Welding stainless tips?

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GHA

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Lots to do, steel boat needing big deck refit so everything bolted down is getting replaced with stainless plates & studs welded to the deck then pushpit etc etc attached to that. Going not too bad so far considering I'm pretty much making it up as I go along based on other people do it so can't be that hard :)

So those who have done it - rods - google comes back with 309L being a good choice but 316L OK. 309 are proving to be difficult to get the hold of down Portugal so looks like it's 316 for now. Then grind clean and paint up over the weld with lots coats epoxy. For the non structural stuff anyway.

So any doom and gloom experiences or any tips in general? Not had too much trouble yet with distortion just doing tacks both sides of a hatch frame which has come out almost flat - but any general tips, links, anything helpful much appreciated.

This is a (intentionally) rough quick test of 316L rod joining some mild to 304 then left in the sun doused in sea water several times a day for a few days -

RQH8TxA.png
 
A roll of stainless steel mig wire is expensive. I've found that the power setting written on the pack of rods was too low for good penetration. But I'm not greatest of welders (but I just blame my eyesight)
 
Bouba said:
A roll of stainless steel mig wire is expensive. I've found that the power setting written on the pack of rods was too low for good penetration. But I'm not greatest of welders (but I just blame my eyesight)
Click to expand...
Stick that I'm using ain't cheap either. DC clamp meter round the neg lead shows what juice is actually getting to the arc, well below the inverter setting with the not really 240v down here .
 
I have a couple of DIY welders, a stick and a MIG that I use occasionally. With neither would i call myself proficient, but my success rate was considerably improved by replacing the as-supplied glass eye-shades with a slightly lighter hue. The suppliers seem to package their machines with the darkest shade, more suited to rather more powerful trade models, to err on the safe side I suppose, leaving the DIY'er literally groping in the dark.
Even better was an auto-darkening mask, but mine failed after a few years, and my present usage doesn't justify the cost.
 
earlybird said:
Even better was an auto-darkening mask, but mine failed after a few years, and my present usage doesn't justify the cost.
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Got one of those, hard to imagine welding without :cool:

Another successful trick has been to draw up hole centres etc for marking out in 1:1 scale in cad then use masking tape to stick the printout onto the piece. Much quicker and more accurate than I can do with micrometer and rule. Plus easy to check nut clearances and the like.

So just welded some more studding into plate, hole then tapped then weld one side. Very satisfying when the other plate slides one with ease :) Quick coffee and back on it.

Can't help thinking I'm missing a load of little handy tricks which will take ages to discover...
 
GHA said:
Got one of those, hard to imagine welding without :cool:

Another successful trick has been to draw up hole centres etc for marking out in 1:1 scale in cad then use masking tape to stick the printout onto the piece. Much quicker and more accurate than I can do with micrometer and rule. Plus easy to check nut clearances and the like.

So just welded some more studding into plate, hole then tapped then weld one side. Very satisfying when the other plate slides one with ease :) Quick coffee and back on it.

Can't help thinking I'm missing a load of little handy tricks which will take ages to discover...
Click to expand...

I don't know where to start. I could say you’re doing a fine job if I was feeling particularly British.
If you never welded, you’re not doing too bad for a first try. The distance from the rod to the weld needs to be constant that is why that picture is showing holes. As the rod melts you need to keep adjusting for that. To weld a stud in place countersink the hole to allow the weld pool to form at more depth. If a nut above surface then do a very short weld per side.
I don’t really understand what you are trying to do, so it’s hard to give you some tips.
 
GHA said:
Got one of those, hard to imagine welding without :cool:

Another successful trick has been to draw up hole centres etc for marking out in 1:1 scale in cad then use masking tape to stick the printout onto the piece. Much quicker and more accurate than I can do with micrometer and rule. Plus easy to check nut clearances and the like.

So just welded some more studding into plate, hole then tapped then weld one side. Very satisfying when the other plate slides one with ease :) Quick coffee and back on it.

Can't help thinking I'm missing a load of little handy tricks which will take ages to discover...
Click to expand...

my auto helmet has adjustable darkness which helps a lot.

If welding a fillet move the rod from side to side so the arc moves from the one piece of metal to the joining one. I find it helps to stop the on side of the weld looking like yours with holes in the weld and also helps the slag to stay on top and not get trapped.

Move from thicker to thinner material and back to the thicker keeping the time on the thinner a little as possible to avoid burning through too much.

