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Epoxy matrix bearing material DIY

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PekkaNF:
I have been considering trying epoxy filled with materials to make plain bearings.

Latest inspiration came from this thread:
http://www.cnczone.com/forums/epoxy-granite/126563-epoxy-bearing-material-method.html
Attached a link to a powerpoint presentation:
Bearing - CNCZ.ppt

3 parts Bronze powder
2 parts Aluminum powder
8 parts Molybdenum disulfide powder
3 parts Teflon powder
3 parts Calcium carbonate powder
1 part Graphite powder
Sufficient epoxy to make a paste with the consistency of soft butter

I pretty much all other materials, but have problem with two incredients.

First is teflon. Most DIY bearing composites seem to contain teflon, probably counting keying it mechanically on matrix instead of bonding?

Don't really get the use here, it is very difficult to bond. Proper teflon powder with epoxy wetting coating is hard to get. I'm considering other plastics. POM plastic granulate is easier to get, but particle size is closer to 2 mm....metal powders I have are around 60 microns.

Another part is calsioum carbonate. I know that it is normal filler for epoxy composites. But I am having hard time understanding use and idea behind it. If it is pure calsite it's hardness is about #3 mohs - i.e. about the same than copper, but lime stone too is calsium carbonate and it sounds abrassive. Also to get kilo of that is not trivial. As a nutrient suplement it costs about 18€/100g, other forms are not that pure and as a epoxy filler grade I sould buy 50 kg of it...

Ideas?

Pekka

John Rudd:
Calcium carbonate = chalk....
Local school supplies?

naffsharpe (Nathan):
To me it looks like the recipe is an attempt to produce an epoxy version of a sintered bearing material. Instead of having the porous nature of sintered materials it is using the CACO3 as a "sponge " to absorb and later release oil/lube.
This idea would only work with the exposed CACO3 so I may be, and quite possibly am , totally wrong-----again!
Nathan.

PekkaNF:
Nathan you may be onto something here....Pretty much all of the fillers will be eposed at the bearing surface. Clearly the idea here is work under lubrication too. Then I wonder the role of the teflon even more.

Didn't come to think that...I was onl thinking of dry operation and transfer of graphite/teflon onto sliding  surface. Dry operation....I could drop the calsium carbonate out or substitute with some bulk type filler?

Pekka

naffsharpe (Nathan):
I think that the Teflon/PTFE should be omitted for a dry bearing at high speeds , (it releases, I think, Hydrogen Cyanide under pressure/heat),and increase both the Moly and Graphite. This then allows the metallic materials to be lubricated in a dry form. That then begs the question, why use a filler (CACO3) , if no external lube is to be used?
If we then use,  at some time, a water soluble cutting fluid , then the Moly will float on a Graphite slurry because the Moly will reject the H2O but the Graphite will accept it ?
Again, I could be and possibly am, wrong !
Am I digging a hole for myself? To be interred by a more knowledgeable member is not the way I want to go!!
Nathan.

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