Winch repair (Cast).

[skotl]

I'm lost with that Chris. Where did Alu get mentioned.

Yet another non-sequitur from Chris, where he parachutes in with an answer/conclusion/agenda/opinion that none of us were looking for

 

[F.J.]

you can get small repair packs. I know Al knows his onions on consumables but MMA just wasn't allowed by my old boss and we took in a lot of broken castings, turned a good few away but then I have posted about gas welding cast before.

How does gas welding fair up against mma or tig? If you dont mind I'll have a dig through your posts for a read

 

[F.J.]

I'd still advocate fabricating a repair piece which you attach to the winch body after tidying up the break. Bolt and/or weld that on and have bolt holes where the original flange was. You're lucky to have both pieces relatively intact so dimensioning the repair should be easy peasy. The bonus is you can make it stronger than the original.

S.

My customer has said he is going to make some clamps to further strengthen the winch but having only seen the thing in the pocs i posted its hard to see the finished job being long lasting

 

[F.J.]

Sticks have a special graphite based coating that runs on very low amps. This restricts the heat but maintains the penetration whilst keeping the casting cool. You need to either keep it cool or very hot (over 538oC), in between causes more problems.
This is why little short runs and peening are recommended

So if i used mma would i not need pre/post heat?

 

[Chris Stevens]

Yet another non-sequitur from Chris, where he parachutes in with an answer/conclusion/agenda/opinion that none of us were looking for

The part pictured by the OP looked like aluminum to me. If not its white cast iron, which I dont think is weldable. Surprising that no one pointed that out?

 

[Kent]

How does gas welding fair up against mma or tig? If you dont mind I'll have a dig through your posts for a read

Please remember this was in the 80s
Had a few sleeps from then lol!
The process was a long preheat with propane under an asbestos blanket ( yep you read that right). The cast rods were actually square and looked just like little rods of cast though they likely contained all sorts of clever stuff.
Again the casting was brought back down slowly under the blanket with a slow heat
All this was generally done by the 80 yrs plus guy who was trained by his dad the firm obviously existed before any electric welding but the guy was bang up to date using the then very latest tig gear on other things like gearbox casings etc
At the time and likely now it wasn't the stuff that paid I was mainly doing stainless and general fabrication
We did have an old milling machine that was bought for scrap with the head casting totally broken in two. Jim fixed it together and it ran true enough to skim many ali cylinder heads post tig welding repairs
Welding repairs with mma were very poorly thought of ( it may have been the rods then available or known)
I never saw a repair come back failed but there were enough turned away

 

[Kent]

They last indefinitely......as I said before the repaired casting can be stronger than the original
Really its down to costs.

Yes I can get my head around that and the strength and stress with cracks it's just the full two parts
Not disagreeing just it don't sit right in my own mind and it's something I am aware of but never done

 

[winchman]

The part pictured by the OP looked like aluminum to me. If not its white cast iron, which I dont think is weldable. Surprising that no one pointed that out?

It does look like ally, most smaller winches are ally.
Personally whilst I know it can be repaired from a liability angle I would only fix it with a new undamaged part.
Whilst we can only see part of the winch I am guessing the motor is doing the breaking too so that casting has a good load on it, but I suspect the winch has been hit or dropped to cause the damage, I recognise it but cant for the life of me remember LOL

 

[Richard.]

So if i used mma would i not need pre/post heat?

Yes. If your welding cast iron you need to do some homework on how to do it properly. You don't want to pull bits of info out of this forum incase you select the incorrect bits.
Pre heat, hold heat, weld(NiFe), peen, weld, peen, check heat, weld, peen. Rap up tight, check heat and bring it down as slow as you can.

 

[Maker]

I've got a box of cast iron MMA rods, don't know if they'd be any use but I'd be happy to send you some if they are;

They're 3.2mm (Assuming you measure the metal, not the flux).
Any use?

 

[Bill Edwards]

So if i used mma would i not need pre/post heat?

Sorry to disagree with Richard, but you do not need preheat.
You do it cold with MMA, weld a small bit at a time (an inch at the most) all the time keeping it cool - you must be able to keep your hand on it comfortably. While it cools peen the weld (tap with a chipping hammer) to expand the filler metal. Then repeat until it is all done.

