Author Topic: 12 Year Corrosion test  (Read 322 times)

Offline Captain Jerry

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12 Year Corrosion test
« on: October 21, 2019, 03:40:49 AM »
Ab0ut 12 years ago, I installed a new filter system on m swimming pool.  It is a three foot tall fiberglass cylinder, about 12 inches in diameter with a pleated paper cartridge inside.  The cylinder is in two halves with the upper and lower half held together with a long 9/16" stainless steel tie rod threaded on both ends. 

Well, these things don't last for ever.  The lower half of the cylinder split under the pressure of the circulating pump so I had to install a new one.  I threw the old stuff out but I just couldn't make myself junk that tie rod so it has sat in my shop for the last 4 months.  It is a horrible ugly looking thing.  "Stainless" is a relative term so after all those years submerged in well water with varying levels of chlorine and other pool chemicals at temperatures from 60 deg F to 120 deg F.  The system is drained during the winter but the rod still stands in a damp closed container.  Corrosion has done its work, with deep pits fro end to end.  But how deep?  Cut and see.

It will pass through the headstock on my 9x20 lathe but is a bit too long to work with so I sawed off a piece for testing.  I put a center hole in one end to support on the live center and chucked it up in the 3 jaw self centering.  The surface is tough and hard on tools so I used an old brazed insert carbide tool bit and started cutting.  After a few passes, I was down to a bright surface but the corrosion pits were still almost shoulder to shoulder.  I continued with the carbide tool taking .005" cuts for a while and pass by pass, the pits got smaller.  The surface was ragged so I switched to a freshly ground, HSS bit and began to fine tune the tool height and the speed/feed to get a better surface. The cut improved but produced only fairly short curly chips as each pit encountered broke the chip. After a few more passes, I began to get long curls with only an occasional tiny pit encountered and finally all of the pits disappeared. 

The clear pass occurred at a diameter of .428" diameter.  From a starting point of .562" to an end point of .428" is .132" or .066" depth for the deepest pit.

I went on to produce a a 6" long, fish bellied connecting rod that may someday find it is hanging from a cross head guide on one end and a crank pin on the other end.

Here is a photographic before and after.


« Last Edit: October 21, 2019, 04:02:21 AM by Captain Jerry »

There are things that you can do and some things you can't do. Don't worry about it. try it anyway.

Offline Admiral_dk

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Re: 12 Year Corrosion test
« Reply #1 on: October 21, 2019, 12:50:30 PM »
I will say that it didn't do too badly + nice result, that might come handy later.

Offline mike mott

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Re: 12 Year Corrosion test
« Reply #2 on: October 21, 2019, 03:13:14 PM »
A great bit of re purposing. And the things we do to follow a hunch.

If you can imagine it you can build it