Which sander to flatten a slab?

[Mark Gibney]

Prashun, yes a belt sander is a great tool for this most times, but it can be slow going. I remember being amazed by the floor edger years back, the speed it cuts at.
Ole - great link. That guy is so good at explaining what he's doing. Don't think I want to risk using an electric planer, not just yet. But I might binge watch that boat building this weekend.
Brice - my vote would be to pay to have it go thru a wide belt sander, but it can be difficult to find someplace. The shop I used to go to upped and moved to Alabama.

Thanks everyone for your input, much appreciated.

[Wayne Lomman]

As a side note, where is your black heart sassafras from? For me it is a local Tasmanian timber which is not tropical at all but a cold rainforest species. Cheers

[Mike Cutler]

Mark

-How big is this slab? If a floor sander would work, it must be fairly large
- How much do you need to take off?

If a belt sander is too slow for you, I would have second thoughts that you'd be happy with any type of a pad sander. A belt sander with the right grit, can remove material fast.
Hand power planer can mess up some wood really, really fast, if you're not careful, and you'll still end up with a sander in your hand.

I know you don't like the router sled, but if you look at the geometry of a router, "bowl bit", there is no hard edge to catch. Used on a light climb cut, it may be a possibility for you. Any sanding solution, other than a machine powered sanding option, is going to be slow and tedious.

[Prashun Patel]

In my experience, there's no fast way to flatten a slab unless you have a super wide jointer and planer.

Even a router sled requires considerable set up and patience.

If you are too far out of flat to want to deal with a belt sander, consider a power hand planer.

[Larry Edgerton]

I use a strait line air board with 40 grit. First I mist the top with spray can lacquer lightly so it does not sink in, then work down the high spots with the straight line. The pads are very hard and will not conform to odd shapes. Next, when I am seeing very little black I move to a random orbit air board with a hard pad starting with 60 grit and moving to 80/100/120 as it gets closer to perfect, then switch to a 6" RO to get to a finishable surface.

The RO air boards are expensive, but a cheap air straight line sander will do the job about as good as an expensive one. Wear gloves, they vibrate a lot. You can go just a bit farther with the straight line and skip the RO airboard.

If it is more than an 1/8-3/16 out I would use a router sled to get it closer.

That will be 2 cents please.

[Mark Gibney]

Wayne, I got the sassafras from a friend who had it for years. Thanks for the info that it is not tropical, I'll read up more about it.

Is it a popular wood to work with in Tasmania?

[lowell holmes]

You might consider hand planing diagonally to flatten the slab and then go from there. Ease the corners of the plane iron to avoid tracks.

After the slab is close to flat, you might finish with a belt and then pad sander.

[Wayne Lomman]

Black heart sassafras is quite popular in Tasmania but not necessarily common. Sassafras is common but black heart only occurs if a particular natural wood fungus is present.

For what it is worth, I would go with the router sled too unless you can find someone with a widebelt sander. Cheers

[John T Barker]

Flatten? As in make flat?

[Tom Bender]

It may be a reasonable task for hand sanding. Make a big sanding block, maybe 4 x 10 and glue the paper to it. A broken sander belt should provide good paper. Give it big handles like a hand plane