Replies

1. 
   UncleDunc | Mar 11, 2003 08:32pm | #1

   I've had pretty good luck using silicon carbide sandpaper, the black stuff, a light touch, and changing paper as soon as it starts to get dull. My theory is that when the grains start getting rounded off, they quit cutting the wood and start burnishing it.

1. 
   SThomas | Mar 11, 2003 08:43pm | #2

   forgive me, but are you suggesting that 'burnishing' might be the cause of why the maple will therefore not stain a s dark as i'd like?

   and thanks much

1. 
   UncleDunc | Mar 11, 2003 09:57pm | #3

   Yes. Just a different name for the same thing you described, closing the pores of the wood.

2. 
   forestgirl | Mar 11, 2003 10:11pm | #4

   IMO, 320's too fine and 150 not fine enough.  Try going to 220, and as mentioned, don't push the paper to its limits -- change it frequently (I also use a crepe cleaning stick on my ROS frequently to keep it clean).  I've used 320 on oak, which has very open pores, but would think that might be a bit much on maple.

   To prevent surprises such as this, you can test the surface before you finish.  After completing what you hope to be your final sanding, dust off the surface and then wipe with distilled water or with a cloth dampened with mineral spirits.  Any imperfections from sanding should show themselves.  It's possible you may have to go to a final sanding by hand to get the best results.

   Good luck!

   forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl   ;-)

   
   

   ---

   Edited 3/11/2003 3:13:17 PM ET by forestgirl

1. 
   SThomas | Mar 11, 2003 10:31pm | #5

   thanks to you both. yo, forestgirl. though i'd wiped with mineral spirits previously, i saw nothing. that, of course, could be a direct byproduct of advancing age. that, or a willful disregard on my part, in the hopes that my eyes were playing tricks. i will also heed your advice and stop at 220 and, though the prospect depresses me no end, finish by hand sanding.

   thanks again

   stephen

1. 
   forestgirl | Mar 12, 2003 01:37am | #7

   I have the same problems with me eyes, LOL.  Do you use the light-glancing-off-the-surface technique when you check for scratches?  The angle of the light your using at this stage really makes a differences, especially for us "mature" folk.

   I haven't had the pleasure of working with maple yet, but I like using wet-sanding techniques on oak.  Also, you might want to look into different ways of coloring the wood.  My recommendations are Great Wood Finishes by Jeff Jewitt, and Jeff's website at http://www.homesteadfinishing.com

   A wealth of info over there, and a forum to boot.  He's answered a couple of my questions directly, and is very good about that.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl   ;-)

3. 
   HowardAcheson | Mar 12, 2003 01:25am | #6

   Here's something that might provide some info. Pay attention to the part about the necessity for hand sanding as the last step to remove swirl marks. All the pro finishes I knew hand sanded as the final step.

   Sanding wood--hard or soft--beyond 220 does nothing more than burnish the wood making staining difficult. This is particularly true if you are using a pigment stain which sits on the surface and relies on "nooks and crannies" to impart color. Closed pore woods such as birch and maple are difficult to stain if sanded to beyond 150 grit.

   A number of years ago a shop I was involved with did series of adhesion tests with various finishes and sealers. As part of this test we explored adhesion based on sanding grit. We found about the same adhesion up to 180 - 220. Beyond 220 adhesion dropped off due to burnishing of the underlying wood particularly when machine sanded. This was tested on birch panels. We also found that the resulting smoothness of the first coat of finish was not materially affected by the smoothnes of the underlying wood for sandpaper grits between 150 - 220.. Thin finishes such as lacquer could be affected by grits less than 180. The smoothest surface for final finishes was obtained by sanding lightly after the first coat of finish was applied and dry.

   So our conclusion was that sanding beyond 180-220 was a waste of time and could be actually detrimental. But, there was a big appearance affect if the surface was not hand sanded in the direction of the grain using the highest grit used on the sanding machine. A ROS at 180 required final hand sanding with the grain for optimum appearence. If not hand sanded, scratches would show. Final hand sanding in the direction of the grain is a must.

   To carry it one step further, sanding at 320-400 grit after the first coat and subsequent coats was the optimum. Any finer and adhesion problems were encountered. No improved appearence was noticed by between coat sanding beyond 320 for varnish. 400 was the sweet spot for thinner finishes.

   I think you will find similar thoughts in the popular finishing books but YMMV.