PSA backed sandpaper and the Veritas Shooting Sander

[Andrew Pitonyak]

I have never used or touched PSA backed sandpaper. Never really gave it a thought until I saw the Lee Valley Shooting Sander (http://www.leevalley.com/US/wood/page.aspx?p=71428&cat=51&ap=1)

Then, I started thinking about PSA backed sandpaper. Well, obviously, this will stick to like anything right? Then I saw a coment with the Stikit Sandpaper that says "Replacement Pads are available for older Porter Cable sanders to allow the use of the Stikit abrasive system"

http://www.woodcraft.com/Product/2000277/3362/Stikit-Sandpaper-120-Grit.aspx

OK, so PSA may not stick to just anything....

There have been times when I thought that it would be useful to be able to just slap some sand paper onto my cast iron table saw top, a piece of granite, or even a piece of wood (like a shop made sanding block or cheater version of the Veritas Sanding Shooter). I don't really want to drop $20 on a roll of sand paper and find it does not stick to stuff.

I see the Stikit brand, which I think is made by 3M. I see that Amazon sells Porter Cable stuff labeled as Adhesive Backed Sanding Roll (http://www.amazon.com/PORTER-CABLE-740001201-2-Inch-Adhesive-Backed-Sanding/dp/B0000223SK) no idea if there is a difference between Adhesive-Backed and PSA. Unsure of the best place to purchase or the brand that I want.

Would use mostly for wood, but, might consider it for lapping metal or similar.

Teach me, please. Do not assume that your seemingly useless comment is something that I already know.

[Michael Kellough]

Given the less than premium quality wood we have to deal with these days edge tools often fail to produce the results I want. Even power tools occasionally cause tear-out etc and the only way to smooth a surface is with abrasives.

I've been making special purpose sanding blocks from wood similar to the Veritas sanding block for years.
Only PSA abrasives stay truly flat on the block and even then the quality of the adhesive effects the quality of the sanded surface and how much use you get out of the abrasive more than the abrasive. If the adhesive is lumpy then the abrasive will only cut at that lump's high spot until the abrasive is worn down. Then that spot will burnish the wood while the areas around it cuts leaving a wood surface with different degrees of scratchedness(?).

In my experience 3M is the best. The 3M adhesive layer is the flattest, smoothest, and most consistent.

[glenn bradley]

Michael hits my highpoints on this subject; quality PSA paper will have a consistent adhesive thickness, come off clean (if not left in place for months) and stick tight so as not to allow buckling/warping of the adhesive material during use. Bargain sandpaper is no bargain; there are other places to save money.

[Andrew Pitonyak]

So the 3M StickIt is probably a good thing then....

[Andrew Pitonyak]

So, are you referring to the stikit gold which is aluminum oxide, or the white which uses carbide. I was under the impression that for wood I wanted the aluminum oxide because the carbide will not "break" with wood. Trying to wrap my head around this.

[Michael Kellough]

I've used the white for decades. It used to be only kind available and it works fine.
You do have to pay attention to the surface it produces because it will stop cutting and start burnishing if you use it for too long (rather than fracture into smaller grains like the Al Ox).

One nice thing about PSA Al Ox abrasives and small sanding blocks is that if the workpiece is small you can put a medium grip on the block (like 100 or 120) and just keep sanding as the grit breaks down into finer particles and get the equivalent of a fine grit surface without changing the abrasive. Then change to 220 or finer and sand till that is well worn and you'll get a very fine flat surface with an extremely simple process.

Friction from sanding will activate the adhesive and it will be difficult to remove if you wait too long. Take the old abrasive off while it's still warm. If you forget use a hair dryer or heat gun to warm the adhesive.

I often put strips of 3M heavy duty clear packing tape on the wood block (smoothly sanded) first to make sure the PSA doesn't lift splinters that would make the abrasive surface lumpy.

[Andrew Pitonyak]

I often put strips of 3M heavy duty clear packing tape on the wood block (smoothly sanded) first to make sure the PSA doesn't lift splinters that would make the abrasive surface lumpy.

Brilliant!