Abrasive choice for RO90

[pony]

Hello all,
I am new to festool world and this is my first post on this site.
I own the RO 90, I am a diyer and I own an 1880's home that has seen a lot of abuse and bad remodeling over the years.
I am using my festool to strip and sand the stairs and a small landing.
From what I have read here many of you would advise me to buy one of the larger sanders, and believe me I would love to, unfortunately it is not in the budget at this time.
So finally my query...
The stairs have very little finish and or paint remaining, and the RO90 with p40 granat made short work of it-- but now I am trying to deal with the gouges, scratches and nail holes-- I feel as if I need to sand down the bare wood more aggressively -- I am not going for perfectly smooth just an improved surface that I can finish with a nice sealer.
Is there a better abrasive than the granat p40 for aggressive sanding of the wood?
I loved the saphir that came with the delta attachment-- but sadly it is not available int the 90mm.
I looked at the rubin too since is is specifically for bare wood-- but it starts at 50 grit if I am not mistaken.
I realize that I will have to sand thru all the grits to get a smooth finish-- I am just trying to figure out my best options for this first more aggressive sanding.
Sorry to be so long winded [smile]

 

[leakyroof]

First, Welocome to the FOG.  Second, the RO90 is generally highly regarded for stair work of all kinds because treads and risers aren't generally that big, AND they have corners, so the Delta pad gives you that extra sanding ability along with the two other modes of the RO90, rotary and Random Orbit.
Third, HOW BAD are these stair parts. 40grit Granat is pretty aggressive!!!  [big grin] OK, not as much as 24 or 36 grit Saphir, I grant you that.. [blink]
Maybe a picture or two will help others to give you advice.  Without being there, I would Think that 40 grit would get ones rough work done pretty well, and you would fill the nail holes with wood filler[I love Timbermate, chose the right color and it really blends in well with the species you're working with].
If you sand decades of wear away with some even more aggressive paper, you're getting the old treads even thinner.
Maybe you find the balance of filled holes, and decent looking surface/finish when you're done?

 

[Alan m]

welcome to the fog.
i love my ro90  i probably use it more then my ro150.
i the 40g isnt rough enough, you could buy some 150mm saphire adn cut them to suit.
it would be more expensive but you would save on time and on 40g disks.

is the stairs painted or varnished

 

[Deadskins]

What a coincidence, I removed 30 year old carpet on my stairs last night and was just taking a break from removing staples when I read this.  I was planning to spend the afternoon using my RO90 and Granat 80 and 120, fill in the holes and use my recently ordered Surfix heavy duty oil next weekend.  I found some nice oak stairs under the carpet, and just need to tighten them up to fix the squeaks.

 

[Alan m]

its a shame to see a lovely stairs covered in carpet like that.
take a few beore and after shots. we would all love to see

 

[pony]

Thanks for the quick responses. [big grin]
I will try to take some photos over the weekend.
I will re- evaluate my desire for more aggressive sanding-- I may have just been tired and angry at the stairs!!

Alan-- I did have a similar thought about buying the  saphir for the RAS 115 and drilling holes in it!!

Granat 40 took the small amount of old paint and stain (only 1 layer of each) off lickity split-- I am now down to bare wood.
Is there any reason to think rubin will be better for sanding out those gouges and scratches?

BTW anyone know why saphir and cristal are not available in the 90mm disc?

I plan to seal the steps ( maybe with Bona if I can swing it!) how far should I plan to sand 120? 150?
I read that you should not sand to finely...

 

[leakyroof]

Thanks for the quick responses. [big grin]
I will try to take some photos over the weekend.
I will re- evaluate my desire for more aggressive sanding-- I may have just been tired and angry at the stairs!!

Alan-- I did have a similar thought about buying the  saphir for the RAS 115 and drilling holes in it!!

Granat 40 took the small amount of old paint and stain (only 1 layer of each) off lickity split-- I am now down to bare wood.
Is there any reason to think rubin will be better for sanding out those gouges and scratches?

BTW anyone know why saphir and cristal are not available in the 90mm disc?

I plan to seal the steps ( maybe with Bona if I can swing it!) how far should I plan to sand 120? 150?
I read that you should not sand to finely...

BTW anyone know why saphir and cristal are not available in the 90mm disc?-  I've been wondering THAT ever since I bought MY RO90. Very Good Question... [huh] [huh] [huh]
Both Rubin and Granat will handle the bare wood just fine. I haven't seen a huge difference in scratch pattern from the two, but I haven't gone looking for it either when you're comparing the same grit in higher grits than the 40grit you were 'attacking' the stairs with.
If you were staining them, I would not go too high in sanding grit, as it can affect the way the stain is absorbed. Then a film finish on top of that once the stain dries, esp. if you're using a waterbased clear.
If you're oiling them, then higher grits up to 240 or 320 don't seem to be a problem, and Festool themselves  uses these two grit levels for their SurFix oil system.

 

[srzsrz]

Mathias Wandel did a nice write-up (and a youtube video too) about covering old stairs with another layer of hardwood.

http://woodgears.ca/home/stair_treads.html

 

[pony]

Very cool!