Sanding Forever

Never been a member of the "numbers" school of woodworking, but I went down and used the little brass bevel measure on my favorites. Looks like the winner is ~45 degrees, made effectively longer by the fingernail sweep and the presentation angle. My bowl gouges favor 35, with the smaller having proportionally shorter grindbacks to work into deeper areas. The big hoggers are more "U" shaped, and have big wings to remove wood quickly, almost like the pointy gouge on the beech bowl. Can't get much angular change by skewing with them because of their steep sides.

Couple of my favorite finishers are 55 degrees, but they're a blunter sweep, which probably brings them to the same cutting angle as the 45 degree.

I'm not sure where those fit in the general population, and I admit that I grind as I cut, setting the tool on the rest, touching the heel of the bevel and moving the handle until it cuts to the edge. Makes the tool its own jig.

Working beyond basic bowls and forms require different approaches and tools. Some versions of undercut lips, deep bowls, multiple levels, verticle (and beyond) sides and such things as beads and coves inside of a bowl makes the use of a "regular bowl gouge", even with some modified grinds, impossible and certainly not able to have that nice long single sweep cut from rim to bottom.

Sometimes, all it takes is a little different presentation of the tool to the wood or a reversal of what's considered "correct" for hollowing a bowl (such as cutting from base to rim to get a deep undercut of a lip for instance). But, sometimes, that just doesn't work well either and another tool is needed to get the best effect. Of course, one can always argue that such forms aren't what they would classify as a "bowl" but as some other kind of hollow vessel.

Either way, I have and gather tools to support what I'm wanting to create and not create what I have tools for.

- Andrew

Several people mention the use of "wax" to provide support to the wood fibers. By wax do they mean parafin or real beeswax or carnauba wax?

--snip--

Doesn't matter all that much. Simple flooring paste wax (Johnson's is one brand) does well. It's a combination of waxes and pretty inexpensive / easy to find. I wouldn't waste pure beeswax or carnauba on this purpose though. Pure beeswax is pretty soft which would make it easy to apply but won't support the fibers as much. Pure carnauba is far too hard to apply (you can cut it with a solvent and/or another wax to soften it) but it'll support the fibers quite well. Paraffin is easy to find, inexpensive, pretty slick, and not terribly soft so that would probably be my first choice in pure waxes to use. But, like I said, just use some extra flooring wax if you have it instead of getting any special wax to do it.

- Andrew

Perplexing. To support them, wouldn't you use something which is more rigid than the fibers themselves?

Paraffin wax (canning wax for UK types) like for microtomes, or harder perhaps, but solvent-thinned mixes like Johnson's and so forth would, it seems to me, have to dry a lot harder than the casually neglected streak I sometimes leave on a benchtop to be effective at "supporting" the fibers. Not to mention, it would certainly flow at the modest elevation in temperature caused by sanding.

I think the effect observed may have more to do with lubrication than rigidity. With lube to lessen case-hardening, the sanding is more effective, because the normal areas don't harden and resist abrasion, leaving the torn areas.

Those who like to consolidate heavily spalted areas to minimize tearout use rigid stuff like wood conditioner, shellac, or lacquer. If the aim is to support, I'd take these over something soft.

Yes. Any wax will do. The point is to make the fibers stiffer and thus easier to cut.

-- Chuck *#:^) chaz3913(AT)yahoo(DOT)com Anti-spam sig: please remove "NO SPAM" from e-mail address to reply. <

September 11, 2001 - Never Forget

Not necessarily. Think of standing a bundle of spaghetti noodles on their ends. They fall over and slip past each other to collapse quite easily. Now, put that same bundle in a vase or pan of water on their ends. They don't as easily tip over or as easily slip past each other to collapse. Once more, put that bundle in a pan of soft wax. They're even more rigid. Depending on the softness of the wax, you don't even have to have them bundled together for them to stand straight up. Don't turn the heat on though ... it doesn't apply nearly as well (but still does apply in a lesser way) to floppy noodles. Try this with a bunch of hollow straws (ie wood being a bunch of hollow straws) and it's even more effective.

It depends on how much heat and what wax we're talking about. If you're causing enough heat in sanding to cause enough heat for a flooring paste wax to completely liquify (which, as mentioned above, will still support the fibers), then you're either/and sanding too long in one place, pressing too hard, or using too high of a grit. It just takes a light touch to sand and not staying in any one place on the sandpaper or the wood too long... even when you have to take large quantities off. Pure Natural Carnauba wax is going to melt at around 180F which is fairly hot. Paraffin wax will melt around 140F which is still hot but could be attained with poor sanding technique. Mixtures of waxes and solvents will melt at different temperatures. Not that that is a problem with proper sanding technique because the fibers are still supported with the partially melted wax and just fluid properties between the fibers.

