Planed Finish VS Sandpaper - Microscopic View

[Normand Leblanc]

Found this video.


Normand

[Joe Tilson]

Thank you Normand. This just answered my question on the thin shaving, think again thread.
Have a blessed day.
Joe

[Prashun Patel]

I can plane some things with ease, others with supreme frustration. I'm in awe of those who can plane everything with ease. I approach each project with the intention of using no sandpaper, and then inevitably hit some vicious tear out and have to resort to it.

[Luke Dupont]

I can plane some things with ease, others with supreme frustration. I'm in awe of those who can plane everything with ease. I approach each project with the intention of using no sandpaper, and then inevitably hit some vicious tear out and have to resort to it.

Same here!

I'd like those proponents of using planed finishes exclusively to go more in-depth on how they actually manage to plane anything, and leave a good surface!

I don't doubt that it can be done! I'm just curious how.

[Andrew Hughes]

Same here!

I'd like those proponents of using planed finishes exclusively to go more in-depth on how they actually manage to plane anything, and leave a good surface!

I don't doubt that it can be done! I'm just curious how.

Picking wood that can be planed.And choosing the boards that have the grain running out on the edges helps.
Stay away from large oval cathedral grain,Knots,and highly figured woods.
Sometimes I can plane most of a build using this strategy.
Knots are the worst I like the way they look in alder.But they are a pain in the a**

Cool video
Aj

[Brian Holcombe]

Same here!

I'd like those proponents of using planed finishes exclusively to go more in-depth on how they actually manage to plane anything, and leave a good surface!

I don't doubt that it can be done! I'm just curious how.

The short answer is that is a combination of reading the grain direction and using the chip breaker effectively. Once you form a set of diagnostic tools (reading the shaving) you can fix pretty much anything that troubles you.

[Frederick Skelly]

OK. I'll admit it - I don't have a CLUE what the conclusion was on that video. Can someone who did please spell it out for me? And how did you conclude this without subtitles in english? (So I can go back, watch it again, and get it this time.)

Thanks guys.
Fred

[Warren Mickley]

I have planed all boards since 1976. I last sanded in 1978. Finishing a board that is not sanded is different and it takes experience, but is not difficult. Sometimes you have to avoid reading the can or an article because the expert many never have seen a fine surface or know how to take advantage of it.

It might be more helpful to think of planing as an art rather than a science. If you are thinking there is some trick or some 1-2-3 recipe, you might be a bit on the wrong track. For this type of thinking it is helpful if you have been trained in some other art. Although it is helpful to watch someone else or have them watch you, to try their plane and have them try yours, good results come from practice and discernment.

[Patrick Chase]

I have planed all boards since 1976. I last sanded in 1978. Finishing a board that is not sanded is different and it takes experience, but is not difficult. Sometimes you have to avoid reading the can or an article because the expert many never have seen a fine surface or know how to take advantage of it.

It might be more helpful to think of planing as an art rather than a science. If you are thinking there is some trick or some 1-2-3 recipe, you might be a bit on the wrong track. For this type of thinking it is helpful if you have been trained in some other art. Although it is helpful to watch someone else or have them watch you, to try their plane and have them try yours, good results come from practice and discernment.

Out of curiosity, what sorts of stains and first finish layers (sealer if any or first layer of topcoat otherwise) do you typically use?

[Patrick Chase]

OK. I'll admit it - I don't have a CLUE what the conclusion was on that video. Can someone who did please spell it out for me? And how did you conclude this without subtitles in english? (So I can go back, watch it again, and get it this time.)

Thanks guys.
Fred

Normand was highlighting the fact that a water drop meniscus has a much higher angle (indicating higher surface tension and lower wettability) on the planed surface than on the sanded one. Joe's point was that certain finishes might not wet out across the surface as a consequence, and he's right. So is Warren, though - the sorts of finishes that you'd actually want on a finely planed surface mostly work with some practice.

[Normand Leblanc]

If there is a part of woodworking where I struggle it's the finishing. I'd be very interested to know what Warren (or others) use and how they do it.

Normand

[Frederick Skelly]

Normand was highlighting the fact that a water drop meniscus has a much higher angle (indicating higher surface tension and lower wettability) on the planed surface than on the sanded one. Joe's point was that certain finishes might not wet out across the surface as a consequence, and he's right. So is Warren, though - the sorts of finishes that you'd actually want on a finely planed surface mostly work with some practice.

Thank you Patrick. So the conclusion is that, the planed surface is so smooth (wrong word, I know) that water beads up on it? Whereas the water doesnt bead as much on the sanded surface - thereby indicating it isnt as "smooth"?

[Normand Leblanc]

So the conclusion is that, the planed surface is so smooth (wrong word, I know) that water beads up on it? Whereas the water doesnt bead as much on the sanded surface - thereby indicating it isnt as "smooth"?

I think that a planed surface is like burnished and that could explain why there is a large surface tension (barrier) when comparing with a sanded surface where the material has been torn from the surface.

On this website, which is about "Surface treatment of wood",
https://www.kruss.de/applications/su...tment-of-wood/
they say:"The difference between the contact angle measured during wetting (advancing angle) and de-wetting (receding angle) is referred to as hysteresis. This quantity describes the effect of roughness on wetting, which is very important in the case of wood."
The contact angle seems to be the angle between droplets and the surface. In the video, the contact angle for a planed surface was obviously very high.

Normand

[Patrick Chase]

Thank you Patrick. So the conclusion is that, the planed surface is so smooth (wrong word, I know) that water beads up on it? Whereas the water doesnt bead as much on the sanded surface - thereby indicating it isnt as "smooth"?

Smooth is a reasonable word choice here. Water has very poor wettability on smooth surfaces, much worse than most real-world finishes. Sanded surfaces have "hairs" that wick the water across the surface and thereby improve wetting.

As far as I can tell the video Normand linked was using the water drop to demonstrate how smooth the planed surface is, not to make any sort of comment about finishing.

[Patrick Chase]

I think that a planed surface is like burnished and that could explain why there is a large surface tension (barrier) when comparing with a sanded surface where the material has been torn from the surface.

Planed surfaces don't have crushed structure as you would see from burnishing. In fact they have much more "open" structure (esp pores) than sanded surfaces.

I think that the meniscus angle on the planed surface represents the "true" surface tension of water on wood. The angle on the sanded surface is greatly reduced by the presence of torn fibers (a.k.a. "hairs") on top of the surface, which spread the water droplet out via capillary forces.

When I did a lot of ski racing this was a big issue when sanding base repairs etc. If you didn't get rid of all of the "hairs" then they would increase wettability and therefore drag. You want any liquid water in the ski/snow interface to bead instead of "sheeting" (this is exactly why we wax skis), so anything that increases wetting is bad news. Hairs from sanding are extremely bad news. I've seen pictures of water droplets on "hairy" vs "de-haired" ski bases that look exactly like the ones you got from the video :-).