Any experience using "Stop-Off" (or a hack) when brazing.

[Captain Dirty]

"Stop-Off" is a sort of anti-flux that prevents braze from adhering to the base metal. It sounds like an elegant way to attach a flanged nut or even threaded small plate to another plate by putting stop-off on the threads of a bolt, using the bolt to hold the nut in place while brazing, and then removing the bolt to replace it with a zerk or similar. Has anyone had experience? Does it require a well practiced touch?

Most of the sites I hit were industrial suppliers with industrial size (1kg) containers and without prices. I am given to understand the stuff is pricey. Are there cheaper but effective hacks (one forum suggested liquid White-Out)?

My intention is to install 2 zerks in the lower flange of my snowblower chute. The metal is thinner than the length of the 1/4-28 nipple on the 90° zerk, and I am fearful that if I drill, tap, and just grind off any of the nipple that protrudes, I will not have reliable thread engagement. I do not have enough space between the flange and the auger housing to manipulate my MIG gun, so brazing seems more appropriate. There is even less space between the top flange and the toothed flange engaged by the chute rotation motor. Comments or suggestions? TIA

 

[California]

Could you tap a small plate, then braze that plate over a hole in the thin material?

 

[mrmikey]

Does it have to be a 1/4-28 grease nipple? Can you get away with a 1/8 NPT coupling (cut in half if the length is a factor,) welded to the chute where necessary and use a 1/8 npt grease nipple?.