helium super leak

[tope]

I have a helium super leak that is too small to locate. Some suggested coating all the connections with the brand name Estane polyurethane. You mix 10 g Estane with 50 g methylene chloride and 50 g acetone and paint the solution on the suspected leak areas. Has anyone tried fixing a very small vacuum leak in this manner?

 

[eigenstate]

I've not tried the Estane-poly method, but you may consider applying a thin coating of Stycast to the suspected area (Lakeshore carries the stuff).

 

[Larry0322]

I have experienced such a problem with a dewar feed leak several years ago.
We us a spray silicone product to seal the leak and it worked very well. I have looked on the internet to see if I could find the vendor, but no luck.