aluminum for bearing babbit?

[Richard Orr]

So here's a few questions:
Anyone out there ever use aluminum for babbiting bearings instead of the regular tin or lead based babbit?
O.K. here's the next question: Has anyone ever used leather piston cups for a feed or wet/air pump?

[Maltelec]

Not sure about aluminium, my mind always tells me not to use aluminium with moving parts, especially with the limited oil systems which our steam engines use.

With the leather piston idea, I have just had to replace the leather piston on my air compressor unloader because it leaked like buggery. Personally I would always stick with cast iron clupet piston rings. The leather would need constant lubrication to keep it malleable, cast iron only needs a drop of lubricant.

[steamboatjack]

For a start "babbit" means a white metal alloy so use of aluminium wouldn't be babbiting.
High grade aluminium alloys are used for forged conn rods of some I.C. engines but that is with full dynamic lubrication, I doubt if it would be any good on a steam engine with boundary lube conditions.
maltelec has missed the point with the second question as this is for feed or air pumps. yes they should be no problem but surely modern day seals such as used in a hydraulic system would be better? Shamban seals for instance offer a range of materials suitable for water.
regards Jack

[marinesteam]

Richard,

Is there a particular reason that you are asking about using aluminum instead of Babbitt?

It seems to me that aluminum doesn't fill any of the requirements of a good bearing material and would be much more difficult to melt & pour than Babbitt.

Take a look at

http://www.thesteamboatingforum.net/for ... it=babbitt

Babbitt isn't that difficult as long as you prepare before getting the metal hot.

Ken

[Richard Orr]

In response to the question about why to use aluminum for bearing material: I have worked with babbit in re-building my steam engine. Fun stuff, but a we bit expensive for the amount you get. But the more important reason is that babbit material may be hard to come by in Central Am. where we will be living - aluminum can always be scrounged up some place or other. I did come across a person who used aluminum for bearing liner but never heard about the long range results.
What interests me about leather piston cups is that I've heard leather has a tendency to burnish rather than score a cylinder.

[Maltelec]

Leather can wear away metal quite easily, just look at a shaft using an old leather oil seal.