OldTools Archive

Recent Bios FAQ

273552 John <john@j...> 2021‑05‑03 home made sanding compound?
GG's

Been a long time since I came out from under the porch, but I need some wisdom
from the the porch.  I need to make a round sanding device.  About 2" -3" in
diameter to sand the inside of a sphere.  So I am thinking of finding a material
to add a grit to, that will break down as using, to continually expose new
sanding grit to sand a spherical inside shape.
What say the group?

John J Black
john@j...
now living in middle Tennessee

Sent via the Samsung Galaxy Note10+, an AT&T 5G Evolution capable smartphone
Get Outlook for Android ( https://aka.ms/AAb9ysg )
273553 John <john@j...> 2021‑05‑03 Re: home made sanding compound?
Maybe a better way to ask this question to the groupwould be...

How would a craftsman of old make a tool to cut an inside of a sphere?

Sent via the Samsung Galaxy Note10+, an AT&T 5G Evolution capable smartphone

Get Outlook for Android ( https://akams/AAb9ysg )
273554 Ed Minch <edminch3@g...> 2021‑05‑03 Re: home made sanding compound?
What material is the sphere made of? Do you need multiple grits?  How will you
get inside the sphere?  What about a piece of syrofoam with grit glued to it?

Ed Minch
273555 Richard Wilson <yorkshireman@y...> 2021‑05‑03 Re: home made sanding compound?
Fascinating question for a Monday morning...

> On 3 May 2021, at 02:47, John  wrote:
> 

>  I need to make a round sanding device.  About 2" -3" in diameter to sand the
inside of a sphere.  So I am thinking of finding a material to add a grit to,
that will break down as using, to continually expose new sanding grit to sand a
spherical inside shape.

- snippety snip - 


You don’t mention whether this is indeed the inside of a sphere - as in, say an
easter egg, with a spherical outer, or, say a mortar, with a spherical
depression in an otherwise substantial object.

Why would that help?
because the one is likely to be on a pole lathe, or otherwise a spinning
workholder, and the other is not.   Abrasive use demands thqat one or other is
moving, and the quicker the better, so a stationary abrasive  and spinning
workpiece works.   And a stationary object and spinning abrasive works.

Case1 - the spinning workpiece.  Make up a curved something to the size of the
interior, less thickness of abrasive.  Glue abrasive to holder - present to
spinning workpiece.  Do not be tempted to make your tool over long and cover a
full quarter of the sphere, unless it is trivial.  It will grab and end in
tears.
If trivial then make up the full spherical size, as per ..


Case 2 - the spherical depression in a lump of something.   Make up a suitable
size sperically domed end stick.  Coat with hide glue.  Dip in abrasive grit.
Repeat several times .  This is a time tested means of making up abrasive
formers.  As the grit is used, the glue will release due to heat softening, and
more abrasive is brought into use.  I can’t give actual experience of using this
this, so the precise degree of undersizing and amount of grit that can be
embedded will be a bit of trial and error.   Making the full spherical shaped
thing is of course, to equalise the pressure as you spin the thing - maybe in a
breast drill, as we were talking of them recently.  If you are pressing into the
dome, then the base will be receiving pressure and the sides will not.

A template, and some practice on a sacrificial trial is called for.

Or, of course, depending on the accuracy needed, you could emulate the above by
gluing up small bits of abrasive paper around the spherical master.


How many to do?
How accurate must it be?
How strong is the substrate?
How good a finish is needed?


I DO hoe you tell us how it all works out.


Richard Wilson
Yorkshireman Galoot
in Northumberland, where the weather forecast is for a decent rain, as it’s a
public holiday.




-- 
Yorkshireman Galoot
in the most northerly county, farther north even than Yorkshire
IT #300
273556 Frank Filippone <bmwred735i@g...> 2021‑05‑03 Re: home made sanding compound?
Given what you wish to accomplish, the technique of TUMBLING comes to 
mind.  In your case, the inside of the vessel is the final product, but 
methods are methods.

If you look towards jewelry making or polishing of small parts, the 
methods and sanding materials are all explained.

The product that does the work is usually something akin to ball 
bearings.  Put them inside the orb with a polishing product and tumble 
for days.

