Vlies on bare metal experience?

[Wuffles]

Looking for something I can use on my RO90 for removing mill scale and light surface rust from mild steel, not planning to paint afterwards, just some spray lacquer.

Which grit should I be looking at buying? Anyone got any experience? I'm currently using an 80 or 120grit flap disc, so an industrial finish is acceptable.

Cheers.

 

[AlexThePalex]

Anything works on metal. For superficial rust on metal you can use normal paper like brilliant or granat 120. Vlies should also work, but might take a bit longer.

I always prefer a wire brush on a grinder though, but if that's not around a sander with paper works if the rust is not too bad.

 

[Wuffles]

Anything works on metal. For superficial rust on metal you can use normal paper like brilliant or granat 120. Vlies should also work, but might take a bit longer.

I always prefer a wire brush on a grinder though, but if that's not around a sander with paper works if the rust is not too bad.

It's more mill scale* with a light bit of rust on top. So you can kind of ignore the rust really, the mill scale is the hardest part to shift.

I've got a couple of brushes that'll go into a die grinder, but it's fiddly and takes a bit of time. Have you tried the Vlies? I've had some of the Mirka equivalent on a roll before now, but it's not a low enough grit to even touch the mill scale.

*I could be using the wrong term. The black/dark grey "primer" that's on steel when you purchase it from a steel merchant.

 

[Tayler_mann]

Anything works on metal. For superficial rust on metal you can use normal paper like brilliant or granat 120. Vlies should also work, but might take a bit longer.

I always prefer a wire brush on a grinder though, but if that's not around a sander with paper works if the rust is not too bad.

It's more mill scale* with a light bit of rust on top. So you can kind of ignore the rust really, the mill scale is the hardest part to shift.

I've got a couple of brushes that'll go into a die grinder, but it's fiddly and takes a bit of time. Have you tried the Vlies? I've had some of the Mirka equivalent on a roll before now, but it's not a low enough grit to even touch the mill scale.

*I could be using the wrong term. The black/dark grey "primer" that's on steel when you purchase it from a steel merchant.

I've used the 240 vlies on steel and aluminum. It really doesn't have sanding power it more so just scuffs it very fine. It works great for prep before painting or in between spraying coats of auto or epoxy. If you are just trying to smooth out .01" or less it should work perfectly. I've found tons of uses for the vlies so it's not a bad thing to have around.

 

[Wuffles]

I'll perhaps try some of the 80 grit and see how that works. I'm hoping it's the equivalent of an 80 grit flap disc but on an easier to control machine.

 

[ear3]

As people have already mentioned, the Vlies isn't as aggressive as sandpaper, and so will be inadequate for any serious rust spots.  I've also found the Vlies to be rather fragile when using it on contoured metal surfaces, and especially those with ridges.  The pad abrades fairly rapidly in that scenario.

I'll perhaps try some of the 80 grit and see how that works. I'm hoping it's the equivalent of an 80 grit flap disc but on an easier to control machine.

 

[Wuffles]

As people have already mentioned, the Vlies isn't as aggressive as sandpaper, and so will be inadequate for any serious rust spots.  I've also found the Vlies to be rather fragile when using it on contoured metal surfaces, and especially those with ridges.  The pad abrades fairly rapidly in that scenario.

I'll perhaps try some of the 80 grit and see how that works. I'm hoping it's the equivalent of an 80 grit flap disc but on an easier to control machine.

It's not the rust that needs to be removed. Removing the mill scale with sandpaper will dull the sand paper almost immediately (I've tried), a flap disc is another thing altogether. The recommended abrasive is silicon carbide (apparently) which I think Vlies is comprised of.

Festool say "Perfect for cleaning and de-rusting metal" so I've been led that way.

It's mostly box section 20mm stuff I'm working with, and a flap disc (even a dull one) has a tendency to remove too much material along with the mill scale. Trying to avoid that too.

