Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines
Builds, Repairs, Show Your Machines! => Technical Tips, Builds, and Help => Topic started by: Scorpion2nz on August 24, 2019, 02:42:03 pm
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This may or may not be of interest.
A few moths ago I purchase a cheap Bing overtype locally.
Upon pickup I was given a Stuart dynamo/generator .
Initial inspection show a couple of issues .
1 pin and pickup spring missing (it was already replace with a dodgy bolt )
Remove bolt ,turn new pin and wind spring from phosphor bronze .
Still no life .
It appears magnets have no sticky ,they are dead and about as usefull as tits on a bull.
Some outside the box thinking involves hold by hand some neodymium magnets on outside of brass case .
We have life .( well sort of)
Strip down completely and hold case in mill.
Mill two recesses through brass and into old magnets (but not penetrating)
Hold 4 neodymium magnets ( 2 layers of 2 )in each recess with hot glue gun (this is temporary)
Photo showing recess was first trial at 1 layer of magnets i later recessed even deeper to take two layers .
[attachimg=1]
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more photos I hope
[attachimg=1]
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Dodgy hot melt glue holding magnets in place
Unsure if to use JB weld type crap which I have an aversion to or soft solder
Solder heat may destroy magnets if it will even stick to the,
[attachimg=1]
https://www.youtube.com/watch?v=d8KCFHTTod4
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Great fix.
The alternative energy crowd use epoxy resin for their magnets, so JB weld, Araldite etc would be my choice.
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Perhaps I'm missing something here Dennis, but is there some reason that the original magnets cannot just be re-magnetized or replaced?
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Perhaps I'm missing something here Dennis, but is there some reason that the original magnets cannot just be re-magnetized or replaced?
I did look at that option but I can not see them coming out with out being broken to be remagnatised
And no guarantee new ones will fit .
Cheers
Dennis
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I should think it possible to re-magnitize them in situ, but likely would not end up being nearly so strong as the path you are currently headed down. I'm guessing that when you are done, you may well have the most powerful Stuart generator going!
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Dennis, I think that was a brilliant repair, though I would definitely secure the magnets with JB Weld type product, sanding surface smooth when dry, then paint and if done well the repair should not be noticeable. Sure beats throwing the generator out or trying to completely disassemble and bust something in the process.
A+ for creativity!
Rog
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Clever.
I'd use JB Weld as the permanent fix.
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Well JB weld or any thing similar is not to be found in my cupboard
But i do have what we refer to as “ Bog “
2 part crap used to fill dents in cars ( i have it for smoothing wood formers for casting )
It it works then great but if not then some armchair shopping will be required and some waiting .
Cheers
Dennis
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Dennis, the two part auto body repair material you call BOG is called Bondo here in the US. I have used it a number of times to repair rust and dents on older cars. It works virtually the same as JB Weld, just sold in larger containers. It will work fine for your purposes so long as all oil and loose residue is removed first. The stuff files easily, so maybe you just glop some on the magnets and the recess around them, then file like a sculptor.
Look forward to the finished product.
Rog
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Please do not use Bondo or BOG.
Here are the reasons:
It is weak.
It actually absorbs liquids promoting rust
I doubt it stands up to heat.
Why should you use JB Weld?
It is strong 💪
It resists almost all liquids
It stands up to heat
It is cheap and easily purchased
I've repaired motorcycle blocks with JB Weld. Example: On my '56 Norton, I made new fin to replace some broken ones. After a dozen years, it's still repaired.
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Seems to work well and as others have said, after a bit of cleanup, shouldn't even be noticeable. 8)
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One note of caution. Always use long-cure (24 hr) epoxy.
The quick-cure stuff will NEVER be as strong. I learned
this the hard way on a KJ Miller boiler. You could hear the
quick-cure epoxy crack as it steamed up to its low operating
pressure. I still haven't gone back to try another fix as the
old epoxy needs to be removed,
Good Luck,
Wayne
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A+ work Dennis.
I agree with others that JB Weld is the way to go.
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I am also from the School of JB Weld.
Fantastic resurrection, Dennis...!!!
Gil
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Please don't use epoxy on boilers. Epoxy weakens with higher temp.