Hey Repairer's!

[tubaguy9]

So...what do you use for lapping compound?
Diamond, Garnet, Pumic, Aluminum Oxide, Silicon Carbide, etc? And why?
I've been learning about using the Pumice way of lapping valves...But have heard all the positives and negatives...
I'll let you guys respond and sort out the jokes...

[tubaguy9]

The pumice comes from the lava soap we use...not necessarily pumice itself...
I should have specified

[Dan Schultz]

Clover brand silicon-carbide lapping compound in various grits. 280 for heavy-duty work like refitting a bell tenon to 1200 for fine stuff. For very light-duty things like removing piston deposits and burrs I use Go-Jo Orange Hand Cleaner with pumice.

[tubaguy9]

I have found that 600--1000--2000 grit paper (with a bit of valve oil squirted on it) works quite well with a lapping block.

What about lapping the valve casing and not the valve itself? Do you take an undersized ground casing mandrel with
sandpaper and valve oil to it?
Wanting to learn as much as possible

[tubaguy9]

This thread scares me...

But I guarantee that your horn's valves have been lapped...

[tubaguy9]

This thread scares me...

But I guarantee that your horn's valves have been lapped...

Not since they've left the factory. I guarantee you that.

Maybe not since they left the factory...but they have been lapped.
If somehow trauma happens to the valve casing, it almost has to be lapped to get it to work right...

[windshieldbug]

This thread scares ME thinking of valve trauma like that...