Tag Archives: RTV

A quick and easy way to snug up a loose flip-up lens cap so it stays on

I like flip-up scope caps and, in general, I have had very good luck with Butler Creek.  Recently, I bought a scope cap for my Hawke air rifle scope’s front objective and the thing wasn’t tight enough to stay on when I would flip it up.  There’s a very simple way to fix a loose cap that I want to share.

This isn’t a magical fix – you do want a cap to be real close to the size you need.  In my case the cap was just a hair too big.  For the “fix”, remove the objective and smear a bit of black silicone RTV glue or Black Goop works too) around the inside of the cap and let the glue fully cure with the cap off the scopeDO NOT STICK IT ON THE SCOPE WHILE WET!  You are using the glue to add mass and fill the space – you do not want to glue your scope on.  I let my dry overnight and the problem is always fixed.

Here is the lens cap and I used black Goop on this one and let it dry & cure all the way before I reinstalled it.  It’s nice and snug now.

Here’s the finished product on my Galadius:

I hope this helps you out.  I prefer black just for looks but you could use any color of rubbery cement you have – just keep it inside the cap out of sight.  What I use more than anything is Permatex Black RTV just because I keep in stock for repairs.


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