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ACM Shell Repair and Stress Testing


Rehab1

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I began this experimental repair process in @Charles McLean topic titled Plastic Welding? Charles topic is excellent and that I hope someone finds the proper method to weld broken EUC shells. Unfortunately I have not had any success plastic welding so I tried a different technique involving a metal strut and epoxy. My initial preparation for this repair can be found in Charles topic 'Plastic Welding?'

This topic is more of an experiment to determine if my simulated repair is successful. I begin with a weight test by first adding first 2.2 kg to the shell, then 4.5kg  and ending with a total weight of 9kg.  

Further experiments will be performed in the coming days that will test torsion and impact resistance of the repair.

 

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8 hours ago, Rehab1 said:

Further experiments will be performed in the coming days that will test torsion and impact resistance of the repair.

@Rehab1  Great video!  I'm looking forward to the other stress testing, the torsion tests, etc.  Aside from roughing up the plastic shell and the aluminum before applying the epoxy, did you use any kind of solvent, or isopropyl alcohol?  I was VERY IMPRESSED that the epoxy was able to hold all that weight.  I wonder what would happen if you used the same technique to add your own internal ribbing and bracing to the inside of the shell?  Something to help distribute some of the force from heavy riding, more along the lines of what the Ninebot One Z10 seems to have going for it?  Thoughts?

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12 hours ago, Rehab1 said:

I began this experimental repair process in @Charles McLean topic titled Plastic Welding? Charles topic is excellent and that I hope someone finds the proper method to weld broken EUC shells. Unfortunately I have not had any success plastic welding so I tried a different technique involving a metal strut and epoxy. My initial preparation for this repair can be found in Charles topic 'Plastic Welding?'

This topic is more of an experiment to determine if my simulated repair is successful. I begin with a weight test by first adding first 2.2 kg to the shell, then 4.5kg  and ending with a total weight of 9kg.  

Further experiments will be performed in the coming days that will test torsion and impact resistance of the repair.

 

Great stuff. I'm actually in the middle of fixing my cracking ACM shell, in the same area.

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7 hours ago, Charles McLean said:

@Rehab1  Great video!  I'm looking forward to the other stress testing, the torsion tests, etc.  Aside from roughing up the plastic shell and the aluminum before applying the epoxy, did you use any kind of solvent, or isopropyl alcohol?  I was VERY IMPRESSED that the epoxy was able to hold all that weight.  I wonder what would happen if you used the same technique to add your own internal ribbing and bracing to the inside of the shell?  Something to help distribute some of the force from heavy riding, more along the lines of what the Ninebot One Z10 seems to have going for it?  Thoughts?

Thanks! I did clean the surface with a solvent after abrading the area with rough sandpaper. I used a solvent designed to dilute contact adhesive but any solvent that does not attack the plastic shell such as isopropyl alcohol would be fine. 

Yes you could add additional metal ribs (struts) to the inner structure for better integrity but I would only strategically place them in similar areas of the shell where there is contact with both sides of the 90 degree aluminum bar to ensure optimal contact. You don’t want metal floating around inside your shell if a free floating rib were to come loose. 

2 hours ago, Marty Backe said:

Great stuff. I'm actually in the middle of fixing my cracking ACM shell, in the same area.

Interesting timing. I’ve had to put off this simulated repair and tests because of my injury. You probably saw my facial grimaces as I was lifting the shell onto the scale. My surgeon would have had a fit!

So far the simulated repair is holding. Next I’m going to use a torque wrench to twist the vertical bar at different settings to see how well it holds up. The final test will be dropping the weighted plates onto the shell from different heights. Something has to give during that test.:cry2:

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4 hours ago, Rehab1 said:

Thanks! I did clean the surface with a solvent after abrading the area with rough sandpaper. I used a solvent designed to dilute contact adhesive but any solvent that does not attack the plastic shell such as isopropyl alcohol would be fine. 

Yes you could add additional metal ribs (struts) to the inner structure for better integrity but I would only strategically place them in similar areas of the shell where there is contact with both sides of the 90 degree aluminum bar to ensure optimal contact. You don’t want metal floating around inside your shell if a free floating rib were to come loose. 

Interesting timing. I’ve had to put off this simulated repair and tests because of my injury. You probably saw my facial grimaces as I was lifting the shell onto the scale. My surgeon would have had a fit!

So far the simulated repair is holding. Next I’m going to use a torque wrench to twist the vertical bar at different settings to see how well it holds up. The final test will be dropping the weighted plates onto the shell from different heights. Something has to give during that test.:cry2:

4

As a friend, I'd advise you to take it easy.  Reserve your left arm for paid work, and doing up your fly, etc.  All these " I wonder if.." projects can wait a few months.  They'll still be waiting for you then. The last thing you want is a gimpy arm for the rest of your life.  You'll never know if one of these optional projects was the straw that broke the camel's back. Chicks dig scars, but they don't dig gimpy arms. :(

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7 hours ago, Rehab1 said:

Thanks! I did clean the surface with a solvent after abrading the area with rough sandpaper. I used a solvent designed to dilute contact adhesive but any solvent that does not attack the plastic shell such as isopropyl alcohol would be fine. 

