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Posted by Grant Erwin on June 10, 2008, 7:43 pm
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I have been building steel stairways inside new town houses, which are of
course made of wood & drywall. The builder called me just now and said his
drywall screws are beginning to become visible, through the paint, texturing and
mud. He thinks that when we sand off the welds (from the square tube, which we
do to make the handrail feel smooth to the hand) that the swarf is magnetized
and is "finding" the sheetrock screws and sticking there, making them apparent
to the eye.
Is this possible? It seems to me that if it were, several things would have to
be demonstrably true:
1. the effect would be much more pronounced in the stairwell than in the rest of
the house
2. dust carefully collected onto a card would be attracted to a paper clip or
other steel object
3. a lot of the dust would be hanging onto the stair railings and beams
themselves.
Anyone have any ideas or information about this?
Grant
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Posted by Up North on June 10, 2008, 7:49 pm
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>I have been building steel stairways inside new town houses, which are of
> course made of wood & drywall. The builder called me just now and said his
> drywall screws are beginning to become visible, through the paint,
> texturing and mud. He thinks that when we sand off the welds (from the
> square tube, which we do to make the handrail feel smooth to the hand)
> that the swarf is magnetized and is "finding" the sheetrock screws and
> sticking there, making them apparent to the eye.
>
> Is this possible? It seems to me that if it were, several things would
> have to be demonstrably true:
>
> 1. the effect would be much more pronounced in the stairwell than in the
> rest of the house
>
> 2. dust carefully collected onto a card would be attracted to a paper clip
> or other steel object
>
> 3. a lot of the dust would be hanging onto the stair railings and beams
> themselves.
>
> Anyone have any ideas or information about this?
>
> Grant
Is the work you are doing happen before the house is taped?
Steve
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Posted by Up North on June 10, 2008, 8:16 pm
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>
>>I have been building steel stairways inside new town houses, which are of
>> course made of wood & drywall. The builder called me just now and said
>> his
>> drywall screws are beginning to become visible, through the paint,
>> texturing and mud. He thinks that when we sand off the welds (from the
>> square tube, which we do to make the handrail feel smooth to the hand)
>> that the swarf is magnetized and is "finding" the sheetrock screws and
>> sticking there, making them apparent to the eye.
>>
>> Is this possible? It seems to me that if it were, several things would
>> have to be demonstrably true:
>>
>> 1. the effect would be much more pronounced in the stairwell than in the
>> rest of the house
>>
>> 2. dust carefully collected onto a card would be attracted to a paper
>> clip or other steel object
>>
>> 3. a lot of the dust would be hanging onto the stair railings and beams
>> themselves.
>>
>> Anyone have any ideas or information about this?
>>
>> Grant
Grant
I do quite a bit of grinding using flapwheels and I have noticed the pieces
I grind do get magnetized, more so when the flap wheel is worn. This problem
reared it ugly head in the paint booth.
I just checked some of the dust with a piece of steel that is not
magetized and it appears that the dust is not magnetic. It seems like the
amount of dust sticking to a sheetrock screw head wouldn't cause rust to
bleed through. I am thinking crappy imported screws with poorly done
phosphate coating.
Steve
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Posted by Grant Erwin on June 10, 2008, 8:33 pm
Please log in for more thread options Up North wrote:
>
>>I have been building steel stairways inside new town houses, which are of
>>course made of wood & drywall. The builder called me just now and said his
>>drywall screws are beginning to become visible, through the paint,
>>texturing and mud. He thinks that when we sand off the welds (from the
>>square tube, which we do to make the handrail feel smooth to the hand)
>>that the swarf is magnetized and is "finding" the sheetrock screws and
>>sticking there, making them apparent to the eye.
>>
>>Is this possible? It seems to me that if it were, several things would
>>have to be demonstrably true:
>>
>>1. the effect would be much more pronounced in the stairwell than in the
>>rest of the house
>>
>>2. dust carefully collected onto a card would be attracted to a paper clip
>>or other steel object
>>
>>3. a lot of the dust would be hanging onto the stair railings and beams
>>themselves.
>>
>>Anyone have any ideas or information about this?
>>
>>Grant
>
>
>
> Is the work you are doing happen before the house is taped?
> Steve
>
>
I have been welding and grinding in these stairwells both before and after
the walls were sheetrocked. However, I never worked with the walls rocked but
not mudded or taped - either bare studs or finished walls.
Grant
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Posted by BobH on June 10, 2008, 10:13 pm
Please log in for more thread options Grant Erwin wrote:
> I have been building steel stairways inside new town houses, which are of
> course made of wood & drywall. The builder called me just now and said his
> drywall screws are beginning to become visible, through the paint,
> texturing and mud. He thinks that when we sand off the welds (from the
> square tube, which we do to make the handrail feel smooth to the hand)
> that the swarf is magnetized and is "finding" the sheetrock screws and
> sticking there, making them apparent to the eye.
>
> Is this possible? It seems to me that if it were, several things would
> have to be demonstrably true:
>
> 1. the effect would be much more pronounced in the stairwell than in the
> rest of the house
>
> 2. dust carefully collected onto a card would be attracted to a paper
> clip or other steel object
>
> 3. a lot of the dust would be hanging onto the stair railings and beams
> themselves.
>
> Anyone have any ideas or information about this?
>
> Grant
I think the drywall screws are magnetized, even before they get driven
with magnetic screwdriver bits. To test this I stuck a handful of
drywall screws (fresh out of the box) in the swarf pile on my bandsaw. I
cut a fair amount of steel on that saw. Most of them came up with lots
of bits stuck to them. A few did not. To see if the swarf was magnetic,
I stuck a couple of different pieces of steel into the swarf and nothing
stuck. I think the drywall screws are stamped or forged, and I think
that impact can cause weak magnetization. The blacksmith guys would know
more about this than I do.
I used to work in a shop that was built with sheetmetal beams and
drywall screwed to them. On the walls behind the chop saw and grinders
you could see every screw outlined with swarf. A year later, you could
see the beam outlines.
Good Luck,
BobH
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> course made of wood & drywall. The builder called me just now and said his
> drywall screws are beginning to become visible, through the paint,
> texturing and mud. He thinks that when we sand off the welds (from the
> square tube, which we do to make the handrail feel smooth to the hand)
> that the swarf is magnetized and is "finding" the sheetrock screws and
> sticking there, making them apparent to the eye.
>
> Is this possible? It seems to me that if it were, several things would
> have to be demonstrably true:
>
> 1. the effect would be much more pronounced in the stairwell than in the
> rest of the house
>
> 2. dust carefully collected onto a card would be attracted to a paper clip
> or other steel object
>
> 3. a lot of the dust would be hanging onto the stair railings and beams
> themselves.
>
> Anyone have any ideas or information about this?
>
> Grant