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Aluminium welding

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Alan Gordon 415/11/2019 16:28:44
91 forum posts
3 photos

What I want to do is build up the inside of a crank case of a small IC engine which I have bored of the square !!! and then rebore it this time correctly, Any ideas of the type of Aluminium welding rods I should use to enable me to build up the inside surface.

Bob Brown 115/11/2019 16:31:16
1010 forum posts
127 photos

It depends on the material and the kit you have, TIG would be my preference.

Alan Gordon 415/11/2019 16:37:35
91 forum posts
3 photos

Hi Bob, It's a small aluminium casting and I was thinking of the low melting type aluminium rods you can get, trouble is I am not sure on the make of rod and where I might get them. I only have a butane torch.

Alan Gordon 415/11/2019 16:37:36
91 forum posts
3 photos

Hi Bob, It's a small aluminium casting and I was thinking of the low melting type aluminium rods you can get, trouble is I am not sure on the make of rod and where I might get them. I only have a butane torch.

Neil Wyatt15/11/2019 16:46:30
17970 forum posts
709 photos
77 articles

Google Alutite, there are alternatives but I find Alutite works well, you can use a steel plate to blank a through hole and fill it from above.

I've used it for joining and repairs.


Oldiron15/11/2019 16:55:34
453 forum posts
22 photos

I have used kits from these people before with good results. It was a while ago so not sure if the details are current. They sell American made kits in different sizes and for different applications. The rods work at approx. 380C. Call them for advice on the application.


Lumiweld tool box kit. L B Restoration Services, Panderosa Farm House,

St Lawrence Road, Bodmin, Cornwall, PL312QU. 01218269746


I hope this helps.


Edit to update web details

Edited By Oldiron on 15/11/2019 17:02:44

jann west15/11/2019 17:43:35
62 forum posts

If your casting is ali, and small-ish, then you will probably find that building up with (TIG) won't be the experience you expect from steel.

Ali welding on small parts doesn't go so well due to the thermal transfer issues - namely aluminium transfers heat too well - and castings tend to be a little disappointing on the material front. YMMV

You would probably do well considering some form of other solution - if it's out of center perhaps you could sleeve it and re-bore ...

I know it seems logical to just overfill with ali and fix from there - but even (really) good ali welders struggle with that ... due to the nature of the material.

I've been there and got the t-shirt ... and watched much better ali welders and I fail in similar circumstances.

Emgee15/11/2019 18:27:48
1542 forum posts
219 photos


If this will be your first time using Lumiweld or other similar products you will be taking a chance if you value the crankcase, especially if it is a casting of unknown material.
If things go wrong you will end up with at least a hole in the case, or worse probably completely ruin it.

The people selling these rods who demonstrate at the shows are very skilled with the product and are using materials of known structure and make repairs look very simple, but that's not to say the product won't effect a repair to your crankcase provided you have the skill required.

The earlier suggestion of sleeving and boring sounds like a good repair method, locating the bush by shrinking or high temp Loctite (or similar) may be considered suitable.


vintage engineer15/11/2019 20:15:47
254 forum posts
1 photos

I have found most of the welding rods are full of silicon and other crap. I normally make my on rods out of the same material as I welding or I just cut up ali sheet into strips.

If you are gas welding ali you need to use American flux as the EU flux has changed and is next to useless.

Alan Waddington 215/11/2019 21:34:48
503 forum posts
87 photos

Define ‘small’ what are the dimensions of the hole, and what wall thickness ?

Alan Gordon 415/11/2019 22:58:45
91 forum posts
3 photos

Gentlemen, Many thanks for all you help advice, I think given the information offered the sleeving and re boring will be the way to go. The casting in question is a crankcase casting of an Atom Minor 3, IC engine. With the benifit of hindsight I should have bored halfway through then turned the castin through 180 degrees and bored the other side rather than bore all the way through on the assumption that the casting was "true" . Still one learns !!!!

Roy Vaughn16/11/2019 10:59:12
35 forum posts
4 photos

I would council against boring the case from both sides because the alignment of the crankpin with the rotor pin depends on having a straight hole with truly parallel faces back and front. The castings leave a lot to be desired that's for sure. Roy

fizzy16/11/2019 12:07:00
1716 forum posts
116 photos

my experience was that the material is such low grade that it was impossible to weld with tig, i tried to weld to lugs on the outside of my heli rc engine. Ended up buying a new casing!

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