Painting sash window nightmare

[Toby Newell]

For paint stripping on my bargeboards I used a Norton Rapid stripping wheel in an angle grinder for the first time last year. With the sashes out definitely the way to go - brilliant tool, but don't put it anywhere near any glass!
https://www.wickes.co.uk/Norton-Rap...g-Disc-for-Paint-and-Varnish---115mm/p/253224

not really great for wood, a bit aggressive! 3M do the best discs. Designed for metal originally. Make sure you wear a mask.

EDIT.

To qualify, they may be great for wood, for stripping thick coatings but they will brush the grain to some extent leaving waves in softwood like pine and opening the pores in hardwood like oak. This may not be that noticeable outside on a roof timber and even inside the look may be desirable, but it is a feature of how they work.

 

[Stevers]

not really great for wood, a bit aggressive! 3M do the best discs. Designed for metal originally. Make sure you wear a mask.

'Aggressive' and 'effective' are two cheeks of the same 'arris' so to speak. Norton state that these are intended to remove wood and paint from wood, and used with care the disk left a lovely smooth finish on my bargeboards, but did create a lot of dust, so yes definitely mask up.

Of course if this is proper old paint then a hot air gun will work wonders on all the corners, but this can be bad for any original glass - don't ask me how I know. :-(

 

[Toby Newell]

Aggressive' and 'effective' are two cheeks of the same 'arris' so to speak

interesting language... born in the East end but never heard that one. I disagree on semantics. 'Aggressive' is normally a pejorative term meaning 'overly coarse or unsophisticated' effective is quite the opposite.

One would expect an effective system to be much less aggressive and more efficient, you would normally call it powerful.

Flap, fibre and mesh discs can be very effective, on open flat surfaces, but can damage some woods and melt some old paints. You will leave ripples, open grain and give a brushed effect which may not be noticeable and you won't be able to do closed corners. On metal they just leave a fine scratch pattern which is good as a key.

Probably ok for barge boards though.

 

[Toby Newell]

Of course if this is proper old paint then a hot air gun will work wonders on all the corners, but this can be bad for any original glass - don't ask me how I know. :-(

again, ok for outside, especially when used with a carbide or cabinet scraper (not cheap shavehook!) but probably not best for indoor work. You know, lead vapour and all that, I'm not one for 'everything is carcinogenic hold your breath and hide behind the sofa' but lead fumes are pretty bad. Mostly because they badly affect juvenile brains and are accumulative toxins. I mean all of us brought up in the 60s and 70s are several IQ points thicker (QED) than our children thanks to leaded petrol fumes, so the effect of paint isn't chronic at least. But bad enough for the EU to be pondering a ban on burning off lead paint indoors.

 

[Stevers]

Manufacturers blurb:
"The Norton Rapid Strip Angle Grinder disc is for fast and easy removal of paint and varnish on coated wood. Made from nylon fibre impregnated with aluminium oxide abrasive grains, giving powerful performance, whilst still respecting hard wood profiles. Max RPM 12,000"

It took me just a couple of hours to remove the failed paint on my bargeboards, the disk left the surface silky smooth, and was pretty good at getting into internal angles - though not closed corners obviously. I used one disk, and that still has some life left in it.

So, Toby, are you speaking from experience of this exact product, or in general about the many sorts of disk intended for metal that I would completely agree are unsuitable for wood?

 

[Toby Newell]

Manufacturers blurb:
"The Norton Rapid Strip Angle Grinder disc is for fast and easy removal of paint and varnish on coated wood. Made from nylon fibre impregnated with aluminium oxide abrasive grains, giving powerful performance, whilst still respecting hard wood profiles. Max RPM 12,000"

It took me just a couple of hours to remove the failed paint on my bargeboards, the disk left the surface silky smooth, and was pretty good at getting into internal angles - though not closed corners obviously. I used one disk, and that still has some life left in it.

So, Toby, are you speaking from experience of this exact product, or in general about the many sorts of disk intended for metal that I would completely agree are unsuitable for wood?

I am speaking from 37 years of experience and study. Yes, your wood may be silky smooth, it will also be slightly wavy with a brushed effect, you may not notice it outside and it may be fine, but you would notice it, especially on softwood, on a horizontal surface. I know what it is! It's a non woven bonded abrasive disc developed by 3M (who developed non woven abrasives called 'Scotchbrite') They are exactly the same as the metal discs except with less aggresive abrasives.

Actually it is irrelevant who makes the disc or what abrasive it is coated with, the physics are that if you apply a three dimensional spinny abrasive thing to wood it will create differential sanding, especially on softwoods to a lesser or greater extent. That goes for non woven, flap discs, star discs and wire brush discs.

As I said, these discs are very effective and brilliant on metal but they can leave artefacts on wood, that is the nature of the physics.

Brushing machines specifically made for this purpose use both wire brushes and non woven type abrasives.

If you want to be pedantic then ANY abrasive will cause this affect, even flat sanding, or sometimes years of walking! But because of the 3D spinny nature the non woven material can squish down around the harder latewood 'hills' and into the softer earlywood 'valleys'.

No I have not used those exact Norton discs but yes I have used tens of thousands of abrasive pieces, including wire, non woven, flap and star discs over nearly 40 years, so I don't need to.

I am not poo pooing your recommendation, I am seconding it, these newer non woven discs are excellent at thick paint removal.

I am simply providing an addendum for people scanning the threads who are thinking of using this indoors on surfaces closer to eye level.

 

[Toby Newell]

and FYI non woven discs have been used for this purpose for decades most notably by 3M (look up 'Roloc') I actually have 150 Roloc discs at the end of my sofa...

Over the last few years Norton has moved into the UK consumer market using aggressive marketing touting to be the best, very American, but a bit QVC like.

They do make some great products, you can buy Norton ceramic discs and wet and dry abrasives at B&Q and they are great. I even use their ceramic A975 discs (not available at B&Q!) in P80 and P120.

It's funny, because a particular new version of these discs using ceramic abrasives are taking over the metal restoration, painting and fabrication industries because they are now more powerful than the traditional flap wheels and solid discs but gentler on the surface. It's not that the idea is new, it's the use of improved ceramic abrasives and bonders. Funny because Norton is touting the older technology metal discs for wood, good on them.

The fact is companies like Sia and 3M sell mostly to business so you don't see them. There is nothing wrong with any of these products, but you might find professionals have been using them for many years and already know their strengths and weaknesses.

If the Nortons ever let you down it's good to know there are hundreds of even more powerful versions available from Norton and 3M just search 'ceramic non woven disc'.

 

[Sarah dobe]

I’ve seen this happen if you fill over filler that hasn’t been sanded , especially two pack , then someone skims over with filler to get a smooth finish water gets behind it and blows in places ..
I’ve used dulux weather shield gloss and not had a problem yet
Also they could have got / added public liability insurance that covered them for hot works