Flap Disk
- Thread starter bczygan
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aka Larry
Well-known member
Since I started used the flap disks, I stopped using grinding disks altogether.
Rewind97
Well-known member
Not familiar with "flap disks" tell me more.
ndnchf
Well-known member
While there are still times I use a hard disc, I really like the flaps too. They are a bit pricier, but well worth while.
dnschmidt
Well-known member
They are the nuts. I believe the first company to develop these was Garryson in England. They are so much better than grinding wheels. I don't think it's possible to to metal fabrication without them.
lakeroadster
Well-known member
Basically sand paper glued to a fiber disc. They come in various grits. Home Depot sells them, Norton is a good brand.
They cut really well and cut smooth, unlike a grinding wheel.
They work nice for contouring wood also... but are a bit smokey.
http://www.homedepot.com/s/norton%20flap%20disc?NCNI-5
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Ign
Well-known member
They're a waste of money for the bulk of fab. Get a rubber backing pad and sanding disc. You'll see your consumable cost drop considerably with similar to identical end result.
If you need more after sanding, a Velcro-backed woven abrasive (Scotchbrite) is the ticket.
And no way any of these replace a grinding wheel unless you're independently wealthy. You still need a grinding disc for serious material removal.
If you try to use a flapper or a sanding disc as a grinding wheel you'll see performance go from amazing to **** in a minute or two. But since that flapper cost you anywhere from $3 to $9 you just keep trying to use it.
If you need more after sanding, a Velcro-backed woven abrasive (Scotchbrite) is the ticket.
And no way any of these replace a grinding wheel unless you're independently wealthy. You still need a grinding disc for serious material removal.
If you try to use a flapper or a sanding disc as a grinding wheel you'll see performance go from amazing to **** in a minute or two. But since that flapper cost you anywhere from $3 to $9 you just keep trying to use it.
readhead
Well-known member
Great for deburring but **** if you want to make something flat. The people that bought my fab shop were fans until stuff started coming back. They conform to whatever you are grinding. The first job that came back had dips on both sides of the weld. Looked pretty until the powdercoat and then they brought them all back. The job had to be redone and the company had to pay for the new powdercoat also. I showed them how to use sanding disks which were faster and cheaper with better results.
Richard Cranium
Well-known member
I have never used a flap disc. I will have to get a couple of diff. ones and see what all the flap is about....
ilovevocs
Well-known member
Takes a lot more than a flap disk for a mirror finish.
Cummins_Tech
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About a 5000grit with some water... not including a polishing compound and buffing.
Sent from my iPhone using Tapatalk
Sent from my iPhone using Tapatalk
dr_clyde
Well-known member
Quoted for truth. I use VSM's ceramic sanding discs, they're the best I've found. They have outstanding life due to the ceramic abrasive, and are about $2 each for a 5" disc. They will move some serious metal if you get a 36 grit one. I use them on my 7" grinder as well for cutting weld bevels on plate.
A flap disc is great for general deburring and the occasional blending job, but they are pretty terrible in terms of tool life and general utility.
You will never not need a hard grinding wheel for some jobs. They still rule the roost for hot rolled mill scale removal and grinding out root passes on pipe welds.
astroracer
Well-known member
I get my flap discs, grinding wheels, etc. here:
http://www.lehighvalleyabrasives.com/
Prices are generally hard to beat unless you run a cross a sale somewhere.
Flap discs are hard to beat for general rough shaping, rust removal and deburring. I still use the grinding wheels for heavy stock removal but the flaps are very hard to beat for general use.
Mark
http://www.lehighvalleyabrasives.com/
Prices are generally hard to beat unless you run a cross a sale somewhere.
Flap discs are hard to beat for general rough shaping, rust removal and deburring. I still use the grinding wheels for heavy stock removal but the flaps are very hard to beat for general use.
