Mirror de-silvering???

[Billy_Mizzen]

Does anyone here have a clever and proven method/trick for stopping mirrors de-silvering, all mirrors seem to suffer this problem eventually, there must be a solution?

 

[AntarcticPilot]

Does anyone here have a clever and proven method/trick for stopping mirrors de-silvering, all mirrors seem to suffer this problem eventually, there must be a solution?

Use steel mirrors. Any "silvered" mirror is going to be susceptible to the the effects of damp.

 

[Vara]

Don't put Steradent in the locker behind the mirror.

A two week cruise with a denture wearer buggered my mirror.

 

[electrosys]

I bought a cheap sextant some 10 years ago - one reason it was so cheap was that it's mirrors had turned to patchy glass !
I duly cut some new mirrors from the girl-friend's cosmetic case, and painted their backs and edges with Hammerite - paying extra care along the edges which I reckoned were more vulnerable to salt air.

They've stood the test of time (so far) - which is more than can be said for my relationship with that girl-friend. Perhaps I should have asked before nicking the mirror ?

 

[pvb]

Mirrors are cheap. Replace them if they look iffy.

 

[Searush]

Hammeriting the backs & sides of new mirrors sounds a good idea. Most mirrors will be cut from larger ones & the edges will be very susceptible to corrosion.

 

[doug748]

Mine was/is starting to go. I varnished the back with traditional yacht stiff about ten years ago. It has got no worse since.

 

[Billy_Mizzen]

All good suggestions, I was thinking maybe a couple of coats of West epoxy on the back of a new mirror would do the trick!

 

[vikinglish]

All good suggestions, I was thinking maybe a couple of coats of West epoxy on the back of a new mirror would do the trick!

I'm pretty sure that epoxy will work better than hammerite... Going to try it myself as have the same problem

 

[electrosys]

I'm pretty sure that epoxy will work better than hammerite... Going to try it myself as have the same problem

I probably would have used epoxy myself in preference to Hammerite on those sextant mirrors - but at that time Hammerite I had, and epoxy I had not ...

 

[Rigger Mortice]

Just make sure that the solvents in the Epoxy or Hammerite don't damge the existing paint. Personally, I would just use yacht varnish.

The other thing to do is to make sure that, when mounted, there is a small air gap behind the mirror so that a degree of ventilation exists.

 

[nigel1]

Its too late for the mirrors on my 10yr old bene.
Anyone know how easy/difficult it is to remove the mirrors from the cabinet doors, any idea on what bene used as an adhesive??

 

[MontyMariner]

epoxy I had not ...

What! No Araldite knocking around the house.

 

[alahol2]

For those who already have an affected mirror, it is very easy and effective to just paint a 'frame' onto the front of the mirror. I've now done this on a couple of boats as the mirrors were in screwed and glued frames which would have caused damage to the bulkheads when trying to remove.

 

[nigelmercier]

I bought a cheap sextant some 10 years ago - one reason it was so cheap was that it's mirrors had turned to patchy glass !
I duly cut some new mirrors from the girl-friend's cosmetic case...

Are sextant mirrors not surface silvered?

 

[Clyde_Wanderer]

Don't put Steradent in the locker behind the mirror.

A two week cruise with a denture wearer buggered my mirror.

By Gum that was unfortunate!
C_W

 

[Clyde_Wanderer]

Use steel mirrors. Any "silvered" mirror is going to be susceptible to the the effects of damp.

Ok so long as they are better than the ones in Tarbert harbour shower rooms
I came out like a butchers table after shaving in them

S/S polishing mops for drills and the various grades of soaps can be bought very cheaply from good tool stores.
Catering equipment s/s sheet will be easily polished up and easily available from such companies.
C_W

 

[electrosys]

Are sextant mirrors not surface silvered?

You have the advantage of me ... I don't know what 'surface silvered' means.

The two small mirrors looked like ordinary glass mirrors to me - with patches of blackened mildewy silver flaking off their backs. One was square: roughly the size of a small postage-stamp, the other - rather than being 'half-silver, half-glass' - was simply half-sized (which made replacement straightforward).

So - I simply cut two new mirrors from a donor of approximately the same thickness glass - applied the paint, then re-calibrated the sextant. That's easy to do out here in The Fens - no need for artificial horizons - we've got the real thing all around !

Just done a Google:
found a bloke who's written a webpage about mirror replacement - the buqqer's copied my technique of using float glass mirrors - and even uses Hammerite ... http://sextantbook.com/category/new-sextant-mirrors-for-old/