Magnafluxed, now what the F

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Scamp Fasty

Scamp Fasty

Going Nowhere Fast
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Ok just got done checking for cracks on a pair of heads and a block with magnaflux. Everything checked out just fine. I started to clean up the block and noticed some of the iron filings were standing up on the corner of the deck. I'm thinking I just turned my block into a magnet, not good.
I read I can wrap the block with the positive lead from an AC arc welder with 5-6 wraps, and then weld on some scrap. The scrap should be clamped on block with ground on opposite side of the scrap. The wraps make a coil and should induce current and a magnetic field. Ground wire should take care of induced current, I think. Anyone ever try this or another method that worked?
 
You got it. However the "inspector" was me and I don't have a clue how to demagnetize a block. Screwdriver-no problem.
 
Never knew a magnetized block was a bad thing. What problems does it cause?

Your idea to degauss the block seems workable. Don't see where you have to attach the scrap to the block though.
 
nm9stheham said:
Never knew a magnetized block was a bad thing. What problems does it cause?

Your idea to degauss the block seems workable. Don't see where you have to attach the scrap to the block though.
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yeah I'm not sure about the ground either unless it is needed to discharge current as current is induced through windings.
 
yellow rose said:
There ain’t enough magnetism there to hurt anything.
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That is what I thought until a 5/32 round file almost was able to hang from the block by itself.
Does magnetism effect bearings and journals? Would it mess with anything else. I don't have a compass on the dash so no worries there lol.
 
What do machine shops do? Magic wand? Degauss table? Giant inductions loops and pass a block through it like my screw driver? (seems a lil heavy)
 
Scamp Fasty said:
What do machine shops do? Magic wand? Degauss table? Giant inductions loops and pass a block through it like my screw driver? (seems a lil heavy)
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I have mag’d hundreds and hundreds of blocks, cranks, rods, axles and miscellaneous junk that comes through a shop (lots of spools in the late 90’s and early 00’s) and the only things that needed to be demagnetized was what I wet Mag’d.

If you are Mag’ing with a hand held 110 or even 220 mag there is no need to demag it.
 
yellow rose said:
I have mag’d hundreds and hundreds of blocks, cranks, rods, axles and miscellaneous junk that comes through a shop (lots of spools in the late 90’s and early 00’s) and the only things that needed to be demagnetized was what I wet Mag’d.

If you are Mag’ing with a hand held 110 or even 220 mag there is no need to demag it.
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Cool, hopefully when I get home it is getting weaker. I still got to bring in block for cylinder work. If after that it still is magnetic I'll take action then. I'm definitely open to suggestions and insight how others demag things big at home, other than a ballpeen east to west.
 
So tiny, tiny, pieces of metal or metal powder being magnetically stuck in a oil galley is no big deal? I know, I know. Brushes, high pressure, this that and the other. But, what if? Higher end(?) shops degauss for a reason. I'm no pro. Just my 2 cents.
 
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I swear I see some of the biggest worry over the smallest problems (or no problem at all) on this site.
 
RustyRatRod said:
I swear I see some of the biggest worry over the smallest problems (or no problem at all) on this site.
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Thanks Rusty but I think YR already beat you to the punch that I’m a mechanical idiot. I’m sure both of you are very good at whatever it is that you guys do. Worry or not, it doesn’t sound like you know how to demagnetize an engine block at home with common tools. Maybe you do but why wouldn’t you just say. I’m really not to worried, I’ll getter done. I’m not in a hurry and if I overlook something that’s on me. I found a way to magnaflux everything at home and I’ll figure this out too. Thanks for your help bro.
 
Scamp Fasty said:
Thanks Rusty but I think YR already beat you to the punch that I’m a mechanical idiot. I’m sure both of you are very good at whatever it is that you guys do. Worry or not, it doesn’t sound like you know how to demagnetize an engine block at home with common tools. Maybe you do but why wouldn’t you just say. I’m really not to worried, I’ll getter done. I’m not in a hurry and if I overlook something that’s on me. I found a way to magnaflux everything at home and I’ll figure this out too. Thanks for your help bro.
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No one said you are an idiot. I’m saying what little magnetism there is is insignificant. If you want to demag it go ahead.
 
yellow rose said:
No one said you are an idiot. I’m saying what little magnetism there is is insignificant. If you want to demag it go ahead.
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Yeah sorry to through you into that. Just doesn’t seem right to have an engine that metal wants to cling too. It is definitely losing its intensity. Mag powder blows off tonight which didn’t move much last night. After reading up on degaussing I’m very curious how to build my own at this point too.
 
