Anyone had experience with Aluminium brazing?

[mike-s]

As i mentioned on a "wanted" thread i managed to strip the thread on the oil pan for my bike, and rather than pony up the cash for a replacement part ($150 is an average asking price in Australia, $70US posted from ebay sellers) so I thought i'd investigate the option of aluminium brazing as at most including buying the torch will be half of the cost of buying from ebay-US sellers.

Now I know it's as much of an art as it is science, but looking at the following youtube video and a few other sites i'm seriously considering the viability of doing something like this, particularly as my application is covered in the below youtube video.


From about 1:00 to 1:40 is the part i'm interested in.

The stuff in the video is from here however they only ship from an overseas location and i've found a bloke located in Bathurst whom has a similar product he sells along with doing his Aluminium pre-fab work. He has an ebay store which has plenty of positive feedback and if it all goes to shit and i destroy the pan, i've still only spent a fraction of the cost of buying a spare.

i'm seriously considering doing this. If i do go ahead, i'll certainly make sure there's a "how-to" thread on it. Aside from that, thoughts?

[h.b.bear]

Hi.here is a thread from 750 turbo club in England, Fastferret is the only one that knows a bit about it but i wasnt sure how to single his comment out,its not a great deal but might help.

http://www.750turbo.com/forum/viewtopic.php?f=4&t=10319

[the kid]

I have tried that sort of thing and still have rods .
Bloody difficult to use . The demo videos make it look easy but it would take a lot of practise to get like those guys .
Temp control is difficult and making sure everything is superclean is really important .

If you want a couple of sticks PM me an address and I will send you some . Might take a while to get to a post office tho

[matt6]

Depending on the availabilitly of engineering workshops handy to you, a good fix would be to get an aluminium "bung" turned up and tig welded into the sump. If you make the bung like a top-hat shape, it will give a greater weld area and be a lot stonger than the original.

[seiko1]

Uncle Steve could do it for you....unfortunately you're a long way away.

If you do attempt it (which I think you should) you will have to be extremely cautious with heat,
a little to much and the pan will cake (crumble).
They say it's melting point is 500 degrees below that of Alum, if that were in celcius,
it would mean the rod melts at less than room temp

[oldman]

Aluminum welding or "brazing" as you put it, is a pain in the arse. With steel or even cast iron there is some indication of the temperature of the metal by the colour. Aluminum just melts into a ball of shit. I would find a professional welder and have him/her do it. I cannot pull up your video so I cannot relate to what you are talking about but a good shot of Jim Beam will assure you that you will have a puddle of melted shit. If you insist on doing it yourself try it on a piece of aluminum that you don't care about such as your cars engine block. After you fuck that up you probably will have somebody else do the work on stuff that is matters. Cheers.

[mike-s]

here's the video as a link. It's not actually melting the aluminium, but using a harder metal with a lower melting point that (if done correctly) bonds with the aluminium.

[mike-s]

Got all the stuff i need for this aside from the rods. As it turns out propane is fortunately sufficient as the torch kit for mapp gas costs 4x as much as the same setup for propane (it's purely down to the material that the tip is made from & its melting point) as propane burns at up to 1900'C and MAPP gas burns at 2950'C. As we're only dealing with a relatively low 380'C or so for the melting point of the braze material it isn't that much of a problem to use propane instead. Either way i just have to make sure the heat is evenly distributed and that i don't use too much of it lest i melt the actual part i am trying to repair!

Sidenote: I also have one of those little butane torches, which although would be hot enough, i would very much doubt would be able to put out the quantity of heat for what we're trying to achieve here. It would certainly suffice if you were working on a much smaller set of parts though.

[ducati_paul]

can't you helicoil it? Aluminium Brazing is a pain in the arse, just when you think you have the right amount of heat in it it turns to a molten blob and all collapses done it YEEEEEEEEEEEARS ago during my welding apprenticeship.

[aggerz]

Spooky I actually ordered some of those rods last week hopefully they turn up soon if they do I'll give them a go next weekend.

Seems like not much support for them here but I figured for the cost ($30) i would give them a bash, not a big loss if it doesn't work out.

[mike-s]

can't you helicoil it? Aluminium Brazing is a pain in the arse, just when you think you have the right amount of heat in it it turns to a molten blob and all collapses done it YEEEEEEEEEEEARS ago during my welding apprenticeship.

Already gone and bought a kit for it, but managed to screw up the install and made things worse, so its now either this works, i pay a machine shop to do it (which would probably cost me close to what a new oil pan would) or i need a new (to me) oil pan. I'm happy to admit to the theory that there is such a thing as too much heat and too big a flame, so will be doing this very carefully/increasing the heat a bit at a time until i get it right. Esp with a flame that goes up to 1900'C.

Spooky I actually ordered some of those rods last week hopefully they turn up soon if they do I'll give them a go next weekend.

Seems like not much support for them here but I figured for the cost ($30) i would give them a bash, not a big loss if it doesn't work out.

Exactly my theory, besides i figure the cost of buying the blowtorch as just buying another tool that can be handy later on if not needed here. At worst i've bought some tools now that i can use for plumbing jobs later and an oil pan, at best i have some new tools.

Also i think that another reason there's less use for/of these things is the risk vs reward thing. That is unless your talking about an extremely old & rare bit of metal that you aren't going to get again for anything less than a small fortune & a shitload of good luck. If i get it working i will certainly be extolling the virtues to all and sundry, if not, well i'll be saying my brazing abilities are less than i anticipated

[oldman]

I didn't mean to sound negative about your project, you may very well succeed in your first attempt and it sounds like your pan is screwed anyway. Just, as earlier mentioned, be careful of the temp as you can go from ok to a puddle of shit in about a nano second. I still could not pull up the video. My computer is old, just like me and the CPU and memory will not accept the Adobe 10.??? upgrade. Thanks anyway. Another way to do it would be to solder it with acid core solder, (the same kind that plumbers use on copper pipes). I believe the melting temp of solder is very low and the acid core would take care of any cleaning issues in the area you are welding. I haven't tried this on aluminum but it works on cast iron. It's not as strong as the original metal but does hold things together ok.
Cheers.

[Jonno]

Can you drill n tap for a larger size plug?

[Smitty]

Can you drill n tap for a larger size plug?

that was going to be my contribution to this... so +1

[mike-s]

I didn't mean to sound negative about your project, you may very well succeed in your first attempt and it sounds like your pan is screwed anyway.

Exactly

Just, as earlier mentioned, be careful of the temp as you can go from ok to a puddle of shit in about a nano second.

No problem, i at least know to look out for the parent aluminium going shiny as *ANY* more heat at that point and it will melt

I still could not pull up the video. My computer is old, just like me and the CPU and memory will not accept the Adobe 10.??? upgrade. Thanks anyway.

No problem, it was worth a shot anyway.

Another way to do it would be to solder it with acid core solder. I believe the melting temp of solder is very low and the acid core would take care of any cleaning issues in the area you are welding. I haven't tried this on aluminum but it works on cast iron. It's not as strong as the original metal but does hold things together ok.

Well one reason i want to use this stuff is that the hardness on the brinell scale is more-so than aluminium, so if i do it right, the thread is going to be stronger than when the part was first cast.

Can you drill n tap for a larger size plug?

My excursion with screwing the helicoil tap has shot the crap out of that idea. There's also insufficient metal there for me to safely take it up beyond a 16mm plug. Which is only 0.6mm larger than the size of the helicoil insert which i mangled the tap for, so insufficient metal there again.

On the plus side i have an old aluminium barrel i can practice on and perform any beginner cockups on instead of where/when it counts.