Author Topic: Crankcase repairs  (Read 225 times)

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DAVIDMORGAN

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Crankcase repairs
« on: 24 March, 2020, 16:36:12 »
Anybody been successful in carrying out aluminium welding. I obtained some rod, which apparently when you heat the base metal to 750 degs, will flow. I have tried using an old fashion blowlamp but cut not get the base metal hot enough. Any help would be most appreciated

chaz

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Re: Crankcase repairs
« Reply #1 on: 24 March, 2020, 17:39:31 »
you would need a higher temp of flame than a blowlamp, oxy acetylene with the oxygen helping raise.

DAVE BRADY

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Re: Crankcase repairs
« Reply #2 on: 24 March, 2020, 18:31:42 »
Hi,

Is this welding rod or something like Lumiweld - for small repairs?

Dave.


Mike Farmer

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Re: Crankcase repairs
« Reply #3 on: 25 March, 2020, 16:57:21 »
 :) :) :)

How much will it cost to replace your casing if it should melt. I would say welding aluminium??----don't even go there unless you have some experience. To get the heat that you need I would suggest that you will require at least a propane torch because in general terms you are unlikely to get the heat that you need from an ordinary blow torch.

My advice would be take it to someone with a TIG welding set up or at the very least MIG with 100% Argon. Or as previously said Oxy/Acetelene BUT that is very seriously for an expert. Ally goes from solid to melting in a split second :(From a casing to a lump of unrecognisable shiny bits)

However: - if you are able to get the heat right etc you could do a good job. Personally I'd farm it out.

Take care

Mike 8) 8)

MGI

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Re: Crankcase repairs
« Reply #4 on: 26 March, 2020, 09:36:06 »
As previously stated, it is difficult to weld aluminium, particularly if it is old and has been heated and cooled and generally stressed. During my apprenticeship the course tutor would repair a kettle, apparently very challenging. If you are anywhere near Worcester there are numerous (literally) specialist aluminium welding outfits around the city. External site welding of aluminium was developed and perfected there and many of the employees of the guy who started it off have subsequently left and started up for themselves. Large fleas have smaller fleas etc.

Mike Farmer

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Re: Crankcase repairs
« Reply #5 on: 26 March, 2020, 11:21:03 »
 :) :) :) :)

Hi again. Follow up to previous post on this subject.

There is a fairly well explained item on alli welding on U Tube.

Go into your browser and find "Aluminium Welding", then find the item "How to weld aluminium without a welder". I found it quite informative. There are probably others on there.

You will see mentioned the point that maybe your ordinary torch will not produce enough heat. I think that you can still get the mixture that burns hotter(propane I think) and it should be usable with your ordinary blow torch. its worth a go with a spare bit of material as a try out.

Best of luck.

Mike 8) 8) 8)

Mike

MGI

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Re: Crankcase repairs
« Reply #6 on: 26 March, 2020, 12:39:51 »
Be wary of distortion...

bikerbob

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Re: Crankcase repairs
« Reply #7 on: 26 March, 2020, 13:54:10 »
I have been retired a good number of years now but when I was at work I used to do quite a bit of specialised welding of different metals. I have welded  a number of motorcycle casings and using TIG welding they were never a problem ecept for carb bodies because they have a higher zinc content. Since retiring I have used that Lumiweld on a couple of primry cases where the footrest has damaged the casing when the bikes have fell over and dented and cracked the cases, but you are heating a qiute thin and very localised area using a propane butane mixture in a blowtorch. I was able to heat the cases up knock the dents out and seal the cracks using Lumiweld but you have to follow the insrutuctions cleaning the arera with a stainless steel wire brush not an ordinary wire brush. I do not think it would be suitable for a crankcase unless it was a very minor crack on a thin part of the case.

Mike Farmer

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Re: Crankcase repairs
« Reply #8 on: 26 March, 2020, 15:27:27 »
 :) :) :)

I've got a drive side casing with a broken stud part of which is still in it. I shall have to carefully dig it out which will leave small but nasty hole. I was going to take it to our local brilliant welding lady, however first I shall try the Lumiweld method. We'll know then A. Whether I'm able to do it and B whether it works and C whether it will take a thread.

I'll let you know later.

Mike 8) 8) 8)

bikerbob

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Re: Crankcase repairs
« Reply #9 on: 26 March, 2020, 15:56:56 »
Mike it can be done I have seen it demonstrated at an autojumble a few years ago preparation is the key it has to be clean no trace of oil or dirt and you have to break through the surface layer of the aluminium it always has a fine layer of oxidization even though it looks clean that is why they advise cleaning with a stainless steel wire brush. The trick is to get the aluminium to the correct temperature first before applying the rod, if it is at the correct temperature when you apply the rod the heat of the aluminium will melt the rod when it touches the case don't be tempted to melt the rod onto the case then try to get it to flow. Think of the rod as a stick of solder where you heat the job then touch the solder to the work and the work melts the solder. Good luck.

Mike Farmer

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Re: Crankcase repairs
« Reply #10 on: 26 March, 2020, 19:50:11 »
 :) :) :)
Hi
That's encouraging as I say I intended to have it welded then this topic came up and the Beesa site sorta took over my intentions and the project seems to have taken on a life of its own. I would also like to be able to report first hand here for anyone who wishes to give it a go.

I understand that its more like a joining compound than a weld in the same way as you say solder and to some degree braze.

Question: - why so important that Stainless brush should be used. Is it simply to avoid FE contamination or have I completely missed something. I have thoughts of trying a couple of experiments when I get the kit. It includes 5 rods so I'll probably have 4 left over.

Enuf guff.

Mike 8) 8) 8)

Csx355

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Re: Crankcase repairs
« Reply #11 on: 26 March, 2020, 20:03:34 »
:) :) :)

I've got a drive side casing with a broken stud part of which is still in it. I shall have to carefully dig it out which will leave small but nasty hole.

Mike 8) 8) 8)

Hi Mike - I had an issue with a broken off stud - the one at the throat of the crank case where the barrel sleeve sits. The usual story, all the casing studs came out sweet as until the last one. 'That might need some heat' I thought just a second before leaning on it one more time with the inevitable result. Anyway I looked up spark eroding and then found an engineering shop local to me that had one. A few days later and they had not only cleanly removed the stud but had also saved the thread and made me a new stud. There are some clever people and is some funky kit out there. Well worth a look.
Bantam - Needing Rescuing
B40 - Nearly Finished
B44 Trail - sort of finished
B44 Road - Nearly Finished
A65 Thunderbolt - Always the next one to do!

chaz

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Re: Crankcase repairs
« Reply #12 on: 26 March, 2020, 21:35:29 »
That's another thing I miss about our old workshop, EDM machines, or spark erosion machines. We had two, rappers, grinders, gear cutters, etc even a foundry and plating shop. Bikers heaven. Any parts with broken drills or bolts get thrown away now. I had a look at buying an EDM workshop near Gloucester a few years ago, apparently did a lot for rolls Royce and aviation companies locally.

bikerbob

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Re: Crankcase repairs
« Reply #13 on: 27 March, 2020, 14:22:49 »
You are correct mike ordinary wire brushes are not hard enough and leave minute paricles of steel behind which will inhibit the flow of the rod.

Mike Farmer

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Re: Crankcase repairs
« Reply #14 on: 27 March, 2020, 16:37:14 »
 :) :) :)

Thank you.

Mike 8) 8) 8)