Frost damage.... Lister Blackstone.

[NB Esk 323]

 

Posted just for interest, it's the repair of a cast iron Serck type heat exchanger, could apply to other engine types. 

This was in a very sorry state and probably only just above scrap.  It had been frozen and repaired several times, including being metal stitched.  Welding over this last repair was problematic, don't know what the "stitches " were made from but they didn't like weld metal.

Anyway, some images of the repair process, hope it's of interest.

 

 

[dmr 931]

Thats impressive, is that stick or TIG?  what part does the can of petrol play in this process?  is it just to make you concentrate extra hard

 

.................Dave

[NB Esk 323]

7 minutes ago, dmr said:

Thats impressive, is that stick or TIG?  what part does the can of petrol play in this process?  is it just to make you concentrate extra hard

 

.................Dave

 

Thanks, forgot to say it's stick 7018 rods (my favourite).  Turned the amps down as low as I dare, that's why the bead is a little crowned.  Other side not so neat, had to lay down a kind of pad, to cover those old stitches.

 

It was cold by the time I was by the petrol can, lol.....

 

 

Edited November 5, 2019 by NB Esk

[GRLMK38 36]

Can you explain what is happening in Pic 2 please?  I'm assuming you haven't been photo bombed by a summer BBQ......

[NB Esk 323]

11 minutes ago, GRLMK38 said:

Can you explain what is happening in Pic 2 please?  I'm assuming you haven't been photo bombed by a summer BBQ......

 

Cast iron is a difficult metal to weld and would be even more so if it wasn't pre heated.  The casting was placed back in the fire several times to ensure it remained hot.  The repairs took about six hours but more than half of that was waiting time, while the casting came back to temperature.

On completion the part was left in the fire to try to normalise the casting with the weld metal.  It was still warm to the touch the following day, so had given up it's heat gradually.  In short, if this process wasn't followed, the repair would be likely to crack.  Hope this is of interest.

 

 

 

 

[noddyboater 75]

I’ve got a knackered K2 cylinder with corrosion that bad that pieces are missing. Do you think by using pre-heating and cast electrodes or stainless mig that mild steel repair pieces could be grafted in, or would similar cast material have to be found? 

[NB Esk 323]

37 minutes ago, noddyboater said:

I’ve got a knackered K2 cylinder with corrosion that bad that pieces are missing. Do you think by using pre-heating and cast electrodes or stainless mig that mild steel repair pieces could be grafted in, or would similar cast material have to be found? 

 

It's only my opinion but I do believe small patches/pieces (of a different material) could be welded into cast iron to replace a missing bit.  Okay they're going to try to contract at different rates but that's what welding tries to do and it's why they have to cool over a long period.

 

If it's an important part, as yours sounds to be, I would try to do this on a scrap item (it's something I've never tried to do) to see what happens.

 

 

[noddyboater 75]

I’ll give it a go with the worst of a bad pair, not much to lose on that one. 

I’ve got some bits of large diameter pipe, about 10mm thick, could work nicely if it welds. 

If not it looks like a trip to Glasgow with a van full of used notes! 

[tree monkey 1703]

2 hours ago, NB Esk said:

 

Cast iron is a difficult metal to weld and would be even more so if it wasn't pre heated.  The casting was placed back in the fire several times to ensure it remained hot.  The repairs took about six hours but more than half of that was waiting time, while the casting came back to temperature.

On completion the part was left in the fire to try to normalise the casting with the weld metal.  It was still warm to the touch the following day, so had given up it's heat gradually.  In short, if this process wasn't followed, the repair would be likely to crack.  Hope this is of interest.

 

 

 

 

Fascinating, but wouldn't the weld material still expand/contract at a different rate to the cast during normal usage anyway?

[bizzard 1990]

9 minutes ago, tree monkey said:

Fascinating, but wouldn't the weld material still expand/contract at a different rate to the cast during normal usage anyway?

It should be ok the way John has done it.  Not dissimilar to the reason why we used to have ''run in'' vehicle engines gently. Not for just so the bearings and bores run in and mate together better but all the different sized and types of metal used with different rates of expansion and contraction need to be gradually normalize and to equalize them as best as possible by keep running the engine up to normal temp and then cooling right down. An engine ran in better and quicker by doing many short runs, heating up and then cooling right down than doing long continuous runs.

[NB Esk 323]

1 hour ago, tree monkey said:

Fascinating, but wouldn't the weld material still expand/contract at a different rate to the cast during normal usage anyway?

 

That's the battle when trying to weld cast iron.  It's often a fingers crossed moment.  When I initially fitted the parts together I had to tack the pieces together to ensure correct mating.  These tacks (later ground out) were made cold and I could hear the familiar tinkle as the cast started to pull.

As mentioned earlier it had previously been repaired by metal stitching, the only reason for this is no one was willing to try welding it.  Some interesting metal stitching videos on YouTube.

 

 

[GRLMK38 36]

4 hours ago, NB Esk said:

 

Cast iron is a difficult metal to weld and would be even more so if it wasn't pre heated.  The casting was placed back in the fire several times to ensure it remained hot.  The repairs took about six hours but more than half of that was waiting time, while the casting came back to temperature.

On completion the part was left in the fire to try to normalise the casting with the weld metal.  It was still warm to the touch the following day, so had given up it's heat gradually.  In short, if this process wasn't followed, the repair would be likely to crack.  Hope this is of interest.

 

 

 

 

Thanks @NB Esk - that makes sense.  I hadn't appreciated the need for pre-heating the whole thing rather than the norm of creating a local hotspot where the weld is taking place.  Every day's a school day....

Edited November 6, 2019 by GRLMK38

[BEngo 214]

3 hours ago, noddyboater said:

I’ll give it a go with the worst of a bad pair, not much to lose on that one. 

I’ve got some bits of large diameter pipe, about 10mm thick, could work nicely if it welds. 

If not it looks like a trip to Glasgow with a van full of used notes! 

Have a look at ghe thread on the Kelvin F4 rebuild by tom_ c, and maybe drop him a pm.  He has done some serious weld repair work to cylinders and may well be able to share some experience.

Slinden are also pretty good at welded cast iron repairs, but they will not be free!

⁹9

N

[NB Esk 323]

 

Short update on the heat exchanger, weld dressed to remove excess material, a coat of sealing paint and it looks to have made a useable service spare.

Thanks for the interest.

 

 

[john.k 18]

There was once a company called "Barimar Ltd" ,who specialized in welding broken cast iron cylinder blocks and heads....some of their repairs were incredible.Most old engine books have a pic of some of the repairs.....one point about using steel weld ,its not got the corrosion resistance of cast iron,so inhibitor must be used in the coolant.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[NB Esk 323]

43 minutes ago, john.k said:

its not got the corrosion resistance of cast iron,so inhibitor must be used in the coolant.

 

True but unable to use inhibitors in this case as the welded area is raw water.  I did "vee " out before welding though, so it has some thickness.

 

 

[hughc 23]

On 06/11/2019 at 14:14, BEngo said:

Have a look at ghe thread on the Kelvin F4 rebuild by tom_ c, and maybe drop him a pm.  He has done some serious weld repair work to cylinders and may well be able to share some experience.

Slinden are also pretty good at welded cast iron repairs, but they will not be free!

⁹9

N

The engine that is the subject of that thread is now running in Heyford. HughC

[Bee 1249]

If it all falls apart I have a heat exchanger of a similar size that could be useful, it won't be a direct fit but I think it would work. I'll post a photo later today.