Ok, here we go. This is my first post on the rec, although I have been
lurking for several years now. Usually any question I need answering I
can easily find by dags, but this escapes me. I just received a Jet
JDS-12B 12" disc sander for my birthday (Yes, I picked it out). UPS
brought it today from Amazon, along with some extra discs from Grizzly
(Woodstock Int. brand). Well, anyway, I cleaned the oils and cosmoline
stuff off of the sander with denatured alcohol, taking extra care to
get the disc itself clean. I peel the backing paper off of my first
disc, taking care to get it aligned JUST right before I stick it on.
(After all, I get only one shot at this, right?) As I press it
carefully into place, it starts coming right back off when I release
it! Ok, so I figure it's one of two things; either I didn't get the
oils off the metal disc, or it's cheap glue from the aisian import
sandpaper. So, I break out the laquer thinner and scrub the metal disc
again. Well, just maybe I got a little more off, but I'm not really
sure. Looks just as bone-dry as before. So, I try the same disc again
and it falls right back off when I let go. Ok, so maybe I ruined the
disc before, or maybe bad glue, so I try the disc that came with the
sander. It's a 60 grit. (What's THAT for, shaping telephone poles?)
Well, same results. The discs seem pretty sticky to me, I feel certain
if I stuck them to any smooth surface I would have trouble getting
them back off in one piece. On closer observation, I see the metal
disc has small well-defined grooves in it, sort of like a record
album, but coarser. Could this be part of the problem? Should this
disc be really smooth? I'm more of a neander woodworker, and this is
the first stationary sander I've ever owned, so am I missing something
For a nice clean surface I like to use Acetone.
Old PSA paper does not like to stick well and Cold SPA paper does not like
to stick well. Try heating the disk or pad and reapplying. Keep in mind
also that PSA does not like to be restuck.
I have one. Bought a psa hook and loop pad for my powermatic 12"
sander. A bit hard to mount discs, because the table gets in the way,
but it works. I just cover the disc with a piece of release paper that
it came on, until I have the sandpaper in the right spot, then pull
out the release paper.
I used laquer thinner to clean the disc of old glue, it's a fairly
smooth aluminum disc, never had any adhesion problems, even when
pulling hook and loop papers off.
I AM having problems keeping sanding discs (less than 1 year old)
stuck to my cross cut fence, which is annodized alluminum, no matter
what I clean the fence with. I'll try heat.
I have had discs that don't stick either. if the paper backing does not stick
well that's a good sign it won't stay on. want a few? (G)
" Eagles may soar, but weasels don't get sucked into jet engines"
I'm going to go through a sequence of more agressive cleanings here--you can
go all the way through or stop when you get to "clean enough". This is
based on years of experience in the aerospace industry and these are stages
that are gone through to prepare metal surfaces for adhesive bonding in
First thing, get a roll of duct tape and use that to test--if duct tape
won't stick then nothing will, and it's a lot cheaper than wrecking sanding
disks. Also, use paper towels or _new_ cloth or something else you're
_sure_ is clean for all cleaning steps--if unbeknownst to you there's a
little grease on the rag you're using you'll never get the thing clean.
Also use solvents from a new can and pour them into a container rather than
holding the can upside down with the rag pressed against the spout--you can
get contaminants in the solvent that way, and again if there's any grease
dissolved in the solvent you'll never get the thing clean.
Next, pull the metal disk off and make sure that it didn't get installed
with the "good" side in instead of out at the factory. If it's that simple
you save a lot of work. While you have it off, soak it in a pan of MEK for
an hour or so then wipe it down and go over it with alcohol afterwards. If
the tape sticks, then put it back on with the "better" side out and try a
sanding disk and you're done. If the tape doesn't stick then you need to
get more agressive.
Next step is to get rid of those tool marks you noticed. Make up a straight
sanding block wide enough to cover the width of the disk, turn on the
sander, and sand the disk surface with increasingly fine grits of sandpaper
until it's smooth and shiny. Wipe it off with MEK followed by alcohol.
Again try the tape--if it sticks, try a disk, if it sticks well enough
If that doesn't work, then it's time to try to get the surface really clean.
