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How long do you tend to sand at each grit?

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Forum topic by mtkate posted 06-30-2009 12:01 PM 3823 views 2 times favorited 19 replies Add to Favorites Watch
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mtkate

2049 posts in 2789 days


06-30-2009 12:01 PM

Topic tags/keywords: maple sanding

Hi,

I have been reading the sanding advice on this web site and now I am wondering if I am sanding effectively. I have been experimenting on maple with finishes and now believe I have a method – but I still get areas of speckle that I believe are caused by my sanding “method”. After I put on three coats of dewaxed shellac (sanding between each layer with 0000) that is cut – I rub on some water based gel stain and that’s where I see the problems. It’s like the little grains in the maple absorb the pigment and the wood gets speckled. I am sure it’s not a problem with the shellac application – the shellac is even throughout. I have also tried oil based tinted finish and I get the same thing unless I sand a LOT (ie. I stripped off a problem and started again, then it went away).

So – my basic question is: if you have a three square foot board of maple, how long do you tend to spend sanding in general on the one side? If I only spend one hour, I get the speckly finish in spots. If I spend 2 hours it tends to go away. Is that a ridiculous amount of time?

Method I use for the one hour sanding:
a. Random Orbital Sander, 80 grit, to remove any machine marks I see. By the way, I got a Porter Cable ROS that is FANTASTIC and I don’t experience any swirl marks. Let’s say a good 15 minutes. Wipe down. I also tried wipe down with mineral spirits to see if I can see stuff but generally I don’t.
b. Random Orbital Sander, 120 grit, sanding until it looks smooth. About 30 minutes. To me it sounds like too much time but if I go less I get speckles in more places. Wipe down.
c. Random Orbital Sander, 220 grit, sanding until it looks smooth. About 10-15 minutes. Wipe down
d. Hand sanding 320 grit with my block sander – again until it looks smooth. I spend about 10 minutes here. Wipe down
e. Hand sand with 0000 steel wool to get out anything I can see in the light. Wipe down.

OK, so my math is a little off and that adds up to more than one hour. When I go for two hours, I spend even more time at the 120, twice as much at the next subsequent steps. However, this means that I would have to spend 4 hours sanding a piece of shelf. It sounds inneffective.

What can I try to be more effective? (FYI – I have used cabinet scrapers with pine and was quite content – but I want to color the pine a bit and I understood from many posts that sanding is the better method for that type of application).

Thanks for your time.


19 replies so far

View Russel's profile

Russel

2199 posts in 3403 days


#1 posted 06-30-2009 12:16 PM

To my way of thinking, you’re spending too much time sanding. I typically sand with a particular grit until I can hear and feel a change in the wood. Depending on the wood, I typically use 80 and 150 grit with an ROS, then hand sand with 150 grit and 220. Then a sealer coat of shellac and sand with 220 or 320. For 3 square feet, that’s about 20 minutes.

I’m also not sure that you should be using steel wool on raw wood. It seems to me you’d be pushing bits of steel into the grain.

-- Working at Woodworking http://www.VillageLaneFurniture.com

View Scott Bryan's profile

Scott Bryan

27251 posts in 3286 days


#2 posted 06-30-2009 12:42 PM

Kate, let me add a little to what Russel has said. With regards to sanding one of the things that has helped me decide when I have sanded enough is to lightly mark the wood surface to be sanded with a #2 pencil. I sand until the pencil marks have been removed. Remove the accumulated dust and grit and then repeat the process with the next higher grit. Like Russel said for a 3 sq ft piece I would spend no more than 20 minutes going through the entire sanding process.

If I am staining a piece I will sand to 150 grit (100, 120 and 150). Sanding to a higher grit (320 in this case) seals the pores of the wood and it won’t take stain well. If I am putting a clear finish on it I will take it to 180. I will then very lightly sand between applications of varnish or poly topcoats with 320 grit by hand just to smooth the surface and prepare the surface for the next layer to bond.

By the way, with regards to your shellac routine you do not need to sand shellac between applications, like you do poly. Shellac will bond with the previous layer by partially dissolving it so you only need to buff the final layer with 0000 steel wool to get it smooth.

