Repairing a cast wacker plate base

[Bill Edwards]

It's basically what I said earlier, in post 5...

If it's cast steel, use a dissimilar rod. You've tried (and failed) with MIG, perhaps this was due to getting it too hot (which I doubt), perhaps it's because it's not the right kind of steel for ordinary filler - that's the issue with castings, you don't know what they contain. That's why a dissimilar rod is the best option as if it is weldable it will weld it.
I doubt if it's cast iron, but that's easily checked. It should be a fairly simple repair, albeit it needing special rods, and if it turns out to be iron a slow one.

 

[reb78]

If you're messing with a casting always get a proper agreement about when sh1t happens and don't do anything safety critical
Two rules before you do anything
Spark test it, unlikely to be cast iron I should have thought

I'm not to worried if it goes wrong. I've spoken to the owner and he said not to worry, but I'd still like to do it if possible.

 

[reb78]

It's basically what I said earlier, in post 5...

If it's cast steel, use a dissimilar rod. You've tried (and failed) with MIG, perhaps this was due to getting it too hot (which I doubt), perhaps it's because it's not the right kind of steel for ordinary filler - that's the issue with castings, you don't know what they contain. That's why a dissimilar rod is the best option as if it is weldable it will weld it.
I doubt if it's cast iron, but that's easily checked. It should be a fairly simple repair, albeit it needing special rods, and if it turns out to be iron a slow one.

Thanks. I'll get some dissimilar rods and give it a try.

 

[the snooper]

It's described as cast here:

http://www.bellegroup.com/?p=parts&as=61

Part no.1

I was refaring to cast iron though, my fault I wasn't clear

 

[Bill Edwards]

Thanks. I'll get some dissimilar rods and give it a try.

I would do a quick spark check first - I don't expect it will be iron as that seems an unsuitable material for such a job, but not knowing about wacker plates I'd hate for you to go buy the wrong rods - cast iron is about the only thing a dissimilar rod isn't good for!

 

[Richard.]

312 is a good electrode to weld difficult to weld materials. But it's a terrible consumable for cast iron so be sure you find out for certain what it is before welding.
Personally I'd tig it what ever it was. If it's a cast steel and proving difficult to weld 312 will sort it. If cast iron I have some Ni50 which I've sucsessfully repaired lots of cast iron with. Nickel iron filler rod.

 

[Kent]

Just watch those fumes mate they ain't good for you

 

[Screwdriver]

It's basically what I said earlier, in post 5...

If it's cast steel, use a dissimilar rod. You've tried (and failed) with MIG, perhaps this was due to getting it too hot (which I doubt), perhaps it's because it's not the right kind of steel for ordinary filler - that's the issue with castings, you don't know what they contain. That's why a dissimilar rod is the best option as if it is weldable it will weld it.
I doubt if it's cast iron, but that's easily checked. It should be a fairly simple repair, albeit it needing special rods, and if it turns out to be iron a slow one.

Yeah, must be a cast steel. I still think braze is the best option then it doesn't matter what the composition is and there will be no problem of HAZ embrittlement. It really isn't that difficult to get large castings up to temperature, you just need to make sure they don't cool down too quickly.

 

[Parm]

With some a dive from the forum, mainly Mr Snooper, I had a go at brazing cast iron last night. Heat it all up evenly to de stress it ( I used a propane torch) then I used oxy propane and flux to braze up my job, it worked a treat

 

[Bill Edwards]

Yeah, must be a cast steel. I still think braze is the best option then it doesn't matter what the composition is and there will be no problem of HAZ embrittlement. It really isn't that difficult to get large castings up to temperature, you just need to make sure they don't cool down too quickly.

Braze certainly does have its uses, but I wouldn't agree that it's easy to cool them properly - I wouldn't be happy doing cast iron unless it was an oven, packing in sand may work but I'd want better on a large piece.
Even heating with a torch it can be easy to get it wrong if a piece isn't small.

I can't see that it won't be weldable, just that it doesn't seem happy with ordinary filler hence it should be done with dissimilar - unless it's iron of course.

 

[MattF]

Cast steel mailable or cast iron?

Isn't that a bit of a contradiction? Malleable is a form of heat treated cast iron. I'd be guessing it's some form of steel. Cast iron would be too brittle, malleable iron would be too soft, I'd guess.

 

[Richard.]

No need to braze cast steel imo. Bit of warmth through it,dish out the crack and fill it up with 312.
They really are excellent consumable for those jobs when all else fails. Pricey mind compared to other SS grades. I always keep a handful on the shelf.

 

[MattF]

Braze certainly does have its uses, but I wouldn't agree that it's easy to cool them properly - I wouldn't be happy doing cast iron unless it was an oven, packing in sand may work but I'd want better on a large piece.

Packing the piece in ash, in a preheated metal box on a fire and letting the fire burn out would be another usable option? Ash retains heat for a shockingly long length of time, and letting the fire burn down naturally would give a very steady cooling.

Wouldn't braze be a bit poor for that type of repair anyway though? Brass/Bronze seems a bit of a soft/weak filler/repair material for something which would be seeing that type of abuse & stress in use.

 

[Kent]

Used to be a slow steady heat up and cool down under an asbestos!!! Blanket

 

[Kent]

Isn't that a bit of a contradiction? Malleable is a form of heat treated cast iron. I'd be guessing it's some form of steel. Cast iron would be too brittle, malleable iron would be too soft, I'd guess.

Terminology and poor punctuation sorry. Mailable is an easy enough weld. Cast steel likewise ( some forms very) cast iron? Not do but I recon a wicket plate out of cast iron

might be expected to last less time than the sales of goods act
Cast iron contains unknowns and often enough fractures more while it's being
welded

 

[Screwdriver]

Packing the piece in ash, in a preheated metal box on a fire and letting the fire burn out would be another usable option? Ash retains heat for a shockingly long length of time, and letting the fire burn down naturally would give a very steady cooling.

Wouldn't braze be a bit poor for that type of repair anyway though? Brass/Bronze seems a bit of a soft/weak filler/repair material for something which would be seeing that type of abuse & stress in use.

I would have thought braze would be perfect. It's not as if the item is actually broken or at least it hasn't completely failed. It appears the crack has been there some time. Braze is more like a flexible glue in this application. It will resist fracturing which would be the big problem with a hard weld. I don't know enough about exotic welding rods, so I assume those expensive rods referred to do the same thing by producing a less brittle weld.

Ultimately though, an additional reinforcing plate underneath is the most robust solution.

S.

 

[Richard.]

those expensive rods referred to do the same thing by producing a less brittle weld.

Well the 312 is very high Cr and a higher ferrite content offering great dissimilar properties and a high strength weld. It's not particularly ductile I don't think but it's good for welding the "unknown" or hard to weld metals usually with no cracking problems where other fillers have failed. 309 is similar but not as high on the alloys or ferrite content, not as high strength either. More for mild to stainless and other stainless too . No stainless filler is gonna weld cast iron mind. Which is why I suggested nickel. It's a very crack resistant material at a range of temps. Al/hotrodder are the top dogs on the in depth bits but I keep a small stock of 312's and Ni50's for those job types and they have always gone well. Don't do much oxy brazing. Done a fair bit with Tig.