Welding Crankcases

[Nourish]

I bought some BA7 plunger crankcases and the lower mount lug is damaged - the one that the stud passes through the frame. It had been welded before but was a right mess.
So I took them into work and gave them to one of our welders - bearing in mind I work for a top Aero Engine maker and the welders are experienced, skilled and certified.
He first put them in an oven and then had a go at TIG welding but had trouble getting the weld to adhere to the BSA metal, it was OK with the previous repair - infact he said that the weld rolled off the parent metal towards the repair. He's put a lot on that I will now cut back but he wasn't happy with it and not too sure if it has fused that well.
Anybody have any experience with this?

[muskrat]

I'd say the cases are impregnated with 60 years of oil and degreaser. Some cases are quite porous.
Cheers

[KiwiGF]

I am not a welder but one issue with welding ally (in particular) is deciding what filler to use, given it should be compatible with the case but you dont know what case is made from. So anyone know a filler that works?

If you have a spare ruined case it could be used to provide filler material, maybe, but as muscratcsays this might introduce more oil into the weld and cause problems from that.

[Stephen Foster]

Possibly the cases are contaminated with old oil but even though Aluminium is welded using A.C (T.I.G) manipulating the earth clamp can sometimes
improve welding ?

Assume the welder ground the edges to cleam metal & used a degreaser ?

These cases usually weld well ..Triumph cases seem a little bit more reluctant occasionally ?

Where are You based ?

If You send Me a P.M. I will give You My phone number if You wish to discuss further ?

Steve ..

[JulianM]

Hi there,

When ever we weld old crank cases and sumps etc we pre-heat many times until the oil and grease stops coming out of the cracks etc,
(you know, the dirty brown marks that seep out of the casting when you heat it up)
When all this stops happening, we clean in brake cleaner thoroughly and re-heat.

Welding is usually done with pure ally rods, or 5% silicone but no Mag content.
Set the square wave on -2 on our Fronius, (it will be different on other types) and use as little amps as we can get away with.

Good luck.
Julian

[Nourish]

Thanks for the replies, I suspect that it may of been causing the problem. We used to have a Hot Trico ethylene degrease tank and I used that to sweat out the oil in my previous casings but alas what with H&S it's gone so this time these cases were just vapour blasted.
I've cut back the weld, re drilled and spot faced the stud hole and it doesn't look too bad. Some of the gasket face of the filter had been filed away, I had some Lumiweld Alloy solder so built the face up with that and fly cut it and now it's as good as new!
As I write this I'm thinking why the Lumiweld wasn't contaminated with the oil unless of coarse the heat of the welding had cleaned it out.
Thanks again.

[Stephen Foster]

I have never used "Lumiweld" is this an Oxy-Acetylene process ?

[Nourish]

I used oxy-propane but use what ever you want - depending how much heat you need to put in it - Google it
Cheers

[bsa-bill]

It's a electro chemical process as far as I can make out from reading the ads, I'm always a bit sceptical of ads  (and most everything if truth was known
) so it would be great if any member /s here who have done it with success could give us all a heads up on it's merits and ease of use or otherwise. Picture too perhaps

Nourish ? anyone ?  

[KiwiGF]

I used a filler rod product which looks to be called lumiweld today to fix a benelli sei 750cc case back in the late 80's, I used a propane torch, it took a long time to heat the case up to temp, no where near enough to melt the ally but enough to melt the special rod.  I would describe it as medium temp soldering. Anyway it fixed the case, which was damaged in a low speed off when I lent the bike to an (ex !) mate, he ground the corner off the case and caused an oil leak from the big end oil gallery. I sold the bike before finding out how long the filler rod lasts..............its probably one up from plastic metal and one down from tig welding?

[Nourish]

I know - I should of taken before and afer shots - but I didn't,
If you were to buy a Lumiweld kit you get a little Stainless steel wire brush, a piece of Stainless wire and the filler rods - all of these have to be kept clear from steel that I remember.
Using it - adding the heat is the biggest problem if your wanting to solder something big like a crankcase, I've used butane cans before but now I have a better set up. Everthing has to be clean and then scrubbed with the S/S brush. Add the heat to the part until the solder melts - pointless just melting the solder onto a cold casing. Once it starts to melt you have to scratch the surface through the melted solder - do this all over the area that requires it to "tin" it if you like and then you can start to add more in to create your joint or as I did just to build up the surface.
 On this job my first attempt failed and it lifted when I tried to machine it - the problem was I hadn't scratched it enough, I tried again with a piece of sharpened 3/16 S/S rod intead of the wire with good sucess.
I had used it before to tidy up some weld on a Triumph timing chest that I put an inspection plug in to bleed the Morgo pump and it worked great except that it does not keep its shine like the timing cover does and so you can see where the solder is.
Cheers

[a10 gf]

Good topic! post a picture of the final result?

[Nourish]

I've uploaded the before pictures from Fleabay so here you are:-

http://i120.photobucket.com/albums/o187/nourish_01/Crankcase12.jpg

http://i120.photobucket.com/albums/o187/nourish_01/Crankcase11.jpg

As you can see here the gasket face had been filed away on the corner.
http://i120.photobucket.com/albums/o187/nourish_01/DSC04799.jpg

The original repair was hollow so the lug was rebuilt with TIG and then the gasket face restored with Lumiweld.
You can see a colour difference on the L/H side of the gasket face where I accidently undercut on the machining before soldering - although it gives the repair a little depth don't you think!.

I have to say that I have never used Lumiweld in a stressed area and there are other brands available!

adm edit: removed picture tags, an uploaded to forum.

[bsa-bill]

Thanks for that Nourish - looks ok, take your point re stressed area's . I think the article I read somewhere was an alloy fin repair, don't recall heat being mentioned (my memory probably) which is why I thought it was more of a chemical thing

[Topdad]

This post hit a memory and I've just managed to remember where it came from ! Have a look at http://www.machinemart.co.uk/shop/product/details/aluminium-repair-starter-kit    they show a video of a guy repairing ally cases , they are car bits but it looked interesting particularly at the price ,comments from more knowledgable people than me would be welcomed . If the link doesn't work then it's Machinemart  and the part no is 010120318 which then takes you the product and a direct vid link showing the repair . Regards BobH.