 

[jbasen]

I haven't tried these personally but I've been told these rapid strip wheels from Norton work well for cleaning up metal.  I was warned not to press hard or you tear up the disk.  You just let the disk and your angle grinder do the work

http://www.amazon.com/Norton-Non-Woven-Depressed-Center-Diameter/dp/B00755XY2Y/ref=sr_1_1?s=industrial&ie=UTF8&qid=1444016260&sr=1-1&keywords=Norton+rapid+strip+wheel

I purchased one to try out but just haven't had a project that requires one yet

 

[Wuffles]

I haven't tried these personally but I've been told these rapid strip wheels from Norton work well for cleaning up metal.  I was warned not to press hard or you tear up the disk.  You just let the disk and your angle grinder do the work

http://www.amazon.com/Norton-Non-Woven-Depressed-Center-Diameter/dp/B00755XY2Y/ref=sr_1_1?s=industrial&ie=UTF8&qid=1444016260&sr=1-1&keywords=Norton+rapid+strip+wheel

I purchased one to try out but just haven't had a project that requires one yet

I've used those, they're good for paint and heavy rust but for the cost of them, you get more life from a flap disc from experience.

That is if they are the same thing as

Good but pricey and a very finite life.

 

[Cheese]

[member=20162]Wuffles[/member]
My initial thought was that you needed to use a silicon carbide abrasive because it is much more aggressive than aluminum oxide abrasives on steel. All Festool abrasives are aluminum oxide based except for Platin 2 and some grits of Vlies. That's the reason the normal sandpaper you use immediately dulls.

The Platin 2 starts off at 400 grit and goes to 4000 grit so that one gets the boot immediately unless you're looking for an extremely fine finish.

Festool doesn't specify what grades of Vlies are silicone carbide based and what grades are aluminum oxide based. One would hope that the 80 and 280 grit Vlies would be silicone carbide based but who knows.

I typically use a Pferd flap disc for cleaning up metal and they are made from zirconia alumina which is in the ceramic family.

Really, what you're looking for is a non-woven web material (3M speak) infused with a silicon carbide abrasive. I'd try using the 80 grit Vlies and see how that works out.

If that doesn't work for you (that probably means it is aluminum oxide based) look for a non-woven web material that is infused with silicon carbide or zirconia alumina abrasives. Just remember that non-woven web materials are a lot more fragile than cloth or paper backed materials so the usefull life may be a bit short compared to conventional abrasive discs.

 

[Wuffles]

[member=20162]Wuffles[/member]
My initial thought was that you needed to use a silicon carbide abrasive because it is much more aggressive than aluminum oxide abrasives on steel. All Festool abrasives are aluminum oxide based except for Platin 2 and some grits of Vlies. That's the reason the normal sandpaper you use immediately dulls.

The Platin 2 starts off at 400 grit and goes to 4000 grit so that one gets the boot immediately unless you're looking for an extremely fine finish.

Festool doesn't specify what grades of Vlies are silicone carbide based and what grades are aluminum oxide based. One would hope that the 80 and 280 grit Vlies would be silicone carbide based but who knows.

I typically use a Pferd flap disc for cleaning up metal and they are made from zirconia alumina which is in the ceramic family.

Really, what you're looking for is a non-woven web material (3M speak) infused with a silicon carbide abrasive. I'd try using the 80 grit Vlies and see how that works out.

If that doesn't work for you (that probably means it is aluminum oxide based) look for a non-woven web material that is infused with silicon carbide or zirconia alumina abrasives. Just remember that non-woven web materials are a lot more fragile than cloth or paper backed materials so the usefull life may be a bit short compared to conventional abrasive discs.

I'd be miffed if the Vlies 80 doesn't last very long at the price  [eek]

I have an old flap disc (a non-ceramic one) that I use for "finer" work, has no abrasive grit left on it but still works alright.

Bought some Dronco Ceramic discs from Germany that I haven't had the heart to even fire up yet. The problem seems to be that most removal techniques are round and are to be used on an angle, and therefore don't work so well on certain shapes. I was hoping to use something flat and round with abrasive all over - the Vlies.

I'll take some snaps later to demonstrate my dilemma.

 

[Cheese]

I'd be miffed if the Vlies 80 doesn't last very long at the price  [eek]

I'll take some snaps later to demonstrate my dilemma.

