Shopsmith Forums

charlese wrote:Sorry - I've never witnessed softened edges. I feel the need to post a contrasting view.

The only way this can happen is if there is too much pressure applied to the operation. Correctly done, ANY sanding should only be done with enough pressure so that only the thickness of the grit is used. Using dull sandpaper could be a major factor causing one to use too much pressure.

If not too much pressure, then the piece had to be tilted somehow.

Didn't really want to admit this, but my very first sharpening of my SS lathe tools was done on a velcro backed disk. The tools came out sharp!! Then I read the safety warning>

Chuck
I will be the first to admit I usually use too much pressure when I sand. I want to be done so I tend to get over eager.

From the softening of the edges I have witnessed I don't think I ever could prove the piece was something other than perpendicular to the disk.

Perhaps my velcro disk is too fluffy but my paper is about 1/16 proud of being solid to the disk. That 1/16 of an inch is enough to allow paper to slightly rap up over an edge. Can I prove this? Probably would take a high speed camera to really examine and see what happened.

All I know is Shopsmith when I bought the velcro kit included a warning that softening of the edges could occur, and suggested sticking with PSA disk if that would be an issue. Is my problem Psychological having been planted in my mind from that warning? Perhaps but I do know on the last knife stand I built I sanded on velco and when I put the wood together I saw a very visible joint. I then resanded on PSA paper and hurray! the seam was tight.

dusty wrote:I think there is an implication here that changing self adhesive paper damages the paper. While this is sometimes true, it is not always. I hardly ever damage the paper when changing it but then I don't leave the paper attached after I am through with a project. Also, I leave my disks in the sun to warm up before I pull the paper. Warming them with a heat gun or in an oven should have the same positive effect. The heat makes the adhesive a bit more friendly.

The implication is definitely there!!! My intention, in fact. While Dusty and others have had good luck changing their non-velcro disks, even they admit that sometimes they damage a disk. I have NEVER damaged a disk when changing grits with the velcro system, and like Chuck, I have knot seen any end result of rounded edges/corners when using the velcro system.

(2 cents, adjusted for inflation)

I currently have 3 discs- 2 conventional and one conical.
Conical-- sharpening Jointer knives; sanding to width; edge sanding boards.

Flat 1-- for PSA discs: sanding to width; chisel sharpening etc.; "Hard" and fast removal; some flat surface sanding.

Flat 2-- Velcro: soft, delicate (pre)finish sanding (with some woods/projects the final finish sanding); quick change artist; fast tho low pressure removal with coarse disc; 50 to 80 to 120 a workpiece in a few minutes.
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I destroyed a Velcro Conversion Disc awhile back by misusing it. Ignorantly tried the "edge sand to width" trick and pretty much crushed the Conversion side of the Velcro at the edge. Hard pressure feeds into the workpiece likewise created an undulating surface which was useless for fine work.

My new Velcro Conversion Disc (an odd story behind that) now is used for low pressure work. and almost only flat to the disc. The caution to not try to take off more than a grit-thickness is well noted. A soft feed is the only way to go.

As for rounding edges, it is possible in at least one instance: the Velcro papers are slightly larger than the Conv. Disc, so the very edge is not held tightly to the base, thus giving it a slight curl out. If I'm sanding a piece that is less than about 10" and keep it centered I get no edge rounding. However, if I'm sanding a piece and sliding it from disc center toward me past the edge I CAN get some edge rounding depending on material softness and sliding rate, and rotation speed. I.e.-- hard wood, slow motor and quick slide = no rounding.

Picture this: clamp a 24" piece to the table, parallel to the miter slots and overhanging the Disc-side edge of the table slightly. Bring the running Disc up to the piece and see the front and back outer edge of the paper create dips in the piece before the main body of the paper hits it. Only takes a couply milliseconds.
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velcro-- I said "almost only flat to the disc". I do use it to filet corners (for instance on the SS mallet head edges) instead of routing. It gives me a softer 'round' and infinitely variable radius. I prefer the Velcro for this delicate work because the PSA 'hard' disc will take off more than you want before you can say "oops!".

But it's hard to control symmetry, even on a 4" edge, and on face sanding there is still some circular marking from the (not very) fine paper. So when I've gotten 90% of the sanding done I stop the motor and run the piece past the disc in stationery mode, either free hand or with the miter gauge, and with Very Low pressure. This is equivalent to using the Conical Disc for a 'finish' sand, quickly removing the swirls. It's also a heck of a lot faster than using a hand-held sanding block to reach the penultimate stage.

Serendipity.
Or a fluke.

After I messed up my first Velcro Conversion disc trying to repair- i.e. remove the old paper and glue- was a real bear. Man that glue and disc are tough stuff!
Gave up trying to get the glue off, and it sat, collecting debris on (in) the glue, for quite a while.

Years later, took half a can of Mineral Spirits and some rags and wiped, wiped
and wiped, and realized the glue was still there and all I did was remove the debris from it.

So I'm convinced the disc is made from glue, and it just has a shiny surface on the back side somehow.

Anaway, since the glue side surface was now quite clear of any sawdust or debris, I figured whut da hay, I'll just put the new Conv. disc right on top. In checking size-- still with the backing paper on it-- over the steel disc I accidentally touched the two together.

And it stuck.
But good.
But it was aligned, so I went ahead and stuck the whole thing, with nothing to lose (backing paper still on).

Well, with the newly learned "soft touch" approach to using Velcro papers, this works just fine, and I can remove the Conv. disc anytime without hurting it.

Now I'm curious to see if I can mount a PSA paper to the steel without removing the backing paper. Sure would be the ultimate easiest swap system I can imagine if I never have to take the backing paper off, on either the PSA or Velcro papers.