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View Full Version : Poly Abrasive Disc, Flap Disc and Cup Wire Brush



RussZHC
05-21-2012, 08:25 PM
Tried using both today as a bit of an experiment.

Found the poly abrasive disc (photo here: http://www.mig-welding.co.uk/paint-stripping.htm) to be what others have "raved" about, though, as stated on that site, it does seem to wear quicker the heavier the rusted area. For paint removal and weld prep I could easily see myself moving to just these.

Flap disc as here: http://www.extremeabrasives.com/flap-discs.php I was less than thrilled with, going strictly by the packaging, yes, it cuts faster but for me the quicker wear/shorter life and the greater cost compared to regular fibre backed discs (used to be typical in autobody shops) is sort of a wash at best. Now it could have been the brand, "Diablo" from Home Depot since for some reason they dropped Norton (?) or it could be the use but I doubt that...

Anyway, anyone else have a favorite brand or a line that is high value for the dollar; or has found either product suited to a particular function/specialized use?

Related: just me or are cup style wire brushes to mount on angle grinders disproportionally expensive?

Bill736
05-21-2012, 11:04 PM
Your application is a bit different than my experience, but I've only used flap abrasive wheels on bench grinders. They cut well, but are expensive, and throw bits of cloth and abrasives all over my workshop. I've gone back to wire wheels .

Don Young
05-21-2012, 11:31 PM
I have used a lot of cheap hand and power wire brushes and find that they mostly do well enough. At one time I was having problems removing rust from a truck bed with a big coarse cup brush on a 7" angle grinder. The brush mostly just polished the hard scale. I broke down and paid something like $60 for a good name brand (which I do not remember) brush. That brush made short work of the rust and I believe it would have cut right through the metal too. So I agree that brushes seem to cost more than they should, but sometimes it is worth it. The good brushes seem to last a lot longer and cut better.

dalee100
05-22-2012, 12:22 AM
Hi,

If you're going to use flap discs, buy 3M. The backing is better and the adhesive is more flexible and stronger, plus they use less of it. So you get far more use out of each disc.

dalee

oldtiffie
05-22-2012, 03:05 AM
I use flap-wheels (3M or equivelent) and slotted and raised grinding wheels (seem to be no longer available - very fast and effective, easy to see where you are working and I have an impression that they were gringing cooler). If I now have to use normal wheels I only use Norton or as supplied from BOC.

Over-heating and "polishing" (instead of cutting) is a waste of time and causes a lot of inclusions.

http://i200.photobucket.com/albums/aa294/oldtiffie/Hydraulics/Hyd-lift5.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Hydraulics/Hyd-lift4.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Hydraulics/Hyd-lift3.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Hydraulics/Hyd-lift2.jpg

Black_Moons
05-22-2012, 04:24 AM
Flap wheels disappoint me greatly, athough my brother says they are awsome, apparently what you need is the sharp edge of some metal, and mash the pad into it to rip off cloth and expose fresh grain.

Apparently the higher quality flap wheels are worth it too.

That said, the cup brushs disappoint me too. The non knoted one I tried just threw tines everywhere! and the knoted ones just don't seem all that great either.. Now...
http://ak.buy.com/PI/0/500/221793982.jpg

These suckers... Now these suckers on an angle grinder just kick paints and rusts ass.

RussZHC
05-22-2012, 08:29 AM
Thanks, what some of you mention is definitely part of the situation I often find myself in (sort of "polishing" the rust or mill scale) which is part of the reason for trying the "poly discs".

oldtiffie: interesting, I've seen similar for wood working (at much finer grits) but as far as I know, have never come across one of those "interrupted" discs for metal (and, from what you said, now after the fact...have to dig around in suppliers back/old storage)

metalmagpie
05-22-2012, 08:53 AM
For removing paint quickly try this product from 3M:
http://www.drillspot.com/products/62779/3m_24241_bristle_disc

Boucher
05-22-2012, 09:07 AM
The Scotch-brite disks are also good in many applications. The 2 size on a right angle air grinder is great for finer details and corners. The 4 1/2" work well on rust.
Quality wire brushes are definitely worth the added expense. A big cup wire brush on a 7 grinder is aggressive but it will eat your lunch if you get careless. Ask me how I know.

oldtiffie
05-22-2012, 10:19 AM
I am pretty sure there is an attachment for oxy-acet for paint removal that works pretty well.

The big problem with "discs" and "brushes" is that you can't be sure there are no inclusions left in the parent metal. This particularly applies to large/flat areas where the disk "rubs" rather than "edges" where the disc "cuts". All ground faces should be treated with phosphoric acid primer.

LHC
05-22-2012, 10:47 AM
Did you find a source for these things in Canada? I have seen people rave about them and the closest I could find was the 3M electric drill mounted version, not the angle grinder one.

Thanks,




Tried using both today as a bit of an experiment.

