A while back I mentioned the green cloth-backed paper sold by Packard looked
a winner. Well, I'm even more convinced now, because I cleaned up a part of
my shelf where the 180 experimental piece had hidden itself, and have used
it on another half-dozen pieces. This stuff is still cutting wood, though
at a finer grade rating, perhaps 240, and holding on to the hooks. Whoever
said the cloth was too stiff should see this 10-minute noodle of a sanding
pad!

I retired him yesterday, firmly attached to the velcro, grit from edge to
edge, and a veteran of over a dozen bowls. Put the old white Rhino 180 on
again, but once it's gone, it's gone.

I have 4 unused 80 grit disks for sale. With as often as I use 'em and as
long as these last....

(That's a joke, Ray)

In article , "George" george@least wrote:
This stuff [used 180 grit] is still cutting wood, though
at a finer grade rating, perhaps 240

Wrong. Worn 180 paper is simply that: worn 180 paper. It may remove wood at
approximately the same rate as new 240 paper, but it is *not* equivalent to
the finer grade. The abrasive particles are still the same (180) size, they're
just dull, and the scratch pattern reflects that.

--
Regards,
Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?

Yeah, right.

Talk to the Tormekers about what happens when you break the corners on the
grains.

Or the users of garnet paper....

"Doug Miller" wrote in message
m...
In article , "George" george@least
wrote:
This stuff [used 180 grit] is still cutting wood, though
at a finer grade rating, perhaps 240

Wrong. Worn 180 paper is simply that: worn 180 paper. It may remove wood
at
approximately the same rate as new 240 paper, but it is *not* equivalent
to
the finer grade. The abrasive particles are still the same (180) size,
they're
just dull, and the scratch pattern reflects that.

In article , "George" george@least wrote:
Yeah, right.

Talk to the Tormekers about what happens when you break the corners on the
grains.

You're talking to a Tormeker now, George. I've had one for three years.
Since you're apparently unfamiliar with the way it works, know that it uses a
stone that's *harder* than the grains to break them into finer grains. It's
not the same process as wearing the grains down through use.

Or the users of garnet paper....

Likewise not the same as wearing the abrasive particles down.

Believe what you want. It doesn't change the facts: used 180 is not the same
as new 240.


"Doug Miller" wrote in message
om...
In article , "George" george@least
wrote:
This stuff [used 180 grit] is still cutting wood, though
at a finer grade rating, perhaps 240

Wrong. Worn 180 paper is simply that: worn 180 paper. It may remove wood
at
approximately the same rate as new 240 paper, but it is *not* equivalent
to
the finer grade. The abrasive particles are still the same (180) size,
they're
just dull, and the scratch pattern reflects that.




--
Regards,
Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?

Breakage of the sharp edges is what it does, same as sanding wood. AlOx
does _not_ wear down in contact with wood. Defies physics.

The smaller sharp points from brittle fractures are effectively finer. When
you re-dress your Tormek, you break away the fractured grains, exposing
fresh gross points.

"Doug Miller" wrote in message
m...
In article , "George" george@least
wrote:
Yeah, right.

Talk to the Tormekers about what happens when you break the corners on
the
grains.

You're talking to a Tormeker now, George. I've had one for three years.
Since you're apparently unfamiliar with the way it works, know that it
uses a
stone that's *harder* than the grains to break them into finer grains.
It's
not the same process as wearing the grains down through use.

Gee I don't know about this Doug. George may be on to something. I will do
a test......I will just use 180 grit until it cuts like 240 and then like
320 and then like 400 and then like 600......and on and on....well you get
the idea........... Think about it Doug, we only have to buy one piece of
sandpaper from now on......................YMMV...........

--

Regards,
M.J. (Mike) Orr


"Doug Miller" wrote in message
m...
In article , "George" george@least
wrote:
This stuff [used 180 grit] is still cutting wood, though
at a finer grade rating, perhaps 240

Wrong. Worn 180 paper is simply that: worn 180 paper. It may remove wood
at
approximately the same rate as new 240 paper, but it is *not* equivalent
to
the finer grade. The abrasive particles are still the same (180) size,
they're
just dull, and the scratch pattern reflects that.

--
Regards,
Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?

