painting back/ sides of secondary ?

[jonstarrysky]

Anyone tried painting International blackboard paint onto the back / side of a secondary mirror without priming first ? It wont run or anything ?

My scope have laid in bits for far too long Flocking is done, new focusser done, Catseye hotspot is stuck down, maybe if I put the mirrors back it will work again :hello2:Jon

[John]

I don't think the back of the secondary will make any difference one way or another but I have seen the sides blackened or flocked to reduce another potential source of stray reflections. I'm not sure about priming but I've a hunch that you don't need to.

[jonstarrysky]

thanks for that John. I did wonder why ppl paint the back as well, reflected light would have to bounce again off the OTA before it might reach the focusser. But light reflected off the sides can go straight down the focusser. Maybe asthetics, to get the whole inside of the scope black to put the mind at rest.

[TopHouse]

I did with mine, I gave the back and sides a good wipe with isopropyl first, then just applied the blackboard paint, worked fine.

Doing the back not only looks better, it gives you less edges to be careful with