turbo exhaust manifold welding cast iron

[flutch]

Yep, the key with cast is to make sure it's clean including removing any rust and carbon then preheat over 150deg then just weld on a patch. Stainless steel has similar expansion/shrinkage rates to cast steel so it's common to use stainless electrodes on cast.

Chronos

THIS, welding non like metals is always finniky with heat, you really do need to make sure that whatever wire/rod you use is not going to expand or contract at vastly different rates than the parent metal. remembering that exhaust manifolds on diesels can get gasses in excess of 700 degrees when under heavy load. this makes a big difference, also heating up/cooling down, creek crossings, and driving into hail/rain and all that crud can have an effect too and over time, do as chronos says and will be your best bet, that or have a new manifold fabricated that doesn't have that hole/crack on it.

[flutch]

Chronos ol mate,,,, there is a big difference btween cast iron and cast steel.

As for general repair work/welding of cast iron,, every piece of cast iron is different to the last or the next.
As we have no control whatsoever over the mixes that are poured, therefore it can require experimentation to find which particular electrode ( and I refer to the MMA process ) to use, and there are a myriad of rods/brands to choose from.

When one in particular gives best result, then you need to work out whether to pre heat, and keep a constant temp throughout the process,,,,, or,,,,,,, go the cold weld method which involves keeping the entire repair area to a minimum temp.
Usually when going the cold method you must be able to place a bare hand on the area without being burnt.
Soon as it gets above that range, you must keep the job in a draft free area, and walk away till the temp drops to an acceptable level.

Either the hot or cold method is usually done best in short/heavy runs with peening of the deposit in between.

If going the hot method, post heating evenly is just as important as pre heating.
Also after post heating, bury the job in a container/bag of lime powder for at least 6 - 12 hours.

Your choice of electrode will also be governed by whether or not you need the repaired area to be machined or drilled afterwards.

The above is only a very brief few of many many rules and techniques that can or will need to be applied.

Also, if grinding for preparation, do NOT grind to a sharp edge anywhere, always keep smooth rounded edges.

After grinding,,, the entire surface that has been ground MUST be filed clean with a coarse file to get rid of the precipitated carbide deposits caused by grinding.
If you weld over carbide surfaces, they will create incredibly hard spots and also induce cracks.

Having done cast iron repairs for many years, I can almost guarantee that any business that does this sort of work would never give a quote on cast iron repairs sight unseen,,,,, let alone give a guarantee on the repair.

Hope some of the above is helpful,,,,,, (PM coming your way)

+1000 my advice is get a new manifold fabricated haha...

[Die Judicii]

Pomemax,,,,

I made mention early in this thread about finding some-one with the "Eutectic Castolin Powder Spray welding torch.
This method (although expensive) is tried and true and is the nearest thing yet to getting a perfect weld and reliable repair on cast iron manifolds etc.

Take it from a couple of old blokes that have both had extensive experience in the maintenance welding field,, and still have fingers in the pie.
I myself used it day after day for years when full time employed in the industry.

The practice of welding cast iron with stainless based electrodes or with a MIG is a process that may appear successful, and can suffice when proper
methods aren't available,,,, but are usually fraught with inherent problems, the most common being extremely hard and brittle deposits and carbide precipitation which will sooner or later cause failure.

[pomemax]

As you say Die Judicii
When proper methods aren,t available , most guys just want it fixed tho and I bet after the 4 years since this post was first posted hes found a solution.
Eutectic Castolin Powder Spray welding torch I have used it quite a bit so I know what your saying think I still have a set up in the works shop not had a calling to use it in the last few years .
Extensive experience in the maintenance, welding field tell me more myself I am a fitter machinist / welder whos worked for the last 47 years in this feild I may know you

[Member-Deleted]

Ahh there you go 4yrs , see that's a good forum, you can learn a lot from other people over a long period of time .

[Die Judicii]

Extensive experience in the maintenance, welding field tell me more myself I am a fitter machinist / welder whos worked for the last 47 years in this feild I may know you

Unless you've been doing new boiler installations and or boiler repairs,,, or worked in Adelaide on the Collins Class submarines,,,
I 'd say our paths have never crossed in this particular field.

[pomemax]

boiler installations and or boiler repairs in Sydney for a few years the last of the grey funnel line ships I worked on was fitting a prop to an aircraft carrier in sydney many many years ago .

[John]

Cast can be welded with a stick welder and the correct rods for the job available at any industry supply’s store BOC gas weld all weld to name a few.
It can be a little hard but with the preparation done right not that hard

First clean the area really well I’d use a dremal to get in to the crack open it up a little to take the weld.
Now your gunna need to send the misses out for the day bit hard at the moment

Turn on the oven set it to 100 degrees put the manifold in the oven from cold and let it slowly heat up to the hundred mark it will take a few hours as cast tends to heat unevenly

Once pre heated weld up the crack be for it cools out don’t turn the oven off

Put it back in the hot oven leave for an hour and a half than turn down 20 degrees for an hour and keep turning down 20 degrees every hour until your at the lowest temp setting

Turn the oven off and leave don’t open it let it slowly cool to room temperature generally takes a few hours

And fingers crossed job done

But it’s not the 100% way of doing it but as good as it get at home and should do the job for
Ps I generally pre heat the welding rods at the same time in the oven

If it want fit in the oven preheat with a flame weld and cover with lime to control cooling if your in a bind sometimes it does work I’ve had to do that with larger things made from cast.
All the best hope it works out for you that’s how I’d attack it coming from my experience in the metals trade as a boilermaker