Found the poly abrasive disc (photo here: http://www.mig-welding.co.uk/paint-stripping.htm) to be what others have "raved" about, though, as stated on that site, it does seem to wear quicker the heavier the rusted area. For paint removal and weld prep I could easily see myself moving to just these.

Flap disc as here: http://www.extremeabrasives.com/flap-discs.php I was less than thrilled with, going strictly by the packaging, yes, it cuts faster but for me the quicker wear/shorter life and the greater cost compared to regular fibre backed discs (used to be typical in autobody shops) is sort of a wash at best. Now it could have been the brand, "Diablo" from Home Depot since for some reason they dropped Norton (?) or it could be the use but I doubt that...

Anyway, anyone else have a favorite brand or a line that is high value for the dollar; or has found either product suited to a particular function/specialized use?

Related: just me or are cup style wire brushes to mount on angle grinders disproportionally expensive?

rollin45
05-22-2012, 11:36 AM
I have found there is a world of difference in good quality flap discs and the cheaper brands, this is true of both longevity and overall usefulness : of course the same is true of grinding discs and wire wheels.

For prepping pipe for welding, I much prefer the flap discs, for years grinding discs were the only thing available, but now one has the choice. Of course for grinding roots etc. a disc is still necessary, but the prep work is much better with the flap discs. There is another advantage to using these in that they tend not throw sparks all over the area, from a safety standpoint they are better than discs as well.

ymmv

rollin'

lazlo
05-22-2012, 12:57 PM
I have the similar experience: the expensive zirconia flap discs remove metal like crazy, but even the best ones glaze over quickly.

I use a grinding disc to remove weld beads, and then blend it with a flap wheel -- leaves a beautiful finish and will last a long time if you're not hogging with it.

To remove mill- or fire scale, I use the pool PH increase powder. It strips the scale off in about 4 hours. It fumes after you mix it -- do it outside.

EddyCurr
05-22-2012, 01:47 PM
Found the poly abrasive disc (http://www.mig-welding.co.uk/paint-stripping.htm) to be what others have "raved" about,

Anyway, anyone else have a favorite brand or a line that is high
value for the dollar; or found either product suited to a particular
function/specialized use?I have good success with 3m's Clean & Strip High Performance disks (http://catalogue.3m.eu/en_gb/gb-aad/Abrasives/Scotch-Brite_Clean_%26_Strip_Discs/Clean_%26_Strip%E2%84%A2~High_Performance_Discs~no code/Clean_%26_Strip%E2%84%A2~High_Performance_Disc~097 34): a
product similar in appearance, but configured as a 4" wheel mounted on
an arbor and driven by a die grinder.

Purchased for another use, this really shines at cutting through mill scale
on steel tubing. Its principal drawback is that it is one item that is not
sold through Greggs, my local 'goto' source for industrial supplies. Acklands
-Grainger stocks them locally but their counter staff are maddening to deal
with.

Norton has some products of this sort that I intend to look into. Something
to mount on an angle grinder would be a help, too.


Related: just me or are cup style wire brushes to mount on angle
grinders disproportionally expensive?I use a couple of imports and feel that $10 for a 3" knotted cup (http://www.princessauto.com/pal/product/8170441/Wire-Brushes/3-in.-Knotted-Wire-Cup-Brush) is not
unreasonable. For safety sake and brush longevity, it is important to use
a wheel rated for the free speed of the tool.

A brush works well for me at removing rust, but, like RussZHC mentions, I
find it just polishes mill scale. The 3M Clean & Strip cuts through scale to
bright metal in no time.

.

EddyCurr
05-22-2012, 02:31 PM
Norton has some products of this sort that I intend to look into. Something
to mount on an angle grinder would be a help, too.Here is a link to Norton's Bear-Tex line of non-woven Strip/Prep/Finish depressed
center wheels (http://www.nortonindustrial.com/Bear-TexNon-wovenDepressedCenterWheels.aspx) for angle grinders.

.

RussZHC
05-22-2012, 06:39 PM
LHC: the initial go round was using products from Home Depot, "Avanti" was the name on the poly disc and "Diablo, Steel Demon" the name on the flap disc.
If you are searching generally (in stores or internet), the "disc" part is somewhat important. I found it moves you from looking at flap wheels (that really are like wheels, the flaps extending sort of like spokes with most often a shaft being the "hub") to looking for things to attach to a right angle grinder.
Those purchases were based solely on what was open late night just prior to a long weekend.

As someone has replied, there are a few systems out there from various manufacturers that are, more or less, meant for die grinders, know about those, would use them IF I had a source of air in the current work "shop" (I have tried them on a electric die grinder and they work well, in my eyes it is a hassle not truly worthwhile). What I am after are variations on what can be attached to a typical angle grinder (in my case a 4.5" Makita), so either threaded hub or slightly larger reinforced hole.