A non-woven web material will never last as long as a a cloth or paper backed product because the basic underlying structure is just too fragile, comparitively speaking.

Snaps are good...

Thinking more about your dilemma, this is what I normally use to get a fresh/clean surface on metals without removing material like the Pferd flap disc does. It can be used full face down on the material to be cleaned and will not remove any metal per se but will just clean up the surface as long as no pressure is applied to the grinder. Again, these provide reasonable abrasive life but only last 1/3 as long as the paper backed version. This is a 2" version, they also come in a 3" version.

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[Wuffles]

I think that's more what I was hoping the Vlies would look like, moving slower and picking up the bits the flap wheel just doesn't get into on the slightly concave surface of a 20mm square tube.

I'll take a snap in a minute and show you what I mean.

 

[Cheese]

You're right, square tubing isn't necessarily flat and the flap wheel will contact the outside edges of the tubing before it contacts the middle section of the tubing.

 

[Wuffles]

Yep, you're on it. So I was hoping the Vlies would pick up the gap left behind, and make it easier for tube too.

 

[Cheese]

Das bench...

This is more like what you need...you can use it flat on the diameter or tip it just a bit to get into the cupping of the tubing.

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https://www.pferdusa.com/products/204p/204p01/204p0101P.html

 

[Wuffles]

You're probably right yes, but still a bit of a faff. I've been doing just that with a flap wheel in a die grinder.

I was hoping with an interface pad on an RO90 and a Vlies pad I could just run along it and get rid of the lot in one swoop - or perhaps not even use the interface pad. I'll swing by my dealer later and see if I can hold one of the 80 grit pads and see just how solid they feel.

 

[rvieceli]

This product does a very good job in an angle grinder.

http://www.coventry-grinders.co.uk/product/norton-blaze-rapid-strip-disc/

If you are going to be using steel a lot in bases etc, you might want to try and eliminate a great deal of the mill scale before you start. Hot rolled (A36) steel is usually the most common at steel suppliers but has the most mill scale from the manufacturing process. Cold rolled steel on the other hand doesn't have mill scale (as much) but it's not as available in stock. They can always order it for you.

You could also take a look at pickled and oiled hot rolled (P&O). It used an acid bath process to remove the mill scale and then the steel is oiled to keep the rust down.

Ron

 

[Wuffles]

That's the same thing [member=18233]jbasen[/member] posted about, but he'd not tried it yet. Might have to try one just because, well, you know.

I learnt the hard way to strip the areas within the tight joints before welding up. Took me quite a bit of time to get in there after it was welded the first time I had a go. If there were an easier method I'd be inclined to strip the lot before even starting, but nothing so far has made it that easy.

Thanks for everyone's help so far.

Was hoping a Festool person might chime in with the marketing spin on the Vlies?

 

[teocaf]

[member=20162]Wuffles[/member]
I would forget the RO90 and the Vlies for this particular application. Being that mill scale is basically a baked on oxidation coating that's part of the hot rolled steel mfg process, it's notoriously difficult to remove.  Even the abrasives that work will tend to screw up your steel surface which will eliminate some of your coating or patina options afterwards, unless you're a masochist that enjoys long hot stretches of surface preparation.  I've had good luck preparing small sections for welding using the delta attachment on a fein supercut because that has a very aggressive sanding motion.

For larger areas you need something as nasty as that mill scale.  You need to use muriatic acid and etch that mill scale right off in a very short time.  Very effective, but it is nasty.  You need eye protection so you don't splash it in your eye and go blind.  You need full skin protection to prevent burning your skin.  And you need very good ventilation, to prevent dying.  Spray on or submerge your steel and in about 20 min, depending on the strength, poof, a mill scale-free surface.  Make sure you rinse it off with water and if you're particularly finicky, you can neutralize any residual acid with baking soda in water.  Rinse again and dry.

Then you can go back to Vlies.

You can watch all kinds of videos on the subject on you tube, but please don't take a shortcut with the protection.  And buy cold rolled steel next time.