"M.J." wrote in message
...
Gee I don't know about this Doug. George may be on to something. I will
do
a test......I will just use 180 grit until it cuts like 240 and then like
320 and then like 400 and then like 600......and on and on....well you get
the idea........... Think about it Doug, we only have to buy one piece
of
sandpaper from now on......................YMMV...........

--

Cute.

Now let's have a quick reality check about sandpaper. The grit is
determined by screen sizes. For our example, let's say that the screen
which traps the 150 grit is above, ours is going to be labeled 180, and
what passes us to the screen below, 240. We begin with a range of sizes,
and adhere them to a backing. The process vibrates them a bit to
distribute, so you've got a bit of the gold-panning effect, where the bigger
roll upward.

Now the larger of those particles, because they are larger, extend farther
from the adhesive or back. They are brittle, and so fracture, producing
_smaller_ grains with tighter abrasive points. They are also more
vulnerable, due to friction, to that phenomenon we all love, breaking free
of the adhesive so as to leave ugly marks as they are chewed through our
smoother surface. As both effects favor the ones who stick their necks out,
worn sandpaper approaches the grade of the lower mesh size as it is used.

With this green stuff, the adhesive appears to be very good, holding grit
far beyond any I've used, including some red resin-on-resin (look at sanding
belts) types. This means I've still got grit making sanding dust beyond the
time the paper-backed 180 has shed virtually everything and is burnishing
the surface like the Kraft paper it is.

In article , "George" george@least wrote:
Now let's have a quick reality check about sandpaper. The grit is
determined by screen sizes. For our example, let's say that the screen
which traps the 150 grit is above, ours is going to be labeled 180, and
what passes us to the screen below, 240. We begin with a range of sizes,
and adhere them to a backing. The process vibrates them a bit to
distribute, so you've got a bit of the gold-panning effect, where the bigger
roll upward.

Now the larger of those particles, because they are larger, extend farther
from the adhesive or back. They are brittle, and so fracture, producing
_smaller_ grains with tighter abrasive points.

I wouldn't mind seeing some substantiation of this claim that the abrasive
particles *fracture* (as opposed to wear).

They are also more
vulnerable, due to friction, to that phenomenon we all love, breaking free
of the adhesive so as to leave ugly marks as they are chewed through our
smoother surface. As both effects favor the ones who stick their necks out,
worn sandpaper approaches the grade of the lower mesh size as it is used.

Think that if you want. Me, I always figured there was a reason that sandpaper
was made in different grits, some coarse, some fine.

With this green stuff, the adhesive appears to be very good, holding grit
far beyond any I've used, including some red resin-on-resin (look at sanding
belts) types. This means I've still got grit making sanding dust beyond the
time the paper-backed 180 has shed virtually everything and is burnishing
the surface like the Kraft paper it is.

No doubt you do. Trouble is, it's dull 180-grit particles. And those are *not*
the same as sharp 240-grit particles.

Do a test: using fresh 180, well-worn 180, and fresh 240, sand up some areas
on a piece of plexiglas where you can see the scratch pattern easily.

--
Regards,
Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?

On Mon, 21 Feb 2005 16:32:39 -0800, "M.J." wrote:

Gee I don't know about this Doug. George may be on to something. I will do
a test......I will just use 180 grit until it cuts like 240 and then like
320 and then like 400 and then like 600......and on and on....well you get
the idea........... Think about it Doug, we only have to buy one piece of
sandpaper from now on......................YMMV...........

I tried it.. damn paper backing wore out after only 100 uses... cheap disposable
crap!



mac

Please remove splinters before emailing

"Doug Miller" wrote in message
...
In article , "George" george@least wrote:
Now let's have a quick reality check about sandpaper.

I wouldn't mind seeing some substantiation of this claim that the abrasive
particles *fracture* (as opposed to wear).

Look it up. You'll learn more if you have to put the effort into it. You
refuse gratis information.

While you're at it, give some thought to how they came up with that Mohs
thingie of what scratches (wears) what. If wood "wears" AlOx - which it
does by breaking the sharp edges - not rounding them, why doesn't it just
blunt your gouge, which is cut by AlOx?

"George" george@least wrote in message
...

"Doug Miller" wrote in message
...
In article , "George" george@least wrote:
Now let's have a quick reality check about sandpaper.

I wouldn't mind seeing some substantiation of this claim that the
abrasive
particles *fracture* (as opposed to wear).

