Sanding pic - 400 grit

Re: Sanding pic - 400 grit

Thomas Skaggs, Foothills of Mount Level

>Cool. Can you get an image after a scraper is used, for comparison?

Tommy

Re: Sanding pic - 400 grit

Frank D. in Montreal

>Hi JL,

Those pics are neat. I have a request, disregard it if you don't have time, but it would be interesting to see the difference between 400 and 180 or 220, which is where many people stop sanding.

Re: Sanding pic - 220 grit 

JL

>

Re: Sanding pic - 220 grit

Joel

>Most interesting - any chance of seeing the 400 and 220 after they have been finished? (in other works - raw wood sanded to either 400 or 220 and then finished wit the same finishing procedure.)

Re: Sanding pic - 400 grit 4 coats Waterlox 

JL

>

Re: Sanding pic - 400 grit 4 coats Waterlox

Joel

>I take it you don't have a 220 grit version to compare it to. I am also guessing that the reason we don't see the grain of the wood is a reflection of the light from the camera off the waterloc film. It does surprise me that there is so much buildup on the wood. but it is extremely interesting how all of the sanding fibers left from the raw wood have disappeared under the finish.

note: an easy comparison test could be done with a wax finish only.

Re: Sanding pic - 400 grit 4 coats Waterlox

JL

>Joel, this was taken with a scanning electron microscope, not a camera. SEM is a more surface sensitive technique than photomicroscopy. The drawbacks are I have to get a real thin slice of material. I then sputter coat it with a gold/palladium mix to better reflect the electron beam. One of these days (when I have enough spare SEM time), I intend to run a full set of comparisons. 220 grit and 400 grit would be one variable and wax, BLO, Tung oil varnish and maybe a wipe-on poly would be the other. I run these samples as "test" samples when I use the SEM. Right now I am busy with other assays and tests which don't involve using a SEM. I figured these were somewhat pertinent because of Bill Tindall's thread on smooth sanding.

Re: Sanding pic - 400 grit 4 coats Waterlox

Joel

>It's very interesting. I am not sure how the photographs correlate to the look and feel of wood after finishing but certainly you get an excellent idea of what's happening.

Bill's question is very interesting because the goal (at least my goal) is to figure out the least amount of work I need to do to get an excellent finish. I typically finish plane, then very lightly sand with 320 to even out any planing, raise the grain, and finish with oil - flooding the surface like the instructions on the Watco can say. Then wax. But I really have no idea is what I am doing is the least amount of work and I am wasting effort - or if for a little more effort or a different effort I could get much better results. I studied woodworking in the 70's and 80's when oil finishes were the rage and I hate finishing so I kind of stuck with it.

Re: Sanding pic - 400 grit 4 coats Waterlox

William Duffield, on the Cohansey

>I guess you don't get any sense of the chatoyance imparted by the finishing techniques if all you can image is electrons dying as they smash into a deposited metal surface :^)

Can you image the surface of the sandpaper using the same technique? That might provide a sense of scale. I see "200x magnification" noted on one of the images, but there are additional changes of scale in the various processes your image passes through to get to our screens, so the real scale of what you are showing us is not intuitively obvioius. What I think a lot of people here would be interested in is comparison of surface achieved with sandpapers vs. plane blades vs. scrapers, especially if the surface of the blades could be shown at the same scale. That would, I think, give us a real physical idea of what happens during the various methods we employ in wresting wood asunder.

In any case, your efforts are appreciated here, and I think you techniques should eventually help us to quantify what is now just a "feel" for the surface quality of a wood surface.

Certainly interesting, but relevant?

bill tindall

>The eye sees light reflected off the wood or wood-finish surface(s). The reflected light will depend on the visible-light optical properties (refractive index, absorbance, etc) of the wood or wood/finish. I can't see a correlation between the optical properties of this system covered by a layer of gold and then illuminated by an electron beam vs visible light. For example, the finish will be opaque to the electon beam which will essentially not penetrate the finish film(actually, not penetrate the gold covering this surface). So all the electron beam sees is a near flat surface (the finish). Visible light penetrates clear finishes and reflects both off the finish and the wood and back to the observer.

Bottom line, the SEM can visualize surface texture but offer little information on what the surface will look like illuminated by visible light.

However, this tool will shed great insight on sharpening and dulling for it will image tool edges with great clarity. I urge you to move your efforts to studying sharpening an dulling.

Re: Sanding pic - 220 grit

Frank D. in Montreal

>Thanks JL,

We're making you work here...:)

Hard to know what to make of these pics but the paper sure seems to cut at 400 grit.

OK, what's it show...I don't get it...

Scott Burr in absoutly sweet Ben Lomond,CA

>Or should I say, how am I suppost to use this? I'm very comfused what to take of these pics...

Perhaps a side by side compareson of the different grits together?

I guess I just don't see what your trying to get across here...

Re: Certainly interesting, but relevant?

JL

>My basic thought is to do a correlation study and include optical microscopy along with SEM. I've got an amount of thin soft maple that I can work with right now - or do you think I should wait until I trim up the hard maple? I could then use that.

The basic experimental design would be:

Grit BLO Tung Oil Wax Poly

220 x x x x

400 x x x x

I would include optical as well as SEM. I could be talked into using 320 grit instead of 400. I would include pics of the sandpapers used for comparison. If someone wants lacquer, decide which commericial lacquer I should use (wipe on or spray can).

Bottom line - is there enough interest for me to do this? We're talking a few hours of work.

Re: OK, what's it show...I don't get it...

JL

>Scott - I am trying to show the basic smoothness of the surface that you get from sanding with various grits. Here is a side by side. 100 grit, 220 grit and 400 grit.

Re: Certainly interesting, but relevant?

Mike L

>JL,

I'd be very interested in seeing more results; even if more out of curiosity than applicability.

Regards,

Mike

Thanks JL...

Scott Burr in Ben Lomond CA

>Seeing them side by side explanes your pics better to me now...

How about a SEM of planed / scraped surface..?

Jonathan Kaplan (OR)

>If you've got the time, energy, and SEM time, I'd be interested in seeing what the surface looked like hand-planed... Preferably at a few different angles (lowish, normal 45, highish, etc)... And what it looked like scraped with a card scraper...

Just a thought. :)

jk