Using the conical sander

kalynzoo · Post by **kalynzoo** » Sat Jan 19, 2008 11:23 pm

I've had my Shopsmith 2 years, but I tried using the conical sander for the first time today. I had glued up some boards for a doll table and thought it would be an easy way to square the ends. However, I kept throwing the paper off the disk. Yes, I was using the conical paper with the slot. Any help here with my technique. Table top is 6in by 12in, 3/4in red oak. I'm making a breakfast set for the American Girl (3 granddaughters). Thanks.

paulmcohen · Post by **paulmcohen** » Sun Jan 20, 2008 12:03 am

Nick has a lesson here.

Bruce · Post by **Bruce** » Sun Jan 20, 2008 12:08 am

Did you tilt the table so it was perpendicular to the face of the conical disk? Was the paper well adhered to the disk?

kalynzoo · Post by **kalynzoo** » Sun Jan 20, 2008 12:27 am

I saw Nick's demo this evening. I didn't use a fence since the work was small, I used the sliding square from the saw table. Yes, I was at 4 degrees. I question if the paper was sticking properly, as it was the first time I used the setup. The paper seemed less than fully tacky, and the disk may have had storage oil on it. Obviously I better clean the disc, but should I spray the paper with tacky adhesive before using it...?

paulmcohen · Post by **paulmcohen** » Sun Jan 20, 2008 12:55 am

The only time I have had this kind of problem was when the disk was too cold, I have gotten into warming the disk slightly (<100 degrees) before putting on the paper. That is all I can think of maybe someone else has an idea.

Nick · Post by **Nick** » Sun Jan 20, 2008 2:41 am

There are four things that can cause a sanding disk to shed paper:
1. The disk is not clean when you apply the paper. I always wipe down the my disks with xylol or acetone just before applying the paper.
2. The disc is not warm enough when you apply the paper. The pressure sensitive adhesive on the disc will not be activated completely unless the disc is room temperature (70 degrees) or above. I usually warm mine to 80 or 90 degrees with a heat gun.
3. You have not pressed the sandpaper down with sufficient pressure. Remember, the adhesive is activated by pressure. The more you press, the better it will stick. I use a veneer roller to apply a lot more pressure then I can with my hands.
4. You are sanding too aggressively. If you try to remove too much stock at once, the sandpaper overheats. The adhesive goes thermoplastic (translation: it softens) and the sandpaper lets go. Never try to remove more than 1/32" at a time when sanding long grain with 60-grit sandpaper, 1/64" when sanding end grain. Halve these numbers when sanding with 120-grit. The smaller the grit, the faster the sandpaper heats up.

By the way, folks, I've scheduled another Sawdust Session on the conical sander. Drew just built a very simple jig that turns it into a reasonably accurate thickness sander -- you'll be amazed.

With all good wishes,

Bruce · Post by **Bruce** » Sun Jan 20, 2008 11:37 am

nick wrote:By the way, folks, I've scheduled another Sawdust Session on the conical sander. Drew just built a very simple jig that turns it into a reasonably accurate thickness sander -- you'll be amazed.

Thanks, Nick. I look forward to it.

kalynzoo · Post by **kalynzoo** » Sun Jan 20, 2008 1:23 pm

I didn't give disc temperature a thought, and it was rather cool, even for Los Angeles. And the disc my have had an oil coat, as it was new. I'll clean it with denatured alcohol and give it some warmth before trying again. Thanks, just gets frustrating sometimes.

kalynzoo · Post by **kalynzoo** » Sun Jan 20, 2008 1:24 pm

I saw Nick's demos on the computer for the first time. I was not aware of this Shopsmith support. Fantastic. Keep up the good work, and thanks.

Nick · Post by **Nick** » Sun Jan 20, 2008 4:32 pm

"I'll clean it with denatured alcohol..."

Thanks for the kind words, Gary. But let me leave you with a thought on denatured alcohol -- it's fine for removing oil when the disc is new, but you will want to graduate to something stronger once you've stuck some sandpaper to it. Alcohol will not dissolve the old adhesive and you need the disc to be really, really clean before you apply a new piece of sandpaper. This applies whether you are using PSA sandpaper or simply spraying ordinary sheets with an adhesive such as 3M 77.

With all good wishes,