Charles McLean Posted March 19, 2018 Share Posted March 19, 2018 Hey everyone, my MSuper V3s+ took a slight tumble down the side of a very large hill and hit a few trees, and rocks along the way. Surprisingly, the exterior of the shell is no worse for the wear. Some scratches and gouges as would be expected, but no cracking. The wheel still rides great. However, the inside of the shell, around where the pedal hanger attaches to the wheel is cracked (just like in the picture above from @who_the that he posted in a separate thread). This isn't my picture, but it's a better pic of the problem I've got so I'm using it. My question to the group is this ... has anyone tried any Plastic Welding? See video link below: Does this actually work? I tried JB Weld epoxy, but that only held for a few days before the crack came back. This plastic welder seems like a good solution, and considering the amount of abuse I put my wheels through, will probably pay for itself in the long run. Anyone got any experience with this sort of thing? Thanks! Link to comment Share on other sites More sharing options...
Hunka Hunka Burning Love Posted March 19, 2018 Share Posted March 19, 2018 Some people recommend melting some Lego pieces in acetone to make a bonding goo. Search for acetone on the forums... Some others have cyanoacrylate glued steel plates to repair their shells. Link to comment Share on other sites More sharing options...
Rehab1 Posted March 19, 2018 Share Posted March 19, 2018 4 hours ago, Charles McLean said: Anyone got any experience with this sort of thing? I bought a unit to weld polypropylene and polyethylene plastic a few years back. I did not have any success and I became frustrated and quit. I should have watched the video first. The trick is you need the exact type of plastic strips that your shell is fabricated from for optimal results. Link to comment Share on other sites More sharing options...
Charles McLean Posted March 19, 2018 Author Share Posted March 19, 2018 1 hour ago, Rehab1 said: I bought a unit to weld polypropylene and polyethylene plastic a few years back. I did not have any success and I became frustrated and quit. I should have watched the video first. The trick is you need the exact type of plastic strips that your shell is fabricated from for optimal results. That begs the question ... does anyone know what kind of plastic the various KingSong and Gotway Shells are made of? My MSuper V3s+ shell seems to all be made out of the same type of plastic, with the exception of the housing for the headlight, charger, and tail light. But, my Tesla looks like it could be made from a couple of different types of plastic. My daughter's Kingsong 14D, looks like it could be made from ABS since it does remind me of the plastic used for Legos. Is there a thread anywhere in here that lists out the types of plastics our wheels are made of? Link to comment Share on other sites More sharing options...
Gimlet Posted March 19, 2018 Share Posted March 19, 2018 Maybe you could trim some small strips of plastic from the edge of the shell itself in non critical areas, that way it's sure to be a perfect match! Link to comment Share on other sites More sharing options...
Rehab1 Posted March 19, 2018 Share Posted March 19, 2018 21 minutes ago, Gimlet said: Maybe you could trim some small strips of plastic from the edge of the shell itself in non critical areas, that way it's sure to be a perfect match! I bet @Jason McNeilor other members have some broken plastic shells lying around they may part with for experimentation. If the welding process works it would be a great a education for forum members. Link to comment Share on other sites More sharing options...
who_the Posted March 19, 2018 Share Posted March 19, 2018 I hope a solution emerges to repair these shells. But given the numerous forces at work within this critical structural element, I'm dubious that plastic welding could represent a durable, permanent repair. The problem with Gotway's designs are that they are underengineered to accommodate the forces at work. They use essentially ZERO internal ribs or trusses in their designs to diminish interior forces at key points. Contrast the inside of an MSuper V3 and a Ninebot Z10. The interior plastic structure of the Z10 is designed to disperse load and impact over a larger portion of the shell. (The brass machine screw inserts — *drool* all dozen or so of them — also distribute force and allow the cover to become a structural element as well.) I also have a theory that one of the first things to break on an MSv3 in a crash is the most rearward screw peg for the shell case. If this screw fails (did on mine), it increases the potential twisting force which, over time, puts more pressure on the internal plastic eventually cracking it. @Rehab1 had an interesting idea to add aluminum angle to those corners, attaching them with epoxy and drilling holes or scoring the surface to enhance adhesion. Link to comment Share on other sites More sharing options...