Frank
273565 Graybeard <veggie@b...> 2021‑05‑03 Re: home made sanding compound?
I live in the center of Shaker country, northern Columbia County, New York and
eagerly read what I can about Shaker craft.

I recall reading memoirs of an elderly Shaker gentlemen who, having served as a
journeyman (in the literal sense) at a number of Shaker colonies, had returned
to Mt Lebanon and was setting up a shop for himself.  He obtained some lumber
from a nearby sawmill (probably Shaker) for his bench then walked to Albany to
buy some planes (25 miles or so each way, sleeping rough).

When he returned to Mt. Lebanon, he gathered some glass bottles, smashed them,
ground the powder to make it finer, then glued the powder to paper to make his
working abrasive (an early sandpaper).

Bottles still being available, I've been tempted myself.
-- 
Graybeard
273566 scottg <scottg@s...> 2021‑05‑03 Re: home made sanding compound?
Patiently waiting for the other shoe to drop.
   Why is it we need to work on the inside of a sphere? What sphere?
    What element is it made of, and why?
  How big is it?
How big of an entry hole is allowed?

  Or can it simply be turned in 1/2's and put together?
If you can open it up, then a scraper ground out for the occasion and 
used on the lathe is going to be fastest.
    yours scott



-- 
*******************************
    Scott Grandstaff
    Box 409 Happy Camp, Ca  96039
    scottg@s...
    http://www.snowcrest.net/kitty/sgrandstaff/
    http://www.snowcrest.net/kitty/hpages/index.html
273567 David Sobel 2021‑05‑03 Re: home made sanding compound?
Could this be for a mancala board?https://www.smithsonianstore.com/product
/african-stone-game-68558.do?code=N2ISGPLA&gclid=Cj0KCQjwvr6EBhDOARIsAPpqUPHdP_n
pf8XSr8dTwVJoGh5Ql6emUWsKgimR5xqO3IA6M75pt0aKa70aAqS1EALw_wcB&gclsrc=aw.dsLoose
sanding grits are easily available on the interweb.  If it is critical to make a
sanding device to sand a half sphere, my initial though is to glue up some thick
leather around a spindle, and shape the leather to fit in the half sphere. As
long as the width and profile are correct, then the thickness could be less than
the diameter of the sphere. Charge the edge if the leather sander with some
loose grit and maybe some.wax to help hold it in place,  and Bob might be your
uncle. Or maybe not. I have never actually tried anything like this myself, so
my initial thought could be way off base (totally wrong Jeff).David SobelSent
from my Galaxy
-------- Original message --------From: scottg  Date: 5/3/21  6:45
PM  (GMT-05:00) To: oldtools@g... Subject: Re: [oldtools] home made sanding
compound? Patiently waiting for the other shoe to drop.   Why is it we need to
work on the inside of a sphere? What sphere?    What element is it made of, and
why?  How big is it?How big of an entry hole is allowed?  Or can it simply be
turned in 1/2's and put together?If you can open it up, then a scraper ground
out for the occasion and used on the lathe is going to be fastest.    yours
scott-- *******************************    Scott Grandstaff    Box 409 Happy
Camp, Ca  96039    scottg@s...    http://www.snowcrest.net/kitty/sgrandstaff/
http://www.snowcrest.net/kitty/hpages/index.html
273569 John <john@j...> 2021‑05‑04 Re: home made sanding compound?
Great Ideas GGs,

The material I am cutting is wood, mostly hard wood.

i will be making a lot of holes.

If i coated a ball, it would have to be somewhat rigid, some flexing could be
tolerated..Thanks all.

John

Sent via the Samsung Galaxy Note10+, an AT&T 5G Evolution capable smartphone

Get Outlook for Android ( https://akams/AAb9ysg )
273570 Christian Gagneraud <chgans@g...> 2021‑05‑04 Re: home made sanding compound?
On Tue, 4 May 2021 at 12:59, John  wrote:
>
> Great Ideas GGs,
>
> The material I am cutting is wood, mostly hard wood.

If it's hollow, can you fill it with sand and/or peebles, and then
rotate the object (with a electric drill or a motor).
I've seen people cleaning all sort of objects by placing them in a
cut-off plastic bottle, and filling the bottle half with sand or small
peebles. Then the container is attached to an electric drill, and is
turned for 5, 10 or 20 minutes.

FWIW.
Chris

Recent Bios FAQ