Scamp Fasty said:
Yeah sorry to through you into that. Just doesn’t seem right to have an engine that metal wants to cling too. It is definitely losing its intensity. Mag powder blows off tonight which didn’t move much last night. After reading up on degaussing I’m very curious how to build my own at this point too.
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Put it together , wont last long anyway -----------the magnatizm that is .
 
The residual magnetism will likely weaken over time and with hot / cold cycles from running. There may be internal areas that will not de-mag for you.

Scamp Fasty said:
...… I read I can wrap the block with the positive lead from an AC arc welder with 5-6 wraps, and then weld on some scrap. The scrap should be clamped on block with ground on opposite side of the scrap. The wraps make a coil and should induce current and a magnetic field. Ground wire should take care of induced current, I think. Anyone ever try this or another method that worked?
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I've never seen it but if they can de-mag ships, a block would be small potatoes.

FWIW, Turning coil current off while a part is still in it will tend to induce magnetism from what I recall. Way back when I demagnetized using a fixed coil, the parts needed to be away from the coils influence before shutting it off to meet the Gauss spec.


There are small portable demagnetizers that can be used such as in the link below or wands. Maybe the shop has one you can try.
https://www.magnetics.com/product.asp?ProductID=49


IDK but a cheap picture tube de-Gauss coil may even work.
upload_2020-6-10_8-41-34.png
 
famous bob said:
Put it together , wont last long anyway -----------the magnatizm that is .
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Looks that way. Last night I left a paperclip hanging from front of block, this morning it’s on the ground. I also gave it a couple firm wacks (East to west). I have also been using a jewelers file on a sting to check the strength of magnetism. Now it seems no attraction is left. It just needed time to settle I guess
 
When somethings magnatized it has an excess of e-, or electrons. It's like the balloon you rubbed on your head as a kid and stuck on the wall. It will demagnatize naturally. Everything in life wants to be balanced. Those extra electrons will find their home by grounding out somewhere, and it will happen quickly. You're fine.
 
66 Valiant wagon said:
When somethings magnatized it has an excess of e-, or electrons. It's like the balloon you rubbed on your head as a kid and stuck on the wall. It will demagnatize naturally. Everything in life wants to be balanced. Those extra electrons will find their home by grounding out somewhere, and it will happen quickly. You're fine.
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Not in this case. That's static electricity which creates an electro-magnetic force.

All iron (and thus steel) has magnetism. The 'net' magnetic force is a result of alignment of the electron spin (nothing to do with extra electrons though). That spin direction can be influenced by outside forces, which is what the magnetizer did to his block. Typically there's enough randomness that there's no net magnetic force, despite still being magnetic in nature. Each grain of the metal will typically have it's own spin alignment, and at the macro level that randomness results in a net zero force.

Unless the magnetizer magnetized the majority of the block (unlikely), then the magnetic field will slowly decay on its own as the spin of the electrons in the magnetized area will be influenced by the non-aligned spin of electrons in the non-magnetized area. Heat the block up, and it will go faster. No need to take it to the 'curie' temperature either. Anything which excites the electrons will help speed up their re-alignment. Normal heat cycling, time, etc will all eventually decay the magnetism.

Demagging the block would be important if machine work is to take place immediately after magna-flux. But if you can wait a week or two, or even bake the block as part of the cleaning process, then it's not likely to be much of a concern. Attempts to remove the magnetism may cause more problems than they solve, or just be wasted effort in the long run. In a production shop, or small parts (which area easier to completely magnetize in the first place), de-mag is far more crucial.

Since OP is already seeing a reduction in the magnetic force it is not likely that it will be long before it becomes a non-issue. By the time the machine shop gets to it he should be fine.
 
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