Summary of recommendations regarding abrasive discs for the RAS 115 and 180

[Danie]

The following recommendations by current owners could help new owners to choose the correct abrasive discs for their specific applications.  I have extracted them from this forum by using RAS and Saphir as keywords in the search function, therefore, this post does not claim to be inclusive. I would appreciate more contributions.

“When I'm scribing crown moulding or hardwoods I'll use 80 or 100 grit because the 24 and 36 grit is big and leaves a rough edge.”

“When I used the RAS and 80 grit Rubin, since I haven't ordered any Saphir and such, it took the paint off fast and still left the Rubin fairly clean.”

“I use my RAS up to 80 grit Rubin for exterior preparation.”

“I am not an expert here, but I have seen posts on this forum stating that the RAS removes material VERY quickly, and using paper below 80 is just too aggressive.”

“On average, I'd say, start cautiously with Saphir 50 and if that doesn't work you can decide to go to a lower or higher grit, depending on what you want. For most jobs related to paint removal, 50 grit will work fine. If you want to shape wood, you can go even lower. If you think you need a higher grit for less agressive sanding, get 80, but if you think you need to go even higher, get another sander like the Rotex or the ETS 150.”

“Saphir 50 is faster than Rubin 40, but it will leave a rougher surface which needs to be sanded further to smoothen it. I mostly use Saphir 50 or 80 with the RAS but always sand after it with the Rotex 150 in random orbit mode using 80 and/or 120.”

“I have a customer that is stripping a house using a RAS and Saphir. He seems quite happy. So happy, in fact, that he has bought more Saphir... He's been using 36 & 50. My understanding is that he's also following up with the ETS 150 using 60 & 80 Granat.”

“A big problem with grits below 60 is they scratch the underlaying wood more, and you'll have to do more sanding with a higher grit to remove those scratches again.”

“I prefer to not go lower than 60 grit, but if I must, I use Saphir 50 on the Rotex 150 or RAS 115.”

"Saphir 50 scratches a bit less than 40 grit paper, and because the paper is so tough, it removes paint faster than Granat/Brilliant/Crystal of equivalent or lower grits, and it lasts WAY longer. A Saphir disk costs double the price of a Granat disk, but can last between 10 and 20 times longer. It also doesn't clog very fast.”

“I know many do not like Rubin but I have found it to be great on bare wood  at 100 - 150 gr.”

“Using Saphir P80 abrasives, it took me about 5 minutes to clean up each of about 100 fence boards.”

“One note when sculpting, because the RAS is so aggressive in any grit, I find it helpful to switch over to the 100 grit rubin for the final touches (before I move to a normal sander), you can still get pretty good stock removal with that grit, but it will leave the surface fairly smooth so you can move over to using 80 or 100 grit sandpaper right away with the normal sander.”

“Also be careful with that 24 and 36 Saphire it can really tear up wood.”

“Using my ras with 24g on red cedar left a smooth surface ready for paint! I'm not joking.”

“I do this nearly every day. When I sand a preexisting floor finish I start lower, using 36 grit, even 24 grit.”

“I must clarify I use Saphir in my shop almost exclusivity. The Saphir still gums, but not nearly as bad. I use it to clear finishes off flooring all the time.”

 

[leakyroof]

A more concise set of sentences could tie all those comments together as a true guide for choosing the abrasives.  Right now, you've got many sections of posts from here on FOG that seem more like random thoughts than an easy-to-follow abrasive guide.  I'll give it a try......
 
Saphir- Very coarse Grits below 80 grit will remove material very quickly in many cases, but allow rough scratches on your material due to that coarse grit. This may require further sanding in higher grits of Saphir or other Festool Abrasive to remove those scratches. Also, users experience less clogging of grits below 50, so if that is if primary importance for your task, it could outweigh other considerations.
What do you think?

 

[Danie]

Thank you for moving the ball forward! I chose to start with the raw data, hoping that experienced owners would be encouraged to share their wisdom.

As far as I can see, new users could start by purchasing Saphir P50 and Rubin 2 P80. It seems that Saphir P50 is quite able to remove paint without clogging too fast. Once the paint or stain has been removed, Rubin P80 could then be applied to remove the scratches and rough edges caused by the Saphir P50.