The thing with case is to keep the whole piece at an even temperature. Any heating or cooling must be done very gradually so it soaks through the entire piece. Easiest is to weld it cold slowly with MMA. And you can buy the rods in small packs, my local welding supplier sells them individually.

 

[Bill Edwards]

I've got a box of cast iron MMA rods, don't know if they'd be any use but I'd be happy to send you some if they are;
View attachment 77396
They're 3.2mm (Assuming you measure the metal, not the flux).
Any use?

They look to be what's needed.
Maker, you don't need that entire box, I could help you out...

 

[Richard.]

Sorry to disagree with Richard, but you do not need preheat.
You do it cold with MMA, weld a small bit at a time (an inch at the most) all the time keeping it cool - you must be able to keep your hand on it comfortably. While it cools peen the weld (tap with a chipping hammer) to expand the filler metal. Then repeat until it is all done.

The thing with case is to keep the whole piece at an even temperature. Any heating or cooling must be done very gradually so it soaks through the entire piece. Easiest is to weld it cold slowly with MMA. And you can buy the rods in small packs, my local welding supplier sells them individually.

Don't be sorry, disagreeing is what it's all about and makes for interesting reading. I don't think welding it cold is the way to go at all. It needs to be an even temp yes but welding it cold doesn't achieve that as you've got localised heat followed by rapid cooling. Bad combination IMO for cast iron. Also there is little point preening a weld that has cooled down. The preheat keeps the welds hotter for longer making the peen/stress relieve far more useful.

 

[Richard.]

I've got a box of cast iron MMA rods, don't know if they'd be any use but I'd be happy to send you some if they are;
View attachment 77396
They're 3.2mm (Assuming you measure the metal, not the flux).
Any use?

3.2 is the core diameter.

 

[Bill Edwards]

Don't be sorry, disagreeing is what it's all about and makes for interesting reading. I don't think welding it cold is the way to go at all. It needs to be an even temp yes but welding it cold doesn't achieve that as you've got localised heat followed by rapid cooling. Bad combination IMO for cast iron. Also there is little point preening a weld that has cooled down. The preheat keeps the welds hotter for longer making the peen/stress relieve far more useful.

But you only do very, very short welds and although you'd think the heat to be very localized it still doesn't get hot. As I say, my rule is to be able to keep it cool enough to keep your hand on and it works, peening it while it cools back to cold does the trick.

I've been taught this way of doing it by an old boy and have never had a failure from it, doing anything from exhaust manifolds to engine blocks.

 

[Richard.]

I'm not saying it's wrong as I've also been told this whole weld it cool or hot thing works so I'm sure there is a proven method I just don't like the thought of striking up on it cold. IMO I'd always weld it hot. Logically (to my mind) it seems a safer bet.

 

[TechnicAl]

I've got a box of cast iron MMA rods, don't know if they'd be any use but I'd be happy to send you some if they are;
View attachment 77396
They're 3.2mm (Assuming you measure the metal, not the flux).
Any use?

Thats very generous.........they are expensive

Eutectic are famous for giving loads of info without actually saying what it is.........Id guess they are Nickel Iron

https://www.castolin.com/en-US/product/eutectrode-244

 

[TechnicAl]

I'm not saying it's wrong as I've also been told this whole weld it cool or hot thing works so I'm sure there is a proven method I just don't like the thought of striking up on it cold. IMO I'd always weld it hot. Logically (to my mind) it seems a safer bet.

The problem with cast iron is that it can change phase which involves a volume change. It happens on the more popular grades at 538oC. The volume change can crack it especially if there are big section differences. So its best to either heat it above 538 or keep it below (ie no preheat). A bit of preheat takes it nearer the 538.
On the other hand preheat will burn off any contaminants

Best way is to burn it off, let it cool and then keep it cool with no preheat and little short runs allowing to cool in between.

 

[Richard.]

Fair play Al/Bill. It doesn't seem right to me to do it cold but happily stand corrected.

 

[TechnicAl]

The part pictured by the OP looked like aluminum to me. If not its white cast iron, which I dont think is weldable. Surprising that no one pointed that out?

Must admit that I cant really tell from the pictures but doesnt the OP think its Cast Iron. If youre there the weight will tell you. I doubt if its white iron though as you need chills to get white and the shape doesnt lend itself to that. White is usually only part of a casting ie the bores in an engine block. If it is white it is unweldable.