Look it up. You'll learn more if you have to put the effort into it. You
refuse gratis information.

While you're at it, give some thought to how they came up with that Mohs
thingie of what scratches (wears) what. If wood "wears" AlOx - which it
does by breaking the sharp edges - not rounding them, why doesn't it just
blunt your gouge, which is cut by AlOx?


So then I do just need to use one piece of 280 grit on a project and keep
sanding with it until it "fractures" all the way to 2000 grit and the piece
is completed?
--


M.J. Orr
http://www.island.net/~morr
ô¿ô
~

"M.J. Orr" wrote in message
...

So then I do just need to use one piece of 280 grit on a project and keep
sanding with it until it "fractures" all the way to 2000 grit and the
piece
is completed?
--

It's like being in the classroom again. Surrounded by those who know
nothing, but keep spouting off.

For you, and the others who haven't the sense to shut up or the ability to
look up

http://www.woodzone.com/articles/sandpaper/

In article , "George" george@least wrote:

"Doug Miller" wrote in message
m...
In article , "George" george@least wrote:
Now let's have a quick reality check about sandpaper.

I wouldn't mind seeing some substantiation of this claim that the abrasive
particles *fracture* (as opposed to wear).

Look it up. You'll learn more if you have to put the effort into it. You
refuse gratis information.

In other words, that's just your opinion, which you are unable to
substantiate.

While you're at it, give some thought to how they came up with that Mohs
thingie of what scratches (wears) what. If wood "wears" AlOx - which it
does by breaking the sharp edges - not rounding them, why doesn't it just
blunt your gouge, which is cut by AlOx?

Hello.... it *does* blunt the gouge. That's why I have to resharpen it from
time to time.

Try the test I proposed, putting scratch patterns on plexiglass, and post your
results. A photo in alt.binaries.pictures.woodworking would be interesting.

--
Regards,
Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?

In article , "George" george@least wrote:

"M.J. Orr" wrote in message
...

So then I do just need to use one piece of 280 grit on a project and keep
sanding with it until it "fractures" all the way to 2000 grit and the
piece
is completed?
--

It's like being in the classroom again. Surrounded by those who know
nothing, but keep spouting off.

For you, and the others who haven't the sense to shut up or the ability to
look up

http://www.woodzone.com/articles/sandpaper/

Interesting article. While it does appear to back you up to the extent of
stating that aluminum oxide fractures to create new sharp edges, I note that
it utterly fails to substantiate your absurd claim that this produces the
effect of using finer sandpaper.

So... put up, or shut up.

--
Regards,
Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?

"George" george@least wrote in message
...

"M.J. Orr" wrote in message
...

So then I do just need to use one piece of 280 grit on a project and keep
sanding with it until it "fractures" all the way to 2000 grit and the
piece
is completed?
--

It's like being in the classroom again. Surrounded by those who know
nothing, but keep spouting off.

For you, and the others who haven't the sense to shut up or the ability to
look up

http://www.woodzone.com/articles/sandpaper/


--


Point out to me where in that article that they claim that "fragmented"
sandpaper cuts like the next finer grit....... If you can't then might I
suggest you head back to that classroom.........By the way......watch much
O'Reilly Factor?????



M.J. Orr
http://www.island.net/~morr
ô¿ô
~

I have read the paper called Sandpaper 101at
http://www.woodzone.com/articles/sandpaper/.
The paper is well done for basic classroom teaching.
The problem in power sanding is not as much as the grit but the backing that
hooks on to the velcro. In industries where the production is on 24 hours
per day 365 days a year the situation is not the same. Cost have to be
controlled to in order to match competition.
Any stopping of the machinery's line to replace a piece of sand paper brings
the cost up.
In order to reduce the machinery down time only quality sand paper is used.
What makes a good sand paper is first the material and heat resistant
bonding agent, the curing time, the proper ambient storage. The shelve life
plays a large role in the performance of the sand paper. Different time
tables are used for shelve life. Once the shelve life has expired the paper
is removed from the production store. Subject to the nature of the
procurement contract, its returned to the original manufacturer for
replacement. Then it is rejected, discounted and sold as no name brand to
re-sellers that do business with hobbyist. They in turn cut and punch the
paper to popular sizes and offer it at basement bargain prices to hobbyists

"M.J. Orr" wrote in message
...



