Repairing iron castings

Does anyone here have experience of repairing cracked iron castings?, I'm
renovating a Lister D generating set and the rear bearing support of the
alternator is cracked, but still in one piece. It's quite a delicate casting
and the crack has sprung apart but can be pressed back together with finger
pressure. It won't be seen as it's under a spun cover so cosmetics aren't
that important, but holding the rear bearing and the brushes is!. Before I
start visiting the local engineering specialists I would be grateful of any
advice.
Greg
Reply to
Greg
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You will need a welder who's qualified to section 2, part 3, sub section D of the MISTUFO reg's
No one else will be qualified to do this repair. You will also need to fill in the 123 page booklet on Working with Welders, H&S City and Guilds. -- Regards,
John Stevenson Nottingham, England.
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Reply to
John Stevenson
could you not try metal stiching, never done it myself but I have seen quite a repairs done using this method. Mike Cole
Reply to
Mike
If welding is the best approach to the repair I will be happy to employ a skilled and qualified welder because I respect the skills people have taken the time and effort to learn, unlike some people here who dismiss them, presumably because they have neither.
Greg
Reply to
Greg
In that case send it up but you still have to fill the form in. I spent 42 years to get to this point, is that enough time end effort for you ?
-- Regards,
John Stevenson Nottingham, England.
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Reply to
John Stevenson
Yes I've heard of such techniques but have no experience of them, cosmetically it would be fine as it's hidden. Greg
Reply to
Greg
Metal stitching requires a fair amount of metal around the crack to be successful. It sounds like this part is rather small and fragile so not suitable. The smallest stitches I have seen are about 1/2" long and need to span the break. -- Regards,
John Stevenson Nottingham, England.
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Reply to
John Stevenson
Greg,
Is it an inline Bruston set or is the Alternator along side the D, the reason I ask is that I have a Bruston set waiting to restore.. You could ask if anybody has a spare on uk.rec.engines.stationary. Have you tried bridgeing the crack by making plates and bolting it together.
Martin P
Greg wrote:
Reply to
Campingstoveman
No it's a side by side, but it's an original alternator and an original bed plate which I've not seen at a rally for many years. When I bought it I realised it needed a new pulley on the alternator and a control box fabricating, but didn't know about the broken casting.
I'll try the group you suggest, but no I haven't dared to try anything yet as I probably only have one chance.
Greg
Reply to
Greg
Since you said that the crack has sprung a bit, I would suspect that some heat treatment will be in order as well as the welding. It's probably going to be something along the lines of:-
V groove the crack, 1 hour at 750 C with the crack clamped closed followed by hold at 350 C whilst welding with High nickel rod, peening the weld between layers and slow cooling from there.
Up to you whether you do it yourself or get someone else to do it. It will need machining after the welding, but it should be possible to get it so that the repair is pretty unnoticeable even in the unpainted areas.
Note.. This isn't from experience since I've only repaired broken teeth on cast iron gears so far, it's from the reading that I've done prior to a little casting repair job that I've got in the works (belt cover for a Meddings Pacera drill)
Mark Rand RTFM
Reply to
Mark Rand
Bona!
Regards,
Reply to
Stephen Howard
original bed
anything yet
Meddings
... mmm ... I would investigate bronze welding with siffbronze. Very adequate strength with much lower temperature and less chance of further cracking. Don't forget to drill a small hole just beyond the end of the visible crack to stop the crack propagating.
AWEM
Reply to
Andrew Mawson
In article , Greg writes
Have you thought about getting a new casting made from the original? Round here I've got a local tame casting place that'll do me a one-off for a very reasonable price (usually a tenner in the beer fund for each casting box) provided I'm not in a hurry (they bung it on the end of the next run they do).
Close the crack with chemical metal/wax, build the bearing mounting surface up with some chemical metal/wax to allow for machining of the casting, plug the mounting holes with chemical metal/wax and you're there, I'd say.
Reply to
Nigel Eaton
Powder welding would be the best method to repair a casting like yours. This is a microfusion process, and will cause far less problems than welding, as it imparts a lot less heat.
However not many people are equipped to do this, so TIG brazing would be my next choice, and failing that gas brazing. The part may require pre heat, but that would depend on where the crack is and the type of cast iron.
k
Reply to
Ken

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