Rehab1 Posted March 19, 2018 Share Posted March 19, 2018 1 hour ago, who_the said: Rehab1 had an interesting idea to add aluminum angle to those corners, attaching them with epoxy and drilling holes or scoring the surface to enhance adhesion. Another project that slipped my mind. Sorry. I do have a KS14C shell I could practice on. Just don’t tell Smoother. Link to comment Share on other sites More sharing options...
Hunka Hunka Burning Love Posted March 19, 2018 Share Posted March 19, 2018 I wonder whether in future designs they could implement flexible metal "ribs" that could be inserted and locked into the plastic frame work in channels to help add an element of strength. A composite design of metal and plastic might give the outer shell more strength during crashes. Or even a metal framework of springy, strong metal alloy (nickel titanium?) might help and allow plastic cover pieces to be bolted on. Link to comment Share on other sites More sharing options...
Stan Onymous Posted March 20, 2018 Share Posted March 20, 2018 6 hours ago, who_the said: I hope a solution emerges to repair these shells. But given the numerous forces at work within this critical structural element, I'm dubious that plastic welding could represent a durable, permanent repair. I agree w/ @who_the about the structural integrity of a plastic weld. I have done this with acetone and that opaque plastic coat hanger cut into very small pieces to fix a dashboard. Part of the trick to the adhesion is the paint the surface to to be welded in the acetone as a preparation for plastic reformation once the acetone dries. I have also been told that Xylol does a little bit better job, but it is more cancerous in fume form and I have not tried it yet. What would be a good idea would be to have 3D patterns for printing. Fixing is so Fonzi. Its a pull and replace world of technology assuaged by a modicum of recycling. I wonder if that mixed with @Hunka Hunka Burning Love'S idea of metal tines or ribs would be a great lightweight solution? Link to comment Share on other sites More sharing options...
Rehab1 Posted March 20, 2018 Share Posted March 20, 2018 2 hours ago, Hunka Hunka Burning Love said: A composite design of metal and plastic might give the outer shell more strength during crashes. Your definitely on the right track when you mentioned composites. A carbon fiber shell would greatly increase the strength but the cost would be prohibitive. The combination of both a plastic shell and metal sub-frame would certainly beef up the strength but the weak link in the chain is still the molded plastic. I found replacing my ACM shell was relatively inexpensive. If the plastic shells were integrated into a metal skeleton I’m afraid the replacement cost would significantly increase. Link to comment Share on other sites More sharing options...
kasenutty Posted March 20, 2018 Share Posted March 20, 2018 I'd like to see a time where you get your own expensive carbon fiber shell and just put it on all different kinds of setups. Maybe a universal shell mounting scheme or something. It would be a lot more fun if these were modular and you could swap motors, control boards, even pedal support mounts between a standard shell anchoring scheme. Link to comment Share on other sites More sharing options...
Charles McLean Posted March 20, 2018 Author Share Posted March 20, 2018 I'd really love to machine / CNC a shell out of aluminum. But, we'd need the CAD file for the shell. Link to comment Share on other sites More sharing options...
Charles McLean Posted March 20, 2018 Author Share Posted March 20, 2018 10 hours ago, who_the said: @Rehab1 had an interesting idea to add aluminum angle to those corners, attaching them with epoxy and drilling holes or scoring the surface to enhance adhesion. I think I'll try something with a steel mesh like in this video. Link to comment Share on other sites More sharing options...
Rehab1 Posted March 20, 2018 Share Posted March 20, 2018 6 hours ago, Charles McLean said: I think I'll try something with a steel mesh like in this video. Excellent find!!! Link to comment Share on other sites More sharing options...
Rehab1 Posted March 20, 2018 Share Posted March 20, 2018 Excellent video on determining the best plastic bonding epoxy. 2 second ad....get over it. Here is a quantifiable chart from all of the tests the host performed using the various epoxies. both JB weld original and Gorilla Glue came out on top after the five categories were analyzed. So I am going to purchase Gorilla Glue being it is a bit more flexible when it cures and then add fasten a piece of 90 degree angle aluminum to my old ACM shell in the same location as @Charles McLean‘s fracture. Off to Home Depot. Link to comment Share on other sites More sharing options...
Smoother Posted March 20, 2018 Share Posted March 20, 2018 I did some plastic welding on a fully dressed motorcycle I was restoring (Honda ST1100). There were lots of cracks in the fairing pieces. There were ABS (very common) So I used milk bottle lids (also ABS) and a soldering iron. Worked very well. Even built up a few pieces that were broken off/missing. Once re-sprayed, you couldn't tell the difference. from this: to this: Link to comment Share on other sites More sharing options...
