Hey guys, another fun week at work, we recored this decent size oil cooler, thought I'd take some pics..

Core is over 1m wide, 100mm thick (2 layers of 50mm tube/fin)

With our process (not bar & plate) we hand weld each tube, We do a candy cane style weld, flip the core, weld it again.. For this, each tube is welded 4 times (twice each end, twice each way)

Using a 2.4mm zirconiated tungsten on the tube to header welds, a 3.2mm zirconiated tungston on the header plate to tank welds..

Filler wire is 1.6mm 4043 for the tube to headers, 2.4mm 5356 for the header to tank welds.

Welder is a Miller Synchrowave 350 LX

Some geeky statistics I was pondering:

There's 27 tubes per 50mm layer, so 54 tubes total (100mm wide), 54 tubes, 50mm per tube each welded both sides (100mm) welds there's approximatly 5.4meters of welding at each end, all hand welded by me.

All welds are dye tested with chalk and penetrant, over 10.8 meters of welding in total, I got 4 pinhole leaks, The chalk/dye test is used by avionics to crack test propellors in planes and shows up with a red dot where the leak is, Once the unit is welded together (with tanks) it's pressure tested to 180psi.

Anyway, on with the pics.. As always, comments, critique..

 

what kind of blade is that ?

 

It's a tungsten carbide tipped blade, It's 4mm thick, made for grinding alloy.. It's a GODSEND.

We buy our blades off a local knife/blade company, Also have a 1.6mm version for sectioning..

 

New Zealand huh? I've been thinking about going there for quite some time. Hook me up with a job and I'll move : P. Sucks being laid off with nobody hiring.

 

I use the same blade but we call it a "meataxe" for obvious reasons. It is the most dangerous tool we use, if it grabs it's impossible to hold even on a small 4" grinder.
I've found the only way to use it is to work from left to right and never the other way.
Regards Andrew from across the Tasman ditch.

 

Neat- so for the dpi it looks like you put the dye inside the tank?

Nice work!

 

I didnt have any knowledge about this before. thanks for updating my knowledge.i will like to know more from you

 

heck i would be into that too.there has to be work somewhere in the world?welding jobs in the portland/vancouver area are non existent.

 

Hah, bad timing.. I nearly got made redundant 3 months ago but was kept on from some good *** kissing.. work is tough at the moment

 

Sorry, I should have explained this a bit more

The chalk goes on the welded side of the header plate, the dye gets dabbed onto the tubes that go into the header, over time the dye will seep through any imperfection/leak.. especially if you put a drop of acetone onto the dye.

We leave them on dye test overnight, fix any leaks that crop up and only when it has no red dots we clean the chalk and dye off the core and steam clean the tubes to remove any dust/dirt/swarf.

Tanks are then welded on and the unit is pressure tested with dry nitrogen to 180psi.

The green stuff in the tank is a powder that aides in detecting minute leaks, it shows bubbles up amazingly

 

that looks like a pain in the ***, why not start with a new brazed core then just weld in the old end tanks?

 

Because this is the process we use, we can custom make any size/thickness core using this process with out the requirement of a vaccume brazing plant.

 

quality work.