mirror cell support

[alacant]

Hi everyone

I need to replace the floating mirror support pads on an ES pn208. The type of material upon which the mirror rests is a bit like silicone sealant which has been allowed to set. It's quite firm but is able to hold the mirror with minimal slip.

I've messaged Bresser but so far nada. 

Question. Does anyone know the material from which the pads are made and/or a possible source?

TIA

Edited January 13 by alacant

[Tomatobro]

If you have no luck in sourcing/identifying the original pads then I would suggest 3M VHB tape. There are lots of copies of this material but VHB is the only one I would recommend.

I think its available as discs as well. A word of caution in that make sure your positioning is spot on as you (with these size of pads anyway) will not get a second chance

[Ricochet]

I don't get the ‘non slip' comment. Are they not PTFE? The pads supporting the mirror whilst not preventing thermal expansion/contraction of the glass is the entire point.

As for a source it is the sort thing that you can often be found available cut to custom sizes on eBay.

[alacant]

6 hours ago, Ricochet said:

‘non slip' comment

OK. Sorry.
Take a ptfe pad and push it against a glass surface; it slides easily.
Now take one of the mirror support pads and slide it against the same surface. There is much more resistance, as if it is tending to stick to the glass, but without actually sticking.

Cheers

Edited January 13 by alacant

[Tomatobro]

I may have got this wrong in that it looked in the picture as if the white pads were stuck to the underside of the mirror glass and held the mirror in place. If there are radial mirror restraints then the pads just push against the back of  the mirror and offer multipoint support. In which case they need to be able to slide and not be stuck to the underside of the mirror.

[alacant]

20 minutes ago, Tomatobro said:

not be stuck

Correct. But...

... at the same time, the pads do not allow the mirror to slip. They are soft(ish). They provide friction, unlike e.g. hard acrylic. The latter would allow the glass to slide easily. 

I think the idea is to allow for expansion and contraction of the glass with temperature, but prevent slipping as the telescope changes angle.

Edited January 13 by alacant