Owning a RTS 400, need to sand a 7cm thick oak tabletop; Rotex or ETC EC?

[Gilles]

I know this topic has been discussed quite some time already, but i am a bit hesitant to 'just buy the biggest machine' and return it if it doesn't fit me. I have a RTS 400 which i use to sand in general and i have a CTL-MINI as well.

Regardig the weight of the machines; if i sand, it are mainly flat surfaces or i would be OK to lay the work flat before finishing it. I think it will be rarely that i have to sand a piece of furniture in the vertical way.

I need to sand my oak tabletop which i've bought, and doing it with the RTS 400 is a PITA to be honest. Here are 2 pics of it:
[attachimg=1]
[attachimg=2]

On this side of the table-top it is like taking of max 1 mm of the entire surface, on the other side there is a slight curve, which would mean taking of 3-5 mm in the middle of the slate. I am expecting that this will be my only tabletop i will ever create. The rest of the works i will be doing are either douglass wood, or MDF furnitures or wooden doors etc.

What type of device would you advise for me? I've watched the videos of [member=15022]parfait3[/member] but i am a bit inconclusive

 

[Gilles]

p.s. i've read thehttps://topcoatreview.com/2017/03/which-festool-sander/ and do not plan on using it on EXTERIOR work (or it will be soft wood)...

 

[nvalinski]

No doubt, that's a job for a Rotex. May want to scrub off the high spots with a jack plane real quick too.

 

[Gilles]

RO125 or RO150? (the pads of the 150 fit on the 125, right?)

Reason for asking; the RO125 is lighter; comes with the softest pad so if i'd buy the hard 150 pad for 50 bucks and the 60 grit 150mm pads i could do the coarse sanding with the 150 disc and switch to 125 for fine sanding. Or is that a terrible idea all-together?

 

[sancho57]

Id find a shop that has a wide belt sander, kick them a few quid to run it through a couple of times then use your RTS to finish sand it

 

[Gilles]

Tried that, nobody has a belt sander which is 1m wide :-(

 

[GoingMyWay]

I'm not sure where in the world you're located, but the Woodgrafter recently did a review of the Festool BS75 E Belt Sander:

If it's available, this seems like the perfect tool for leveling off a tabletop with the sanding frame.  I think an RO150 would be a more versatile tool overall though, especially if you think this is the only tabletop you're ever going to make.

 

[Svar]

If you need to take 3-5 mm from an oak slab then forget sander. Use router sled or hand plane.
When removing bulk material choose cutting over abrasion whenever possible.

 

[RussellS]

How I would do it.  Not a recommendation of which tools to buy.  Taking 1-3-5mm of oak off a big flat surface.  1. Scrub plane set to take a small cut.  Only use in the areas you need to take a lot of wood.  2. #5 plane set to take a medium cut.  More for taking out the grooves the scrub plane left and smoothing the top down sort of flat.  3. #7 plane to make the top flat and smooth.  4.  RO150 sander with some 150, 180, 220, 320 grit paper.  Only because I am not a great #7 planer and still need to smooth everything further.

I've also used a Makita 4x24 belt sander with 60 grit paper.  No thanks.  As someone else mentioned, you want to cut the wood off, not grind it off.  Key with handplanes is to use the right one set correctly.  Scrub takes a lot of wood.  #5 set medium deep blade smooths scrub plane grooves.  #7 smooths everything and makes everything flat.  Then a random orbit sander to add more smoothness.

A scrub plane and a #5 might get you to the point of using the random orbit for the final smoothing.  If you don't want a #7.  But really long #7 planes are fun to use.

 

[elfick]

Sounds like one side is flat and the other isn't... how about a router with a planing sled?

 

[rvieceli]

You need to fashion a router sled to flatten that easily. Doesn't have to be fancy on permanent. There are several resources here and on the internet to help you out.

Here's one on the forum but there are others here as well just search "router sled" here and the internet.
https://www.festoolownersgroup.com/...ents/router-planing-sled/msg422040/#msg422040

Ron

 

[KelleyCrafts]

I'm going to have to agree with a few of the others. Sounds like a great job for a router sled and it's cheaper to build than the boxes of abrasives you'll have to buy to do the job, let alone time it would take to sand that thing down vs time to build and use the sled.

 

[nvalinski]

I'll agree with the others a router sled may be something to look into if you don't want to hand plane it. I still think you'll need to finish it up with a Rotex. Personally, I'd go for the 150. Never used the 125, but I've heard it wobbles a bit more because of the smaller pad diameter to keep flat. Also, I've since kicked all of my sanders over to the 150 diameter due to getting more surface area out of the sanding pad and standardizing on one size. There isn't any clear advantage I see of a 125 over a 150 unless it doesn't fit into a certain space, which is rare.

 

[Gilles]

I thought about making it straight with a router actually; think i am going to try that and go for the RO150 anyway to smooth it off. For an oak tabletop which i am going to stain, would grits 60 (for the rough pieces on the side) in Abranet HD followed by Granat 80, 120, 180, 320 be a wise choice in terms of grit steps and sizes?

Also; i assume i need the hard pad (part #202463) and the protection pad (part #203343) as well, right?

 

[Michael Kellough]

You’ve got two kinds of “sides”. The cut ends and the debarked edges.

60 grit and a hard pad would be good to start for the cut ends if you want to keep them square. A soft pad if you want to soften the geometry.

For the natural sides you just want to clean and soften to keep the organic charm.
A sanding mop like this is good.

 

[nickao]

Not sure what you make but I have used my 5" sander one or two times in the last 10 years. People get good with the tools they are accustomed too, I sand very mall parts with my RO 150 and the times I need a smaller sander I go to my RO90, not a 125(I do have).

In short anything I can use a 125 for I can use my 150 for, so why bother with the 5" sanders at all.

I would  get 6"  sanders galore, one less expensive  5" for those rare times and one RO 90.