Thread: Flap discs

Metal generally. More aggressive than a wire brush but less brutal than a grinding disk.

They work on wood, but not very well because they are designed for something tougher to wear the flaps down and expose more grit. They tend to burn a bit. A planer with disposable tungsten blades worked far better for cleaning up rough/sand impregnated recycled timber.

Got a use in mind?

Originally Posted by JillB

Can anyone please tell me about the green coloured flap discs that are fitted to a 4" angle grinder?

What are they used for?

May be other colours too such as blue and brown. If you start to see spots towards the centre you need to review what's in your drink bottle.

There are a wide range of grits too, but as Robomaniac has said primarily for metal.

Regards
Paul

Thanks Shannon & Paul, very helpful comments.

I was looking for something to remove old paint and rust off a steel bracket used to mount a water pump on a wall. Sounds like the ideal thing

Originally Posted by JillB

Thanks Shannon & Paul, very helpful comments.

I was looking for something to remove old paint and rust off a steel bracket used to mount a water pump on a wall. Sounds like the ideal thing

Unless there is a lot of rusty pitting I think flap discs are too aggressive on rust and the substrate metal. A wire wheel that fits on a angle grinder is less aggressive and will still do the job.

Flap discs are useful for removing welding spatter and prepping joints for welding. Also useful for newbie welders to tidy up pigeon poo welds

Originally Posted by JillB

I was looking for something to remove old paint and rust off a steel bracket used to mount a water pump on a wall.

I picked up a flap disk (Flexovit from memory) the other day similar to the image attached from Supercheap Auto for around $15 or so I think they can be had for about half the price but it was just one of those cases of it being available at the time. They come in a few different grits perhaps 60, 80 and 120???

I started using it to help strip some rust and paint off the jointer I am restoring. It seemed to do a good job of the surface rust, removing the rust and polishing up the steel / cast iron quite well to accept a new paint finish. On the painted surfaces I found that it seemed to heat up the paint a little creating a sticky substance whilst the disk was being applied (ie solid again shortly after removing the heat of the disk).

I am not sure if the term "flap disk" is generic and can be applied to a number of different products however I found the one I purchased was just like a sandpaper disk for the angle grinder and did a far better job at removing the surface rust and polishing than it did at removing any paint.

Just my experience anyway.

Cheers

Stinky

The price of these discs comes down significantly if bought in quantities. I have in the past bought ten or more at a time. For a 4" grinder the price should be less than $3 each and less than $4 for a 5" .

Ebay is useful there.

Regards
Paul

Here is the info you guy's need.

Flap discs are available in all standard sizes, 100,115,125,178mm.
the Blue/green Discs are Zirconia /aluminum oxide abrasive , and should be used on edge work, weld s etc, stainless steel and aluminum,.

The brown discs are aluminum oxide and are best foe flat areas , on mild steel.

I would not recommend them for paint removal, as the material will clog , the best for paint removal are a product called STRIP-IT DISCS , these look like a nylon scourer on steriods, and will remove paint and surface rust without damage to the material .

Jeff
vk4

Originally Posted by vk4

Here is the info you guy's need.

Flap discs are available in all standard sizes, 100,115,125,178mm.
the Blue/green Discs are Zirconia /aluminum oxide abrasive , and should be used on edge work, weld s etc, stainless steel and aluminum,.

The brown discs are aluminum oxide and are best foe flat areas , on mild steel.

I would not recommend them for paint removal, as the material will clog , the best for paint removal are a product called STRIP-IT DISCS , these look like a nylon scourer on steriods, and will remove paint and surface rust without damage to the material .

Jeff
vk4

Jeff

Thanks for the colour clarification on the flap discs.

The strip discs are excellent for light rust removal and paint removal when you don't want to damage the under surface such as car body panels or machinery surfaces. I recently stripped a bonnet to bare metal. It was perfect.

However it was useless on weatherboards. There the disc of choice is a fibre sanding disc used in conjunction with a rubber backing disc on, again, an angle grinder.

Btw most of these discs suffer from some degree of clogging. It can be alleviated by holding a rubber sole to the disc. The heat generated draws some of the clogged material out. Best to use an old shoe as you'll be sorry if you use the favourite walkers. I only used one strip disc for the whole bonnet using this technique. It also works on belt sanders, particularly if you don't allow the clogging to become too bad before taking remedial action.

Horses for courses.

Regards
Paul

Paul,

Strip-it Discs are best at 1800-2400 RPM, Standard angle grinders run at 6500 - 10,000Rpm, and while the disc will work it will soon wear out before it's real life .

For cleaning a BELT/DISC RESTORER , is better than the runner sole, These are available from most Abrasives outlets and tool stores,they are like the old gum rubbers but much larger.

Jeff
vk4

Originally Posted by vk4

I would not recommend them for paint removal, as the material will clog , the best for paint removal are a product called STRIP-IT DISCS , these look like a nylon scourer on steriods, and will remove paint and surface rust without damage to the material .

Jeff
vk4

Thanks for the info Jeff. I had originally intended to get the nylon scourer on steroids however I didn't manage to find one at Supercheap. I may have to try Total Tools before trying to attack the paint again.

Cheers

Stinky

these are best used on a sander / polisher , AT THE LOWER SPEED .

even resin fiber discs are the same, the higher speed causes too much heat at the work surface, and the paint melts before the disc can cut & clear the paint.

If you do not have the low speed machine it would be better to hire / buy a machine .

Jeff
vk4

The other thing they are great for is cleaning up cheap cast iron tables on machines. Cheap fly cutting left circular cutter marks in the top of my bandsaw table. The are not very deep but affect the smoothness greatly. I used a couple of flap discs to take the peaks off but left the troughs (not to affect the flatness of the table too much, just improve the surface finish). Bit of work but now the workpiece slides through much better even under the downward pressure of the blade.

+1 for strip it disks. THere were 2 different brands when I got mine, and I got blue ones. Used them on a 4" angle grinder with no problems. I have used them to strip steel balustrades, and also on timber deck rails when I got sick of using a heat gun.

Robomanic,

you can try a sheet of wet&dry wrapped around a piece of flat steel(machined if possible) and wd40 as a lubricant, to rub back the table.

I would start at 800-1000Grit and finish with 2000Grit, Your table will then be smoother than a baby's B*M.


Jeff