Lubricating oil for sonic testers

I got my new ultrasonic tester out today to check it out and it says to use a drop of "lubricating oil" on the probe, but it didn't come with any. Looking on the interweb, a type of glycerin seems to be the most used product, but on cast iron, vegetable oil could be a substitute? What do you use?

Thanks, Brian

I use grease to make the soundwaves come through the curved cylinders onto the flat probe. I also do not use the recommended iron calibration value, but use the one giving best corresponding measurement on top of a cylinder near a waterhole that you can auctally measure with a dial caliper.

Mine came with a small bottle of testing solution, I think it is the same stuff use for medical sonic testing
I have use white lubriplate type grease and got the same numbers so maybe you can to
Find a smooth thin machine area on a head or block and measure it with a micrometer or even a set of dial calipers and then measure it with your sonic tester and see how much difference you get If it is a small amount, less than .0030 I would use it and go from there
Can you calibrate your tester to a known thickness by adjusting the frequency ? If so maybe you can do that also

My tester came with a small quantity of silicone grease, when it ran out I use silicone dielectric grease (Dow DC4); no difference when comparing the two.

Lubriplate engine assembly grease works well for me. I also like using a mic or caliper to verify the read out.

Dielectric grease worked for me also, also did the test on a couple of measurable spots on the block. The ears where the motor mounts bolt up work good for me.

Just got mine couple days ago. Was wondering the same thing as i dont know what glycerin is.

I bought a case of 4oz bottles years ago from Grainger when it was much much cheaper. It will last several lifetimes. Lol. Amazon has several list too.


https://www.grainger.com/mobile/product/REED-INSTRUMENTS-Ultrasonic-Couplant-Gel-161D96

You need to seek out the kindest nurse you know and ask for some ultrasound gel. The stuff they smear on momma's belly. Nothing finer.


If you are single make it a dual purpose mission. : D

hahaha, yeah. Can you use baby oil? I think you can get the ultrasound gel at rite-aid.

Vasaline it works for anything

ok, yeah, great! Ill try that.

Another vote for vasoline, cheap easy to find and works great

Lithium grease works well. Hell, I've even used spit in an emergency.. No Joke..

Dave

I was recently playing around w/ a sonic tester a friend of mine loaned me. It came w/ a bottle of special oil and I compared the readings from the supplied oil to regular white lithium grease I've been told to use in the past. They read exactly the same.

I tried the cooking oil and it works great as well.