Very tough sanding disc

[dave7108]

I have a 150mm dual action sander. I need to strip yacht varnish off a smooth decking board (there are no grooves) 5m x 3m6m so a fair bit. What's the roughest quickest disc I can buy that would strip it back to bare wood. I'm thinking that even if it's stripped quite rough it would be quicker to do that then quickly rub a 120 or 180 grit over it to smooth it over. One alternative is a planer but there are the odd screws heads.Is a floor edging sander any good? These use 24 grit. A full sized floor sander (hired) is probably over the top but not out the question.

[Chris Stott]

I would think you might struggle to get such a large expanse of wood flat if you sand it like that.

Why not use a chemical stripper?

[CSR Performance]

I've been using these strip/poly discs for a number of jobs recently, they maybe too abrasive for your needs, but they are very effective.

https://www.amazon.co.uk/Elsjoy-Stripping-Grinder-...

[Collectingbrass]

Any sander needs the screw heads driving down, so that's job one. I think you would regret your life choices if you didn't hire a floor sander for this job, and save the one you already have for the detail elements.

[guitarcarfanatic]

Festool Saphir - it's about 5 x as tough as a normal pad. It also comes in P24 if you want to make really good progress (especially when paired with a gear driven sander like the Rotex / others).

[shtu]

Floor sander is the only sensible option for an area that size, it'll take forever with a handheld sander of any sort.

It's not just the abrasive roughness, it's the size of the abrasive surface and the pressure that can be applied. Floor sander (massive, heavy belt sander) wins.

Watch this, then ask yourself how many hours it would take crawling around on your knees with a 6" DA, https://www.youtube.com/watch?v=3b1NXA5-zTE

[Simpo Two]

I would use stripper and a scraper. The rougher the sanding disc you use the deeper the scratches will be - just so you can spend even more time sanding them out...

[Plus4Four#]

Check the decking for protruding fixings. Screw/hammer/ push flat/below surface.
Hire a floor sander as it's basically a floor. Use a hand sander for awkward spots.
The floor sander will use suitable grades of abrasive so rough sand, then finer to finish.
The dust will be horrendous! I did floorboards in a room with one. All nails checked and punched down if needed. Full PPE needed plus regular breaks and even sealing doors etc wasn't 100%. Some dust escapes. Hand sander to finish edges.

[OutInTheShed]

Yacht varnish covers a whole range of products, most of which have no place on a yacht.

A lot of it is prone to gumming up sandpaper.

You may find it's easily removed with a carbide scraper, either with or without a hot air gun.

Floor sander may bend the board and give a bad result or take off a lot of wood, easy to lose the face of ply.
Some varnish resists sanding better than the wood does.