The nitty GRITty on sanding

[b4man]

I hate to sand. Always have. I wonder if it's because I'm A D D or just too lazy to run through the process one grit count at a time. Anyway, I'd like to know what others use from paper manufacturers to power equipment.

I would like to know more about what to realistically expect from a sheet of sandpaper and know when it's time to replace it. Which sanders are better for various applications. When is hand sanding more favorable? When is enough, enough?

It would be nice to learn better techniques and spend less time and money trying to get it right.

I look forward to your responses. I always learn more than I ever knew I didn't know!:widea:

 

[MikeH]

I can't really answer the question, but I can say I've found the joy of scrapers. It amazes me how such a simple tool can give such a smooth surface. It's also fun to see the shavings come off so thin you can see right through them.

 

[Mike Davis]

I bought a 10 or 20 pound box of scrap paper from Klingspor 15 years ago. It's about half gone. I think I paid a little extra and requested mostly finer grits, but there's nothing over 220 in there.

I usually start with 80 or 110 then go to 220 on a palm sander. Then after a couple coats of danish oil I go to 400 or steel wool depending on the wood, how well it is taking the finish and how I want it to look. The 400 I use on a sanding block by hand.

When the paper clogs I throw it away. On dry wood that takes a while, on varnish it goes pretty quick. There's a pile of paper on the floor when i finish. I sweep it up when I through.

Like you I just want to get it done, so I don't waste time agonizing over it. Hold the wood at an angle to the light and the scratches stand out. When the scratch pattern is even all over go to the next grit. I usually start with what ever I need to get the worst blemish out and double each time I change grits.

Straight off my planer with fresh blades I may start with 220 then go to 400.

If I haven't changed the blades in a while or start from the band saw then 60 grit gets the job.

If I really want a fine finish I use a scraper, but most of my stuff isn't worth the effort.

 

[b4man]

"I usually start with what ever I need to get the worst blemish out and double each time I change grits."

I get the first part but don't understand the "double" changing grits.:wconfused:


I've never used scraper cards. Might need to try them!

 

[Mike Davis]

If some thing is really bad and I have to start with 40 grit then I go to 80, 120 or 150, 220, 400.

If I start at 220 then 400, maybe 800. Double the grit number.

I don't see much advantage in going up 100 at a time as in 100, 200, 300, 400, 500, 600, that seems excessive to me.

 

[b4man]

I thought that's what you meant Mike and thanks for explaining it. I read somewhere that 10 strokes should be enough to accomplish each "grit" task by hand. I've tried that on end grain cuts and it pretty much smooths it out.

 

[walnutjerry]

You will probably get as many different opinions on sanding as the people that reply.

Here goes my usual process: After glue up I scrape the joints to remove excess glue that I may have missed earlier. Then I send it through the drum sander with 80 grit on the drum. That gets everything flat. A drum sander will leave streaks anywhere there is any build up on the paper. Then I go to the ROS, starting with 80 grit to get rid of the streaks left by the drum sander. I stick with the 80 grit until the streaks are gone. This is probably the longest time with any grit used. I think the key is not to go to the next grit until it is ready. Then I proceed with 100--120--150--180--220, each time just enough to remove the scratch marks from the previous grit. On occasion I will go on through 240--320--400. I normally use a wipe on mixture of oils and varnish or urethane. When I do I will lightly rub the surface down between coats with 320 or higher, repeat the process until I see the depth of finish I want to see. Just before the last coat of finish I abandon the sandpaper for a pad much like a pot scrubber. When that last coat is dry I rub over lightly with a fine pad, wipe of the residue and rub out with brown paper(like the grocery bags).

There are times I will wet sand with silicon carbide paper early in the process but after the 120 grit so the grog or slurry it makes fills the pores in the wood.

I agree with some of the other posts in that if you master the scrapers you will use a lot less sandpaper.

I guess it boils down to preference and patience!!

Jerry

 

[nelsone]

Scrapers can frustrate you until you learn how to get the bur on them, then it's quite an [SIZE=-1]epiphany![/SIZE]

 

[JackLeg]

Barb: To make your paper, belts and discs last longer, get you one of the rubber sticks and clean your paper occassionally. I use one often, especially on disc and belts.

 

[TracyP]

This thread came in at just the right time. I have lots of pieces to sand in the near future. I know I wasn't the thread starter but thank all of you for your good answers.

 

[b4man]

Thanks Jerry. Good info.

I have a rubber sandpaper cleaner but I forget to use it so thanks Reggie for reminding me.

I spent the day sanding Sunday and today when I looked over the project I'm working on I was disgusted. Looks like I may spend tomorrow sanding again. If I have an opportunity to drop by Woodcraft tomorrow I will pick up a couple of scrappers and give it a try.