I also think that lubrication has to do with good sanding. Probably not as much as you do though. Too much lubrication is worse than none from my experience. If you (meaning the turning community at large, George) need lubrication, at least in the grit stages where tearout is being taken care of .... 150 and below, then you're doing something else wrong. I like lubrication at 600 grit and above but very very little.

I feel that actual case hardening is far harder to do than what many turners think. You've really got to be pushing HARD and with completely dull paper/too fast/etc. to get actual case hardening. You'll have no more feeling in your fingers as the heat will have burned them off by that time if you're hand sanding. It's far easier to do with power sanding which is kind of ironic since it's so much more effective on large areas and you need to do so much less of it normally than hand sanding.

I do agree that IF you have some kind of case hardening on the non-problem areas, however, that you've got to take special care with those areas along with the problem areas. It can be tough to balance those two areas and, sometimes, you just have to work the problem areas themselves first and then blend those with everything else.

I, too, use those types of other products (including epoxy, white and yellow glues, thinned finishes, polymers, etc.) on particularly nasty problem areas (not just or even always spalted areas) to get a better sanding AND cutting effect.

The problem may be, depending on what the final finish is going to be, that those types of products are likely to soak into the wood further than you're going to be taking off by cutting or especially sanding. So, if your finial finish is going to be a lacquer anyway, then it's not a problem to use a lacquer sanding sealer or a thinned lacquer as a "conditioner" to help cutting and sanding problem areas. Shellac, in that case, would be fine too. Waxes don't penetrate very far (although a wax mixture with a thinner/solvent in it may ... at least the solvent) so you're going to be taking it off with cutting/sanding and not have to worry about it much. No real problems with being flexible with final finishes that way.

Another problem that I've been running into lately is in post-turning decorative effects. Use of these products that penetrate just for sanding help, will cause problems with stains, dyes, paint and other treatments needing to penetrate the wood in order to get the effect you want.

What I do, if it just isn't responding to the waxing to support the fibers, is to go ahead and try the other products after that and try to plan accordingly to my final finish. Sometimes, on very small areas and with a final finish that compliments it, I'll just use mineral oil and let it soak in a bit. It's all that's needed for a final cut or light sanding sometimes.

We're not completely on opposite ends on this issue .... but it'll get around to it somehow, I'm sure. No questions in there, George.

- Andrew

Think of supporting cooked pasta with sauce?

Sorry. I doubt this has much to do with it, not the least for the reason that sanding to the bottom of a torn fiber demands removal of the untorn.

You lost me. Can somebody translate?

- Andrew

Nah, he's just a contrarian non-thinker.

Once again, the crushed fibers are going to be softer than the non-crushed, and wax, as we know, is a lubricant even when not fluid, which would aid them in slipping by one another. He may have sanded that way for years (presumably because he hasn't learned how to cut without digging out), but it doesn't mean the mechanism he postulates is correct. If incorrect, might just be a better way of doing things, which he'll never discover.

Carnuba melts at ~200F, most mixes at less, especially solvent-thinned.

I'll stick by the speculation that it's not the torn stuff that wax makes easy, but the untorn, which has to be taken away to get to the bottom.

I have come to the conclusion that it is physically impossible for you to read a post and not contradict or "correct" it in some way.

FYI, a wax-saturated wood fiber (with ANY kind of wax) is a whole lot "stiffer" and easier to trim off than a whispy, hair-like fiber, bending in the breeze of your gouge. I have used this technique countless times in just the 3 years that I've been turning, with very good success.

Just ONCE, try investigating the veracity of someone's claim before opening your big, know-it-all, contrarian trap and hitting the ENTER key.

-- Chuck *#:^) chaz3913(AT)yahoo(DOT)com Anti-spam sig: please remove "NO SPAM" from e-mail address to reply. <

September 11, 2001 - Never Forget

While you and I (I'll leave out everyone else as it's not fair of me to speak for them) know this and have experience in it, there are those monitoring this group that don't. And they are, rightly so, wondering about it themselves. A very simple test for them is just to rub some wax into those tearout areas and sand (powersanding will make it go quicker) JUST that area. That means not turning the lathe on and using a small enough sanding disk to just be sanding the tearout and not the surrounding area. You will, of course, make yourself a little divot in that area but that's a good indicator that it's working. Compare this to doing it without a wax or oil or whatever. Make up your own mind on it's effectiveness and what's going on. In the end, it's really just about what works and not necessarily how it happens although it can be helpful sometimes in what's really going on so that you can apply that knowledge elsewhere if needed.