If you do burn a hole, work around the hole with short tacks to build up the edged and always chip slag from the centre of the hole frequently.
 
do not spare the rod, it is a false economy, get it in close and keep it there, working the pool. Mild needs a bit more work if you are welding it to similar thickness stainless so favour the mild and "catch" the stainless with the pool slightly less. A few tests will show you visibly what works. The worst failure of "part time" welders is not being analytical. try a couple of welds, note what you were doing and the results, then adjust settings, your feed with the rod etc. It will click with practice. Dont panic if you get it wrong, there is always the grinder and have another go.
 
I welded all my stainless bollards to the steel deck some thirty years ago with a standard arc welder and they haven't fallen off yet. Can't remember what the rods were but I seem to remember they were green and the slag "pinged" off as the welds cooled.
 
solent clown said:
do not spare the rod, it is a false economy, get it in close and keep it there, working the pool. Mild needs a bit more work if you are welding it to similar thickness stainless so favour the mild and "catch" the stainless with the pool slightly less. A few tests will show you visibly what works. The worst failure of "part time" welders is not being analytical. try a couple of welds, note what you were doing and the results, then adjust settings, your feed with the rod etc. It will click with practice. Dont panic if you get it wrong, there is always the grinder and have another go.
Click to expand...

:cool: :cool:

Ta V much, fell that might actually finish one day reading that. Be a few days before tentative baby steps of stainless to mild steel deck. So far so good, pain doing a refit and living aboard, I know the camera is in here somewhere.... :)
The plates which will get welded to the deck for the pushpit are done, tapered the studding & seem OK welds with no cracks.
 
PCUK said:
I welded all my stainless bollards to the steel deck some thirty years ago with a standard arc welder and they haven't fallen off yet. Can't remember what the rods were but I seem to remember they were green and the slag "pinged" off as the welds cooled.
Click to expand...
I’ve alway believed that if the slag falls off on its own or with very little help then you’ve done a good job.
Don’t forget to use grinding discs specifically for stainless
 
Rogershaw said:
my auto helmet has adjustable darkness which helps a lot.

If welding a fillet move the rod from side to side so the arc moves from the one piece of metal to the joining one. I find it helps to stop the on side of the weld looking like yours with holes in the weld and also helps the slag to stay on top and not get trapped.

Move from thicker to thinner material and back to the thicker keeping the time on the thinner a little as possible to avoid burning through too much.

If you do burn a hole, work around the hole with short tacks to build up the edged and always chip slag from the centre of the hole frequently.
Click to expand...

Thanks, have your photo site bookmarked, shamelessly pinching ideas from there :)
 
There is a Stainless supplier up on the road from Loule to Tavira, a bit after the crossing with the Faro San Braz road, good prices and stock.
Also Gonzalves & Nunes in Portimao have wire and rods. Must be someone in Faro, but wasn't my backyard.
 
DownWest said:
There is a Stainless supplier up on the road from Loule to Tavira, a bit after the crossing with the Faro San Braz road, good prices and stock.
Also Gonzalves & Nunes in Portimao have wire and rods. Must be someone in Faro, but wasn't my backyard.
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Rods available, but 309L proving tricky to source. Inox place out by the stadium (maybe same place you mentioned) might have some but long way on a battered fold up bike :)
Not even sure 316L won't be just fine anyway.. though need to research structural strength for a couple of stainless angle brackets to go on for a Jordan series drogue, might be fine with so much weld in sheer, should have a look though . Ta
 
On that thickness of plate ,stick welding is the easiest process, for Stainless to Mild steel, you want 309, 3.2mm run around 100 amps DC.
Just grind out all off the bad weld and prepare the surface. Clamp the return reasonably close to the weld area, and get a decent mask, a passive one is fine, perhaps shade 9EW, if you are welding outside in bright sunlight,
Cheap auto helmets are optically poor and can give you a distorted view.
Here is a link to my website, knowledge base,well worth a read.
http://www.rapidwelding.com/dynamic/KnowledgeCentre.aspx?c=STICKDOCS
All the best Roy
 
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When cleaning up the weld area, use a NEW flap disc and only use a grinder disc for stainless or else the dust of non stainless gets embedded in the stainless
 
GHA said:
:cool: :cool:

Ta V much, fell that might actually finish one day reading that. Be a few days before tentative baby steps of stainless to mild steel deck. So far so good, pain doing a refit and living aboard, I know the camera is in here somewhere.... :)
The plates which will get welded to the deck for the pushpit are done, tapered the studding & seem OK welds with no cracks.
Click to expand...

And whilst you are at it take plenty of pix and write it up for PBO, nice beer tokens when printed!
Stu
 
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