I will be picking up a vintage wooden (ply) kayak to renovate for my g/friends Christmas this weekend.

Naturally, this means I will need to buy new power tools.

First on the list is a new sander, I have a wee detail sander but will need something bigger and beefier for removing large swathes of old varnish from thin plywood.

What would you recommend?

Festool Rotek, not cheap, but superb piece of machinery…

How did I know that was coming!
I’ve the ro150 and yes it’s a superb sander. The mirka sanders are pretty good too but are in a similar price bracket.
Whatever you buy I’d go for a round orbital sander and buy decent sheets for it.

Festool Rotek + Festool Cleantek = zero dust from sanding, don’t even bother with a mask it’s so good.

[url=https://flic.kr/p/oj7XQr]Festool Rotek 125 Sander[/url] by Ben Freeman, on Flickr

I have one of these.
Tremendous bit of kit. Easy to control, powerful, reliable.

https://www.hilti.co.uk/cutting%2c-sawing-and-grinding/sawing-and-sanding/sanders/r2085

No idea what they cost these days though. Hilti are a bit crap about from whom you can buy their stuff.
Doh. £255 direct from them.

Festool stuff is great but you get into a lot of expense beyond the initial purchase price as they only take festool’s own discs – which are good value but expensive and not widely available.

For flexibility and the most capacity out of one tool theres a 150mm random orbit sander that in various disguises is sold by Maffel, AEG and Metabo. In fact they’re they’re all made in the same factory to differing specs and come at different price points but the core mechanism inside is the same which means….

They’re switchable between an 2mm and a 6mm orbit. the 2mm is ideal for fine sanding and the 6mm is a bigger orbit than anyone else makes and is good for rapid removal of material. I use it as a carving a shaping tool.

The maffel is too expensive and hard to find. The metabo is easiest to find and is about £150, the AEG is cheaper but harder to find. I’ve had both the AEG and the Metabo – the latter is easier to hook up to a dust extractor the AEG required a bit of bodging with random bits of plastic pipe off-cut to get a good connection. The disks are standard across lots of models so theres a wide range of options available and easy to buy locally if you don’t have a handy Festool dealership.

Nitromors.

Won’t shifting all that varnish by sanding it off just clog the machine and cover everything with dust? I’d be inclined to get it off with a stripper, then worry about tidying up afterwards.

As for sanders, I’ve always gone for the cheap ones and considered them disposable – am I missing a trick?

am I missing a trick?

You’re getting sanders clogged up and getting dust everywhere… so yes 🙂

price as they only take festool’s own discs – which are good value but expensive and not widely available.

I buy all my Festool consumables from FFX, who are pretty cheap and have free next day delivery….

Won’t shifting all that varnish by sanding it off just clog the machine and cover everything with dust?

Use a medium grit paper like 150 and it should come off without clogging up the paper. Lower grit papers do clog up badly eg 60g on my kitchen floor was a PITA, 150g pretty easy. Wasted a few hours finding out though…

That’s useful, thanks.

Would a belt sander be OTT for thin plywood?

probably aye- – they’re pretty aggressive – more a tool for shaping than finishing

Festool, Mirka and Mafell for (presumably,sorry) someone who isn’t in the trade for getting skanky varnish off an old boat? 😀

We’ve just got a Mirka Deros at work. Beautiful and light machine, excellent dust extraction. Would I take it anywhere near a ropey old kayak? Would I eck! 😀

For that sort of work I’d get a cheap thing from screwfix or somewhere. I don’t think you’re going to be bothered by the intricacies of orbit size etc while you grind away at the flaky remnants of yacht varnish..

Festool indeed… 😉
#STW

For that sort of work I’d get a cheap thing from screwfix or somewhere.

Theres plenty of cheaper options. The only reason I don’t use them though is the manufacturers seem to make it deliberatly impossible to attach propper dust extraction. If you don’t have the means to deal with dust anyway then that doesn’t really matter but if you do then its a shame not to have the option. The little attached bag things are pretty useless no matter how fancy and hi tech the styling of them. They catch something but the finest and nastiest dust just gets thrown in the air.

