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Post by Bob on Dec 3, 2021 16:10:10 GMT -5
I've probably been using my 10" lapidary saw now for freehand trimming maybe half a year and am now on my 5th or 6th gallon of oil. I bought 1 gal of dedicated lapidary saw oil from KN. I have bought at least 1 gal of horse laxative mineral oil from the local farm and ranch supply. I have bought several gals on Amazon of "food grade mineral oil". Just today from Highland Park has arrived a 5 gal container of "pure low viscosity mineral oil". It was no more expensive than others at that quantity.
Some of you cut a lot. Does the brand and type of oil matter? I've never attempted to compare or test and would have no idea how to do that.
If it's merely a matter of viscosity, with low being better, I'm going to guess that that might not be hard to test. Is the viscosity important and is lower better?
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Post by Starguy on Dec 3, 2021 16:24:19 GMT -5
BobAny food grade mineral oils should work. I knew an old timer that used a mix of kerosene and motor oil in his slab saw.
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rrod
having dreams about rocks
Member since December 2020
Posts: 72
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Post by rrod on Dec 3, 2021 19:44:35 GMT -5
I have bought at least 1 gal of horse laxative mineral oil from the local farm and ranch supply. This guy knows how to party!
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Post by broseph82 on Dec 3, 2021 19:58:52 GMT -5
I've probably been using my 10" lapidary saw now for freehand trimming maybe half a year and am now on my 5th or 6th gallon of oil. I bought 1 gal of dedicated lapidary saw oil from KN. I have bought at least 1 gal of horse laxative mineral oil from the local farm and ranch supply. I have bought several gals on Amazon of "food grade mineral oil". Just today from Highland Park has arrived a 5 gal container of "pure low viscosity mineral oil". It was no more expensive than others at that quantity. Some of you cut a lot. Does the brand and type of oil matter? I've never attempted to compare or test and would have no idea how to do that. If it's merely a matter of viscosity, with low being better, I'm going to guess that that might not be hard to test. Is the viscosity important and is lower better? I think he relabels Stellar Lubricant oil as his own. If you’re out in the West you can get a good deal. Nice and thin with an orange scent to it.
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Post by hummingbirdstones2 on Dec 3, 2021 20:02:24 GMT -5
Yeah, the thinner "white" oils flush through the cut quicker. Better cooling and lubrication for the blade.
The stuff I've been using is called Finavestan U 85 NF. Not "food grade", but approved for pumps and equipment not directly in contact with foodstuffs.
If you look up the data sheets on this stuff it will give you some numbers for comparison with other types.
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Post by rockpickerforever on Dec 3, 2021 22:11:06 GMT -5
Bob Any food grade mineral oils should work. I knew an old timer that used a mix of kerosene and motor oil in his slab saw. Hey Brent, just an FYI. The Bob you have been conversing with has a different screen name (it's not bob), he is actually "petrifiedbob." Tag him like this: @petrifiedbob It will post like this: Bob The person you tagged with the screen name of bob has not been logged in since 2005. There are a few RTHLings that use a screen name different from their account name. On a computer, you can hover your mouse over the apparent name to see the actual name. On a phone, you have to go to their profile page to fInd out. I know these things because I have been here forever, lol. Not a huge thing, but I assume you'd like him to be notified of your post.
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Post by Starguy on Dec 4, 2021 1:01:05 GMT -5
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Post by rockpickerforever on Dec 4, 2021 1:07:02 GMT -5
You are most welcome, Brent Starguy.
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Post by Rockoonz on Dec 6, 2021 23:29:20 GMT -5
BobAny food grade mineral oils should work. I knew an old timer that used a mix of kerosene and motor oil in his slab saw. Flash point is important too. I went to a sale at a shop that burned to the ground using fuel instead of the correct oil to "save money".
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Post by Bob on Dec 7, 2021 0:24:58 GMT -5
Don't worry I won't be using low grade jet fuel (kerosene) in my saw or mixing it with my oil. I've seen plenty of sparks in my cutting.
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Post by Peruano on Dec 7, 2021 11:52:15 GMT -5
There are two issues here. Is it all the same? and Are the differences important a. to Bob; b. to most of the community.
Certainly specific gravity and viscosity vary and are important (to me). I can tell that the particulates (rock flour) settle out markedly in light oils (forming a almost dried paint layer in the saw tank) and tend to stay suspended forming a pudding mud in heavier oils. If the crap is being carried to your blade big time rather than less so, it probably is affecting your cutting temp and rate. However that being settled out versus suspended sure influences how to and how often the saw is cleaned. I use both heavy and light oils and in fact tend to mix them in response to seasonal temperatures. The thick stuff is a bit too stiff in winter shop temps. Saw oil is like many other consumer products -- you can spend as much as you want, but price is important too!
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Post by stephan on Dec 7, 2021 14:52:08 GMT -5
I have bought at least 1 gal of horse laxative mineral oil from the local farm and ranch supply. This is how our club bought it, as that was the best price.
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Post by greig on Dec 8, 2021 9:48:04 GMT -5
Bob Any food grade mineral oils should work. I knew an old timer that used a mix of kerosene and motor oil in his slab saw. Flash point is important too. I went to a sale at a shop that burned to the ground using fuel instead of the correct oil to "save money". I never considered that the saw oil could catch fire. I have seen plenty of sparks, especially when stone is dry(ish). duh. I will be more careful in the future.
