Sharpening a paint scraper

[Rob Blaustein]

Just wondering how people sharpen these. I have several around including one with a carbide tip that I got from Lee Valley, but they are all dull after lots of paint and finish scraping. I think the painters typically just run a file over the edge. I have a coarse (220 grit equivalent) DMT diamond stone and some water stones (1000/4000) but was wondering what effective grit is useful vs overkill. Is there a special technique or is it like a chisel where you flatten and then do the bevel?
--Rob

[Todd Burch]

I have two flavors of "paint scrapers". One that has a knife edge, and that is what you are referring to I believe, and then I have putty knives that act as paint scrapers. These latter types, I put a square edge on the business end. For the first flavor, I flatten the back (well, I get all the gook off of it, which does the same thing) and then put a slight convex bevel on it, which is done by raising the handle end as I pull it backwards on whatever stone I happened to grab out of my stone drawer.

Todd

[Cliff Rohrabacher]

I just take a sanding belt to mine. I'm going to abuse it anyway what do I care about the quality of the edge?

As for the Carbide: get a medium or coarse $50.00 DMT whetstone. Honestly, I can't see carbide as a viable material because you can't field sharpen it easily.

Those Green grinding wheels will cut carbide but they make a mess of the edge. The guys used to whack 'em and break 'em when shop managers would install them instead of the diamond wheels.

[Todd Burch]

Carbide dust is a carcinogen. Stay away from the grinder!!

[Rob Blaustein]

I just take a sanding belt to mine. I'm going to abuse it anyway what do I care about the quality of the edge?

As for the Carbide: get a medium or coarse $50.00 DMT whetstone. Honestly, I can't see carbide as a viable material because you can't field sharpen it easily.

Those Green grinding wheels will cut carbide but they make a mess of the edge. The guys used to whack 'em and break 'em when shop managers would install them instead of the diamond wheels.

I have the DMT stone so can use that. I almost always use the scrapers at my house so the hassle with carbide that you mentioned isn't really a factor for me.

[Larry Edgerton]

If you are scraping paint anything beyond a fine file is a waste of time. You need to sharpen about every five minutes and your stoned edge will be wiped out by the paint on the first pull. Don't over think the job.....

[Mark Versprille]

I can't see the reason for a carbide edge. When I'm refinishing a floor I just keep a fine file in my back pocket and every 20 feet or so tune up the edge.

[Cliff Rohrabacher]

Carbide dust is a carcinogen. Stay away from the grinder!!

I can't find any information that supports your statement.
http://www.osha.gov/dts/chemicalsampling/data/CH_267100.html

http://www.mastercuttool.com/Assets/msds.pdf

Have you any more information than the bare allegation?

[Mike Cutler]

Cliff

If the composition of carbide is broken down it can consists of cadmium, chromium,tungsten and lead among other things.

Each of these materials have their own associated health risks, and would be present in the dust created during grinding operations. A search on the individual element/components will identify those risks.
Some of the individual metals are pretty nasty.

An internet search using "Hard Metals" and "lung cancer" brings up some interesting pages/data that would seem to support Todd's statement.

[Todd Burch]

Have you any more information than the bare allegation?

Hi Cliff. My bare allegation comes from my friend, who used to own and operate a commercial sharpening service that his father started.

[Clifford Mescher]

Hi Cliff. My bare allegation comes from my friend, who used to own and operate a commercial sharpening service that his father started.
I told my machinist brother. He has been sharpening carbide tools for over 40 years. He said he can't remember anybody getting cancer but that is not very scientific. It could very well be a coincidence. Clifford.

[Frank Drew]

Those red-handled paint scrapers from Red Devil (the ones with the slightly hooked blades) can be very useful tools; kept sharp with a mill file, and used sensitively, they can remove dried glue, level inlays, get into corners, etc. I think the single-bladed 1" size is the most useful, but also have the 2" and 3".

[John Callahan]

My carbon steel scrapers (Hyde, Red Devil) I sharpen with a mill file as Frank does. My carbide scrapers (Sandvik, now called Bahco) I don't sharpen. They stay sharp far, far longer (a big deal to me if I have a whole house to scrape); the scraper blade has two edges- just reverse it when it gets dull. imho the replacement blades are relatively inexpensive considering how long they last. The Bahco's are much more comfortable and work so much better the Red Devil/Hyde tools don't get used so much any more.

[Jason Roehl]

When I'm scraping loose and/or peeling paint prior to repainting, I use a carbide scraper, with either a 2- or 2 1/2-inch blade. They stay very sharp for a long time, and their death is usually indicated by a bunch of nicks in the blade from hitting nails hidden beneath years of paint. The initial outlay is about $10 ($15-20 for the 2.5" version), with a 2-edged blade, and replacement blades are a few dollars.