There was a 125mm Ryobi sander that was cheap and had a proper circular dust port….. but I didn’t suggest it because I thought it was no longer available…. but seemingly theres a handful still here:

here

They do a pretty good job for finishing and smoothing and disks are cheap. Not really up to shaping much though. They last a fair while but the orbit mechanism does give out after a while.

Would a belt sander be OTT for thin plywood?

Yes, A belt sander will have a flat base so won’t be very effective (or too effective!) on the canoe’s curves. Good ones are heavy and you’ll be knackered in no time.
I assume orbitals will have a soft base that will mould to any curves, within reason.

You could try a cabinet scraper to remove the initial layers of varnish. It’ll save a lot of work, and expensive sheets.

cordless makita lxt orbital, takes standard discs .

If its varnish use a hot air gun and a proper scraper to get the varnish of and then go over with a random orbit sander. Makita do a 125mm for around £80-90 which is pretty reasonable and easy to connect to vac/extrac.

Best disc’s I’ve found are the bosch ones and they are cheap in boxes of 50 though to be honest you’ll only use a handful for a kayak.

Be prepared for a bit of trail and error to find the best method in case its not actually varnish on the boat, yacht varnish comes of very easily with heat hence the problem with going straight in with a sander as it starts to melt a bit.

the manufacturers seem to make it deliberatly impossible to attach propper dust extraction. If you don’t have the means to deal with dust anyway then that doesn’t really matter but if you do then its a shame not to have the option. The little attached bag things are pretty useless no matter how fancy and hi tech the styling of them

Very true. Definitely look to connect a vacuum. Dust extraction improves a lot with Mirka Abranet discs, but I find them a bit delicate if you accidentally catch an edge, plus if used too aggressively/cack-handedly I find the Velcro hooks can actually melt. At least, that that’s what my students seem to do.

On any orbital sander for ‘rough work’ I’d suggest buying some ‘interface pads’ which protect the original hook and loop attachment. You can get thicker spongy ones too for curved surfaces.

Sanding is completely the wrong tool.
cabinet scraper is what you want. Cost about £5, learn to sharpen it and you’ll have the varnish off ten times quicker.

If you get a sander powerful enough to take off the varnish it will tear into the plywood in the blink of an eye then you’ll spend hours tidying that up. One thing I’ve learned in woodworking over the years is sanding is for dummies.

And applologies, I know that “your entire question is wrong, don’t do that” posts are quite useless when they don’t explain the “right” way to do it . It’s well worth everyone learning about the lost art of scraping and planing though, often works much better.

Cabinet scraper as has been said. Maybe nitromors too.

A random orbital sander is what you want, but to buck the trend, I have a ryobi 125mm one that cost 30quid, it’s one of the main tools I use in my business and it’s done three years and still OK.

I will buy a Makita one next though.

P.s get the sanding discs from toolstation online.

Pps use foam gloss rollers to re-varnish, lots of tack cloth pre varnish coats, and a good dollop of white spirit to thin the varnish. Do not varnish in damp conditions.

I have used the scraper & plane method before but in my experience it works best on hard wood but scores plywood very easily. As

I’m expecting the kayak to be circa 4mm ply at best and I want a bright finish, so would prefer the gentler sander method. That said, I may try the heat gun method – never used one before but fond memories as a lad my dad using one to strip paint of old Victorian doors…

I won’t be having the Luxury of dust extraction so it sounds a comparatively basic sander will do.

I won’t be having the Luxury of dust extraction so it sounds a comparatively basic sander will do

You can just use a vacuum cleaner eg Henry etc….

Really makes a huge difference, sanding almost becomes pleasant with one.

Fair enough on choosing sanding. As for dust extraction, can thoroughly recommend the <£50 wet/dry vacs screwfix do should you decide to try dust extraction.