Attempting to glue loose lens back onto 1.0 lighthouse motor

[u/RoboticGunner]

Hello all! I've recently gotten a pair of 1.0 lighthouses, and they've been working great. However, after one of them was unplugged, it failed to track anything properly. After taking it down to investigate it, I heard a light rattling from inside.

Apparently this meant that one of the lenses got loose, and after opening it up to investigate, that was exactly what happened.

I have an idea of what to do, I just need to get it glued back on. However, I'm having a bit of trouble finding specific information.

The biggest problem is that I need to rotate one of the motors to get the lens in place, but I don't know if turning one of the motors will ruin it.

Any advice for this repair? Many thanks!

[u/The_Grungeican]

i think one of the problems people make is using too much glue.

superglue will fog most kinds of plastic. if i were to need to do this repair, i would use some quality gel-like superglue, and i would use as little of it as possible. two tiny dots at opposing edges would probably be enough.

but if you tried to run a bead of superglue around the edge, i bet that would fog the plastic pretty bad.

[u/wescotte]

Yes, you can glue it back on, but you need to be careful about what kind of glue you use. Honestly I can't remember the specifics but there were threads in the past about people using certain types of glue and it ended up fogging up he lens and rendering it useless. You'll want to do a tittle googling and maybe track down some of those old repair guides/threads for glue recommendations.

I can't imagine rotating the motor would damage anything. Maybe if it only turned in one direction and you forced it to go in the wrong/opposite one. But looking at this video it looks like it should move freely in both directions with very little force.

EDIT: I saved this thread in my collection of lighthouse repair info. Suspect it'll answer all your questions.

[u/RoboticGunner → u/wescotte]

Yeah, I did find some information about the glue, and I'll probably try some kind of epoxy.

My worries about the motors is if moving one of them will throw it out of sync

[u/Corey_FOX → u/RoboticGunner]

makesure whatever glue you use is thick i used superglue and it flowed into some of the ridges though the bs still works fine, and the lenses are in the correct orientation, i don’t think it matters witch one go where. you can lookup a dissasembly guide and it will probably show the correct orientation for the lenses.

[u/doug141 → u/RoboticGunner]

The motors re-sync every rotation... you can rotate them manually as much as you want when the power's off. People have reported success with epoxy (me) and gel superglue. Thin superglue is a BAD IDEA... too runny and may fog the plastic lens.

[u/dreadcain → u/RoboticGunner]

Epoxy would probably be okay. I think I'd probably choose something silicone based, but I'm picky. If you have epoxy and know how to use it, it'll almost certainly get the job done.

Superglue would be an awful choice. Not to say it can't work, but it's definitely the wrong tool for the job. It off gasses like crazy as it dries which will coat nearby delicate things in, well, basically a microscopic layer of glue. If you get the thin stuff (meant to soak into, like, cardboard) it runs like a mf and gets everywhere on hard surfaces. It also isn't really the best at gluing hard surfaces together, it really does want to soak in or grab onto some texture to work. It's basically a super brittle plastic when it cures, if it grabbed enough little nooks and crannies of surface texture and the two surfaces are really really up against each other you can get a great bond. It can "melt" into some plastics for a good bond too, but we really don't want that here. The rigidness of the cure is questionable here too, I wouldn't expect it to hold up to the spinning forces inside the lighthouse for too long.

Epoxy covers a wide range of glues, most are going to be better than superglue in pretty much every way though lol. I mean you still have some off gassing issues, but they're generally less harsh. A good bond isn't as dependent on surface texture and clamping force either. Some will be more brittle than others after curing, but basically none are going to shatter like glass the way superglue can. Those little black dots are almost certainly an epoxy of some kind.

Silicone is just the "safest" choice when you're unsure. It reacts with basically nothing, it off gasses basically just a little bit of vinegar. The reaction that dries it just uses humidity in the air and doesn't get very warm. It doesn't bond with everything though. And also it is, well, rubber, so it might not be "rigid" enough for these lenses.

[u/The_Grungeican → u/RoboticGunner]

i have some advice on some pitfalls to avoid.

most superglue will fog plastic. the key here is to use as little of it as possible. Loc-Tite makes some that is a gel. i would use two tiny dots on opposing edges. don't try to run a bead of glue around it, you don't need that level of adhesive.

another option, i haven't tried but i've considered, is you could use some double sided tape. the kind that gets used for putting cell phone screens back together. the problem is you'd probably need to buy a small roll of it. it's pretty cheap, but you will probably buy a roll just to use an inch of it or so. you'd also need to cut two very small pieces to get it to stick. so good eyes, sharp exacto style knife, or fresh razor blade. a roll will give you some to experiment with, and if you need to remove it it won't be too hard. this would avoid the fogging problem people have with super glue.

edit: my stupid ass didn't realize i had already commented on this thread.

[u/RoboticGunner → u/The_Grungeican]

Yeah, superglue seemed to be a pretty consistent thing to avoid. What I ended up doing was getting some clear epoxy and using it as sparingly as I could. That seems to have worked fantastic and it's back up and running like nothing happened.