MM Questions and more

[Galanw]

How do you know when MM is worn out? The higher numbers are so smoothe that it's hard to distinguish worn from new.

Also, aside from tapping or brushing the dust off, how and when do you wash it? And approximately how many pens is a 1X3 strip good for (with or without CA finish)?

Also, does a BLO CA finish darken the wood more than a shellac friction polish, or is it just my imagination (or lousy technique)?

Also the 1500 MM grit that is rated as the equivalent of a 400 grit actually feels finer than a 600 grit wet/dry. Again, is it my imagination?

TIA Galanw

 

[Dario]

On MM, I think it is worn once it is not cutting anymore, i.e. does not produce dust anymore. I think the worst enemy of MM is uncured finish. It will clog it and form a film over the abrasive. Another is heat so don't go so fast.

My first set lasted me till 2 weeks ago and I think I used it for more than 50 pens (maybe much more). I think it is still good so it is washed and will be stored.

I wash mine using a toothbrush and dishwashing liquid. I read others put in the pants pocket or lingerie bag and wash in the washing machine.

There is a grit equivalency chart but can't recall which is which now.

If you haven't checked yet, look at Russ Fairfield's site re: the color change.

 

[RussFairfield]

We should not be comparing sandpaper and MicroMesh because they are different. They are a different grit particle, a different specification and tolerance, and they leave a different scratch pattern on the surface. Yes, MicroMesh appears to be a finer grit, and that is because it is a different grit.

Comparing the grits on 400 grit sandpaper and 1500 MicroMesh, while often being stated as equivalents, they really are not. The 400 is a number designation for a distribution of grits, most of which are between 300 and 500, but tolerances allow for a wider distribution on either side of that, and as wide as 3 grit sizes by some manufacturers. The smaller don't matter, but those larger ones control the scratch pattern made by the paper. The sandpaper also uses a sharper grit particle, so it feels sharper, and leaves a "V" shaped scratch on the surface.

Micro Mesh has a much tighter size destribution within a a specified grit. When it says 1500, that means between 1450 and 1550 particle sizes, with an almost Zero tolerance for anything outside of that range. MM uses a different grit designation, so it won't be confused with sandpaper grits; and that is also why it costs more. The grit particles on the MM are also a more rounded shape, so they don't appear to be as sharp, and they leave a "U" shaped scratch on the surface. Since a "U" is more reflective than a "V", the MM leaves a surface with more gloss than the sandpaper.

Now that I have sufficiently confused this issue......

 

[wdcav1952]

As usual, Bravo and Thank You Russ!!

 

[guts]

galan,all i know is that i would not finish a piece of wood without m.m.,i think a guy named griz quoted a finish is only as good as the prep work before,or something like that.

 

[JimQ]

As for washing it, I use a mayo jar half full of warm water and a few drops of dish soap. Shake vigorously, rinse the same way several times, you do NOT want any soap under a finish, lay out for 2 - 3 minutes to dry. (May take longer elsewhere.)

JimQ

 

[davidrei]

I tried the putting the MM in the laundry thing (both in pants pockets and in a mesh bag) and found that some pieces came out with the abrasive separating from the backing, usually where the piece got folded in the spin cycle. I think from now on, I'll stick with a toothbrush and dish soap in the sink link Dario.

 

[Daniel]

As far as how soon it will wear out. My first set lasted for over 100 pens. since than I have been using several sets so I am not sure how many pens thay have done so far.
i also look for them to stop cutting. no more white powder when sanding the CA.
I did learn something about MM when I did the last Bulk Buy for it. the first none sheets are carbin, you know the stuff that lasts forever. but the last three are aluminum oxide. this leaves me to suspect they will not last as long. my observations tend to confirm this as well.

 

[Blind_Squirrel]

Here is food for thought: Are you really getting the higher numbers of the MM clean when you use a toothbrush to clean them? Because of the size ratio of the toothbrush bristle to the size of the particles, wouldn't cleaning the higher MM with a toothbrush be like trying to clean a mouses fur with a 2x4?

In the past I too used a toothbrush, but I am going to give the half full jar a try.

 

[JimQ]

I also use a toothbrush on the really bad spots on the low number MM first.

JimQ

 

[Galanw]

Thanks for all the advice. I'm off to the laundromat.

Galanw