questions about sanding....

[mbmcewen]

Hi all, I guess I have a rather noob question about sanding all though I probably sand cabinets several hours out of each week.

When I sand cabinetry, I usually finish the build completely and then sand the finished cabinet. Doors are done with one extra step...sand the panel before the door is built, then sand the whole door again.

However, when I try this on my personal projects...usually somewhat finer. (like this - http://www.woodworking.com/dcforum/DCForumID17/967.html) I get all sorts of scratches where I end up going across the grain of one piece in order to sand another. Or, I have to go across the grain in order to sand at all.

So, how to fix this? I can use tape. I have done this with varying degrees of success. Or, I could sand all pieces before assembly. I have not tried this and frankly I wonder about its practicality....famowood, small scratches incurred during glue up, etc

What do you guys/gals do?

Thanks a bunch,
Matt

[cabinetman]

Your best bet is to use a ROS (random orbit sander). You can sand over woods that are not grain aligned with no problem.

[Cody Colston]

I generally sand everything to P120 grit prior to assembly and then final sand after glue-up with both an ROS and by hand.

Cody
Tyler, TX

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[HAMMER23H]

I do the panels before assembly, the frames I sand with ROS to 220 after assembly. It seems to work ok for me.

[deepsplinter]

When possible, I'll assemble then sand. But some places you just have to sand first.

I usually go to up to 150 grit with my ROS, then hand sand (with the grain, of course) with 150. Some times I'll go finer or even stop at 120, depending on the type of wood, or if it's going to be stained or painted, or left natural.

On doors, I'll put my thumb on the stile where I need to stop hand sanding. It's kinda rough on thumbs, but it keeps me from sanding across the grain.

[arcticfox46]

On your bench from the link - I see face grain, edge grain and end grain.


Each of those grains react differently with sanding.

You have end grain AND face grain where the tenons come through.

OK - on something like that - I would sand the :wood: to a much finer grit than 220 :before: finishing.* I would go up to 400-600 grit.

First I would ROS with 120-150 then ROS with 220 then hand sand with 220.

Normally - I will do sanding after assembly and I would do so in the case you used as an example.*

Normally I will ROS wood to 220 grit then hand sand with 220 and no more.

BUT - for the project you showed I would deviate and continue to hand sand to 400-600

[mbmcewen]

Thanks for the replies, and I do make extensive use of the ROS. But, looking at the linked thread of the bench, where the bench legs meet the top at 90 degrees...to use the ROS on the bottom up against the legs would eat a groove into the legs. I guess this scenario can come up frequently...where two faces meet at a perpendicular joint, how do you sand each face up to the other one without leaving scratches?

Is that where sanding to a much higher grit comes in...that way the scratches, which technically are still there, are so fine they aren't seen?

[cabinetman]

It may require a very controlled sanding with the grain by hand, taking short controlled strokes. Some areas may be scraped with a very sharp chisel with bevel up and a light touch.

[mbmcewen]

>>Some areas may be scraped with a very sharp chisel with bevel up and a light touch.


Darn....I was hoping to avoid that! Thanks ;)

Matt