Today I went to a more industrial source, who has both Walter and Norton as well as some Klingspor products.
Found some relative inexpensive wire wheels, Walter, (they are not quite flat but certainly not cup either) they do far more what I am after regarding post weld clean up.
Also trying a flap disc from Walter, it cuts quicker than the "Diablo" did but I think, for me, the issue is still the same, it works really well to blend welds (and it was much better on paint than the "Diablo") but on a flat surface, going into corners, "L", you almost have to go at it horizontally as well as vertically (and the item I am working on is awkward to turn one way) but even then, from the little I have done, the leading edge seems to wear quickly...I do know I saw a version of the "Diablo" that was designed precisely for welds in such corners, it had a radius from the factory which should help..
The poly discs in the size I am after they were out of (from Norton; they did have for 7" and 9" of the "Rapid Strip") but certainly not quite as cheap as I had hoped, based on the cost from Home Depot. I know they work extremely well and since the ones I have seen are fairly thick after a short time working into those "L" corners, on welds, they sort of form their own radius (I sort of start a bit high and come down and then a short "along").

Generally I am after minimizing how many variations on a theme I keep some stock of...I have been disappointed by some course fiber reinforced grinding discs from 3M which, theoretically, are meant specifically for rust removal (I bought from an auto body supply place with that in mind). They cut very well but clog/glaze over/dull quickly and a lot of the surface area of the disc is "lost" (at least I have never figured out a way to move in from the outer inch or inch and a half or so).


One detail I noticed this morning looking through various catalogs, is the "attack angle", the way I understand it, there is a difference as to how upright the grinder is held,
"Type 29" is meant for more upright (often labeled as "removal") whereas "Type 27" is often listed as "finish" [re: flap disc].


I don't know how it is in other parts of Canada and certainly not in the U.S. or Europe but I am often butting my head up against a wall regarding abrasive suppliers. In particular, the major names. The difficulty always seems to be that no one is really a "full line supplier".
I will spend time and money looking for a product that does what I want it to do and am willing to pay the premium that 3M and Norton command/demand BUT I can not afford to experiment with their entire product lines and find it aggravating when someone who supposedly carries the entire Norton line (as example) and I go in there after I do the research to narrow the choices down and then am often told, sorry, we don't stock that (which I get) or sorry, we won't bring that in (which I don't get)...at the same time, if the local supplier will only bring it in a box of 10 at a time say, I can swallow that IF I GET TO TRY A SAMPLE FIRST and that appears to be a tough ask [they don't normally carry something and so don't want to bring in a single as a sample based, I feel, that my "large" purchase may only be a box of 5 or 10].
Internet sources become the fall back position, so to answer LHC's question in a different way, Canadian sources: well not entirely satisfactory.

Edit: to add, came across "Keen Abrasives" yesterday during an EBay search, unfortunately (?) for some reason, they don't ship to Canada (through EBay) but they do have an online store and list this:
http://www.keenestore.com/servlet/the-153/Type-27-Stripping-Discs%2C/Detail
which is exactly the format I am after (now just got to get here)

loose nut
05-22-2012, 08:20 PM
I use flap-wheels (3M or equivelent) and slotted and raised grinding wheels (seem to be no longer available - very fast and effective, easy to see where you are working and I have an impression that they were gringing cooler). If I now have to use normal wheels I only use Norton or as supplied from BOC.

Over-heating and "polishing" (instead of cutting) is a waste of time and causes a lot of inclusions.

http://i200.photobucket.com/albums/aa294/oldtiffie/Hydraulics/Hyd-lift5.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Hydraulics/Hyd-lift4.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Hydraulics/Hyd-lift3.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Hydraulics/Hyd-lift2.jpg


We use a courser version of these to bevel pipe and plate at work. Cut a 10"std pipe (zip wheel) and bevel for welding in a few minutes, much quicker then it takes to do it with a torch and then finish grind.

EddyCurr
05-23-2012, 02:03 AM
Edit: to add, came across "Keen Abrasives" yesterday
... they do have an online store and list this: http://www.keenestore.com/servlet/the-153/Type-27-Stripping-Discs%2C/Detail
which is exactly the format I am afterThe Keen #71028 4-1/2" x 7/8" Stripping disk is a dead ringer for the
Norton NRN09649 (full p/n 66261009649) 'Rapid Strip, Non-Woven,
Depressed Center, Type 27 discs' sold by Acklands-Grainger.

My vote is that these come from the same plant in Mexico and just
have different labels afixed to the backing plate. The Keen photo
looks exactly like the Norton 09649 I now hold in my hand.


I don't know how it is in other parts ...Don't be disheartened. WPG is hardly the back-of-beyond.

As for vendors carrying a full line, that might be an unreasonable
expectation. They carry the portion of the line-up that addresses
the needs of their primary clientel, be it automotive, industrial,
construction or whatever.

Use the catalogs. Telephone first, instead of cold-calling by car.
Ask branches with none on hand to check stock at other locations.
When all else fails, enquire politely about whether they would recommend
someone else in town that might have what you are asking for.

.