 

[Gofor]

You may want to pick up Bob Flexner's book: Understanding Wood Finishing. According to him, most people way oversand and waste a lot of effort that does not add any quality to the finished product. He also covers scrapers. After many years painting metal things (from cars, to airplanes, to buildings (wood and metal) and water towers) I am learning a lot from it because of teh differences in the materials.
It will answer your question on grits, when the sandpaper is shot or needs cleaning, what type is best to use, how to do it most effectively (ie time and effort) etc. and he also covers a lot of work arounds. It definitely is not a book designed to sell you on the latest/greatest gimmicks out there, or expensive brand names or tools.
I am only about 1/3rd of the way through it and am impressed. He also has the book set up so you can go straight to what you are trying to do without having to read all the technical stuff, altho there is a lot of good info in the first chapter.

Go

 

[Trent Mason]

This is a very interesting topic.

If I glue up two pieces and there is a noticeable ridge, I usually sand with the belt sander (80 grit) using a light side to side motion, never stay in one place too long, as tempting as it may be.

For finshing, I use the ROS, starting with 80 grit, then 150, then 220. I've only done one project that I actually cared enough to go further than that and in that one, after the 220 on the ROS I hand sanded with 600. Cleaned it off with mineral spirits, let that dry, then finished with Tung oil (for that project). Between coats I sanded with 0000 steel wool. The wood is as smooth as glass.

One thing I might note is that if you are using the ROS, don't make the same mistake I did when I was sanding (lead) paint off an entertainment center all day one time. I got down to my last sheet and sanded through the paper and ruined the sticky side of the sander. After that, the new sheets wouldn't stick to it (Porter Cable $50 ROS from HD, Hook and Loop I think). So now I'm without a functioning ROS and will need to buy another one. Check your sandpaper a lot just to make sure you don't ruin your sander.

HTH,

Trent

 

[woodylarry]

Trent, You should be able to replace just the pad. Klingspors or some of the other vendors should have them. BORG may have it also.

 

[DavidF]

I would say Jerry has my system exactly other than I start with 150 on the drum sander. I found that the 80G scratches were just way to difficult to remove and the 150 does a fine job of truing the panel up unless I really screwed up the jointing. If that's the case I use a hand plane and card scraper first. One tip that I do use now and really works is to change the angle that you sand with respect to the grain as you change grits. Never going across the grain, but at a 20 - 30deg angle. This makes the sanding go much quicker. As I get towards the 150G 180G mark then start to straighten up and go with the grain. This applies mainly to hand sanding but I do the same with the ROS. If I really want to $%&k up a project I use the belt sander!

My normal schedule would be 80,100,120,150,180,220 if no jointed panels are involved. I always stop at 220 before a finish of any sort, I have found that going further than that doesn't seem to make much difference if you haven't skipped a grit. I pay particular attention to polish up the end grain as well to avoid it sucking up too much finish and looking blotchy or dark Between finishes it's usually 320, 400.

 

[Sandy Rose]

I'm the same way with sanding...but if you have a really sharp hand plane and a good scraper, you shouldn't have to use much (if any) sandpaper.

 

[walnutjerry]

I would say Jerry has my system exactly other than I start with 150 on the drum sander. I found that the 80G scratches were just way to difficult to remove and the 150 does a fine job of truing the panel up unless I really screwed up the jointing. If that's the case I use a hand plane and card scraper first. One tip that I do use now and really works is to change the angle that you sand with respect to the grain as you change grits. Never going across the grain, but at a 20 - 30deg angle. .

The angle to the grain sanding is a good tip David. I do that even on the drum sander-----the angle varies with me according to the width of the panel I am sanding. I have a 38" wide sander so I angle the panel to maximize use of the width of the drum and keep the sandpaper wearing as near the same as possible. May be a useless habit but it is the way I choose to do it.:wsmile:

Jerry

 

[b4man]

Went to Woodcraft today specifically to p/u Bob Frexnor's book "Understanding Wood finishes" Go recommended. When will I ever learn? :BangHead:Of course they didn't have it, have in the past. So, I got "The New Wood Finishing Book" by Michael Dresdner. Could have bought Jeff Jewett for $40 but just couldn't bring myself to spending that.
I also got the cabinet scrapers in a set. I get my book home and soon realize there's no info on scraping in it. It does talk in plain language about sanding but it's mostly about finishes. Good info anyway.

Back to scraping. I haven't tried it out yet. Is there anything I need to know before I teach myself how to use the scraper? :dontknow::help:

Thanks to all who are sharing the great info!

 

[DaveO]

Back to scraping. I haven't tried it out yet. Is there anything I need to know before I teach myself how to use the scraper? :dontknow::help:

Putting a good burr on a scraper is the most important part of using one sucessfully. Other than that, when your thumbs start burning it's time to take a break.
Check out this link -

http://www.dovetailkid.com/2008/01/tuning-and-using-card-scraper.html

Dave

 

[NCPete]

Putting a good burr on a scraper is the most important part of using one sucessfully. Other than that, when your thumbs start burning it's time to take a break.
Check out this link -

http://www.dovetailkid.com/2008/01/tuning-and-using-card-scraper.html

Dave

you're supposed to stop when the thumbs get hot???? that is the way I would keep warm in the (unheated) shop during our cold winter month.

Wood Magazine (?) has an article on a scraper holder. I've got it around here somewhere, but am kind of afraid to look for it. May even have the magazine wrong, but I am sure plans could be found for it.