Stan Onymous Posted March 20, 2018 Share Posted March 20, 2018 I tried the screen mesh to fix a fiberglass roof crack in my Subaru 360. It repaired the crack, but the metal screen rusted through the white fiberglass to form a little orange patch. The screen and fiberglass repair clearly looks like a scar. Its raised about a centimeter at the top height of the scar. I saw that 3M Scotch Weld Adhesive Epoxy DP420NS is used to fasten the front of MTA Busses to the frame of the Bus. Its got a great shear strenth and adhesion, and its what the professionals use for building vehicles, so check that stuff out before going into the Housewife aisle for the DIYers Link to comment Share on other sites More sharing options...
Stan Onymous Posted March 20, 2018 Share Posted March 20, 2018 25 minutes ago, Smoother said: There were ABS (very common) So I used milk bottle lids (also ABS) and a soldering iron. Worked very well. Even built up a few pieces that were broken off/missing. Once re-sprayed, you couldn't tell the differenc That is a great idea! What is your technique? Did you lay the patch pieces in the crack and melt them in with the soldering iron, or did you melt the plastic pieces and paint them into the cracks? Link to comment Share on other sites More sharing options...
Smoother Posted March 20, 2018 Share Posted March 20, 2018 26 minutes ago, Stan Onymous said: That is a great idea! What is your technique? Did you lay the patch pieces in the crack and melt them in with the soldering iron, or did you melt the plastic pieces and paint them into the cracks? My technique was exactly...a little bit of everything. Sometimes I had to do a job twice, but I had plenty of milk bottle tops. It was very much a suck it and see exercise. Mostly on the unseen side so cleaning up the patch was not necessary. but on the shown side, a good sanding works, followed by paint. I also used the superglue and baking soda method for cracks that @Shad0z recently mentioned. I'm not sure how well it holds to plastic over time, but it sticks to wood like, well, eh.. glue. I have repaired several powered paragliding propellers with that method, and was happy to fly with them for months afterwards. Link to comment Share on other sites More sharing options...
Rehab1 Posted March 20, 2018 Share Posted March 20, 2018 I purchased everything I need for the experimental repair at Home Depot. 3/8x1/2” angled aluminum and Gorilla Epoxy (I had lots of choices but this glue works for both metal and plastic). Blending the 2 part resin Angled aluminum with perforations for optimal adherence. Both surfaces roughened up for optimal adhesion. Thick layer of Epoxy. Repair strut positioned in place. The vertical strut will be used to conduct various stress tests once the epoxy has cured. Edit: On one test tomorrow I will start adding weight to the shell to determine how strong the epoxy is. Link to comment Share on other sites More sharing options...
Charles McLean Posted March 23, 2018 Author Share Posted March 23, 2018 Hey everyone, I posted in the Gotway Facebook page (https://www.facebook.com/groups/GotWay/permalink/1752952064763108/) asking what type of plastic the MSuper shell is made from. I got a few responses, and one guy posted a response with a link to the plastic weld repair work he did on his MSuper shell. He said he's put 5,500 KM on his wheel after the repair with no issues. Anyway, the pics are great ... check them out here: https://yadi.sk/d/X7BnrF403QD6Yq Now I just need to find the right plastic welder! Link to comment Share on other sites More sharing options...
yourtoys7 Posted March 23, 2018 Share Posted March 23, 2018 Many methods could/ would work, but it all comes down to whats available to you. Epoxy might just be the most simple solution that anyone can do + it is all hiden on the inside :)) Link to comment Share on other sites More sharing options...
Roo Williams Posted March 24, 2018 Share Posted March 24, 2018 Part of me wonders why they are being built with the shell paradigm in the first place. Obviously electronics, motor and battery need to be weatherproof, so seal them in containers of some description, but they could almost be mounted into a rollcage style structure of aluminum tubes with padding mounted in the right places for contact with legs and modular mudguards that can flex and be replaced. EUCs spend most of their lives in constant fear of the immediate potential to be bowled across the ground at speed, yet current designs have more in common with a kitchen toaster than a bike or dune buggy. I might do a little sketch now. Link to comment Share on other sites More sharing options...
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