You need a test for cleanliness that is more precise than "will tape stick"
and on smooth metal that test is called a "water break free surface". Pull
the disk off the sander and throw it in the sink and scrub the Hell out of
it with Comet or Dutch Cleanser or whatever is your favorite scouring
powder--don't use BonAmi--don't know why but the specs always said
specifically not to use it. "Old Dutch" if you can find it is the best.
When you're done, rinse it off and see if there are any spots where water
beads up or where there's a hole in the water film on the surface. If
there are, scrub those spots some more until the water film after rinsing
is continuous over the surface--that's a "water break free surface" and
it's as clean as you're going to get without going to a chemical etch. Dry
If the sandpaper won't stick to a water-break-free surface then you've got
If you can't get a water-break-free surface then there's some exotic
contaminant on the disk that's going to take a chemical etch to
remove--without knowing what the disk is made out of I can't tell you what
to etch it with.
Reply to jclarke at ae tee tee global dot net
I thought those machined concentric circles were designed to keep the disc
from sliding under mild prolonged pressure, and help with cooling. If so,
removing them would make the disc hotter and facilitate glue creep.
I'd think twice about removing obvious machining, especially given the ease
of just lapping the plate. There's probably a reason, even if it's not the
one I mentioned.
Sound like toolmarks to me. Toolmarks are the result of, well, not removing
toolmarks. I can't see where striations about the size of the grooves in a
phonograph record are going to provide much cooling anyway--if anything
they'll provide insulation and prevent heat from being conducted into the
plate. Might keep the disk from sliding, but I've never had that problem
myself. In any case it seems to me that having it well stuck down is more
likely to keep it from sliding than reducing the contact area.
As for "the ease of just lapping the plate", that's just another grinding
process, removes the same things that sanding the plate with a block will
If they're clearly machined on purpose that's a different story.
Reply to jclarke at ae tee tee global dot net
Crudely put, but yep, the 12"/6x48 ain't the only 12" Jet out there anymore.
What I get for ASSuMEd information.
Said unit is, as I described, milled with concentric circles, an undeniably
deliberate act, and at the depth to which they are milled (well beyond a
phonograph record) , they're not going away with sandpaper.
I am thoroughly convinced they were tool marks, as they WERE spiral.
Even if they were intentional, they were the source of the
non-adhesion problem. I'm still going to closely examine the new disc
when it arrives.
I've had so many PSA disk that wouldn't stick to my 12" disk sander I gave
up even trying. Franklin makes a "Sanding Disk Cement". I coat the back
of the disks (even the PSA) with their adhesive, let it dry, and apply the
disk. You have to use a heat gun to get them off. See:
Buffalo, NY - USA
(Remove "SPAM" from email address to reply)
Regular old rubber cement is excellent for attaching paper to metal,
if both sides are coated and allowed to dry. I've used it on aluminum
T-bar sanders for years.
I'd spend the $0.79 on a bottle and see if it works on the disc
First of all, I want to thank everyone for their responses and their
help. (Especially John; I appreciate the time you spent typing in THAT
one!) The more I looked at this disk, the more I decided those fine
grooves are in fact tool marks caused by too rapid of a feed rate when
machining the disk. I called Jet today, and spoke with them about it,
and they pretty well decided the same thing. They said they were going
to ship me a new disk and that I should have it in a few days. Well, I
went back to the shop this evening with the intention of removing the
disk from the sander, but I found the disk is VERY solidly pressed
onto the motor shaft and that I don't have the means to remove it
without the fear of warping it. So, I jointed a 3x3 of ash and some 80
grit PSA paper and went to work on the spinning disk. It took about 5
applications of sandpaper to get all of the grooves out, but I did
manage to get them out and maintain flatness of the plate as verified
by my straightedge. A few passes with some 120 grit, and it was nice
and shiny. Then, I took the SAME sandpaper disk that wouldn't stay on
before and stuck it onto the metal disk. It stuck with an insatiable
appetite. I can only imagine trying to peel the thing off later when
it's worn out. Now, what am I going to do with the other metal disk
when it get's here? ;)
Thanks again everyone!
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.