Broken Gear Repair





Introduction: Broken Gear Repair

About: I can imitate improvise and upgrade as long as i can

Simple way to fix broken gear

Step 1: Materials Needed to Fix Broken Gear

you need a plastic steel epoxy, Popsicle stick, any mixing medium for your epoxy mixture and brush and detergent soap or dish washing liquid.

Step 2: Cleaning

Be sure that your gear is free from oil and dust. use dish washing or powdered soap and brush to clean the gear

Step 3: Epoxy Mixture

mix the two compound and apply it on the broken area.

Step 4: Curing

wait for an hour to harden the epoxy, since the epoxy is not hard enough and the epoxy is flowing slowly, you need to monitor the flowing or moving of the epoxy not to stuck in one area of the gear

Step 5: Moulding the Teeth

After an hour the resin will going to be hard, just like a clay, position the new mold gear in its gear partner, then rotate slowly to adapt the teeth of the other gear by the way you need to put some grease on the other gear so that the epoxy will not stick to the other gear. rotate it slowly till the rotation will fit to each gear.

Step 6: Total Curing

remove the gear to the gear box assembly and cure it on a well ventilated area for a day

Step 7: Cured Epoxy Gear

Install the hardened gear in the gear box, assemble the parts. this gear part belongs to my meat grinder.

Step 8: Video



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    You just gave me a temporary fix for my RC. I gunned it one too many times, and the gears tore themselves apart. The Chinese boat arrives in a week. I only have to wait a day and Revvor'll be out, skidding in the warehouse or streaking along the road.

    1 reply

    I would like to make a mold of the finished gear in case there is another breakdown. Can someone tell me what kind of silicon or other material is used to make molds? Friends in Scotland were making molds of fancy wooden objects when doing a makeover on older homes but I don't know what they were using.


    For a long-term replacement, make a mould from the repaired item, then use that to cast a new one-piece item, free from the risk of an add-on section breaking away.

    Use very thin plastic sheet, saran wrap instead of the grease.

    прекрасно, спасибо.

    I wish I saw this earlier... :)

    Thanks. I'll keep this in mind.

    I used your idea and repaired a worn gear on a powered lift chair. It worked out great, saved me spending $200 on a new motor/gearbox since I couldn't just order a new gear. Thanks.

    I did this on my kids powerwheels Jeep. The gear appears to be identical to the one used in this instructable.... WELL DONE SIR!

    Perfect. What if gear is from steel ??


    Well done, thank you very much. I will keep this in mind for future gears.

    Thumbs-up on that one! The skill quotient involved leans heavily towards that of "timing" and its due, requisite attention.

    Thumbs-up on that one! The skill quotient involved leans heavily towards that of "timing" and its due, requisite attention.


    A clever way to repair some gears!

    In step five, you say "After an hour the resin will going to be hard, just like a clay, position the new mold gear in its gear partner"

    Perhaps you meant, "BEFORE the resin has fully hardened, when it has the stiffness of clay, position the epoxy-coated gear against its gear partner. "

    That was EXACTLY what I was looking for, I have to fix a broken gear in my car's rear door power lock. A new one is way too expensive, and I don't have access to a 3d printer.
    I just hope I'll find this kind of epoxy resin here in Italy.

    3 replies

    Hi! In Spain you can find in plumbery stores a very good epoxy paste that it's used like cold soldering. Here it's commercial name it's Collak, but I supose that will be easy to find something similar in a plumbery store in Italy. It's like a clay with both components in the same cylinder, you just have to smash it, and it's very quick. Also it's supposed that it has a good mechanical resist. And use gloves!

    Or see if Sugru will work...

    Just be sure to use the strongest version of epoxy you can find, and not the "quick steel" which would set to quickly to mold the gears with. Good luck. I've fixed stuff on cars with epoxy before. It works unless it's on a part that has to take heat.