Got some VuFold external bifold doors in oak veneer and some oak framed windows. After about 2 years the original treatment has started to fail and I need to sand off & re-treat. Bought a Makita quarter sheet palm sander and some 40 Grit red paper but it doesn’t seem to be very efficient in stripping the wood. Am I using the correct tool ?

40 grit sounds very harsh – you only want to take the surface finish off and 40 grit may well scratcht the wood underneath.

pressing too hard can be a problem with electric sanders – all you really want to do is keep the abrasive in contact with the surface, not press down on it.

I’ve often foudn you can do the job quicker on complex shapes like doors by and windows by using a sanding block and doign it by hand.

Try something you can use wet and dry (maybe 120 or 180 grit) if you go down the hand sand route.

wwaswas the wood is pre-treated with a varnish. The 40 grit red isn’t exactly eating away at the wood. Wondering if I should be using 40 grit white

to re-varnish you really only need to take the shine off the existing surface, not remove it back to bare wood, though?

wwaswas. Not re-varnishing. Varnish will not stand up to the elements, particularly UV light. Using Cetol HLS followed by Cetol Filter 7

+1

Hand sanding will give a better finish following the wood grain. 120 grit to get the loose stuff off, 180 to finish. Knock the sand paper against a hard surface will stop it clogging as quickly. I can normally take a painted door back to the wood in 20-30 minutes and get a much better finish than I would if I used a power tool.

If you must use a power tool then the hand is just for holding it in place and direction, the sander does the work so don’t push down on it or stops it vibrating and doing it’s job.

Using Cetol HLS followed by Cetol Filter 7

Just ordered some of that this morning after doing far too much research, good to see it mentioned in a good context.

I also use Osmo Oil which does the trick on hard woods