Mesh-Backed Sandpaper vs Normal Sandpaper

[cpsmusic]

Hi All,

I'm about to embark on the repair of a rusty steel-frame casement window. I need to strip it back to bare metal so that means removing a lot of paint and rust with my little GMC hand sander.

Over at The Sandpaper Man they sell mesh-backed sandpaper. Just wondering if anyone has any thoughts on this stuff vs normal sandpaper. For what I'm going to do, which would work better?

Cheers,

Chris

[rod1949]

Use an angle grinder with a cupped wire brush... and safety goggles.

[elanjacobs]

...and a mask. A full face shield is probably a good idea too

[cpsmusic]

Use an angle grinder with a cupped wire brush... and safety goggles.

Thanks for the tip! I did a test run with a wire brush in a drill and found that the brush didn't last very long but I'm thinking that it was poor quality.

I think I'll give one of the tool places a call tomorrow and ask what they recommend.

Cheers,

Chris

[havabeer69]

mask the area off and use a compressor and sand blast it off.

for reference the mesh stuff just helps with dust extraction not cutting ability

[qwertyu]

Use this with angle grinder

Access Denied (https://www.3m.com.au/3M/en_AU/p/d/b5005028017/)

The purple 3M one cuts SUPER fast and last a long time. I have tried other ceramic grained versions of these - eg the smith and arrow - and it was no way near as efficient. Wasn't worth the cost saving. In my experience much faster than wire brushes

I would imagine using a meshed sand paper it will destroy the paper. mesh papers are a bit fragile

[GraemeCook]

Chris

The risk with all the above methods is that if you inadvertently touch the glass with the sanding pad or the wire brush then you will irreversibly scratch the glass. This is another way of saying that my hands are not steady enough to use those methods.

Personally, I would try a chemical strip first - a gel type paint stripper - followed by a light sand with a detail sander. It is really important that you get the primer coat on quickly after the final sand, before the next generation of rust starts.

The other option is to use a tungsten scraper. This should be quite fast on the flat areas, but a little fiddly on the edges. Tungsten is harder than glass so you would have to be really careful not to scratch the glass.

[cpsmusic]

Use this with angle grinder

Access Denied (https://www.3m.com.au/3M/en_AU/p/d/b5005028017/)

The purple 3M one cuts SUPER fast and last a long time. I have tried other ceramic grained versions of these - eg the smith and arrow - and it was no way near as efficient. Wasn't worth the cost saving. In my experience much faster than wire brushes

I would imagine using a meshed sand paper it will destroy the paper. mesh papers are a bit fragile

Many thanks! Never seen these but they look like exactly what I'm after.

Cheers!

[cpsmusic]

Chris

The risk with all the above methods is that if you inadvertently touch the glass with the sanding pad or the wire brush then you will irreversibly scratch the glass. This is another way of saying that my hands are not steady enough to use those methods.

Personally, I would try a chemical strip first - a gel type paint stripper - followed by a light sand with a detail sander. It is really important that you get the primer coat on quickly after the final sand, before the next generation of rust starts.

I'm going to remove the glass as the rust is in behind it.

[GraemeCook]

I'm going to remove the glass as the rust is in behind it.

Well, in that case, you can add a heat gun to your list of options.

[cpsmusic]

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[cpsmusic]

Use this with angle grinder

Access Denied (https://www.3m.com.au/3M/en_AU/p/d/b5005028017/)

The purple 3M one cuts SUPER fast and last a long time. I have tried other ceramic grained versions of these - eg the smith and arrow - and it was no way near as efficient. Wasn't worth the cost saving. In my experience much faster than wire brushes

I would imagine using a meshed sand paper it will destroy the paper. mesh papers are a bit fragile

Any idea what the difference is between the purple one and the green one?

[qwertyu]

I dont, I would assume the green would be less abrasive. Do you have a link?

[cpsmusic]

I dont, I would assume the green would be less abrasive. Do you have a link?

I think that the green ones have aluminium oxide abrasive whereas the purple ones have silicon carbide.

