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Lumiweld Information

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Stan Thomas
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Joined: Sat Feb 13, 2016 2:14 pm
Location: Penkridge. Staffs.

Lumiweld Information

Post by Stan Thomas »

I am having to make an aluminium water pump impeller by machining the hub then milling slots into which the six vanes will be fixed and welded into position.

An easy solution would be to use Lumiweld or any of the similar low temperature aluminium welding rods (More like a solder really). However, by query is this:

Lumiweld and the like has a high zinc content (to provide the low melting point) which has a propensity to erode in water - which is why its used as a sacrificial anode on ships propellers etc.

Who has any experience with the Lumiweld or kindred products and would you think it would be safe to use - or is tig welding the only real option - unless of course you have any other suggestions!!

Regards to all

Stan.
Last edited by Stan Thomas on Mon Sep 14, 2020 12:50 pm, edited 2 times in total.

Sydsmith
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Joined: Sun Feb 14, 2016 11:15 pm
Location: Aberystwyth Wales

Re: Lumiweld Information

Post by Sydsmith »

Stan, as I am sure you have found, the soft weld material suppliers all say they have high corrosion resistance but are very short on detail. The American brand Alumiweld seems to suggest that their product is bullet proof, though they again don't give any detail about electrolysis, which I guess is the main worry, especially if lumps of alloy were to detach them selves inside a water pump due to corrosion.

I have never used that type of product in your situation so sorry I am no help, I expect you have thought an email to the suppliers. Syd

Stan Thomas
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Joined: Sat Feb 13, 2016 2:14 pm
Location: Penkridge. Staffs.

Re: Lumiweld Information

Post by Stan Thomas »

Hi Syd,

Thanks for your reply. The "suppliers" cannot coment upon the chemistry of the product - only the manufacturer would know that - and I can't find any info about who they are - other than its an American company.

That said, Marcel came up with a good comment insofar as the antifreeze is a corosion inhibitor, but as you say, chunks of aluminium flying round in the water pump is not a cheery thought!

P.S.
Which Medieval Conquerer killed people by spinning them round in water??

Vlad the Impellor!

Sydsmith
Grumpy
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Joined: Sun Feb 14, 2016 11:15 pm
Location: Aberystwyth Wales

Re: Lumiweld Information

Post by Sydsmith »

It seems to be a sign of the times Stan, no one wants to commit to anything in case someone sues them if things should go wrong.
How about making your impeller in another metal, brass perhaps and brazing the webs in place, or perhaps machining grooves for the webs to locate them firmly then drill and countersink the webs and use machine screws to hold them in place?

I am stumped on the spinning killer, I guess there is a joke there somewhere :D Syd

Stan Thomas
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Joined: Sat Feb 13, 2016 2:14 pm
Location: Penkridge. Staffs.

Re: Lumiweld Information

Post by Stan Thomas »

Hi Syd,

Good suggestions - but the impeller is a shallow dish only some 80mm in diameter x 30mm deep with insufficient thickness to fit the webs with screws (*).

The Problem of working in brass is the delicacy of brazing it all together - given the brazing rod has virtually the same melting point as the brass itself even sif bronze ones, and it is virtually impossible to control the overall uniformity of the temperature during the brazing operation.

(*) Without the benefit of thermostats, early cars purposely had less than potentially effiicient water pumps to accelerate warm up time from cold, then as the coolant temperature rose, the increasing effect of thermo-syphon came into operation.

You are also right how companies are "legally apprehensive". I bought an electric kettle recently which had a large label on it which read:

"CAUTION - MAY CONTAIN HOT WATER"

Regards from Vlad the Impaler (Google it!).

Sydsmith
Grumpy
Posts: 1002
Joined: Sun Feb 14, 2016 11:15 pm
Location: Aberystwyth Wales

Re: Lumiweld Information

Post by Sydsmith »

Interesting problem Stan, I can see you have thought this one through, I guess it is a part that is unobtainable or you would not be asking the question. One solution could be to cast a new blank out of aluminium the machine it to fit not for the fient hearted though.

Your mate Vlad the Impaler, not the sort you would want to be up against :D

Big Col
Posts: 496
Joined: Tue Feb 16, 2016 12:45 pm
Location: Leeds

Re: Lumiweld Information

Post by Big Col »

Could a water pump specialist suggest an alternative impeller that could be adapted to fit your needs.
There is one in Wolverhampton but there name escapes me at the moment.
Colin,
I may be slow but I’m rough as well !

Stan Thomas
Wise Guy
Posts: 665
Joined: Sat Feb 13, 2016 2:14 pm
Location: Penkridge. Staffs.

Re: Lumiweld Information

Post by Stan Thomas »

Good idea Big Col - the one in Wolverhampton won't sell parts, niether will the other four companies I've tried.

I've machined a hub and milled six slots to take the correctly shaped "vanes" already, but need to get them tig welded into place - having done a test piece with Lumiweld - which I'm not satisfied is strong enough. However, thanks for all your interest and suggestions.

Regards to all,

Stan.

P.S.
Million-to-one shot, but does anyone know of any sleeves for a 35/120 to help my friend in Newcastle who is rebuiding his 1928 sleeve valve? It's imperative what few of these cars are left should be preserved and not finish their lives ignominiously fitted with a "leaping stick" engine.

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