Setup for Sharpening with Sandpaper of Film

[Tim Andrews]

Hello All,
I’ve come up with a slight tweak of the sandpaper method for sharpening that might be of use to someone else. I’ve been using double-stick 3M films from Lee Valley attached to a 12” square marble tile with good results, with one frustrating problem. The adhesive works so well that it takes forever, and a lot of elbow grease, to scrape off the old sheets when it’s time to replace them.

The first attempt was to simply tape the sections of film in place, not using the double stick surface, with duct tape. This was OK. The biggest problem was the thickness of the tape didn’t allow my chisels or plane blades to lie completely flat when flattening the back of the blade. Also, the tape sometimes didn’t hold well.

The solution that worked for me was to buy some 4” x 12” glass tiles from HD that are completely flat. A pack of 6 cost $14. I cut the 8 1/2×11 sheets of film into thirds, which fit perfectly on the tiles. I tried using Gorilla Tape, which seems to work slightly better than duct tape. Plus, with the 4” wide tiles, it can wrap it around the bottom for a more secure connection. The heaviest film curls slightly on the edges, but flattens out when using it. The tiles have some sort of backing which works well to keep them in place when sharpening. The tiles store easily, and you can pull out just the finest grit or 2 for touch ups while you work.

Hope this proves useful for someone else.
Cheers,
Tim

[Phil Mueller]

Tim, I’ve been considering the 3M files on glass as well. Just curious, did you try like goo-b-gone or other solvents to remove the paper?

[Andrew Pitonyak]

I thought that most people glued this stuff down. I am unsure how they removed it when it was time to put in another one; which is why I am posting here... to find out.

[mike stenson]

I thought that most people glued this stuff down. I am unsure how they removed it when it was time to put in another one; which is why I am posting here... to find out.

I use 3m 45 (the lowest tack I can find, and the same stuff I use for gluing templates to wood) to glue paper to glass for lapping, it'd work the same for sharpening. I totally ignore the instructions and just spray the sheet, and then apply while still wet. Cleanup is generally only some all purpose cleaner and a rag, I'll clean it with glass cleaner before applying.

[Tim Andrews]

Andrew, the 3M films are self adhesive. Some people use sandpaper that needs to be glued.

Phil, the hard part for me is getting the film off, before any type of solvent can be used since they don’t penetrate the film. I have to use a putty knife and lots of effort. Once the film is off, the residue isn’t a problem.

I’m engaged in a conversation elsewhere, and one gentleman replied that his sheets peel off easily, which surprised me. The only logical explanation would seem to be the surface to which the film is adhered. I’m waiting for responses, but I suspect that he is using plate glass, while I was using a glossy, smooth marble tile. The glass might be a slicker surface. I’ll post an update when I find out more.

[mike stenson]

Andrew, the 3M films are self adhesive. Some people use sandpaper that needs to be glued.

Phil, the hard part for me is getting the film off, before any type of solvent can be used since they don’t penetrate the film. I have to use a putty knife and lots of effort. Once the film is off, the residue isn’t a problem.

I’m engaged in a conversation elsewhere, and one gentleman replied that his sheets peel off easily, which surprised me. The only logical explanation would seem to be the surface to which the film is adhered. I’m waiting for responses, but I suspect that he is using plate glass, while I was using a glossy, smooth marble tile. The glass might be a slicker surface. I’ll post an update when I find out more.

Glass is, indeed, a smoother surface and would clean easier IME than a polished stone

[David Carroll]

I've moved onto diamond plates, but I used to use granite tiles and various types of self adhesive abrasives. I used a wide painter's window scraper that has a long handle and a 3-inch wide blade (replaceable). It took some effort, but it was quick work to remove the paper/film when worn.

DC

[Andrew Pitonyak]

Wow, that was a lot of good information fast.

I've been thinking about getting some of the super fine abrasives, but I'm not sure I really need them just a question of want

[Tom M King]

The 9x12 Granite Surface Plates, that Woodcraft sells on sale several times a year, hold sandpaper in place just fine with only water splashed on the surface. No glue needed. The plate is kind of heavy if you need to move it around though. I have a couple sitting on my sharpening sink drainboard, so no worries about moving. Using wet-or-dry paper, the wet used sheets just get pulled up, rinsed off, and left out to dry. The 9x12 is plenty large enough to use a whole sheet at the time.

[Mark Daily]

I use 3M repositionable spray adhesive. After using up a sheet of sandpaper, just peel it off and put a new one down. No need to remove the adhesive.

I can use any kind of sandpaper which is cheaper than PSA paper.

[Rob Luter]

I use the PSA version of the 3M film on glass that's been mounted on MDF. The blocks are sized to take 1/3 of a sheet. Heat them up a bit with a hair dryer and they come right off. A little Goo Gone and a paper towel cleans up the glass just fine.

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[George Yetka]

I started on the films on a piece of tempered glass.They cleaned off very easily. But I didnt have great results so I switched to diamond(didnt love that either. enjoying wetstones)

I used a razor blade only for cleaning off the surface of the glass. a fresh square razor blade took film and glue. I was using the films from lee valley as well.

[Tim Andrews]

Thanks for all the great responses, this site is a wealth of information from members who are willing to share. When I'm back home today, I'm going to try adhering a piece of film to one of the glass tiles that I bought from HD, and see if that peels off easier.

Rob, nice idea on the hair dryer. You don't think my wife will mind if a bunch of sawdust blows out when she starts using it, do you?

[Jim Koepke]

I can use any kind of sandpaper which is cheaper than PSA paper.

How fine of a grit can one purchase in standard sandpaper? A local automotive supply store carried as high as 2000 on my last visit a couple of years ago. My copy of The Grand Logarithmic Grit Chart puts that at about 7µ for ANSI bonded abrasive sheets. The 3M sheets have grit particles as low as 0.1µ. The seven micron size grit particles can produce a very usable edge.

For rougher work a granite slab with abrasive PSA from rolls works well. It is a bit difficult to remove at times. As Rob suggests, a heat gun or hair dryer is helpful. A wide putty knife also helps. Depending on the adhesive paint thinner may also be of help. Try different solvents sparingly to find which works best for your PSA.

One last thought. If the spray adhesives work well, could they be sprayed on the PSA backing? How about a sheet of mylar or even card stock? The PSA sheets could then be set down on a surface that can be replaced easily.

jtk

[Andrew Pitonyak]

How fine of a grit can one purchase in standard sandpaper? A local automotive supply store carried as high as 2000 on my last visit a couple of years ago. My copy of The Grand Logarithmic Grit Chart puts that at about 7µ for ANSI bonded abrasive sheets. The 3M sheets have grit particles as low as 0.1µ. The seven micron size grit particles can produce a very usable edge.

I have purchased higher, but do not remember off hand how high without checking my stock of paper. I see 3000, 5000, and 7000 readily available for wet / dry automotive use. Amazon sells 5000 grit from 3M. No idea what that is in Microns.