[cpsmusic]

Use this with angle grinder

Access Denied (https://www.3m.com.au/3M/en_AU/p/d/b5005028017/)

The purple 3M one cuts SUPER fast and last a long time. I have tried other ceramic grained versions of these - eg the smith and arrow - and it was no way near as efficient. Wasn't worth the cost saving. In my experience much faster than wire brushes

I would imagine using a meshed sand paper it will destroy the paper. mesh papers are a bit fragile

If I get a few of the 3M Clean & Strip discs, any recommendations as to the size - they make a million different ones and they seem to be hard to get so I'll have to order them :~

Also, I don't own a grinder so I'm planning on getting a small one for the job - probably a BOSCH 750W 100mm Angle Grinder GWS750100. If I get one of these it will limit the disc size to 100mm (?) - any problem with that?

[aldav]

Looking at those pictures I'd be chucking the window and installing an aluminium one. 125mm angle grinders are much more useful than 100mm ones, but I guess if this is the only thing you'll ever use it for it doesn't really matter.

[cpsmusic]

Looking at those pictures I'd be chucking the window and installing an aluminium one. 125mm angle grinders are much more useful than 100mm ones, but I guess if this is the only thing you'll ever use it for it doesn't really matter.

I've looked into all of the alternatives. Getting the window replaced was going to cost around 4 grand which for a small bathroom window seemed too much! I also looked into getting the window repaired however I couldn't find anyone who would do it. The only person interested would only do the whole block (12 apartments). I also looked at getting the window sandblasted however the job was too small for them too.

[qwertyu]

Is there a sydney tool or blackwoods near you? Ive bought them off the shelf from them. Might only need 1

Ive only ever used 125mm grinders, I suppose the usable area of 100mm grinder is a lot less.

I have a $30 grinder I got at Masters many years ago. I dont use grinders much and usually reach for the cordless one now but that $30 was well spent. For a tool I hardly use it was great value and when using these paint and strip or flap discs etc I put close to my entire body weight on it sometimes and it never missed a beat. Grinders are fairly simple tools and I presume what you pay for most in more expensive ones are ergonomics, maybe more compact motor, less vibration, more quiet but I reckon for some occasional DIY it could be ok?

I see bunnings has a cheap 125mm grinder
Just a moment... (https://www.bunnings.com.au/products/tools/power-tools/grinders?sort=PriceAscending&page=1)

seems to have good rating? Might be worth it?

But for this type of thing or sanding discs on grinders, Im pretty sure you can put a 125mm disc on a 100mm grinder. Not that Im advocating for it

[droog]

Im pretty sure you can put a 125mm disc on a 100mm grinder. Not that Im advocating for it

Check the arbour size first.
A lot of 100mm grinders use 16mm arbour while 125mm use 22.23mm, there may be exceptions out there.

There are also 115mm discs with same bore as 125mm

[cpsmusic]

I'm thinking a 125mm grinder would be a better investment as the 125mm discs seem a lot easier to get. I thought they'd be a lot more expensive that the 100mm but they only seem to be marginally more expensive.

[Gary H]

For fifty bucks you can get an Ozito 125mm grinder from Bunnies with a 3 year warranty, so you should be finished the job before the warranty runs out :D

[GraemeCook]

I am still concerned that an angle grinder is too agressive for this job, especially in inexperienced hands. Accidentally touch the glass and the abrasive will mark the glass, probably irrecoverably.

In my view, the flat areas of the frames might be doable with very high care. Problem areas are"

External corners outside the arc of the grinding disk,
Edges of the steel window frames that butt against the glass,
Especially the internal corners due to the grinder arc, and
Anywhere where your attention wanders for a second.

I have notated the problem areas in red.

527405

[cpsmusic]

I am still concerned that an angle grinder is too agressive for this job, especially in inexperienced hands. Accidentally touch the glass and the abrasive will mark the glass, probably irrecoverably.

In my view, the flat areas of the frames might be doable with very high care. Problem areas are"

External corners outside the arc of the grinding disk,
Edges of the steel window frames that butt against the glass,
Especially the internal corners due to the grinder arc, and
Anywhere where your attention wanders for a second.

I have notated the problem areas in red.

527405

The glass is coming out as there's areas of rust in behind it.

[GraemeCook]

The glass is coming out as there's areas of rust in behind it.

That will make it a lot easier.

That will leave only the external corners - Is it feasible to remove the steel sashes?

[cpsmusic]

That will make it a lot easier.

That will leave only the external corners - Is it feasible to remove the steel sashes?

Haven't had a close look but from what I can see they're held in with large rivet-like pins top and bottom so I don't think so. I will check this though because if the sash can come out it will be easier.