Yes you could add additional metal ribs (struts) to the inner structure for better integrity but I would only strategically place them in similar areas of the shell where there is contact with both sides of the 90 degree aluminum bar to ensure optimal contact. You don’t want metal floating around inside your shell if a free floating rib were to come loose. 

Interesting timing. I’ve had to put off this simulated repair and tests because of my injury. You probably saw my facial grimaces as I was lifting the shell onto the scale. My surgeon would have had a fit!

So far the simulated repair is holding. Next I’m going to use a torque wrench to twist the vertical bar at different settings to see how well it holds up. The final test will be dropping the weighted plates onto the shell from different heights. Something has to give during that test.:cry2:

The twisting motion on the shell as it's used is where the real stress happens. In my case, the shell more or less disintegrated all along the area where the 6 bolt holes are. So I'm installing bar stock in that area that then attaches to other parts of the shell, via bolts. I'm making a video too - as part of my ACM to ACM2 conversion video.

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1 hour ago, Marty Backe said:

The twisting motion on the shell as it's used is where the real stress happens. In my case, the shell more or less disintegrated all along the area where the 6 bolt holes are. So I'm installing bar stock in that area that then attaches to other parts of the shell, via bolts. I'm making a video too - as part of my ACM to ACM2 conversion video.

Looking forward to seeing your repair! Between your repair, mine and plastic welding something has to work!

Here are my final 4 tests which includes twisting. On one test I should have worn safety gear. My god was I jumpy. :wacko:

Closeups of ACM shell after all tests were completed.

40249514584_fd6d8dd6c2_b.jpg

 

40249514434_f0a1f8268e_b.jpg

 

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54 minutes ago, Rehab1 said:

Here are my final 4 tests which includes twisting. On one test I should have worn safety gear. My god was I jumpy. :wacko:

@Rehab1 Another great video!  I am impressed that the Gorilla Glue epoxy held up as well as it did.  I think I'm going to try that on my MSuper V3s+ shell!  Very informative!  I'm also looking for a good plastic welding kit and I've got a message into Gotway asking them what type of plastic their ACM and MSuper shells are made out of so I can do a proper repair.

Thanks!

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20 minutes ago, Charles McLean said:

@Rehab1 Another great video!  I am impressed that the Gorilla Glue epoxy held up as well as it did.  I think I'm going to try that on my MSuper V3s+ shell!  Very informative!  I'm also looking for a good plastic welding kit and I've got a message into Gotway asking them what type of plastic their ACM and MSuper shells are made out of so I can do a proper repair.

Thanks!

Thanks. If you lived closer I could just shave some plastic off the shell and give it to you for experimentation.

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3 hours ago, Rehab1 said:

Thanks. If you lived closer I could just shave some plastic off the shell and give it to you for experimentation.

Well, once I figure out what kind of plastic it is, I'll be sure to let the group know ... then it's off to buy and try a plastic welder!

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On 3/22/2018 at 12:25 PM, Rehab1 said:

Looking forward to seeing your repair! Between your repair, mine and plastic welding something has to work!

Here are my final 4 tests which includes twisting. On one test I should have worn safety gear. My god was I jumpy. :wacko:

Closeups of ACM shell after all tests were completed.

Great tests. I particularly liked the impact test. Besides your epoxy holding up, I'm impressed with the toughness of the shell. Makes me wonder why they develop cracks to begin with.

:thumbup:

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3 hours ago, Marty Backe said:

Great tests. I particularly liked the impact test. Besides your epoxy holding up, I'm impressed with the toughness of the shell. Makes me wonder why they develop cracks to begin with.

:thumbup:

Chemical fatigue as a result of expose to "saline water!"

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5 hours ago, Marty Backe said:

Great tests. I particularly liked the impact test. Besides your epoxy holding up, I'm impressed with the toughness of the shell. Makes me wonder why they develop cracks to begin with.

:thumbup:

Thanks Marty! My guess is possibly riding through rough terrain over an extended period of time. ;)

40275977164_1f884626cc_b.jpg

 

 

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9 hours ago, The Fat Unicyclist said:

Chemical fatigue as a result of expose to "saline water!"

Ha ha - nice try. But I've only ridden my MSuper's in the ocean - and does salt water actually affect plastics and rubber?

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54 minutes ago, Marty Backe said:

Ha ha - nice try. But I've only ridden my MSuper's in the ocean - and does salt water actually affect plastics and rubber?

Suppose I should have photoshopped in some Fukushima waste. :) 

The way you care for your wheels....you will not have any issues. Just keep rinsing them off. 

 

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