Sandpaper on the bay

[Ichinichi]

This post follows up a question I raised in another thread here at the workshop.

I went and looked through all 800 or so US based auctions for sandpaper on ebay. The going rate for you-pick-the-grit wet/dry seems to be around $0.75 to $1.00 per sheet of 9x11 shipped with grits ranging from 80 to 2500 grit.

Here's the best deal I found: 25 sheets, u-pick for $18.50 shipped

This equates to $0.74/sheet of wet/dry sandpaper.

25 Sheets WET - DRY 9 x 11 Sandpaper You Pick the Grits - eBay (item 160332411549 end time May-31-09 16:46:30 PDT)

They have 80, 100, 120, 150, 180, 220, 360, 400, 500, 600, 800, 1000, 1200, 1500, 2000, 2500 grits available.

Bruno recommends progressing from 220, 400, 600, 800, 1000, 1200 to 2000 on the wiki.

Any input in terms of quality or type of sandpaper from restorationmeisters welcome.

Conflicts of interest: I am in no way affiliated with the seller.

[onimaru55]

Good price. Just make sure its good quality like 3M or something equivalent tho I haven't seen 2500 in the cheap n nasties. Might be an OK deal.

[pjrage]

Not a bad deal. If you jump on it, let us know how it compares to the 3M stuff..

[Ichinichi]

how is "quality" measured within the context of sandpaper?

[onimaru55]

how is "quality" measured within the context of sandpaper?

An even scratch pattern, showing sieve size is consistent when they sift the abrasive particles.
Some papers cut deep & irregular patterns making previous scratch removal awkward. Look at a 'Micromesh' scratch pattern compared to any wetndri and it is even smoother but way more exe.

[adrspach]

I have to agree with the quality of the paper as I found myself the hard way. Those cheapies just do not last as long as decent stuff. I am not rich enough to buy cheap stuff.

[BKratchmer]

Sandpaper has, in essence, three main points for quality. (I'm the son of a professional woodworker, so I have an unholy and unhealthy knowledge and passion for things like sandpaper and precatalysed lacquers.)

1.) The paper: Ideally a sandpaper has a backing that is both highly durable and flexible. Not floppy, mind you, but that can be bent without breaking or forming creases. A good sheet of sandpaper should be stiff enough to hold a shape, but flexible enough to be rolled into a fairly tight tube without forming any angles. (Test this against a known quality sandpaper, like 3M or Mirka). The paper should also be tougher than the grit or the product being sanded- if this isn't the case, you'll find the paper sands through or turns into shreds very quickly.

2.) The adhesive: Good sandpaper will be made with a strong adhesive that matches the flexibility of the paper. A weak adhesive will shed grit all over the place, and ultimately cause uneven scratching. A strong adhesive keeps an even plane, and allows fractile grit to work its magic. Depending on what the paper is made for, this should also be insoluble in most solvents, and stay firm under high temperatures.

3.) The grit: Grit is easy to find, time consuming to grade. A good company will sieve these meticulously, using screens or centrifuges to separate them by fractions of a micron. A company looking to save time and money will be much less careful. One big lump on a piece of sandpaper will make inconsistent scratches- a bunch of them will create a second plane above the surface of the desired grit, keeping you from ever sanding the way you'd like to. This can be evaluated by using hand feel, a dissection microscope, and the way a block of wood/ceramic/glass etc feels being pulled by its own weight across the grit in comparison with a good paper. Every grit will have its own feel- learn roughly what these should be and you'll easily recognize the gliding-rasping feel of a block sliding over too few too large particles of grit. (Think serrated razor- where it catches, it really grabs, but it doesn't catch enough)



Well....that ends my little eulogy. Hope it helps.

[Ichinichi]

Well, I'm glad I held out! Anyone with a good source of 3M paper?

[adrspach]

Only sad thing abot this is to get decent sandpaper in required grit somewhere localy otherwise the postage can be ridiculous.

[Walt]

Well, I'm glad I held out! Anyone with a good source of 3M paper?

Love 'em or hate 'em, but Wal-Mart has 3-M "Wetordry" in their automotive department in grits up to 2000 and most auto supply stores carry wet/dry sandpaper for doing bodywork. Surely one or the other of these businesses is a neighborhood near you. It's hardly a dependable source, but I find sandpaper quite often at flea markets. This morning I bought three full packs of 3-M wetordry in 320, 600 and 1500 for a total of one dollar.

Regards - Walt