Removing secondary from GSO(?) holder

[markse68]

I’ve decided I have secondary induced mild astigmatism that’s messing up my star shapes (stars change shape with different colour filters slight focus shifting) so I thought i’d remove the secondary and re-bond it with the usual 3 blobs of forgiving silicone or double sided tape. Simple huh 🤔 Anybody succeeded in doing this with one of these mirrors and their housings? It’s like the old GSO plastic mount except it’s aluminium and the shroud around the mirrors edge makes it very difficult to get in there to pry it out. I’ve tried soaking it in alcohol, acetone, warming the housing with hot air but it doesn’t want to budge. Maybe it’s siliconed in 

I’ll keep at it - hoping the black paint will give eventually  but wondered if anyone had tried and succeeded and had any tips? Thanks!

Mark

 

[benzomobile]

I definetely hate GSO  mechanic  solutions ...

Beppe

[markse68]

16 minutes ago, benzomobile said:

I definetely hate GSO  mechanic  solutions ...

Beppe

yes although apart from the extra obstruction (several mm) it could be quite a neat solution- there’s screw holes both ends for clips and there was one clip I removed, but then they went and bonded it with super strong adhesive 🤔🤦‍♂️ hopefully a longer soak in acetone will do the trick 

Mark

[benzomobile]

8 minutes ago, markse68 said:

yes although apart from the extra obstruction (several mm) it could be quite a neat solution- there’s screw holes both ends for clips and there was one clip I removed, but then they went and bonded it with super strong adhesive 🤔🤦‍♂️ hopefully a longer soak in acetone will do the trick 

Mark

Do you you tried soaking it in boiling water?

B

[markse68]

21 hours ago, benzomobile said:

Do you you tried soaking it in boiling water?

B

no i didn’t think of that but i will if acetone doesn’t work- thanks!

ps i don’t know it’s gso- it came with my frankenscope which i think has vixen spider.

Edited September 8, 2021 by markse68

[Bruce Leeroy]

I've never removed a secondary mirror but from memory I think I've read about using a guitar string or fishing line to saw/rasp behind the mirror....take that advice with caution👍😬

[benzomobile]

1 hour ago, Bruce Leeroy said:

I've never removed a secondary mirror but from memory I think I've read about using a guitar string or fishing line to saw/rasp behind the mirror....take that advice with caution👍😬

I am afraid that the seat where the mirror is glued has deep edges ...

B

[markse68]

Success!  

Soaking overnight did the trick- it was stuck with silicone but with no spacing to allow it to give. I lost a bit of the bottom rear edge but that shouldn’t affect anything hopefully unless it’s released some stress or something and causes the first surface to warp?

I couldn’t get behind it to try a thread Bruce unfortunately.

I’ll stick it back with VHB tape and the top clip for safety and see if that fixes the astigmatism 🤞

Mark

[Bruce Leeroy]

25 minutes ago, benzomobile said:

I am afraid that the seat where the mirror is glued has deep edges ...

I did see that but I thought the 45 degree angle of the mirror may have drawn it down and under 👍🤓.

[benzomobile]

34 minutes ago, markse68 said:

 ...  some stress or something and causes the first surface to warp?

...

I’ll stick it back with VHB tape and the top clip for safety and see if that fixes the astigmatism 🤞

 

I think you don't have to worry about that.

Well done!

B

[markse68]

Thanks Benzomobile. It’s back together now and the sky is clear 😃 Time to find out if it made a difference