"George" george@least wrote in message
...

"M.J. Orr" wrote in message
...

So then I do just need to use one piece of 280 grit on a project and
keep
sanding with it until it "fractures" all the way to 2000 grit and the
piece
is completed?
--

It's like being in the classroom again. Surrounded by those who know
nothing, but keep spouting off.

For you, and the others who haven't the sense to shut up or the ability
to
look up

http://www.woodzone.com/articles/sandpaper/


--


Point out to me where in that article that they claim that "fragmented"
sandpaper cuts like the next finer grit....... If you can't then might I
suggest you head back to that classroom.........By the way......watch much
O'Reilly Factor?????



M.J. Orr
http://www.island.net/~morr
ô¿ô
~

"Denis Marier" wrote in message
...
I have read the paper called Sandpaper 101at
http://www.woodzone.com/articles/sandpaper/.
The paper is well done for basic classroom teaching.
The problem in power sanding is not as much as the grit but the backing
that
hooks on to the velcro.

As I said, floppy as overdone mafalda, but holding on tightly each time it's
reattached.

What makes a good sand paper is first the material and heat resistant
bonding agent, the curing time, the proper ambient storage.

The second point mentioned - the adhesive holds tightly to the grit, even on
the edges, where you'd expect a bit of peelback or breakdown.

The shelve life
plays a large role in the performance of the sand paper. Different time
tables are used for shelve life.

That remains undetermined. The stuff I got is fresh - to me. Unfortunately
that's about all we can say about any paper we get. Unlike the higher-carb
beer they don't give us a "born on" date.

Then there is the way it's used. I am a low-heat sander, so I don't have a
lot of problem with velcro melt, or with cloth separation, where they seem
to use some pretty crummy glue. One variety of paper which I'm _not_ buying
again is extremely prone to paper/cloth detachment, and smells like hide
glue, which seems utterly inappropriate for the purpose.

"Doug Miller" wrote in message
om...
http://www.woodzone.com/articles/sandpaper/

Interesting article. While it does appear to back you up to the extent of
stating that aluminum oxide fractures to create new sharp edges, I note
that
it utterly fails to substantiate your absurd claim that this produces the
effect of using finer sandpaper.

So... put up, or shut up.

Ok, one last time to learn to think. If the finer papers are made with
smaller pieces, and the bigger pieces break up into smaller ....

Well George, I am a light sander and with some sand paper purchased at
bargain price the backing peels off. I have no peel off with known brand of
sand paper.
Here, the resellers are not always storing their sand paper at a constant
ambient temperature. During the winter they lower the thermostat at night
to save money. This produces condensation and on long term its promotes
de - lamination.
Have a good day
"George" george@least wrote in message
...

"Denis Marier" wrote in message
...
I have read the paper called Sandpaper 101at
http://www.woodzone.com/articles/sandpaper/.
The paper is well done for basic classroom teaching.
The problem in power sanding is not as much as the grit but the backing
that
hooks on to the velcro.

As I said, floppy as overdone mafalda, but holding on tightly each time
it's
reattached.

What makes a good sand paper is first the material and heat resistant
bonding agent, the curing time, the proper ambient storage.

The second point mentioned - the adhesive holds tightly to the grit, even
on
the edges, where you'd expect a bit of peelback or breakdown.

The shelve life
plays a large role in the performance of the sand paper. Different time
tables are used for shelve life.

That remains undetermined. The stuff I got is fresh - to me.
Unfortunately
that's about all we can say about any paper we get. Unlike the
higher-carb
beer they don't give us a "born on" date.

Then there is the way it's used. I am a low-heat sander, so I don't have
a
lot of problem with velcro melt, or with cloth separation, where they seem
to use some pretty crummy glue. One variety of paper which I'm _not_
buying
again is extremely prone to paper/cloth detachment, and smells like hide
glue, which seems utterly inappropriate for the purpose.

In article , "George" george@least wrote:

"Doug Miller" wrote in message
. com...
http://www.woodzone.com/articles/sandpaper/

Interesting article. While it does appear to back you up to the extent of
stating that aluminum oxide fractures to create new sharp edges, I note
that
it utterly fails to substantiate your absurd claim that this produces the
effect of using finer sandpaper.

