Problem with 90mm Angulon

[Deleted member 19578]

I picked up a 90mm angulon & noticed there seemed to be something resembling "Shneideritis" around the edge of the front cell, but when I removed the cell I found a lot of black dust... Turns out the black paint has flaked off of the glass on both the front & the rear cells.

So- does anyone have a good solution for re-painting the glass? I don't want to use something that will either flake off again, or might not dry correctly & gunk up the shutter.

TIA
John Moore

 

[unclemack]

Hi John, that's what Schniederitis is - anti-reflective paint on the ground edges of elements coming adrift in tiny bubbles and then falling off as flakes.
Remove all the original paint first of course, I preferred to scrape it off rather than risk abrasives or wire brushes etc.
I've used different types of matt black paint, all were fine, not sure what Schnieder used (but it comes off so...)
An artist's rigger (long hair) brush I find is the easiest to use for this job.
Lightly press the element or cell with blu-tak to a slowly-rotating mount until it runs true, hold the brush steady - like on a potter's wheel.
Let all solvents fully evaporate before reassembly - a few days if possible.

 

[Deleted member 19578]

Unclemack- thanks for the info... I can do that!

 

[John Koehrer]

I've used frisket to mask off the f&r surfaces & sprayed it with flat black paint from ye olde hobbye emporium. 3-4 very light coats, barely misting the glass so it doesn't run & builds up slowly.
For either method let it dry very thoroughly, at least overnight.