Re-oiling sintered bearings

[echris 1,425]

I wasn't sure where to post this, since it's not WH related, so I put it here in general talk.

When rebuilding a snow blower recently, I made a mistake and left a few sintered bearings in mineral spirits overnight.

This is the exact process recommended to de-oil sintered bearings. "Soak ~12 hours in an aromatic solvent." Oops.

I found an article online that linked to the following chart which shows the correct process for re-oiling sintered bearings.
The best process is to soak in an oil bath in a vacuum chamber. You can achieve maximum oil content in around 25 minutes.

The alternative is to soak in heated oil for over 20 hours. I'm not crazy about the idea of leaving oil on 150-175 degree heat for that length of time.

Fortunately, my neighbor has a small 1' cubed vacuum oven.

The process worked exactly as described. Almost as soon as the oven started pulling a vacuum, the bearings started bubbling, indicating the oil was displacing the air in the bearings.
About 20 minutes later, the bubbling was almost gone. Another 5 or so an there was no longer any activity.

Hope this helps someone else properly re-oil a sintered bearing.

 

Edited November 1, 2020 by echris