So... put up, or shut up.

Ok, one last time to learn to think. If the finer papers are made with
smaller pieces, and the bigger pieces break up into smaller ....

*You* learn to think. Smaller pieces does not necessarily mean a finer cutting
edge. What do you get if you break a square in half?

One last time: learn to back up your claims. Where can you substantiate your
claim that worn sandpaper of one grit is equivalent to paper of a finer grit?
You do that, and I'll admit you're right. You can't do that, and I'll continue
to say you don't know what you're tallking about.

Just because worn 180 paper removes stock at about the same rate as new 240
paper does *not* mean, as you appear to think it does, that it's doing the
same job. Try the test I suggested on plexiglass, and look at your scratch
patterns.

--
Regards,
Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?

Ok, one last time to learn to think. If the finer papers are made with
smaller pieces, and the bigger pieces break up into smaller ....

If you mean a big piece breaks into two (or more) smaller pieces, that
is not so. As I understand it, the edges of each piece of aluminum oxide
fracture, to reveal new cutting edges on one, slightly smaller piece of
grit.

So if we now consider the paper as a whole, as it gets used, there will
still be the same number of cutting points per square inch. But they
will not be so high, and there will be bigger voids between them. This
is not the same as finer grit paper which has more cutting points per
square inch and only small voids between them.

--
Derek Andrews, woodturner

http://www.seafoamwoodturning.com
http://chipshop.blogspot.com
http://groups.yahoo.com/group/toolrest/

"George" george@least wrote in message
...

"Doug Miller" wrote in message
om...
http://www.woodzone.com/articles/sandpaper/

Interesting article. While it does appear to back you up to the extent of
stating that aluminum oxide fractures to create new sharp edges, I note
that
it utterly fails to substantiate your absurd claim that this produces the
effect of using finer sandpaper.

So... put up, or shut up.

Ok, one last time to learn to think. If the finer papers are made with
smaller pieces, and the bigger pieces break up into smaller ....

--


Ok One last time........Just for you.....!! How many particles are on 180
grit paper? How many particles are on 2000 grit paper. Fracture the 180
grit particles all you want there will NEVER be any more particles on that
paper.


M.J. Orr
http://www.island.net/~morr
ô¿ô
~

"Derek Andrews" wrote in message
...
Ok, one last time to learn to think. If the finer papers are made with
smaller pieces, and the bigger pieces break up into smaller ....

If you mean a big piece breaks into two (or more) smaller pieces, that
is not so. As I understand it, the edges of each piece of aluminum oxide
fracture, to reveal new cutting edges on one, slightly smaller piece of
grit.

So if we now consider the paper as a whole, as it gets used, there will
still be the same number of cutting points per square inch. But they
will not be so high, and there will be bigger voids between them. This
is not the same as finer grit paper which has more cutting points per
square inch and only small voids between them.


OK, join the rest. It isn't the shaggiest dog in the world.

SHEESH!

"M.J. Orr" wrote in message
...

Ok One last time........Just for you.....!! How many particles are on 180
grit paper? How many particles are on 2000 grit paper. Fracture the 180
grit particles all you want there will NEVER be any more particles on that
paper.

M.J. Orr
http://www.island.net/~morr
ô¿ô
~
Does this mean that a closed coat paper of one grit sands finer than an open
coat paper of the same grit?
Does it make a difference what the abrasive material is?

--
Martin
Long Island, New York

I had noticed that older worn sandpaper would give a smoother surface
than the next finer grit of fresh paper would. After pondering this for
a while, I figured that it was due to clogging, and you ended up
burnishing instead of sanding. I think this is at least possible.
robo hippy

















mac davis wrote:
On Mon, 21 Feb 2005 16:32:39 -0800, "M.J."
wrote:

Gee I don't know about this Doug. George may be on to something. I
will do
a test......I will just use 180 grit until it cuts like 240 and then
like
320 and then like 400 and then like 600......and on and on....well
you get
the idea........... Think about it Doug, we only have to buy one
piece of
sandpaper from now on......................YMMV...........

