air dried black walnut bowl - wood wee bit soft

Re: air dried black walnut bowl - wood wee bit sof

David Walser

Walnut sands very well. That is, sandpaper cuts it more easily than most other hardwoods. You might try wet sanding it with walnut oil (or another oil finish). The oil will lubricate the sandpaper, keeping it cool. But, it won't prevent the sandpaper from leaving scratches. That's what sandpaper is supposed to do, after all. If you have the shape of your piece the way you want it, and all you're concerned about are the scratches left by the coarser sandpaper, wet sand with higher grits (320 or 400) to remove the scratches. Because walnut sands so well, it won't take long to remove the scratches left by even 80 grit sandpaper.

Or, maybe the sandpaper you're using has some stray extra-coarse grit on it. It happens.

Re: air dried black walnut bowl - wood wee bit sof

David Smith

I agree with David W.'s comments. I was having an issue with sanding lines and come to find out my sandpaper discs had inconsistent grits. I would stand from 180 and get to 320 only to get deep lines from that inconsistency and have to start over. I've since switched to a different disc and no longer have that issue.

I turn a fair amount of spalted birch which is a soft wood. I'll sand with 180 then 220, rub the turning down with walnut oil, wait five minutes then start wet sanding starting back with 180 to 600. I get excellent results when wet sanding softer woods and also like that there is no sanding dust.

Re: air dried black walnut bowl - wood wee bit sof

Dick Coers

You'll have to give us the sanding schedule, what grits, and if you are hand sanding or power sanding. If you start sanding with 80 grit, you have a deep scratch to remove and it takes effort to remove it. You can't move on after the next grit until all the previous scratches are gone. Use a strong light at an angle to be sure of your work. On some stubborn scratches in end grain, I will take a slightly damp rag and wipe the wood down. Let it dry, then keep sanding. The water will swell surface fibers and stand them up. I'm no fan of oil sanding. It will foul the abrasive and I consider it more of a polishing method. Not a wood removal method.

Re: air dried black walnut bowl - wood wee bit sof

joe mohnike

dampen the bowl and let dry, sand with 320, dampen again and let dry sand with 400. then buff with wood shavings. I have a reversing motor on my lathe and it helps a lot in the sanding process. You think you have it smooth but when you reverse the motor and start to sand the fibers are bent and the paper really grabs. Raising the grain by dampening helps to reduce this problem.

Re: air dried black walnut bowl - wood wee bit sof

Don Stephan

To my thinking, wet sanding is not going to have any effect on whether sanding leaves scratches, but it can pack fine sawdust into the scratches and if the liquid is something dries hard cures (such as boiled linseed oil or other oil, as opposed to water that simply evaporates) the packed sawdust and dried liquid can remain in the scratches.

In addition to using quality sandpaper and cleaning the surface after each grit, a recommendation I have often seen is that the next grit should be no finer than 150% of the prior one. In other words, after 100 grit for example don't jump beyond 150 (150% of 100) and after 150 don't jump beyond 220.

And if sanding while the lathe is running, I tend to have more difficulty removing scratches if the lathe speed is greater than about 250 rpm and if the sandpaper lingers in one place rather than constantly moved between headstock and tailstock.

Re: air dried black walnut bowl - wood wee bit sof

John K Jordan

I do several things:

- Most of my sanding is with the lathe off.

- I usually sand with the grain or figure, then across the grain, then with the grain. I make sure every scratch from the previous direction is gone before moving to the next finer grit. My theory is if I can't easily get 240 grit scratches out with 240 paper it will be very difficult to get them out with 320.

- Instead of sanding with coarse paper I use hand scrapers to remove any tool marks or tearout.

- I haven't power sanded with a rotary pad on an angle drill for years. Instead, I find a small pneumatic Grex random orbital sander is far better. For one thing, it can be used at a low speed for very gentle sanding. I have 2" and 1" pads for it. I learned of the Grex from Rudy Lopez. For bigger things I also occasionally use a 3" pneumatic ROS I got from Ken Rizza.

JKJ

Re: air dried black walnut bowl - wood wee bit sof

David Walser

The problem with using a pneumatic sander is very few of us have an air compressor that will adequately power one. But, I agree, if you have the proper air supply, nothing beats using a pneumatic sander. They're smaller and lighter weight than electric tools. I feel the same way about screw drills. I'd much rather use a pneumatic screw drill than a cordless or corded electric drill.

Starting the sanding with........

JamieDonaldson

....80 grit usually lengthens the sanding process due to the deep scratches produced. If you do good tool work you should be able to start sanding with 150 or possibly 220, thus eliminating the deep grooves. I strive to begin power sanding with 220, then 320, then 400 if needed. Wet sanding should be only for the higher grits, as much for sanding as for finishing.

Re: air dried black walnut bowl - wood wee bit sof

John K Jordan

>>>The problem with using a pneumatic sander is very few of us have an air compressor that will adequately power one.

When I built my new shop I put in a 5hp compressor with air outlets plumbed all around the shop, and a 5hp cyclone DC, both in a sound insulated cabinet. Life is good.

But I still use hand scrapers and hand sanding more than the ROS powered sanding, often with oil.

JKJ

Re: air dried black walnut bowl - wood wee bit sof

John in Lutz

I have recently turned some very punky splated maple. I had a lot of tear out. I was planning to finish the bowl with a film finish. I turned it down to where it was ready for the finishing cut. Then I coated it with a one pound cut of dewaxed blond shellac. You have to keep adding the shellac to the surface until it will absorb no more. Then I did the final cut and the fibers were stabilize by the shellac. They cut well and sanded well. You could probably also use a thinned lacquer sanding sealer.

This only works when you are planning a film finish in the final product.

a lot of work to take out a sanding scratch

Re: air dried black walnut bowl - wood wee bit sof

ebd

Thanks for all the information. I guess I will just bite the bullet and hand sand through my normal sequence till I get to 600 or 800. I wish I hadn't touched the bowl while it was spinning. The grit was too coarse and now it's going to be a PITA following the crazy grain by habd to get the fine scratches gone. Oh well - live and learn.

Re: air dried black walnut bowl - wood wee bit sof

Brad Vietje

Crappy sandpaper with little grit size uniformity is, well, crappy sandpaper. I also agree that very light sanding with a lubricating oil will help here.

Safe spinning,

Brad Vietje

Newbury, VT

OY!  But the NOISE!

Re: air dried black walnut bowl - wood wee bit sof

ebd

Forgot to say - I never use crappy sandpaper. Learned that lesson a long time ago. LOL