I had a good look on eBay, but nothing there did exactly what I wanted; some were close, but many would have been difficult to fit in the limited space available. In the end I decided to make my own - which is why I was asking all sorts of questions about plug welds, sorting problems with my welder, and so on.
I started off with a heap of bits and pieces, many of which came off my shelves.
materials
The tube was checked for squareness, the edges were tidied up, and a baffle was shaped and drilled. This baffle was plug-welded inside the tube, and was intended to force the vapour downwards.
baffle plate
finished baffle
test fit
A bronze bush was silver-soldered near the top of the tube, for the inlet.
inlet bush
Then two bushes added for the oil sight glass, scrounged off another (inferior) oil catch tank.
sight glass bushes
The inlet pipe (bought off eBay) was soft-soldered into its bush.
inlet tube fitted
Then the end plates were shaped up on the lathe, out of a piece of 10mm aluminium sheet I had on my shelf. Appropriate holes were drilled, and a 1/4" BSPT thread put into the base plate, for a drain tap.
end plate machining
end plate blanks
end plate drilling
completed end plates
The end plates are held on with a M6 threaded rod and fancy nuts, with a generous amount of silicone RTV sealant everywhere. Lots of stainless steel pan scourers were stuffed in before the caps were fitted for the final time. A 1/2" tube was fixed into the top plate with Loctite, fixing screws added, a spacer was made on my 3D printer, and a bracket made to mount the tank to some pre-existing holes in the chassis.
tank and bracket
Finally, the whole thing was installed and connected to the crankcase vent with 1/2" bore pipe. Space is tight, but I can get to everything - with a stretch.
finished tank 1
finished tank 2
I don't yet know if it will work as planned - the end caps may leak, despite the tight fit and sealant, and the plastic spacer may prove to be too weak for the job. However, I now have the basic components and any problems that pop up should be easily fixable (hopefully!).