I tried it.. damn paper backing wore out after only 100 uses... cheap
disposable
crap!



mac

Please remove splinters before emailing

"robo hippy" wrote in message
ups.com...
I had noticed that older worn sandpaper would give a smoother surface
than the next finer grit of fresh paper would. After pondering this for
a while, I figured that it was due to clogging, and you ended up
burnishing instead of sanding. I think this is at least possible.
robo hippy

Probably less clogging than simple grit shedding. As mentioned many times,
the stuff breaks into smaller pieces and dislodges from the adhesive. With
higher smooth paper to grit ratio, you'll heat rather than cut, eventually.

I take clogging to be that fiber grab which I can remove with my file card
or that crepe stick. What always happens when you try to sand a piece too
wet.

Geo

I got it - too bad I have loads of the Rhino "waste-of-money" paper as well!

Ray


"George" george@least wrote in message
...
A while back I mentioned the green cloth-backed paper sold by Packard
looked
a winner. Well, I'm even more convinced now, because I cleaned up a part
of
my shelf where the 180 experimental piece had hidden itself, and have used
it on another half-dozen pieces. This stuff is still cutting wood, though
at a finer grade rating, perhaps 240, and holding on to the hooks.
Whoever
said the cloth was too stiff should see this 10-minute noodle of a sanding
pad!

I retired him yesterday, firmly attached to the velcro, grit from edge to
edge, and a veteran of over a dozen bowls. Put the old white Rhino 180 on
again, but once it's gone, it's gone.

I have 4 unused 80 grit disks for sale. With as often as I use 'em and as
long as these last....

(That's a joke, Ray)

"Derek Andrews" wrote in message
...
SNIP .......
So if we now consider the paper as a whole, as it gets used, there will
still be the same number of cutting points per square inch. But they will
not be so high, and there will be bigger voids between them. This is not
the same as finer grit paper which has more cutting points per square inch
and only small voids between them.
SNIP .........
=========================
Not necessarily true. Open coat and closed coat use the same grit size, but
don't have the same number of points per given area.

Ken Moon
Webberville, TX

In article . net, "Ken Moon" wrote:

"Derek Andrews" wrote in message
...
SNIP .......
So if we now consider the paper as a whole, as it gets used, there will
still be the same number of cutting points per square inch. But they will
not be so high, and there will be bigger voids between them. This is not
the same as finer grit paper which has more cutting points per square inch
and only small voids between them.
SNIP .........
=========================
Not necessarily true. Open coat and closed coat use the same grit size, but
don't have the same number of points per given area.

Doesn't alter the fact that worn 180 is not the same as new 240.

--
Regards,
Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?

Ken Moon wrote:
"Derek Andrews" wrote:
So if we now consider the paper as a whole, as it gets used, there will
still be the same number of cutting points per square inch. But they will
not be so high, and there will be bigger voids between them. This is not
the same as finer grit paper which has more cutting points per square inch
and only small voids between them.

SNIP .........
=========================
Not necessarily true. Open coat and closed coat use the same grit size, but
don't have the same number of points per given area.

I don't see how that is relevant. It seems to me like you are comparing
two different products and complicating the issue even further.
--
Derek Andrews, woodturner

http://www.seafoamwoodturning.com
http://chipshop.blogspot.com
http://groups.yahoo.com/group/toolrest/

"Doug Miller" wrote in message
om...

Doesn't alter the fact that worn 180 is not the same as new 240.


Well, now we've finally gotten to something I agree with.

It isn't the same, it just leaves a finish which compares with, because the
maximum grit size has shrunk..

Or do you still believe the bush burns but is not consumed?

"Ken Moon" wrote in message
ink.net...

"Derek Andrews" wrote in
message ...
SNIP .......
So if we now consider the paper as a whole, as it gets used, there will
still be the same number of cutting points per square inch. But they will
not be so high, and there will be bigger voids between them. This is not
the same as finer grit paper which has more cutting points per square
inch and only small voids between them.
SNIP .........
=========================
Not necessarily true. Open coat and closed coat use the same grit size,
but don't have the same number of points per given area.

Ken Moon
Webberville, TX


So then Ken, do you beleive that worn 180 grit open coat is the same as new
240 grit open coat
OR
that worn 180 grit closed coat is the same as new 240 grit closed coat???

For bonus points just answer...... Yes/No

--

Regards,
M.J. (Mike) Orr

In article , "George" george@least wrote:

"Doug Miller" wrote in message
. com...

Doesn't alter the fact that worn 180 is not the same as new 240.

