Thread: Fixing leak in Alloy Pump Housing

At work we use a 2 part epoxy called "belzona" it's deigned for building up worn pumps. Short I that could It be tig welded?

You can weld it up using Cronatron 510 rods and a DC arc welder.

Bruce,

When I was a youngster I used Devcon Steel Putty to repair one of my KTM's magnesium crankcase castings. It was in a pretty exposed location near the gearbox spocket. Exposed to mud, water, gravel and sand. Never failed. May be worth a look -http://itw.nx.net.au/devcon/product.aspx?productid=56

I have a casting flaw on my little mill's saddle filled with it. Still using the stuff 40 years on.

Bob.

Selleys Kneed It normally works provided the area is totally ground clean and the epoxy hardens fully.

Pays to grind the hole so it tapers away from the pressure.

Also depends on how much pressure it's under. Anything over about 50 psi and it will be doubtful.

What sort of psi are we talking here ?

Rob

Originally Posted by nearnexus

Selleys Kneed It normally works provided the area is totally ground clean and the epoxy hardens fully.

Pays to grind the hole so it tapers away from the pressure.

Also depends on how much pressure it's under. Anything over about 50 psi and it will be doubtful.

What sort of psi are we talking here ?

Rob

Rob
Good question, however I do not know the pressure these fire pumps use.
Might try ringing around, I would guess at least 50 psi.
Thanks for your thoughts.
regards
Bruce

The good old Davey Firefighter single stage pumps that everyone recognises will deliver 700KPA (or 100PSI for those preferring a civilised measurement), so I should imagine that you would be looking somewhere around this figure, if yours is a twin impeller pump,then 150PSI could be on the cards quite easily. This is unlikely though.
Knead it could work if you can access the inside of the casing and taper the hole so it acts as a cork more than a patch. Clean metal will be essential.
I would suggest that a look inside the casing wouldn't hurt anyway as there could potentially be a few nasty surprises if corrosion has taken hold. If it's worth repairing, (remember that a new Honda powered pump is not that expensive these days), then I would lean towards some type of weld repair (Tig most probably).

Thanks Karl
This is a 35 yr old firefighting pump single Impellor so its probably around the 80 psi or so. It could be worth taking it apart & checking the inside as you have noted.
Itdoes not look too bad & still operates quite OK its just my friend would like to fix the small leak.
In the real world we hope we never have to really use these fire fighting pumps,& its good to have them fully operational.
The Devcon Steel Putty that "Anorak Bob" has mentioned is also a good possibility, & I think the idea of taking it apart & patching from the inside using a vee sounds good.
regards
Bruce

You don't actually have to take the pump apart to achieve the tapered "V" section.

I've done this on alumnium water jackets on inlet manifolds that have rotted through, by using an air die grinder (yes that fabulous pencil one I have) with a rotary burr.

It's easy to achieve a taper by inserting into the hole and working in a sloping radial motion.

Use a small diameter, straight cylinder, carbide burr.

edit: The problem is getting the two pack in the taper, but judicious use of a piece of bent wire will spread it around the area you force it into. Better with the pump apart, but it will work this way.

Rob

Bung a suitable stainless self tapper in it with a bit of locktite or araldite on it.

Another option...

Durafix Australia - Aluminium Fluxless Repair Rods

Originally Posted by Master Splinter

Another option...

Durafix Australia - Aluminium Fluxless Repair Rods

Thanks Splinter,
You saved me a trip out to the shop as I couldn't think of the name..
I can't speak highly enough of this product, it's easy to use and is stronger than the parent metal.There are some videos on Youtube showing the use and ease of it. And it can be used with propane or map gas...
I use it all the time for thread repair in engine heads etc; when customers #### everything up..
Matt

EDIT...
If you want to go this rout, PM me and I will post you a stick, I was fortunate enough to be given 5kg of the stuff and the previous owner would be happy for me to share it around to other engineers etc;

Matt

Drill and tap it and screw in a stainless steel bolt. You may need to grind the internal end off.
Always empty and dry the pump for the winter storage. Leave bungs out to allow air through them.

Regards,

Originally Posted by Master Splinter

Another option...

Durafix Australia - Aluminium Fluxless Repair Rods

+1 on this stuff.

The only issue is that you will have to disassemble the pump to apply heat with a torch.

You used to see guys demonstrating/selling this stuff at flea markets years ago - very impressive at fixing holes in Coke cans (usual demo).

I have a few sticks somewhere, but most of mine got snaffled by the Bro inlaw, who is forever using this stuff.

Good gear.

Rob

Originally Posted by Karl Robbers

I would suggest that a look inside the casing wouldn't hurt anyway as there could potentially be a few nasty surprises if corrosion has taken hold.

I agree with Karl - once corrosion has eaten through in one place you need to check what is happening elsewhere. As this is a bit of emergency equipment, better safe than sorry. Last thing you want is to start it up when needed and find other leaks. I'd lean towards welding it up too. While Devcon et al are really good products I would have a worry that they would shake loose and again, in a critical application you don't want that.

Michael