-- Challenges are what make life interesting; overcoming them is what makes life meaningful- Joshua Marine

View miles125's profile

miles125

2180 posts in 3470 days


#3 posted 06-30-2009 12:47 PM

Assuming you’re using good sandpaper, after a couple minutes you’re not really improving the sanding stage, just removing wood. Of course noticable blemishes and defects require added attention.

-- "The way to make a small fortune in woodworking- start with a large one"

View FatScratch's profile

FatScratch

189 posts in 2767 days


#4 posted 06-30-2009 02:05 PM

I also had problems with stain – all kinds of stain – turning out somewhat speckled. The stain sits on top of the wood and leaves small pieces of pigment on the surface. After taking class at Woodcraft, I was turned on to anyline dyes, which actually penetrate and color the wood fibers, much like a tatoo. The finish always looks better in my opinion – much more even than stain. I also spend only a few minutes sanding, anything more and you are just thinning out your wood.

View patron's profile

patron

13537 posts in 2805 days


#5 posted 06-30-2009 03:07 PM

im not much on finishes , but you might check out a sealer before everything , as it evens the field for finishes.
as far as sanding ,im an 80 grit guy then maybe 150 for smooth .
then just 220 in between finish coats .
maybe someone here can expand on this ?

-- david - only thru kindness can this world be whole . If we don't succeed we run the risk of failure. Dan Quayle

View PurpLev's profile

PurpLev

8523 posts in 3113 days


#6 posted 06-30-2009 03:21 PM

sounds like WAY Too much time for sanding… for a 1 sqft of maple ? maybe 10 min top for the entire process of (80 if you REALLY need it) → 150 → stain → finish → 220

if you’re finishing the piece here are 2 things to keep in mind:

1. you’re not trying to get the wood itself to be glass smooth – the finish layer is the one you want to buff out to that smoothness

2. if you sand the wood too much – you’ll evidently close it’s pores which will not take the stain properly.

another things that was already mentioned here is – if you buff the raw wood with steel wool you’re leaving small steel fibers in the wood itself – not a good thing to have (this will be forever trapped under the finish layer later on.

P.S. Ever since I started using scrapers , I do not worry about sanding anymore – only things I sand are the finish layers (only after the 3rd layer of poly) and my chisel/plane blades.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View CharlieM1958's profile

CharlieM1958

16242 posts in 3682 days


#7 posted 06-30-2009 03:25 PM

Everyone has made good points, but I’m 100% with Scott. I think your problem is that you are trying to get a totally smooth surface before you apply the stain, and it’s just not absorbing evenly because you’ve sealed off the pores.

I also agree that 20 minutes of sanding is plenty for that size piece of lumber, but I judge by feel more than by time.

-- Charlie M. "Woodworking - patience = firewood"

View mtkate's profile

mtkate

2049 posts in 2789 days


#8 posted 07-01-2009 02:01 AM

Thanks everyone. I knew my routine was a little nutty but I could not find anything about work effort time. Common sense is not so common! At least I have a mini-project for tomorrow (Canada Day). I glued up some more maple boards and they are awaiting the next trial run.

Scott, thanks for the pencil mark tip. I completely forgot about it – someone had told me that long ago in a class.

Well, if this helps another beginner I don’t mind to have braved my naivety to the lumberjock world!

View DaleM's profile

DaleM

952 posts in 2848 days


#9 posted 07-01-2009 02:23 AM

“After I put on three coats of dewaxed shellac (sanding between each layer with 0000) that is cut – I rub on some water based gel stain and that’s where I see the problems.”

According to what you wrote, you are putting on shellac, then staining? Water based stain will not spread evenly on top of shellac from my experience. Stain first, then shellac, or the stain will only absorb into any grain you have raised when sanding over the shellac.