Well, now we've finally gotten to something I agree with.

Odd... My position hasn't changed. I've been saying from the beginning that
they're not the same. You agree with me now?

It isn't the same, it just leaves a finish which compares with, because the
maximum grit size has shrunk..

I dispute that. Do a scratch test on plexiglass so you can *see* the
difference.

Or do you still believe the bush burns but is not consumed?

Worn 180 will *not* leave the same finish as new 240. Characterize, or
cariacaturize, that statement however you wish; it's still correct.

--
Regards,
Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?

As long as we are still revisiting this important issue; didja ever
notice how friends, relatives and customers, as they fondle a velvety
smooth bowl, feel our pain with a real concern for the agony of skipped
grits and the heartbreak of recycled papers?

I tried to substitute a used 2200grit brown paper bag from A&P for a
2600grit paper bag from Kroger's, but it wasn't the same.

Grits are often fractured or torn from their backing in steps of 100,
120,150,180, 240, etc. instead of 90, 140, 195 etc. Who picked these
numbers ...why? How many grits are available or must we recycle worn
intermediates for the inbetweens?


Turn to Safety, Arch
Fortiter



http://community.webtv.net/almcc/MacsMusings

"M.J." wrote in message
...


"Ken Moon" wrote in message
ink.net...

"Derek Andrews" wrote in
message ...
SNIP .......
So if we now consider the paper as a whole, as it gets used, there will
still be the same number of cutting points per square inch. But they
will
not be so high, and there will be bigger voids between them. This is
not
the same as finer grit paper which has more cutting points per square
inch and only small voids between them.
SNIP .........
=========================
Not necessarily true. Open coat and closed coat use the same grit size,
but don't have the same number of points per given area.

Ken Moon
Webberville, TX


So then Ken, do you beleive that worn 180 grit open coat is the same as
new
240 grit open coat
OR
that worn 180 grit closed coat is the same as new 240 grit closed coat???

For bonus points just answer...... Yes/No

--

Regards,
M.J. (Mike) Orr


Mike,
Ken was commenting on Derek's statement that finer grit paper has more
cutting points per square inch. If the cutting points per square inch is an
indication of fineness, does that mean an open and closed coat paper of the
SAME grit will give different finishes. Just so we are on the same page, an
open coat paper has less abrasive material and more open area to resist
clogging.

To all,
For a given grit, does the finish you get depend on the abrasive material
used for the sandpaper.

Does particle size distribution have an effect on finish? Or do we
believe that every particle on the paper is the same size?

--
Martin
Long Island, New York

Arch,

Please stop it, you are killing me!

ROTFLMAO

We have a microscope here so the people involved could send me two or
three samples and I could publish the result.

Course -- I think that spoil the fun and the debate. ;-)

I am pretty sure that garnet fractures - and that's how it stays "sharp"
but for AlO (Aluminum Oxide) paper? Not sure. Suspect that it abrades
and clogs - not fractures and clogs. At least that's what the standard
"material engineering" texts would have you believe -- assuming I can
remember where I saw it. :-)

....So maybe you split the argument up to consider the various types of
sandpaper and we can all gird for battle here. :-))



George wrote:
"robo hippy" wrote in message
ups.com...

I had noticed that older worn sandpaper would give a smoother surface
than the next finer grit of fresh paper would. After pondering this for
a while, I figured that it was due to clogging, and you ended up
burnishing instead of sanding. I think this is at least possible.
robo hippy


Probably less clogging than simple grit shedding. As mentioned many times,
the stuff breaks into smaller pieces and dislodges from the adhesive. With
higher smooth paper to grit ratio, you'll heat rather than cut, eventually.

I take clogging to be that fiber grab which I can remove with my file card
or that crepe stick. What always happens when you try to sand a piece too
wet.




--
Will
Occasional Techno-geek

Will wrote:
We have a microscope here so the people involved could send me two or
three samples and I could publish the result.

Course -- I think that spoil the fun and the debate. ;-)

I am pretty sure that garnet fractures - and that's how it stays "sharp"
but for AlO (Aluminum Oxide) paper? Not sure. Suspect that it abrades
and clogs - not fractures and clogs. At least that's what the standard
"material engineering" texts would have you believe -- assuming I can
remember where I saw it. :-)

Sorry had that backwards... :-(


...So maybe you split the argument up to consider the various types of
sandpaper and we can all gird for battle here. :-))



George wrote:

"robo hippy" wrote in message
ups.com...

