i have a slight tear/crack in the amber lense on my back light. it's a new hella lense so i need the make every effort to save it.

what is the best/best type of glue to use?

Interesting. No help here but I'd like to know as well.

I repaired a cracked euro lens. Super glue the crack and then sand and polish. It won't disappear but it can be made better.

The design of the original lens required that the segments be glued. For years they have Come apart and would need to be re glued. Also the segments would not always line up correctly and the buckets would warp after years of use, so proper alignment was always a problem, even now.
Here is the glue to use, even Hella used it:Click to view attachment

thanks for the info, i was hoping this would do it as i have an unopened tube in the cupboard

https://www.toolstation.com/shop/Adhesives+...Adhesive/p80659

i won't use a generic superglue as i've found it discolours plastic.

the split is not in a join but just under the moulding for the retaining bolt thread.

what about this?

https://uk.rs-online.com/mobile/p/acrylic-adhesives/0144406/

i don't know what type plastics are used in light manufacture.

Superglues are not the best choice for bonding plastics, the joints are brittle and crack easily. Plastic glues are a far better choice because they fuse with the plastics, and epoxies remain somewhat more elastic than superglues.

I’m sure your right but I didn’t want to put real money into the repair. Just diy so it looked decent and usable. It did seem to work fine.

Use something similar to what George recommended. I used Weld-on brand. You want a solvent weld for acrylics. I went to the local glass shop and they gave me an opened tube for free. There are different viscosities and for a crack, you want a thin, watery version that you apply with a needle so it can seep into the crack. Mine was broken at the original glue joint. Here's the result.





I also repaired a crack using the needle method but don't have a pic. Worked great though. The trick is to clamp the pieces or crack together tight and then apply the solvent so it gets sucked into the crack by capillary action. The perfect amount fills the area without any excess. Too much, and the solvent melts whatever it touches to leave a visible blemish. Too little and you have voids that will be visible. A good repair is invisible or close to it.

In the UK that is what you get. Here in the states the pros use a different material. I am a pro.

George do you keep yours in the refrigerator? It goes bad in a hot climate. Let it warm up to room temperature.

Brent had the right idea but cracked plastic is in no way easy to repair as the glued parts that have come apart.

Bob B
Click to view attachment Click to view attachmentClick to view attachment

i've never had much luck glueing plastics but i'm not paying another £150 for a lense if i can help it.

Thanks for the advice, i'll pick some of the rs glue up and see how it goes.

absolutely in the refrigerator!!!!

OT: a tube of silicone will last forever in the fridge, too.