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Post by Bob on Feb 14, 2022 12:40:11 GMT -5
Well, last night I used up the last of my normal cheap mineral oil, and started using the "special" Highland Park oil from the 5 gal container. I have poured a little of each into a container to compare later as to whether I can tell any difference or not. As I was pouring the new oil and seeing it splash a little, I thought I might have seen evidence of that it's thinner (less viscosity) but wasn't sure. Ditto during the cutting--couldn't be sure.
But one very surprising thing happened. In recent weeks, as I've been changing the oil tank of my saw after every cutting session, I've noticed that it takes about 45 mins of continuous hand trimming for me to start seeing brownish crud starting to appear in the oil enough to be noticeable (as long as I don't cut something that immediately screws up the oil like hematite). And I've learned from experience that if I keep up the pace, about 30 mins later it will be cloudy brown enough for me to have a bit of trouble seeing my cut marks on the rocks through the oil. So I have to stop for that day. So I generally can trim no longer than 75 mins max and so most sessions I just call it an end after an hour. Obviously, if I had a saw with a larger tank than my 1 gal I could go longer, but I like how small and portably my saw is. I can lift the whole thing full of oil and move it in my garage from one place to another.
But I kept waiting for it to happen with this new HP oil. Finally, after 1.5 hrs of continuous hand trimming--the longest I had ever gone--I started to see the brown, but by then my hands were tired and I needed to quit anyway. But I could still see through the oil fine. So for some reason, this oil allowed me to cut much long until it was cloudy--about twice as long which seems impossible. I wonder, if it really is thinner, if rock dust in it settles so much more quickly that the oil in the tank stays cleaner longer because the rock dust in it is settling to the bottom significantly faster.
"HP Cool Cut high-performance low odor, non-toxic commercial mineral oil cutting coolant with high flash point for all cutting environments" is what HP says on their website. Of course, this is just one use but if this continues I will be very happy and glad I purchased this.
I've been wondering what type of tests to do on the two different types of oil I have in little containers. I thought one test might be to drop something in, and time how long in seconds to drop to the bottom equal distances, such as a little rock chip or BB. I guess it ought to drop faster in thinner oil. Another might be to put in a strip of cardboard from a cereal box, and time how long it takes the oil to soak to the top. I can of course also visually compare the meniscus line, but I bet that won't be easy. If you have ideas, please let me know.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,558
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Post by jamesp on Feb 14, 2022 13:24:31 GMT -5
When I bring home a load of rocks I try to saw them all over a week's time in a 'cutfest' to get the task over with. They are often larger 5 to 10 pound dead hard silicified corals or 2 to 4 pound agate cobbles cut on an 18 inch saw. I do use 75% diesel fuel mixed with 25% unused 10W-40 to reduce the flash point.
After they are sawn they are set out in the weather in full sun on a sheet of black rubber conveyor belting for a month or two depending on the season until the fuel/oil smell has about evaporated out. The smell is almost unnoticeable by then.
I have used the expensive rock sawing oils. They perform fine but the particles settle slowly and get stirred back up after the first rock is cut making the oil thicker than I like. They also 'wear out' quicker.
To me the best oil to use is the one that precipitates rock mud out the fastest and of course doesn't slow the saw down while cutting at a good rate. This has been my experience with the 75/25 diesel/10W-40.
Clean oil is the best oil for low energy sawing IMO. By morning the mud in the petroleum brew has settled to the bottom and began to become tacky and the oil is dead clear. About all the suspended mud is only from that day's cuts. When cleanout time after a month of not sawing a trowel is needed to help peel the tar like layer congealed at the bottom and can not be run thru a cotton sheet to filter it because all the rock mud has turned into sheet of rubber like substance and the oil is dead clear.
The saw blade is well adjusted to perpendicular and the finish on the face of the rocks is close to a 400 grit finish.
The smell sucks and waterproof gloves are the only way to go when using the diesel mix. Probably not everyone's choice but it works for me.
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Post by Bob on Feb 21, 2022 10:13:56 GMT -5
Well, I tested the 2 oils. I dropped a BB in each. It dropped so fast could not tell difference. But when I swirled it around some in bottom of this transparent plastic container, I thought it might have swirled just a tiny bit faster in the HP oil. Then I dipped a toothpick in each and watched the drop form and fall off and could not tell any difference. Then I put a drop on a brown grocery sack, and timed how long it took the drop to be absorbed into the paper and no actual shiny oil visible: HP 2:01 mins and other 4:13. Then I cut two strips of this grocery sack paper, 2" x 1/4", and put the end in the oil and timed how long for oil to soak all the way to the top. The paper was about half in the oil starting. HP 40 mins; other 63 mins.
A day later, I have the grocery sack paper on which I put the drop. I drew a line around it when the oil was absorbed. With both oils, they have gone past that line about 3-4mm. The wet parts of the paper are just round wet spots on the paper darker than the unused paper. The HP oil spot though is a little bit lighter, as if it's evaporating to the air a bit faster.
So it does look to me like the HP oil is thinner and maybe that accounts for the better cutting I'm experiencing. It costs about $25/gallon, and based upon my experience thus far it's well worth it. I really like that the rock dust settles out if it faster too and I get clear oil to pour back in quickly.
I have noticed that Minn Lapid Supply sells its own oil also, similarly priced, which is called Slick-Cut, which is also supposed to be a blend of oils. When I use up this HP oil, I might try it out.
I think I have also noticed a bit more misting into the air from the HP oil, so perhaps misting increases the thinner the oil.
Before buying this HP oil, I had perhaps gone through 10 gals in a bit over a year of cheap mineral oil horse laxative and local F&R supply and also basic mineral oil sold on Amazon by the gal.
Keep in mind I'm only doing hand trimming not any auto-feed slabbing.
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