Mark
Coach James
Well-known member
Someone will most likely say the author of the article is all wrong, but I found it helpful.
http://www.fabricatingandmetalworking.com/2011/11/how-to-select-the-right-flap-disc/
Coach
http://www.fabricatingandmetalworking.com/2011/11/how-to-select-the-right-flap-disc/
Coach
aka Larry
Well-known member
Thanks for posting that link. I agree with it being helpful.
If you're doing a lot of production work, it's just too expensive. But if you want your world rocked a little, try one of the Freud Diablo flap disks. They're different.
lakeroadster
Well-known member
They would be pricey for a fab shop... but for a guy working in his "Garage" (as in Garage Journal) they work great.
PugetDude
ALLIANCE MEMBER
I use them for final smoothing out my fillet welds- after I use a grinding wheel to remove most of the evil. 
I bought ~ 50 of them for a about a buck apiece when Lumber Liquidators tried their brief foray into online tool sales. Anyone even remember their "NORGE" brand?
I agree that a rubber backing pad and a good sanding disc will outlast a flap disc. That is what I use when I'm not trying to get into corners, or don't need a really flexible pad. Heck of a lot cheaper and you're not changing discs so often.
I bought ~ 50 of them for a about a buck apiece when Lumber Liquidators tried their brief foray into online tool sales. Anyone even remember their "NORGE" brand?
I agree that a rubber backing pad and a good sanding disc will outlast a flap disc. That is what I use when I'm not trying to get into corners, or don't need a really flexible pad. Heck of a lot cheaper and you're not changing discs so often.
Musicinabottle
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Oh grinding discs still have a spot, but the flapper wheels are the **** no doubt. I've been using them for nearly 10 years.
md21722
Well-known member
Try grinding down metal using a 3M Green Corps 24 grit grinding wheel. Then try it again with 3M Cubitron 40 grit flap. The difference is night and day. The speed increase going from the grinding wheel to a good flap is unimaginable at first. Time is money too. As far as I know the only places where flaps fail is on hot weld like in a shipyard.
Ign
Well-known member
Flappers **** for rust removal. That's the one spot they REALLY start out amazing and within 30 seconds you're scratching your head wondering what happened.
Generally for rust removal I use a WIRE CUP BRUSH, or wire wheel on my bench grinder if the work allows. If you need more after that really only a hard disc will do it.
Smokin deal here and cut like a mofo https://www.lehighvalleyabrasives.c...randed+|+50+Grit+Ceramic+|+VSM+148491&Search=
Loscaldazar
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That's a bit too general of statement.... A flap disc can be SIGNIFICANTLY quicker than a hard grinding disc and has much higher removal rates while still having very good life.
Flap discs only **** as a grinding wheel when you are using the wrong grit, using a cheap disc, or are using the wrong abrasive type. You need to use a 36 or 40 grit flap disc for heavy material removal. You can get by with a 60, but it's slow. 80 grit is super slow and clogs with rust easily. Most hard discs aren't this high of a grit either.
As far as abrasive type, Aluminum Oxide is worthless in a flap disc. Aluminum Zirconium has good material removal rates, and life is okay. They will remove material faster than most hard discs.
Ceramic abrasives have very aggressive removal rates and self sharpen as you use them. They'll remove metal faster than any other angle grinder consumable I am aware of. They also have significantly longer life than the Al-Zr discs. Not as long as a hard disc, but still quite long. At $3 a piece from Lehigh Valley they're a good deal.
Cheap flap discs (and I don't mean price) just **** in general. The DeWalt ones aren't that great, as are most flap discs you buy at big box stores or welding supply stores for $5-6. Diablo, Walter, Lehigh Valley, 3M are good choices (with Lehigh being the cheapest by far). The Walter ones outlast the Lehigh, but with the walter being 3x as expensive and only gaining about 33% more life than the Lehigh, the Lehigh still offers the best $/performance factor.
The shape of the flap disc also comes into play too. The conical type remove metal faster and stays cooler than the flat type.
