magnets

[badcars2]

anyone ever used super duty epoxy to reattatch flywheel magnets. like the stuff ford used to mount body panels now instead of welding. i can fix the flywheel body pretty easily i thiink and have it balanced at a friends shop..

 

[Lawn Masters]

I'd imagine that at high speeds, that any thing you use to reattach the magnets, would probably let go. this isnt to say that it might last a few hours, which is possible, but somehow I dont think it would. now, imagine those magnets coming toward your arms, or the ground at full throttle. VERY scary thought to me if they let go.

Now, I dont know for sure, but IMO, it would be safer, and cheaper just to find another flywheel and ignition system instead to use.

 

[Lakeside53]

Don't... It's incredibly dangerous. The are buckets of used flywheels available...

 

[BlueRidgeMark]

anyone ever used super duty epoxy to reattatch flywheel magnets. like the stuff ford used to mount body panels now instead of welding..

So.... Just how fast do those body panels rotate, anyway?



(that's a clue)

 

[Simonizer]

Not a good idea. The force on those magnets is proportional to the square of the angular velocity. F=mv^2/r. That coupled with vibration and resonance at 12000 rpm spells danger. Cheers.

 

[johndeer40]

Funny you mentioned Magnets. I broke the flywheel on my dad's McCulloch 1-46 last week and used liquid steel to "fix" the area around the Magnet. Well it worked great until I reved it up. The "fix" went flying! Found a flywheel on Ebay and hope it fits.
Oliver

 

[ShoerFast]

Having used a product called Devcon as it has been approved for some non-structual repairs in aviation, brings ideas, as it has a 45K plus shear strength.

But I have to agree, getting a used flywheel is your bet,,,,, there is no way that if it even did work, that your time would be less then the price of the used part.

 

[Crofter]

Shoerfast, should that perhaps be 4.5K?

My father had a very noticeable scar on his nose after an old laminated wooden pulley from a line shaft blew up. He made sure I had a very healthy respect for centrifugal force. No patch jobs on flywheels please.

 

[Simonizer]

This isn't so much a sheer strength problem as an equivalent tensile strength of the bonding area. The units are PSI or MPa. When you say 45K I assume you mean 45000 PSI. This soulds like an extremely lofty claim. At any rate, I don't recommend this repair.Cheers.

 

[badcars2]

i didnt do it to the flywhell but in the demo they claim 70k tensile strength, over lap weld vs. overlap bond of this material. lay the metal 3 inches overlay one on top of another, bead down each side,cure one hour. we hooked it in the frame machine at my old work place, blew two holes in in of course. pressure come up, hooks tore out before epoxy failed. granted no centrifical force but 70K psi, sounds pretty stout to me..

 

[Simonizer]

i didnt do it to the flywhell but in the demo they claim 70k tensile strength, over lap weld vs. overlap bond of this material. lay the metal 3 inches overlay one on top of another, bead down each side,cure one hour. we hooked it in the frame machine at my old work place, blew two holes in in of course. pressure come up, hooks tore out before epoxy failed. granted no centrifical force but 70K psi, sounds pretty stout to me..

Sounds like an excellent product. I must research this, thanks.

 

[ShoerFast]

Frank
Devcon has a 45,000 psi tensile strength, it's fun stuff, as it is made to replace / fill (buy buliding up and reworking worn) 6000 series aluminium.
It is a 2 part filler, mix 50 / 50% till the color was consistant, prep the area and coat the worn areas, cure and rework,,, couple of tricks worked well,,,, if you would start your rework as it's setting up, it worked very well.
The areas that it worked the best were areas like the landing gear door fallowers, they were hi vibration, and non-structual ,,,Devcon saves a lot of time and money.
If you took the left over Devcon as it was usally mixed with scrap pieces of aluminium, set them on an anvil and pound it with a hammer, the aluminium would brake first every time.

 

[BlueRidgeMark]

... I reved it up. The "fix" went flying! Found a flywheel on Ebay ....

Whoa! You found it on EBAY?!?!? Man! Their servers are in UTAH! That's a long way from Florida! I knew a disintegrating flywheel has a lot of force, but all the way from Florida to Utah? How big were the pieces?

Wow.

 

[BlueRidgeMark]

This isn't so much a sheer strength problem..

Sheer strength? So, is that like heavy duty lingerie or sumpthin?

 

[Crofter]

I am sure curious about that compund that has the tensile strength you guys claim. Devcon I believe is a Dupont Tradename for a wide range of different adhesives and fillers. Can you tell us the particular product name. Generally their tensile strength is in the 3 kpsi range with compressive strengths approaching 10 kpsi.

 

[ShoerFast]

Devcon fillers

Frank
There could be some published data on Devcon that might say that it was a 3 kpsi tensile strength filler, sort of like the working loads for ropes, as there like 1/10th the real load.
The Devcon I had used was with former Rocky Mountain Airways, and had to be labeled from our engineering department as they did the ASTM D1002 testing. There is a good chance that the aviation version is not much different then the over the counter Devcon.

As it can be drilled and tapped, just like cast aluminum, the torque on the bolts were also the same,so it has to be close to aluminum tensile strength also.
The only way that we could use it as an approved repair was to prove to the FAA that is was stronger then the original part.

Here is link to over the counter Devcon : http://www.devcon.com/devconcatsolution.cfm?catid=18

Kevin

 

[Crofter]

Shoerfast, not trying to jerk your chain, just that those figures are higher than anything I have ever seen for epoxy compounds. If the figures were actually in Mpa. they would be approximately in line. 45Kpsi. roughly equal to 6525 Mpa. which is about right for compressive strenght for metallic filler compounds. Even tho it is still higher than anything I can see for tensile strength. Course, I am just quibbling here. Have you ever used the compounds for replacing hoof wall when you get a shoe ripped off and no place to put the nails? Horses here; not airplanes! Lol.

 

[ShoerFast]

Frank
It's a hard sell for me to use fillers, as I spent way to much time in da old school, but the first time I snapped a bolt off, (trying to strip the treads) on an old Devcon repair of mine (after the part was replaced with a new one) I was sold just a little!

For hoof filler I use Quick-Ploy or Equathane, it sets fast and is as strong as the hoof its self. There are a couple tricks for that also, just put the shoe on, (as you can always at least get 2 nails in) and fill whats missing, let it cure then drive the rest of the nails in, rasp it out and it looks like a hoof!

Horses can tell that there is filler there, as they seem to walk like there hoof is stuck in a pail for the first few steps!

But back to the repair for a flywheel magnet, they do use Devcon for centrifugal pump repairs,,,,, I wouldent be that last person to try it, on my own saw, but you could bet that I would be reving it the first few times with a long string!
Kevin

 

[johndeer40]

Mark,
You didn't see the white hot streak across the Midwestern sky last Wed. about 9PM. Some of the smaller pieces [about the size of a dime] reentered the atmosphere over the Smokies. Those old McCulloch's really have the toque.

 

[BlueRidgeMark]