Howdy, all. Me again. A question about final sanding this time. I sand my projects (well, the surfaces that are likely to be touched) to
400 grit before I stain/poly them. Is this overkill? Will the poly fill in a rougher surface and still have the same smoothness? Will sanding the wood to 200+, then smoothing the poly with 300/400 produce the same result?Brian
Many finish product manufacturers only specify sanding up to 240 grit, with some even saying you only need to go up to 180. I suggest that you would only need to go to 240 and maybe less if you use a grain sealer to level off the surface. You don't want it glass-smooth or what will the finish stick to?
I cannot remember when I have used anything past 180.
Hate to buck the conventional wisdom here, but I think you are spot on. I usually sand to the same level. I can clearly feel the difference after finishing. I have not had any problems with finish "sticking" to finely sanded wood. I usually work in oak and walnut. It may make no difference in a project that is never touched, but I feel it is essential to sand to 400 grit if anyone is going to handle the wood. It just feels better.
Bill
Brian Phillips wrote:
Any Sanding past 180 to 200 on raw wood is a waste of time and sandpaper, there is no benifit to the final finish whatsoever it does not harm anything at all either.
It is the finish and what you do to it that gives that final feel, now here you can sand down to your hearts content
Good luck, George
On 2 Oct 2003 22:49:03 -0700, snipped-for-privacy@hotmail.com (Brian Phillips) pixelated:
If you're just going to stain and poly them, why bother to sand them at all?
(Uh, huh. Saw me coming, eh?)
I don't agree. the wood looks better. if the wood has figure it really looks better. depending on the sandpaper some if it burnishes the wood better and that looks nicer. if you use a oil and a wax it even makes a bigger difference. now if you plane the wood it will look even better. but sanding to a finer grit will get it close to the look of hand planing.
But if it's an oil finish (granted the OP was talking about poly), where there wouldn't be any buildup, then it would seem to me that you would have a benefit to sanding with a finer grit.
Neither do I. I've been told many things by many people, mostly what has already been said here.
There is no rule. You should use your best judgment, bolstered by experience, based on the species and condition of the wood, the intended finish, and the intended use.
For polyurethane, lacquer, or other relatively thick finishes there's not much of a difference if you sand past 220. By the time you have your final finish, the texture of the underlying wood is largely covered by the finish anyway. For oils, waxes, and other thin finishes, the texture of the wood becomes more important to the final smoothness.
In general, the harder and more closed-grained the wood, the more benefit you get from sanding to higher grits. I don't sand soft woods beyond 220. But I sand hard maples and other woods to 400 or 600 for pieces I know will be picked up and handled. Woodworkers whose hardwood work I admire sand up to 800 or sometimes four-digit grits.
Only if you clean the dust from the pores afterward. Else, you have on a micro scale what you see when you use wood putty to cover nail holes.
BTW, you can burnish the wood without sandpaper, too.
While a lot depends upon the type of wood and the choice of finish, I routinely take those projects that are going to have a hand rubbed oil finish to 320 grit. Having stopped at 180 on some projects, and gone to 320 on others, I suspect from my experience doing this that anyone who says there is no difference is probably not speaking from a great deal of practical experience.
Personal Choice, I would never use poly on wood It was a junk finish when it was invented and still is now, Serves absolutely no purpose to good woodworking. How many on the group are always writing in about the problems they encounter with Poly, How many I ask have not had to sand it or used steel wool to smooth it out, so what was the sense of of sanding past 200 for Also remember Wood is wood , it is not a stable substance, It moves it, always moves everything in the worls affects its movements. every type of liquid will raise its grain no matter how fine it was sanded, I know this is going to inflame a lot of you, Not my intention, everyone will do things the way they feel the best, I said the fine sanding would not harn anything but it does affect the amount of stain the wood will naturally absorb
I ask this of this entire group that from what I have read here a lot of use use hand scrapers & hand planes, How do you sand ?????with a ROS ?????? Be honest One of the worst inventions ever made to sand wood with, Convenient Yes, Less laborious yes. The absolute best way to sand wood is by hand, with the grain of course. Yes I use ROS, But do on certain pcs resort to total hand sanding, And truth be known very rarely over 150 on raw wood and I will stand my work up with anyones.
Now where the hell did I put the damn flame jacket.
Good Luck George
LOL ...
Yeah, that ol' Sam Maloof must be a real hack with his use of poly and all.
In general, if you will be applying a film finish sanding beyond 220 is a waste of time. For an oil finish I'll often sand to 600/800. For small object that will be handled and viewed closely such as pens, I've gone beyond 1200.
-- Jack Novak Buffalo, NY - USA
I always have gone to 180, with 220 on end grain, with pretty good results. I'm in the middle of a local Woodcraft finishing class taught by a 20+ year RPM employee (Think Behlens and Zinsser, among others).
He recommends stopping at 120, except for end grain or oil finishes. The hands on part of the class has me agreeing with him.
Barry
I've had excellent results with wiped on poly, cut 50/50 with mineral spirits. I usually prefer shellac or an oil/varnish mix, but I use the wiping poly when I need a really tough finish. I know it's not easily repairable, but it usually holds up better in the first place.
I have some pieces that knowledgeable folks have not been able to guess it's a poly finish.
Barry
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