Now I'm not saying you're wrong and that flap discs are the answer for everything, but choosing the right flap disc helps eliminate a lot of the negatives people have about them. Plenty of reasons still to stick with hard discs (slower, but longer life and way cheaper) still.
Musicinabottle
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Absolutely, spot on. To each his own, but the notion that a conventional grinding wheel is rendered obsolete or that it's impossible to fabricate without a flapper wheel is just pure crazy. They're awesome for so many things but if you want to take down welds or some serious metal, go conventional grinding wheels. If you want to polish or shine the steel or aluminum up, then the flap wheels are awesome.
Musicinabottle
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Headphones, safety shield, hardhat, gloves, exhaust fan.............
MikeF2316
Well-known member
This is an excellent point. I've started using a complete face shield. Goes on over the (reading) glasses that you're used to. It can be a bit of a pain to keep clean, and the transparent plastic needs to be replaced fairly often.
I caught on to flap disks a couple of years ago. They're great in certain situations. But if you're learning to weld and want to remove that ugly lump you left behind, then a hard disk is better. Plus you'll want some thin hard (aka cut-off) disks. And a second grinder, because you often need to be alternating between different disks.
Superbec
Well-known member
dr_clyde
Well-known member
Here is a photo I took a while back comparing the size of my newest Metabo 6" grinder to a 4-1/2" Hitachi.
The disc on the Hitachi is a 5" 36 grit disc. I use those for the bulk of my fab work. Behind it is a Milwaukee 4-1/2" plastic backer pad. The hard disc like on the Metabo I use mostly for removing mill scale on HR steel, and the occasional slot or spot where a flap or sanding disc won't fit.
The disc on the Hitachi is a 5" 36 grit disc. I use those for the bulk of my fab work. Behind it is a Milwaukee 4-1/2" plastic backer pad. The hard disc like on the Metabo I use mostly for removing mill scale on HR steel, and the occasional slot or spot where a flap or sanding disc won't fit.
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Musicinabottle
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Here is a photo I took a while back comparing the size of my newest Metabo 6" grinder to a 4-1/2" Hitachi.
The disc on the Hitachi is a 5" 36 grit disc. I use those for the bulk of my fab work. Behind it is a Milwaukee 4-1/2" plastic backer pad. The hard disc like on the Metabo I use mostly for removing mill scale on HR steel, and the occasional slot or spot where a flap or sanding disc won't fit.
I had a Metabo (german made) back in the mid 1980s. Those guys sure built a damn good tool.
sberry
Banned
I have never used one, I can sand with a hard disk. I agree they have their place and certainly for those on all electric but I use sanding disks on air power. Mostly 7 inch and occasionally on a 5 if space is tight. I gut the old 7's to fit the 5
Burgerkong
Well-known member
The don't take off material evenly, especially if you're grinding say a protruding steel nub flush threaded into an aluminum block. Drives me nuts, had to break out the grinding wheel.
SMKS
Well-known member
For the things I do, flap discs are better than grinding wheels.
IndyGarage
Well-known member
Like others have said, they cut real nice when they are new - but quickly break down.
The good thing about them is they will continue to cut for a long time and can take bit of a contour on their edge to get into corners.
They do leave a very lumpy surface finish on harder materials.
The good thing about them is they will continue to cut for a long time and can take bit of a contour on their edge to get into corners.
They do leave a very lumpy surface finish on harder materials.
IndyGarage
Well-known member
Here is a photo I took a while back comparing the size of my newest Metabo 6" grinder to a 4-1/2" Hitachi.
The disc on the Hitachi is a 5" 36 grit disc. I use those for the bulk of my fab work. Behind it is a Milwaukee 4-1/2" plastic backer pad. The hard disc like on the Metabo I use mostly for removing mill scale on HR steel, and the occasional slot or spot where a flap or sanding disc won't fit.
How the heck do you keep grinders looking like brand new? Mine look like they've been through a war 30 minutes after I start using them.