. That pre-purge helps immeasurably clear the area of atmosphere for a better weld.

BugHunter wrote:If a magnet sticks to it, it's most likely 4 series stainless. 416 is the most likely. This stuff will rust. Some variants can be hardened, though not nearly as much as typical hardenable carbon steels.

If a magnet doesn't stick, it's most likely 3 series. 304 being the most common.

PH Stainless (Precipitation hardening) also is ferrous (a magnet sticks). Examples would be 15-5, 17-4, 18-8... This stuff can be hardened, welded, and machines beautifully in the annealed state. It also is dimensionally stable in heat treat. Full hardness can be achieved at 900F in the case of 17-4 for instance. With so little heat it just doesn't warp very much.

It's hard to convey just how slow a blade needs to go in order to cut stainless without wrecking a blade. When I'm cutting it in my bandsaw, (metal cutting saw), you can read the info on the blade as it passes by. Guessing here but let's say 2-3" per second. Very slow. That's also with constant coolant running on the blade. Even at that, blades don't last forever. Especially so in thin cross sections, they rip teeth out like they're free.

Whatever the slowest speed a saw will provide, that's what you need with stainless. Might not be slow enough, but don't even consider using 2 on the 1-10 scale.

I actually have a bar of stainless that looks to potentially be a bracket or tooling of some kind that is quite magnetic, that's what clued me into thinking some of what I had wasn't even all 304 or 316. It also had a little bit of light rust on a couple small areas. I'm 98% sure it's not galvanized, and the sparks were totally different from some confirmed 304 I had.

The square tubing I have that destroyed a sawzall blade an inch into the cut is also magnetic, abut I realized it was primarily around the corners.

sbaker56 wrote:I actually have a bar of stainless that looks to potentially be a bracket or tooling of some kind that is quite magnetic, that's what clued me into thinking some of what I had wasn't even all 304 or 316. It also had a little bit of light rust on a couple small areas. I'm 98% sure it's not galvanized, and the sparks were totally different from some confirmed 304 I had.

The square tubing I have that destroyed a sawzall blade an inch into the cut is also magnetic, abut I realized it was primarily around the corners.

I've often threatened to buy one of the laser spectrometers for identifying steels. You see them at the scrap yards where they shoot the scrap you bring in and determine what metal it is, then price accordingly. They also use it to tell if you've brought in mixed-metal, or if the bins of stuff you brought were actually one alloy.

They cost about 2 grand, but when you have a lot of unidentified steel laying around like I have, it could easily pay for itself. My steel rack has 1000s of pounds of steels that were here before I purchased the business, many with the paint cut off the ends telling what it was, and thus not knowing what it is, it's basically useless to me. One of these days I want to buy one and won't have these issues any more. Might also be nice for purchasing steels where I'm convinced the steel company is screwing me selling something that isn't what they say it is. If you ever hear some stories from people who worked at the places, you start to see just how underhanded they are. For instance, things like 2 different SKUs for parts, one for the real stuff, and one for the fake stuff that's sold to people who don't know any better and don't check.

[quote="BugHunter"I've often threatened to buy one of the laser spectrometers for identifying steels. You see them at the scrap yards where they shoot the scrap you bring in and determine what metal it is, then price accordingly. They also use it to tell if you've brought in mixed-metal, or if the bins of stuff you brought were actually one alloy.

They cost about 2 grand, but when you have a lot of unidentified steel laying around like I have, it could easily pay for itself. My steel rack has 1000s of pounds of steels that were here before I purchased the business, many with the paint cut off the ends telling what it was, and thus not knowing what it is, it's basically useless to me. One of these days I want to buy one and won't have these issues any more. Might also be nice for purchasing steels where I'm convinced the steel company is screwing me selling something that isn't what they say it is. If you ever hear some stories from people who worked at the places, you start to see just how underhanded they are. For instance, things like 2 different SKUs for parts, one for the real stuff, and one for the fake stuff that's sold to people who don't know any better and don't check.[/quote]

For 2k it would be very tempting if I had a lot of unknown steel or a source I expect to contain other alloys, although it would defeat the purpose I go scrap diving for in the first place, to save money. I have some grader blade pieces laying around that I've considered trying to make tooling with and I haven't because I have no idea what it even is beyond hardenable.

Is there a place where one could be rented? Even if you had to leave a 2k deposit, it would he worth a hundred or so rental for a day, to use on your stock, to ID and label .

One of the local pipe suppliers has one here. They check imported fittings for lead content.

VA-Sawyer wrote:Is there a place where one could be rented? Even if you had to leave a 2k deposit, it would he worth a hundred or so rental for a day, to use on your stock, to ID and label .

I hadn't thought of that. I'll have to look into it.

Poland308 wrote:One of the local pipe suppliers has one here. They check imported fittings for lead content.

The local scrap yards have them here. I get to see them in operation every time I take scrap.

I think it's probably rare to find 400 series in bar stock. Mostly found in sheet for pots, pans and appliances. Doesn't matter anyway as it welds very well with 308/316 fillers.

Coldman wrote:I think it's probably rare to find 400 series in bar stock. Mostly found in sheet for pots, pans and appliances. Doesn't matter anyway as it welds very well with 308/316 fillers.

It’s very common in round stock though. Used quite regularly in firearm barrels.

Anyone here use a jazzy 10 cup? I have one in the cart right now doing the standard back and forth I've done like a dozen times before. Does it ever feel any more in the way than a ceramic 8 cup?

sbaker56 wrote:Anyone here use a jazzy 10 cup? I have one in the cart right now doing the standard back and forth I've done like a dozen times before. Does it ever feel any more in the way than a ceramic 8 cup?

I have one and a #12 Fupa. I’ve been pleased with both for flat, fillet or butt welds. I tend to still revert to an 8 for tubing, but have found occasions when the 12 worked best.