I had noticed that older worn sandpaper would give a smoother surface
than the next finer grit of fresh paper would. After pondering this for
a while, I figured that it was due to clogging, and you ended up
burnishing instead of sanding. I think this is at least possible.
robo hippy


Probably less clogging than simple grit shedding. As mentioned many
times,
the stuff breaks into smaller pieces and dislodges from the adhesive.
With
higher smooth paper to grit ratio, you'll heat rather than cut,
eventually.

I take clogging to be that fiber grab which I can remove with my file
card
or that crepe stick. What always happens when you try to sand a piece
too
wet.





--
Will
Occasional Techno-geek

M.J. Orr wrote:
"George" george@least wrote in message
...

"M.J. Orr" wrote in message
...

So then I do just need to use one piece of 280 grit on a project and keep
sanding with it until it "fractures" all the way to 2000 grit and the

piece

is completed?
--

It's like being in the classroom again. Surrounded by those who know
nothing, but keep spouting off.

For you, and the others who haven't the sense to shut up or the ability to
look up

http://www.woodzone.com/articles/sandpaper/


--



Point out to me where in that article that they claim that "fragmented"
sandpaper cuts like the next finer grit....... If you can't then might I
suggest you head back to that classroom.........By the way......watch much
O'Reilly Factor?????


There is an implication -- when something breaks in two - you now have
two smaller pieces. So.... You would have to measure and see the degree
of degradation of particle size...

However, since not all pieces would fracture you would probably get some
scratches from the larger pieces until _all_ pieces fracture. A little
tougher than it sounds I would think -- to ensure that many thousands of
particles all had at least one fracture...

So I would think that measurement would show a significantly smaller
number of "large" scratches as time went on - but probably at least
_some_ larger scratches from the "few" remaining pieces still within the
original particle size distribution.

An applied scientist would tell you that "100 Grit" meant most of the
particles would be "darn close" to 100 - but there would be a
distribution of particle sizes (probably fairly sharp) about the mean
(average) particle size. Now if you fracture the majority of the pieces
all you have to answer is "How do they break?". Do they break in two?
Or... does a small piece break off a piece that stays on the paper.

Inquiring minds want to know! Or do they? :-))






M.J. Orr
http://www.island.net/~morr
ô¿ô
~




--
Will
Occasional Techno-geek

"Will" wrote in message
.. .


Will wrote:
We have a microscope here so the people involved could send me two or
three samples and I could publish the result.

Course -- I think that spoil the fun and the debate. ;-)

I am pretty sure that garnet fractures - and that's how it stays "sharp"
but for AlO (Aluminum Oxide) paper? Not sure. Suspect that it abrades
and clogs - not fractures and clogs. At least that's what the standard
"material engineering" texts would have you believe -- assuming I can
remember where I saw it. :-)

Sorry had that backwards... :-(

They've already been published. Read the referenced "Sandpaper 101." That
some will not acknowledge it in no way alters reality.

Note the crystalline structure http://webmineral.com/data/Corundum.shtml
which, when fractured, dislodges conoidal fragments, creating new points.
Logically, loss of matter would reduce the particle size, physically, it is
still freshly sharp.

Now, with a hardness of 9.0, it takes some work to find something which
would abrade it. The two common minerals found in some woods which are
capable of actually abrading steel, calcium oxalate (yep, kidney stones)
and Quartz have no effect, other than possibly fracture.

What we call "wear" in sandpaper has much more to do with the other parts -
the adhesive and the backing. The adhesive has to hold the grit in place
against some pretty strong impacts, while allowing flex in the backing, so
it doesn't break away prematurely.

Thus the original post, where I remarked that this particular type of
abrasive seemed to have the right stuff. It held the backing and the grit
so firmly that the first did not delaminate, and the second were selectively
demolished, though not released, so as to cut without heat buildup (from the
slick spaces between grit) producing a finish equal to the next finer grit.

Not surprising, given that a fracture or two would reduce even the largest
to the level of the largest in the next grade.

So, _I_ have done the research. I would say if you have not,you should, or
not attempt puerile challenges to one who has.