Homemade lapping compound
I have a major shutdown coming up and am looking at having to do a ton of lapping and polishing when we do tear down and rebuilds. ??Would graded silicon carbide powder($4 to $12/lb) mixed with 50/50 mineral oil and light grease work as well as "Clover Compound"? Making our own would save a bunch. Any feedback appreciated.
the old sailor
You would need 2240lb less the weight of the oil to make a ton of lapping compound. Or 2000lb if you are in the USA.
Personally, I wouldn't mess with it. You are already saving x$ by reconditioning a sealing or bearing surface. But if its comming out of your pocket, you'd be surprised what you can do with toothpaste.
I lap on a daily basis with Clover. I used to by dry but would never do it again. I like the consistency of premix and really don't like the hassle of mixing. Dave
I lap on a daily basis with Clover. I used to buy dry but would never do it again. I like the consistency of premix and really don't like the hassle of mixing. Dave
What are you trying to lap. If you are trying to lap some half inch valves, use the Clover. If you have an 8 foot runner to repair, forget buying that stuff.
Buy the Silicon Carbide in big carboys, lard oil in barrels,and kerosene. Mix, drip, and lap.
I use the garnet grit used for sandblasting for very coarse lapping... Makes stones flat in no time when rubbed against glass..
YEARS ago my dad used to buy military surplus plug in radio crystals 10 for a dollar. He would remove the silicone crystal (4 screws) and grind it using Comet Cleanser on a piece of glass to change the frequency to use in C B radio base stations. At the time (1950's) IIRC C B crystals were $5. each!
Don't know if the Comet would work for you but he sure did some fine grinding with it.
I recently lapped a 1 5/8" brass tube to reduce the out-of-round error it came with. Used as a cylinder in a replica of James Watts original experiment
Since the only lapping compound we have sittin around is really coarse, i used Ajax, a brand of household cleaner. Seems to be a mixture of something like diatomaceous earth, soap and sand. I mixed it with some kerosene, let the sand settle, poured it off, let the fines settle, poured it off, mix the fines with oil and go !
Worked fine. Obviously way too much trouble for anything bigger or any serious number of workpieces.
You gotta be careful, sand with grains as big as 10-20 thou is not exactly what you want in a lapping compound....
Job/work piece description would be helpful...
If you are lapping a soft material you may wish to use a lapping compound that breaks down with use, so as not to continue lapping...
Bon Ami cleanser springs to mind.
My shop is connected to a place called Covington engineering. They sell all kinds of lapidary supplies from graded carbide to aluminum oxide. Depending on what is is you are lapping and how fine a finish you need you could even step up to a cerium or super cerium paste.