BTW, this is a standard practice not just in the woodturning world these days but also has been for a long time in planing and surfacing flat boards with both powered and hand tools. Often, in figured wood, you'll get some tearout while running it through the planer or hand planing (although the wax does get on the hand plane bottom so that's not a great test for this discussion). It'll also do that when you run it through with the grain running "up" into the direction opposite to the way the blades turn. The blades will tend to lift up the grain a little (remind you a bit of lifting up unsupported grain in a woodturning, eh?) and you'll get some tearout. The most often way of taking care of this, besides running the board through in a different direction if possible, is to simply wet (water, solvent, wax, etc.) that tearout area and run it through again. Only that tearout area has the water, solvent, wax on it. Same idea and mechanism as what's mentioned in the above paragraph but it might be easier for others to understand and replicate it themselves in this context.

As with anything in an open forum, don't take ANYTHING or ANYONE'S (I absolutely include myself) word for it. Test it yourself. That's why I try to offer examples and tests that you can do yourself. Situations are different. Products are different. People work differently. And you can't know who exactly that person on the end of that post really is or thinks.

- Andrew Don't feed the trolls, man.

...............................^^^^^^^^^^ (duh)

PLONK!

-- Chuck *#:^) chaz3913(AT)yahoo(DOT)com Anti-spam sig: please remove "NO SPAM" from e-mail address to reply. <

September 11, 2001 - Never Forget

Hallelujah!

Rubbing, with the exception of certain practices best dealt with in other forums does not make things "stand up," so those who apply their wax that way, whether the lathe is rotating or not, already know they're not standing things up. Those who apply a solvent-thinned wax, like those who apply its cousin, oil, already know that neither expands or raises the grain of the wood appreciably. That's what that polar solvent water is for. Note, water will raise the grain through and under either an oil or wax finish given carelessness. So with the non-polar, nothing raised, nothing supported, merely lubricated, and with solvent thinned or warmed waxes, absorbed a bit.

Now we all know that oil and wax (cousins on the same continuum) soften the surface of the wood, which is easily demonstrable by a fingernail, and with remarkably few exceptions, are more easily deformed, even in their solid form, than the undamaged wood structure. That fingernail again. If anything, especially as the surface is warmed by a bit of friction, it's the porous wood that supports and holds the wax.

Of course, there's that final point, that fibers gouged and damaged below the surface of the surrounding wood are never reconstituted, but can be taken down to an undamaged surface after the surrounding and _supporting _ wood is removed.

We've all honed with oil or water, some of us have wet-sanded automobile finishes or polished lenses for telescopes using the same principle -a little bit of lubrication keeps things moving faster, allows the grit to gain better purchase versus the non-grit portion of the surface. Therefore it's not surprising that it also works with wood, and varies as to the degree of surface penetration versus lubricity, depending on what's used. The worst, in this regard is water, which allows the fibers to clog our paper over and over - because it's a poor _lubricant_.

Now the crow and the chimpanzee both pick up tools to help them get at things they cannot otherwise reach - "what works."

Humans, on the other hand, strive to know "what's really going on" to improve or adapt. So, rather than sticking that stem over and over into the termite mound and hoping the guards will attack and hold on to it, take a lesson from the anteater, and put some stickum on it....

In the end, it's really just about what works and not

Yep, think the fact that alcohol has some grain-raising capability - shellac- is related to its semi-polar nature, not to the become visible when I put on a coat of oil

Nope, sorry, George. You're trying to prove your point by stating things that just aren't true in actual practice. Simply stating them doesn't make them true. Do a test, if you are actually interested, of this and you'll see that as a wax (obviously not a rock hard wax stick!) is applied to wood fibers, it fills in the gaps (to varying degrees depending on viscosity of the wax and how much you can rub it in, etc. of course) between those torn fibers and provides support to them. Hey, even just rubbing a waxy or greasy substance in my hair makes it stand up! Amazing proof! I've already given tests in my previous posts for those that really are interested. Obviously, you didn't perform the tests or have come to an opposite conclusion. Do you have a test to help us see your point?

