Aluminium casting repair

v10mike · Mar 27, 2011

I have been suffering a steady loss of coolant from my 1934 Alvis, and tracked it down to the lower radiator hose connecting pipe. When I removed it, I was amazed it held any coolant at all -it looks like the car has been run at some time without inhibitor, and the aluminium pipe has suffered catastrophic electrolytic corrosion. The flange has been eaten away at one end, and the hose attachment at the other.

The rest of the pipe seems to be in fair condition, so can anybody suggest someone who is skilled with a TIG welder, preferably near Cambridge, who could have a go at repairing it for me?

pedrobedro · Mar 27, 2011

I would look for a smelter who can re-manufacture the part for you rather than a welder to repair it. There looks a lot of impurities in that and cleaning it up may not leave a lot of it to work with.

outofthefire · Mar 27, 2011

Does it have to be ally, by the look of the corrosion wouldn't stainless be better

julieanncharters · Mar 27, 2011

looks like a typical bit of cast ali i get asked to repair.
usually marine heat exchangers.
tend to look like this when no anodes fitted to the boat.
die grinder to clean off the worse then boil out the crap with tig passes and regrind till no more poo comes to the surface before attempting to add any filler rod.
get same problem with ali combi boiler heatexchangers were the pipes connect to the heating .
should be do-able from the photo but would take a bit of work
as allready quoted ,might be cheaper to get a new one fabricated out of stainless

aametalmaster · Mar 28, 2011

I 3rd the stainless steel new part route...Bob

andy pen · Mar 28, 2011

Definitly go for a stainless one,had a similar problem on an old mazda so I miged up a stainless one, as I have never tig'ed, worked a treat, and looks loverly on the engine.Unless you really need it to be as original remake in stainless it will never corrode again.

v10mike · Apr 2, 2011

Well, before plunging into fabricating a new one, I thought I'd have a go at repair. I've been meaning to try out one of the "wonder" aluminium brazing products, so this seemed a good time to see if they lived up to the hype. I used HTS-2000, which allegedly requires less surface activation to form a good bond.

I used the Dremel to grind back to clean (ish) metal, and got stuck in. Not easy; although there is a 200C difference between brazing temperature and melting the aluminium it is very east to overheat and I lost most of the outlet end on the floor at the first go! So I turned up a new end on the lathe, tinned both sides thoroughly, and its turned out pretty well -not perfect, but since the cooling system is unpressurized I think it will work. At the flange end I used a bolt and penny washer to make up a mold, and filled in both ears.

The centre section seems reasonably solid.

It certainly looks better than the "before" picture!

James325 · Apr 2, 2011

I think you should be pleased with that! It looks good.

pedrobedro · Apr 2, 2011

What more could you want? It looks perfect and functional. If you'd said you'd bought a new one I'd have believed you.

gordon stephenson · Apr 2, 2011

With time and patience that has turned out great, I'v used Techno weld etc several times and in the right situation can can the best method available.

Wozzaaah · Apr 2, 2011

Cracking job Mike, well done! :clapping:

Drains · Apr 2, 2011

That's superb. I'd not have believed it without seeing the pic. You live and learn!

awemawson · Apr 2, 2011

While it's off the car I'd want to tackle those pinhole corrosion craters in the 'squashed' bit

chimpface · Apr 2, 2011

That looks like a really good job you've done . Just a suggestion , but maybe it would be a good idea to take it to a foundry now its back to the correct shape etc and get a quote to make another or batch for others as well in case the repairs dont last .

Shox Dr · Apr 2, 2011

Good work, just goes to show.

brightspark · Apr 2, 2011

chimpface said:
That looks like a really good job you've done . Just a suggestion , but maybe it would be a good idea to take it to a foundry now its back to the correct shape etc and get a quote to make another or batch for others as well in case the repairs dont last .

if the original was used as a pattern metal shrinks on cooling . so the cast part would be smaller than the original. you would also have to have a sand core made to suit the pipe . wooden patterns are made slightly larger to allow for shrinkage. it would cost a fortune to produce as a 1 off . nice job made of original

chimpface · Apr 2, 2011

brightspark said:
if the original was used as a pattern metal shrinks on cooling . so the cast part would be smaller than the original. you would also have to have a sand core made to suit the pipe . wooden patterns are made slightly larger to allow for shrinkage. it would cost a fortune to produce as a 1 off . nice job made of original

Yes , but its where they would get the original dimensions from isnt it . As for cost you cant really say that would cost a fortune as they might have a cheaper method of doing it that you are unaware of .
Also , metal shrinks on cooling , well i never , who ever would have thought of that ! :rolleyes:

It was only a sensible suggestion to help the chap .

Aluminium casting repair

v10mike

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pedrobedro

Man at Matalan

outofthefire

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julieanncharters

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aametalmaster

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andy pen

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v10mike

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James325

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pedrobedro

Man at Matalan

gordon stephenson

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Wozzaaah

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Drains

Yeah, nah.

awemawson

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chimpface

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Shox Dr

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brightspark

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chimpface

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