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deepsplinter
11-28-2007, 08:49 AM
What are the pro's and con's of scraping over sanding?

I have always sanded everything, but lately I've been curious about scraping and have a few questions.

Can scraping eliminate sanding?

Can you scrape end grain?

Will scraped wood take stain like sanded wood?

I'm not asking about honing or burnishing. I've read articles about setting up your scraper, and it sounds pretty straightforward (with some practice)

cabinetman
11-28-2007, 09:28 AM
Once you get into scraping, you'll wonder how you got along without it. If you don't have any you can experiment with a very sharp chisel. You may have to experiment with different stroke angles for the degree of "bite". Use pressure on the pull stroke. IMO scraping is faster and more thorough than sanding.

Scraped finishes will take stains, dyes, and topcoats. If you haven't left "scrape lines" due to a ragged edge or burr on the scrapers edge, it leaves a very smooth finish. If you did, a light dress up with sandpaper may be in order.

You can buy dedicated card scrapers or ones that have different shapes. You can use chisels. I've made them from old jointer and planer knives. For the 1/8" steel stock I made handles that the knife slips into a saw kerf.

Sawduster
11-28-2007, 11:16 AM
Some sources recommend sanding after scraping and/or planing if you're going to be staining the wood. Depending on the size of the burr raised and its smoothness you may make a surface too smooth for accepting stain, so a light sanding with 180-220 grit might be recommended.

Postman
11-28-2007, 12:00 PM
For what it is worth, the hand joinery class I took at the Marc Adams School covered sharpening and using scrapers. I brought a couple Two Cherry scrapers to the class which have a very high hardness on the Rockwell scale, kind of like their chisels which are great. I never could get a burr on the darn things good enough to get more than sawdust scrapings. Marc Adams told us that there aren't many scrapers that have the right hardness of metal. He had a couple Sandvic scrapers that he sharpened in the class that really performed. Sandvic is a Swedish company that was bought out but the company that bought them is still making scrapers the same way. I don't remember the name but if you Google Sandvic scraper it will come up with the name. I bought a couple of them but haven't used them yet so this is all I can say. Marc was saying you don't have to sand after scraping. I also heard David Marks say the same thing.

Postman
11-28-2007, 12:06 PM
I forgot to mention- like Jerry said, a good burr like Marc Adams had really makes a smooth surface and may be too smooth for staining.

TDHofstetter
11-28-2007, 12:16 PM
I'm not so sure a burr CAN leave a surface too smooth for stain... unless the burr is rolled over and the scraper is burnishing instead of cutting. A sharp burr will always cut fibers instead of burnishing, and the unburnished fibers should take stain as perfectly as well-sanded wood will.

Good clean sharp 2000-grit sandpaper won't leave wood too smooth for stain, right?

-- Tim --


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Sawduster
11-28-2007, 12:25 PM
I really don't know since I can't remember the last time I used stain, unless you want to call iron filings to ebonize some oak staining. But . . . there are those who claim that anything beyond 220 (and some say 180) grit reduces the wood's ability to take stain. I would say that a very sharp smooth burred scraper is slicing wood fibers more than tearing them out, but there are those who claim to get as smooth and shiney of a surface from a scraper as they get from a smoothing plane. Either they are way better at putting an edge on a scraper than me, or their plane iron needs sharpening. I've never been able to get a shiney surface from a scraper, while my smooth plane leaves a gloss on most of the woods I work with.

cabinetman
11-28-2007, 12:34 PM
Some woods scrape better in one direction over another (with the grain of course).

Neonsilver
11-28-2007, 01:41 PM
> But . . . there are those who claim that
>anything beyond 220 (and some say 180) grit reduces the
>wood's ability to take stain.



That would depend on if it's a dye stain or a pigment stain.

Sonny Edmonds
11-28-2007, 10:25 PM
Scraping can be really cool. But it is rather time consuming for large flat areas.
I prefer to sand with my ROS. With Hook & Loop papers, I can run down the grits rather quickly.
And because I use air driven sanding, the aggression is very varyable with flow and pressure.
But sometimes scraping is the very best way observe the grain in the wood, and work down specialised or smaller pieces.
Some folks prefer to a passion to scrape and hand plane woods.
Try scraping and you'll see why. Sanding tends to leave a clouded surface until wiped with thinner, or a finishing step is taken (oil, sealer, 1# cut shellac, etc.).
I can't say as I have ever had issues with finishing even 12,000 grit sanded woods (lathe work). Wood is porus to some degree. So it soaks up finishes.
Dry wood is thirsty wood.

:D

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krethjr
11-29-2007, 10:57 AM
The place were I really like to use scrapers in on highly figured wood. I will still "final sand" with 220 or 320 (sometimes wet-sand), but I use scrapers to get the wild figure smooth first.

Jim

JBark
11-29-2007, 05:11 PM
I got my woodwork training at a shop that specialized in 18th century repro's and antique restoration of 18th century stuff. Our method for wood prep was to scrape machined wood, sand with random orbital sanders to #180, hand sand with #180 to make sure no orbital marks were on the surface. We all had Stanley #80's at our benches. We worked in figured birch, maple, cherry, walnut and mahogany. We also planed and scraped our poplar secondaries (not fun.) The advantage of a scraper in my thinking is that you are going to cleanly remove planer and jointer marks without question, sanding takes multiple grits and far more time to get the surface to the same point. Sanding sometimes leaves the ugly marks even after a good bit of sanding.

Our finishers told us to stop going beyond #180 as it was making the finishing difficult. They used both oil stains and aniline dyes. In answer to another question; yes, you can scrape end grain. If you are serious about using a scraper of any kind there is not enough to be said for keeping the edge good and clean, sharpened like a chisel before attempting to turn the aris. Remember, any minor chip in that surface will be left on the surface with each pass.

Card scrapers and curved scrapers are great for where you need them, if you don't mind the burned fingers...they get hot!

John