Nope. Solvents DO raise and fill grain quite well. Of course, water is a solvent as well, but I'm talking about the mineral spirits (paint thinner), naptha, acetone, xylene, etc solvents here. Want another test? OK. Simply take that papertowel (most brands being a wood product still) and dip the edge of it into water, and the other solvents. Watch for the capillary action to raise it up beyond where it's touching the liquid. Try it with a red oak stick and you'll probably see it come out over the top end of the stick. Heck, even take that solvent-thinned wax and try it with that. Granted, there's not as much free liquid in that mixture so it's not going to raise it as far as just plain solvent liquid. Or just take some lamp oil or mineral oil or any light oil and try that too. There's a reason why the wick oil lamps of yesteryear worked (although with cotton as the wick for durability reasons). I'll let you come to your own conclusions and not ruin it for you or, more importantly, for those that actually want to see for themselves.

Hmmmm water softens wood too. Most liquids do if they're allowed to sit and not evaporate. If anything, the solvent-based waxes won't stay around as long because they evaporate quicker than just water. Nothing new there. You're really reaching on this one, George. So, you're saying that it's not the wax that's supporting the wood, but it's the wood supporting the wax? Hey, whatever gets the job done and however you want to phrase it, man. Either way, there's support there for those few fibers waving in the wind as it gets mowed down (yes, along with the non-tearout areas too, George) with the gouge or the sandpaper.

Yeah, but I think maybe the point you're missing is that as you are removing the non-damaged (tearout) areas, you are often just simply laying over the fibers on the border of the damaged | non-damaged areas. So you keep going and going and going and then there's no wood left. You still have those fibers that have layed over or plucked out below the surrounding surface wood (tearout) because they had no support to keep them from doing that otherwise.

I absolutely see your point that you have to get the non-damaged areas down to the bottom of the tearout areas. BUT, you can't ignore those tearout areas and treat them as if they weren't there. You need to do something in order to help prevent those areas from getting worse or just simply tearing out with each revolution of the lathe and/or sandpaper.

I'm not really following you here because you are using phrases like "moving faster" and "gain better purchase". Those aren't very descriptive. Kinda vague, eh? How about this .... wet sanding does a couple of things for those items you mentioned above along with steel (like chisels and automotive parts, etc.).... Mainly, it allows the particles being freed by the abrasion to become suspended in that wet sanding lubricant (water, oils, etc). This keeps those particles up and out of the way of the abrasive action so as not to clog it up. Now, with extremely fine edges (like in some chisels or knives), wet sanding/sharpening isn't good. Why? Because those tiny suspended particles actually are hitting and dulling with each "stroke" the edge causing it to stop getting finer and finer. But I digress. For finishes, like the auto finishes you mentioned, the wet sanding allows those particles to get up off the surface of the finish and not scratch it as much with each "stroke". I do this with some woodturnings too. Another major reason for wet sanding is to reduce heat in the process. If anything, wet sanding something makes the abrasive action less instead of more ( your "gain better purchase" which I think you were suggesting the opposite in that phrase?) because you have those particles up and out of the way instead of helping the abrasive action. However, you get into other problems because of it (non uniform scratches, heat buildup, clogging, etc.) and it's usually best to get them out of the way even though it's less abrasive to do it that way.

I agree (and have on many occasions to on this point) that lubrication when sanding (or even cutting sometimes) our woodturnings is good. I don't feel that it's as important as you do. Contrary to your above statement, however, I find that the oils and waxes (which are better lubricants I think we both agree on) are far far worse at clogging sandpaper than just water acting on the fibers to clog it. Being a poorer lubricant, the water is being more effective in the abrasion as can be seen by the fibers clogging your sandpaper. I can't really offer any other test than to simply put some water on one piece of a woodturning (a simple spindle turning will suffice although it might be more effective with some good coves with endgrain showing ... it'll hold the oils and waxes better ) and then another section use an oil (mineral oil is fine) and then another with some paste wax or other soft wax. Sand them and see for yourself. Maybe your water is different up there.

Either way, just use whatever works out best for you in regards to lubrication during sanding. As I see it, lubrication isn't all that important as long as you're not really trying to hog out a lot of wood by doing it. Short, quick blasts, and keep it moving to different spots so that the heat doesn't build up with the sandpaper works wonders, George.

Ummmmm, OK. Good to know, George.

Hope this helped,

- Andrew