what do you use for gluing optics and components in place?

[ghosttrain]

Thanks. So you mean alcohol vapor wont damage it as well and alcohol can be used for cleaning the optics too as long as you dont physically touch the optics with a sponge/cloth/etc or did I totally misunderstand?

[planters]

No, you got it.

Alcohols including isopropyl (rubbing), ethanol and methanol are all fine with optics. Very pure methanol is considered the standard for last stage extremely clean optics. You will often find less than the purest alcohols, if allowed to evaporate on the optic, will leave a residue from impurities. If that occurs and you can not access the best methanol then use a puff of air to blow the drops off the surface before they can evaporate. If you do this , you will see the same less than perfect alcohol will leave little to no residue.

Cleaning is like government, a necessary evil. The less the better.

[ghosttrain]

Great tip, thanks.
Am I correct to assume if I dont manage to blow the drops off in time and have residue on the optics I can just apply more alcohol? Or is that not desired and similar to having a cloth on the optics?

[planters]

Yes, no harm done. Just repeat until you're satisfied.

[masterpj]

oh scanner mirrors! I thought just optics.. in that case I recommend 2 part epoxy. Reason being it can be removed with a hot soldering iron incase you break a set of mirrors.. I found it very tough to glue mirrors on square.. hanging upside down trick hasn't worked for me.. I had to eyeball it with one eye closed.. but it was very confusing even when looking at it from different angles.. I also noticed a lot of glues have the tendency to pull the mirror in a direction you don't want to as it dries.

Pangolin also has a jig to glue mirrors on.. I wish jigs like these were public or available to buy but sadly since there are no standard scanner sizes from varying brands and models you'd need such a jig per product.. which is a shame.

[planters]

Pangolin also has a jig to glue mirrors on.. I wish jigs like these were public or available to buy but sadly since there are no standard scanner sizes from varying brands and models you'd need such a jig per product.. which is a shame.

No, you don't really need a custom jig if you are not looking for assembly line convenience. You can use the scanner mounting block to hold the motor and rotate it before clamping to get the shaft notch horizontal. What you need is a precision XYZ stage such as is used for positioning optics. Tab the mirror in place with dbl sticky tape or a spot of RTV and then move the mirror into position, toothpick a drop of glue and then lower the Z control to achieve contact. This takes a little set up, but is not frustrating.

[ghosttrain]

Dont the shafts holding the scanner mirrors have an indentation on their tip where the mirrors can be put? Or is it just a flat area? Hard to tell since mines whole area is covered with white epoxy.

[planters]

The smaller ones do and that is what I meant by the notch. The really big or heavy duty scanners have a slot some even with screw clamps installed. The difficulty that requires a jig or a precision movement device is that the mirror may not be placed dead on centered on the shaft or the mirror's long axis may not be glued parallel to the shaft. The notch will not prevent these errors.

[ghosttrain]

I see. Thanks for all the info.

BTW since we are talking about scanner mirrors now Ive always had this question: is there an advantage in term of performance with using octagon shaped mirror instead of cutting an ordinary rectangle? The first one seems harder to cut perfectly.

[planters]

The bane of scanners is the mass of the mirror. There is a wealth of information on this site regarding the trade off of mirror size and the slowing of scanning speed doe to inertia. The corners of a rectangle are not utilized effectively in X/Y scanning and the reduction of inertia is worth the effort.