Sandpaper question
smithfarm
After reading Brent's excellent shapening pages I'd like to ask a
question regarding sandpaper life. I live in Europe, so getting ahold
of the 3M microfinishing films is challenging. I'm trying some other
locally-available sandpapers first.
The first paper I tried is a locally manufactured P150 grit Silicon
Carbide paper that says it is waterproof. I obtained some spray-on
glue and sticking it to the glass was no problem. Then I proceeded to
rub the plane iron on the paper. I was surprised at how fast the
silicon carbide stopped cutting the metal. The grit just "smoothed
over" really quickly and stopped cutting. Is this to be expected from
ordinary sandpaper?
My theory is that the backing paper is too soft - the pressure from
the iron pressed the grits down into the paper. So, I need something
with tougher backing - sound right?
Thanks,
Nathan
Brent Beach
On 03/08/2011 7:18 AM, smithfarm wrote:
> The first paper I tried is a locally manufactured P150 grit Silicon
Much too coarse if it gets anywhere near the edge. I use a coarse stone,
which is about 220, for grinding the primary. I am careful to not grind
near the edge.
> Carbide paper that says it is waterproof. I obtained some spray-on
> glue and sticking it to the glass was no problem. Then I proceeded to
> rub the plane iron on the paper. I was surprised at how fast the
> silicon carbide stopped cutting the metal. The grit just "smoothed
> over" really quickly and stopped cutting. Is this to be expected from
> ordinary sandpaper?
The 220 grit in my stones last very well. It is not a problem with the
SiC, assuming they are using good SiC.
> My theory is that the backing paper is too soft - the pressure from
> the iron pressed the grits down into the paper. So, I need something
> with tougher backing - sound right?
If the grits are pushed down they would still cut unless they were
completely buried in the sheet. Even if the sheet was flexible and let
them tilt, they should still cut.
It could be the binder that holds the grits on the backing. If you can
shake the paper afterwards and all the abrasive falls off, it is the
bond that is not working.
Perhaps you are pressing too hard? I press pretty hard when grinding,
but lightly when honing.
My stones are Norton, which is now owned by a European company -
Saint-Gobain. You should be able to find that in Europe. I don't know
much about Norton's sheet abrasives. They have a line called SandWet
that includes 2000, 1500, 1200, 800 in 9x11 sheets. You might be able to
find that in a larger DIY store.
Another manufacturer of pretty good abrasives is Klingspor - I use their
belts but not their sheets although I may get some sheets to test. There
is a store in the USA that sells the full Klingspor line which includes
SiC in sheets in 1200, 1500, 2000 grit. They also sell AlO at 600 grit.
That would do for honing. Klingspor is a European company, so there
stuff must be available there. The US store sells 5 9x11 sheets of 2000
grit SiC for $3.85. Something like that should be available in Europe.
There is a link from my beltsander page to this company.
There is a UK distributor linked from my 3M page, but he is pretty pricey.
If you find a European distributor for 3M, or a good mail order sit for
Klingspor or Norton, can you send my a link so I can add it to the web
pages somewhere?
The very fine sheets, if used as I use them (with a jig, light mineral
oil, only for microbevels), last a long time. You won't need many sheets
of 1/0.5 micron, 5 micron abrasive. If you get 5 sheets of each from the
US or the UK, that should last a lifetime. The 15 micron is used up much
more quickly. Finding a local supplier of a good 600 grit SiC or AlO may
save you money.
> Thanks,
> Nathan
>
Brent
--
Victoria, B.C., Canada