If one’s budget allows purchasing 4 packets, I would consider the following:
Saphir P50 as a general starter option
Saphir P80 as a starter when removing lighter finishes from hard woods
Rubin 2 P80 to smooth the scratches caused by the Saphir grits.
Rubin 2 P100 or P120 to smoothen bare wood.

I would consider Saphir P24 and Saphir P36 only when working with wood flooring that is covered with thick finishes or shows some severe edges and scratches. These two rough ones would also be a good option when sanding log ends.

I do realize that my conclusions are based on inductive reasoning and not on any experience, and I would, therefore, appreciate the input form experienced users.

 

[AlexThePalex]

Saphir P50 as a general starter option
Saphir P80 as a starter when removing lighter finishes from hard woods
Rubin 2 P80 to smooth the scratches caused by the Saphir grits.
Rubin 2 P100 or P120 to smoothen bare wood.

I think this sums it up pretty good if you only have a RAS available. But since there's only two kinds of papers in the lower grits available for the RAS anyway, it's not that hard to figure out.

I own the RAS 115 and the Rotex 150, and I tend to stick to Saphir 50 only on the RAS, and then progress to Granat 80 on the Rotex. I think the RAS is best for rough removal only, and clean up be done with a proper sander. 

 

[Cheese]

I used the RAS today on a neighbor's picnic table that she wants to refinish. After removing the 1/16" thick painted finish, I concluded that the top is composed of a combination of 2" x 6" cedar, fir and treated boards. I was really impressed with the Saphir paper, it lasts forever. The table top was 3' x 6' and after the paint was removed, the Saphir disc still looked new.  I used 36 grit on the surface and as long as you use a gentle touch, the paint is easily removed without much abrasion to the surface.

After the 36 Saphir, I used a ETS EC 125/150 loaded with 40 Granat. Then 80 Granat and finally 180 Granat. It's now ready for primer & paint.  [smile]

Another interesting aspect with the RAS is that its relatively slow disc speed compared to a RA grinder (4000 rpm vs 11000 rpm) is that when used to grind down small amounts of construction adhesive, the lower speed doesn't melt the adhesive and spread it across the disc. So after removing 1/16" of paint, sanding wood and removing construction adhesive, the Saphir disc still looks new.

Thanks [member=5277]Alex[/member]  for the heads up.  [smile]

 

[Mike Goetzke]

I have a couple projects that the RAS would speed up so I bought one.

On abrasives - thanks for this post. Like the other sanders, wish Festool offered smaller quantity packs of abrasives then I could have a bigger variety to choose from.

I have seen several users buy the Fiberfix pad and purchase non-Festool abrasive discs for this sander. Is this a better solution for a weekend warrior? Or do the Saphir and Rubin papers last much longer?

Thanks
Mike

 

[Alanbach]

[member=4518]Mike Goetzke[/member] - I also just purchased a RAS and have been watching videos and reading up. I also saw that many purchase the fiberfix pad and use third party abrasives. I saw a particularly interesting video where a paint contractor that works on old homes said that he uses that setup to avoid the problem that the RAS has with melting the stick fix pads in heavy duty paint removal situations. Apparently Festool does not make sanding discs for the 4 1/2” fiberfix pad so the only choice is other brands. I have read that the Saphir lasts forever and excels where there is paint or other film finishes to remove, not as great for raw wood. I have used Rubin 2 before with my Rotex and it also lasts really well and it is better on raw wood as it will definitely clog up with paint and other films. I find Rubin interesting as it kind of has two distinct personalities. One, right at first, very aggressive and effective, then the second personality is not as aggressive but still works great and then kind of lasts forever. The Rubin is more for raw wood and cleaning up the raw wood after the Saphir might have left some deeper scratches.

I bought a box of Saphir 50 grit and I will probably buy some Rubin in 80 as my initial purchase (as suggested in this thread).

 

[Michael Kellough]

[member=4518]Mike Goetzke[/member] - I also just purchased a RAS and have been watching videos and reading up. I also saw that many purchase the fiberfix pad and use third party abrasives. I saw a particularly interesting video where a paint contractor that works on old homes said that he uses that setup to avoid the problem that the RAS has with melting the stick fix pads in heavy duty paint removal situations. Apparently Festool does not make sanding discs for the 4 1/2” fiberfix pad so the only choice is other brands. I have read that the Saphir lasts forever and excels where there is paint or other film finishes to remove, not as great for raw wood. I have used Rubin 2 before with my Rotex and it also lasts really well and it is better on raw wood as it will definitely clog up with paint and other films. I find Rubin interesting as it kind of has two distinct personalities. One, right at first, very aggressive and effective, then the second personality is not as aggressive but still works great and then kind of lasts forever. The Rubin is more for raw wood and cleaning up the raw wood after the Saphir might have left some deeper scratches.