-- Dale Manning, Carthage, NY

View davidroberts's profile

davidroberts

1025 posts in 2950 days


#10 posted 07-01-2009 03:18 AM

ah yes, sanding. For abrading the shellac, lose the 0000 steel wool and use 3M Scotch-Brite rubbing pads. You can buy individual ones at most woodworking stores. Type in “Scotch-Brite maroon” on Amazon and the page will discuss the maroon, gray, and white pads. The white is just for rubbing out (no grit), the gray and maroon are ultrafine and medium grit. You will not need to worry about leaving steel wool bits stuck in the wood or shellac sealer. You really don’t need to sand between each coat of shellac, just after the last, in my humble opinion. And with your sanding habit (hehe) you are probably taking off to much of the very thin shellac coat each time you sand between coats. Water based finish and steel wool don’t go together well. Micro bits of the steel wool can (actually will) become embedded in the wood and shellac and when water base is applied, will live a tiny rust mark. This may be some of what you are seeing. Just a guess. Like Bently said, in sanding, it’s all about the scratches. You only want to sand away the previous scratch pattern, no more. Sanding much past 220 and like Scott said, you seal the pores. What Purplev said, you may want to consider trying a cabinet scraper in your mix of preparing the wood for finish. I’m hooked on them, but read up on how to turn a hook. For a wussy man like myself, I like to use a homemade card holder. A card scraper will heat up under friction and can be uncomfortable to use after a minute or two. Put a small square frig magnet on the front and back to minimize the heat problem, or spend money at Lee Valley (I think) and buy one ready made.

I’ll shut up here in a minute. If you don’t already, use Norton 3X sandpaper. Stays sharper longer. Don’t be afraid to change your paper often, and let the paper do the work. No strongman pressure need apply.

-- Better woodworking through old hand tools.

View Jim Crockett (USN Retired)'s profile

Jim Crockett (USN Retired)

852 posts in 3197 days


#11 posted 07-02-2009 09:13 PM

I think you are sanding way too much.

Start sanding with the highest grit you can use to remove machinery marks on your stock. Planers, jointers, etc. leave marks on the wood – your first grit is used to remove these marks. Generally, unless your stock is very marked, I would start with 100#. Sand until all of the marks I mentioned above are removed. Change your sanding pad to 120# and sane only until you remove all of the sanding marks created by the 100# paper; same for 150# to remove sanding marks from 120#; same for 180#. This is generally where I end, with 180#. After I have sanded at this grit with my ROS, I will then hand sand with the same grit to ensure any orbital marks are removed.

This is pretty much what Bob Flexner, the finishing guru, recommends in his books.

Make sure you thoroughly clean your stock of sawdust between grits so that you don’t unnecessarily mark the wood with grit that came off the sandpaper previously.

Use good quality sandpaper – Norton 3X, Mirka Gold, 3M Sandblaster. Abranet comes highly recommended – it is a mesh sandpaper – although I haven’t tried it yet. A bit more expensive but reportedly lasts much longer than Aluminum Oxide sandpaper and enhances dust extraction greatly.

Jim

-- A veteran is someone who, at one point in his/her life, wrote a blank check made payable to "The United States of America," for an amount of "up to and including his/her life".

View mtkate's profile

mtkate

2049 posts in 2789 days


#12 posted 07-03-2009 03:42 AM

Bob Flexner – I will have to google him for books. Thanks. Still have not tried the next boards – got a miserable flu/cold (not the swine flu!!!) and can’t tolerate sawdust even with a mask right now. It’s a curse!

View Elaine's profile

Elaine

113 posts in 3087 days


#13 posted 07-15-2009 04:53 AM

Try Michael Dresdner for finishing, he has an RSS feed. As with others before, I mostly use scrapers and hand planes myself although I occasionally use sandpaper from Klingspor which is a right down the road. I prefer shavings over dust. It’s all about feel, you’ll get used to it. Someone mentioned using glass from old windows on LJs as a scraper, you might want to try that on some scrap.

View Kindlingmaker's profile

Kindlingmaker

2656 posts in 2991 days


#14 posted 07-15-2009 05:35 AM

I use 400 grit wet/dry between coats and feel the surface. If it feels near glass like then its time to blow off the surface and apply another coat. ...just me.

-- Never board, always knotty, lots of growth rings

View Bob #2's profile

Bob #2

3809 posts in 3486 days


#15 posted 07-15-2009 05:04 PM

I tend to use a card scraper a lot more now than I used to.
It seems to clip off those little fibers at the surface where an abrasive can turn them to fuzz depending on the grain pattern.
So for me it about 10 minutes at 80, 5 at 120 or 150 and ten with a sharp card scraper.
This is just and estimate as each peice can vary .
p.s. Todd Clippinger has a very good piece here on Card scrapers.
http://lumberjocks.com/toddc/blog/6848

Bob

-- A mind, like a home, is furnished by its owner

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