I also have a scraper handle that came with a set of 6 steel (HSS? High-carbon?) blades, each blade with 2 profiles on it for detail scraping. That saved my bacon on an exterior window job. The handle even has a little metal file inset into it, held in place by a magnet.

Nothing else in my repertoire, scraper-wise, other than wire brushes and my trusty-dusty painter's 5-in-1 (don't leave home without it), which I generally keep pretty sharp.

[Rob Blaustein]

When I'm scraping loose and/or peeling paint prior to repainting, I use a carbide scraper, with either a 2- or 2 1/2-inch blade. They stay very sharp for a long time, and their death is usually indicated by a bunch of nicks in the blade from hitting nails hidden beneath years of paint. The initial outlay is about $10 ($15-20 for the 2.5" version), with a 2-edged blade, and replacement blades are a few dollars.

Jason--how do you sharpen your carbide one?

I guess I was seduced by the claims in the LV catalog that the carbide scrapers stay sharp way longer. I used mine to remove old floor finish around the edges of a room prior to sanding and refinishing. But its profile didn't let me get into a few tight spots and I had to also get a SS one which when new seemed sharper than the worn carbide one. I'll try the DMT diamond stone and see how that works.

[Cliff Rohrabacher]

I told my machinist brother. He has been sharpening carbide tools for over 40 years. He said he can't remember anybody getting cancer but that is not very scientific. It could very well be a coincidence. Clifford.

I worked machine shops for about 20 years and there was never any issues.
I rather suspect the metals are unavailable to the body.

[Cliff Rohrabacher]

Hi Cliff. My bare allegation comes from my friend, who used to own and operate a commercial sharpening service that his father started.


The expression "bare allegation" was not intended to and should not have caused offense. The allegation was absolutely bare.
You didn't offer anything to substantiate it at all. you didn't cloth it or flesh it out, it was naked.
That's all it meant.

And the reference to the sharpening guy is no help either. Who knows how expert he is. I don't.

[Clifford Mescher]

Hi Cliff. My bare allegation comes from my friend, who used to own and operate a commercial sharpening service that his father started.
OK. I am curious. How did your friend determine that sharpenimg carbide will give you cancer? I am worried about my brother. Clifford.

[Jason Roehl]

Jason--how do you sharpen your carbide one?

I guess I was seduced by the claims in the LV catalog that the carbide scrapers stay sharp way longer. I used mine to remove old floor finish around the edges of a room prior to sanding and refinishing. But its profile didn't let me get into a few tight spots and I had to also get a SS one which when new seemed sharper than the worn carbide one. I'll try the DMT diamond stone and see how that works.

I don't sharpen them. When one edge is unusable, I flip it around to the other edge. When they're both done, I get a new blade.

I don't use carbide when I refinish a floor. If I absolutely have to use a scraper for some reason (I usually use the Festool Deltex for corners), I use a T-shaped scraper, and keep the edger handy with 100-grit paper on it for sharpening.

[Greg Deakins]

When I do a window or some detail I have a bag of scrapers of all sorts. Big ones, little ones, carbide ones, irregular shaped ones, dull ones, sharp ones, etc. It seems each job has its own requirment, or several. Because I am a maniac high on a ladder, my carbides generally lose their life after a fall onto concrete, which shatters the brittle edge. Because each type of blade has at least two edges, it feels sufficient to let 'er go after they are used up, and head into town for replacements.

[Scott T Smith]

I sharpen my carbon steel scrapers on a disc sander. It's fast, easy and accurate. The blade heats quickly, so you need to dip them in water ever few seconds.

After sharpening, I'll knock the lip off with a fine grit stone. Usually only takes a minute or two for the complete task.

Carbide tools are sharpened with a wet hone. The water captures the dust and prevents the health issues.

[Dave Cavner]

I don't follow these forums much but always seem to end up here when I'm researching something. If someone is looking at this thread down the road, I found another data point from a carbide scraper vendor. Use it or not, but if it works and saves someone time and effort, so much the better. I've not tested it so it may be overzealous marketing for all I know.

From:
http://www.eco-strip.com/ScraperCare.html

"How about sharpening these (carbide paint scraper) blades?
These blades will stay sharp much longer than you'd expect. If you notice that they are not scraping as cleanly or as fast as before, remove the blade from the handle. No expensive grinder or sharpening jig is needed. Just place the flat (not beveled) edge down a piece of 150-220 grit sand paper for metal. With a few fingers applying some pressure, rub the blade in circles for about 10-20 seconds. That's it!! "

[glenn bradley]

Mill file for my carbide one. Coarse stone to recover if I lose "straight".