I bought a box of Saphir 50 grit and I will probably buy some Rubin in 80 as my initial purchase (as suggested in this thread).

This is characteristic of aluminum oxide. AO is very sharp but friable. It will cut very aggressively when new and as the sharp mountain tops break off it’s abrasiveness subsides making it equivalent to a finer abrasive. If the scale of the project is right (a medium sized table top) you could use one disk of 80 grit right through to first coat of finish. It does take longer to “sand” using the progressively more worn disk but it avoids the initial very aggressive stage of a fresh disk at a nominally finer grit.

It bugs me when experts say to move the sander at a slow steady rate without mentioning that the area you first apply the new disk to will be abraded much more than the area two feet farther along. I think when switching to a new disk (especially if AO) the tall sharp mountain tops should be sheared off by wiping the loose disk over the edge of a board, or, you should move the sander rapidly over the entire work surface to evenly distribute the deeper scratches resulting from a fresh abrasive. Then switch to slow and steady.

 

[Cheese]

Here's the 36 grit Saphir disc after removing 1/16" thick paint/stain/whatever from a 3' x 6' table top. On the same project it also was exposed to bare wood, a half-dozen screws hidden from view and cured construction adhesive.

[attachimg=1]

 

[AlexThePalex]

I have seen several users buy the Fiberfix pad and purchase non-Festool abrasive discs for this sander. Is this a better solution for a weekend warrior? Or do the Saphir and Rubin papers last much longer?

Fiberfix pads are more durable than Saphir and Rubin. Saphir is more or less a fiberfix pad, adapted for a hook and loop pad. I don't think Rubin is durable at all, on the contrary, I find it wears out very quickly. When the sharp tops are gone, it is useless to me. But maybe I'm, just too impatient.

I am not that fond of using a fiberfix pad, you can only use an area on the edge and the spindle in the middle leaves for too much unuseable real estate. I much prefer the full RAS discs, Saphir.

I don't understand why Alanbach would say the RAS is not good with wood, lots of people here use it for scribing as it hogs away wood easily. And when removing paint, you always have to take care to make the angle of the sander not too steep or it's easy to bite into the wood.

 

[Cheese]

I am not that fond of using a fiberfix pad, you can only use an area on the edge and the spindle in the middle leaves for too much unuseable real estate. I much prefer the full RAS discs, Saphir.

I agree...I've used the fiberfix style pad on Milwaukee grinders and because of the central hold down nut, you're forced to hold the tool at an angle. When doing that it's much easier to cup the material you're sanding/grinding.

I prefer to keep the full face of the sanding disc in contact with the material to produce a non-cupped surface.

I purchased the fiberfix pad for the RAS because that's what I've been used to using. However, I now doubt I will use it much because the full face method produces a flatter surface. 

 

[Mike Goetzke]

This is great feedback from experienced users!

One more question - is the hard backing pad a good addition or do you just use the standard soft pad?

Thanks

 

[Cheese]

This is great feedback from experienced users!

One more question - is the hard backing pad a good addition or do you just use the standard soft pad?

If this was directed to me Mike, I swap out the soft pads and use hard pads on all of my sanders including the RAS.

 

[Alanbach]

[member=5277]Alex[/member] - I don’t think that I said that at all. I did say that Rubin 2 is better for raw wood than Saphir and Saphir is better when removing film coatings. I did reference using Rubin previously on my Rotex on raw wood.

To the contrary, the main reason that I bought the RAS was to scribe cabinetry and to shape raw wood.

 

[AlexThePalex]

My apologies [member=66185]Alanbach[/member], I misread that, you're right.

 

[ScotF]

I prefer the soft pad for sculpting and shaping wood,  especially concave parts. The hard pad is best for scrubbing and convex or flat parts in my opinion. A light touch is best to avoid burning the pad. It is amazing how quickly this machine removes material. It is too bad thursd one is going away. Another lost gem.