When to switch grits?
I am sanding one side of a 4′ long by 12″ wide board of #2 pine and using a Bosch 1250 DEVS sander set on 6. The board has not been jointed or planed.
I am starting with 80 grit. How long do I need to sand? 30 sec, 1 min, 5 min?
Once I finish with 80 grit, and go to 100 grit, how long do I need to sand? 30 sec, 1 min, 5 min?
100 to 120. Same question.
Basic question: How do I tell when I am done with one grit and ready to go on to the next.
Thanks for your help.
Edited 2/28/2005 6:45 pm ET by jaa
Replies
I switch grits when I get the results I expect with the grit I am using. In your case I would switch from 80 grit when the saw marks are gone. For succeeding grits I change when the scratch pattern of the new (finer) grit is the only one present. There is no set time to sand. I use a DeWalt random orbit sander and move the sander fairlyl slowly (5-10 ft/min depending on the grit, coarser grits slower) across the board. This leaves the surface ready for the next grit after one pass. With the final, finest grit, I sometimes go over the board twice.
In other words you sand till its done! Hope that helps.
Doug
jaa,
I switch to grits when I run out of cream of wheat. ;-))
You will want to change to a finer grit when the one you are using has done what you want it to do. If you are removing machine ripples, when they are gone, then change to finer grit. When the sanding marks from the first grit are replaced by the finer ones, change to a finer grit. So on til you are at the place where the finest grit has done its thing.
If you are having trouble seeing what I'm talking about, try putting a random squiggle on the board with a pencil. (Be careful not to imprint the soft pine, just write on it) When the marks are erased by the coarse sandpaper, you will be there. You need good light to see the sanding scratches, to be able to tell when they've been replaced by the finer ones.
The resin in pine will tend to clog the paper and reduce its effectiveness. Replace the paper when it gets clogged, you will just be wasting your time otherwise.
Good luck,
Ray
You took my line!
LOL,
Mikeplease excuse my spelling.
"Grits" Southerners Unite! As a young girl in North Carolina, I used to have grits and hush-puppies for breakfast, sitting in my aunt's sunny kitchen. Yum!forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the "I Rocked With ToolDoc Club" .... :>)
A "tarheel", eh? I was a "leatherneck". Spent some formative months in that part of the world. Place called Camp Le Jeune near Jacksonville.
Met a lady in Jacksonville named Myrtle.. back when the occassional woman was still named Myrtle. She ran a boarding house on First street near the edge of downtown. Sunday mornings she put on a feast that included the finest grits I've ever eaten.
The two dollar breakfast followed the Saturday night poker game she hosted that began at sundown and lasted until breakfast. She also sold bootleg liquor out of a footlocker her ex husband left behind.
I've not been to North Carolina since I shipped out for Vietnam in 1967.. but I think of it often and would love to go back someday.
Okay, I'm through now.
Bill
jaa,
Everytime I make something I have to remind myself that milling, joinery and glue up is only half the project..wood prep and finishing is the other half.
The key question is what should the wood look like and feel like before you apply finish...and what it the most efficient way to get to that point. The sanding dust can hide blemishes (tearout, scratches, dents) and each wood type will require a bit different prep time. Don't be afraid to dust off the wood between grits (or bowls of cream of wheat) and wipe down with mineral spirits. Run your fingers over the piece and look at the wood from different angles.
I prefer to use sanding blocks (4x4 squares with cork glued to bottom) because on the medium and higher grits it only takes a few passes to bring the stock to the next level and I don't want to be swapping out papers all the time. Good luck
What do you want the board to look like when you're done? Are you going to paint it? Stain it? Use it for a fence outside?
Why are you starting with 80 grit sandpaper? Is it rough? If it's a board you bought at Home Depot you should be able to start at about 150.
If you really want to do yourself a favor, buy a good handplane, sharpen the blade, and spend about 60 seconds running the plane over that board. You might not need to sand it at all.
Mark,
Not to steal this thread, but, I'm finishing up my first piece (shaker clock) using planes only....I'm going through withdrawal. It's all can do to keep from reaching for the sandpaper...
That's great. I'm about to build a kitchen table and plan to do the same thing. It will be from cherry which is notoriously easy to plane, so I'm hoping there won't be significant tearout.
In preparation, last night I re-sharpened my jointer plane to an incredible sharpness. I took shavings off a test piece of pine thin enough to read through, but more important the resulting shine on the test piece was incredible. I'd never get close to that sanding.
What wood did you use for the clock?
mark,
I used maple on my clock. Yes, the wood does shine, and like yourself, I just kept the waterstone and strop set up and hit it frequently with the jointer blade. Also, i sharpened both scrapers for the little/awkard areas. It's tough..not having the wood all white with dust ...hope I make it.
"planes only...." Any scrapers? They're addictive!forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)Another proud member of the "I Rocked With ToolDoc Club" .... :>)
FG,
I'm trying to keep the scrapers to a minimun because it doesn't give the hard finish that a plane blade will. There are a few spots where the wood is just rough..the scraper can smooth that a bit. It might also work to rub the piece down with wood chips like you do on a lathe...Hmmm...maybe I'll try that.
how did you know about Home Depot?
80 definitely took out the ripples.
I just have the feeling that I am sanding much too long (better too much than too little).
Thanks all, for the tips, I will spend more time looking at the wood and less time leaning on the sander.
If the 80 grit worked to get rid of the ripples quickly, then it was the right grit.
To try to answer your question more directly....
Say you had a 12" by 2' piece of pine and you had just finished with the 80 grit. That means there are no imperfections on the surface other than the scratches left by the 80 grit sandpaper itself. You'd jump to, say, 120 grit paper, and your only goal is to sand until the 80 grit scratches are replaced with 120 grit scratches. That would likely take between one and two minutes on that size piece. The same for 180 grit and then you'd be done. So to answer your question, most of the time you spend will be on the initial grit. Everything else goes quickly.
Another tip is that it's fine to use the random orbit sander for the 80 grit because it's fast. But after that, I prefer to sand by hand because with the random orbit sander I'm always left with some of those swirly marks. Sanding by hand really doesn't take much longer and you're assured of a clear surface. Of course, you should use sanding blocks for doing this. I have a separate block for each grit.
If you think 80 grit sandpaper gets rid of the ripples quickly, you should see what a sharp plane blade does!
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