Moh's hardness test on window!!!

[Paul_B]

Nothing to do with bushcraft but I wonder if anyone has ideas.

Our son has inherited my interest in geology (I got it from my dad). He's also inherited his mother's lack of care for things. Result was he thought nothing of carrying out the test for quartz on one of our expensive AAA+8 energy efficiency double glazed windows. Cue a 3 inch long scratch in the middle of a large glazed panel.

I was wondering if there's anything that could be done to hide the scratch? I know cracks on car windscreens is different but I just thought I would ask the question. There's enough very practical and inventive people on here so it's always possible someone knows a solution. It's just that my partner told me about it and having seen it I will obsess about it. It'll annoy me now.

Appreciate any ideas and your time to actually read this query.

 

[Toddy]

Speak to @Graham_S

Years ago he bought and split up and sold among a group of us, the fine sandpapers used to take scratches out of the cockpit windscreens for Harrier Jump Jets and the like.
They went down in grade until you could polish gold with them

I have no idea if Graham has any sets left, but they were absolutely brilliant for putting a shine back on a well used knife.

Failing that, I suppose it depends on how enthusiastic your youngster was with the quartz and whether ordinary stuff meant for buffing out scratches would do.

Sorry, not being of much help. I'd offer my set of the cockpit polishing stuff but Son1 has absconded with it, and I'm pretty sure I'm not getting it back.

M

 

[Tengu]

Polish it out?

Start with a fairly course paste, then use a finer and finer?

 

[Paul_B]

Would that work if done by hand?

 

[Toddy]

Graham said that it was how they did the aircraft windscreens. I know the papers I had (well, really they're fabric rather than paper) were definitely hand use and not fitted to a machine.

You could try something like Tcut on a scrap bit of glass to see how you get on.
I suppose the worry is that you end up with a big blurry bit on the glass instead of just the score. I think the blur would be worse tbh.

M

 

[TLM]

The papers used on aircraft are aluminium oxide, while in theory harder than window I dont think it works. One would need diamond or boron nitride and even then the amount of eldow grease would be huge. (I have gone through a course in aircraft window polishing)

Waxing the scratch will help for a while but not very long, I dont know if the acrylic resin used on car windshields can be used like this, you would have to ask somebody who does those repairs.

I know glass is polished with machines and diamond paste but I have no experience on that but quarzt does get a nice shine so it should or could work on glass.

 

[Toddy]

That's a pretty cool thing to have on a resume
QUOTE, TLM, "(I have gone through a course in aircraft window polishing) "


I know that some of the fabric sanding sheets I had were cerium based. I don't know if that's any harder or softer than aluminium as a polishing paste/paper.
I know that for polishing mirrors cerium seems to be the stuff though.

34X Deep Scratch Remover ,Glass Polishing Kit 8OZ Cerium Oxide And 2'' Wheel Pad | eBay

Professional wool pad + sandpaper + cerium oxide powder + polishing wheel, practical DIY repair glass kit. 1 Bag of High-grade Cerium Oxide Powder. Material: yttrium oxide powder, plastic, wool, etc.

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[TLM]

That's a pretty cool thing to have on a resume

Maybe kind of. It was a two week course in Sweden. I have worked on some aircraft windows since but not on any fighter canopies as the modern ones tend to be polycarbonate instead of acrylic and they usually have a hard surface coating.

Cerium oxide is not very hard but seems it has some other properties that make it suitable for final polishing. Very dense and chemically somewhat curious.

While it might be possible to polish the scratch out I doubt is would be moneywise sensible. One would have to ask to make sure.

 

[Stew]

Just buy a new window....

 

[Toddy]

Big window, expensive, AAA+8 double glazing.....
I think I'd learn to live with the irritation, tbh.

 

[Paul_B]

Think that is my only option TBH?I think a deep scratch like this would need polishing a big area to work well.

At least we know that rock sample was quartz!!! I can't be too hard on him since it was self learning from a book. I have been encouraging an interest in geology, I'm looking to create an interest so we can go out collecting together when a little older. Besides thinking about it now, I think I did the same thing, several times!!! I just did it in a discrete place and very short. My son for three inches or so right in front of his face when standing up. That's the spot in check to see if the dog is waiting to come back in. Makes it very obvious to me.

Yes, expensive window. Complete unit which would cost probably a grand. When the sun shines in February and it's cold the glass feels hot on the inside but cold outside. It allows the sun's energy inside. Put it this way it shows up the lack of insulation in the walls. Better insulation than sold stone by some way. Our radiators are hardly warm in winter once the place has warmed up. Before they were warm all night. Every little helps and they were a lot of help. At the time they were the best the window company could get. There was an AAA+10 available with another supplier but they were fiendishly expensive, more than I am paid for the house!!

 

[Stew]

You’ll never polish a deep scratch out with stacks and stacks of work that runs the risk of making more issues and once committed to sorting it, you’ll have to finish it all the way through to perfect.

I hand sand my knife blades at times and know the work it takes to get scratches out there. I wouldn’t even attempt it on glass.

if you can’t live with it and it’ll always bug you, new is the only option.

 

[Stew]

Would the scratch cause a potential point for a full on crack to form? I’ve had issues at a site with glazing panels cracking from items stuck to the windows so could see it

 

[Mesquite]

Would the scratch cause a potential point for a full on crack to form? I’ve had issues at a site with glazing panels cracking from items stuck to the windows so could see it

Yes it would, apply the right amount of pressure and it'll crack or break with real ease

It's surprising how little you have to flex the glass once it's cut like the OP has described. IIRC it's less that 0.5deg for the glass to break

 

[Toddy]

How do those windscreen fillers work then ? Do they work ? or is it just a fudge kind of thing ?

 

[Stew]

How do those windscreen fillers work then ? Do they work ? or is it just a fudge kind of thing ?

Could be worth a try. I have a scratch in my windscreen that they couldn’t get out 100 percent but did make it road legal again.

 

[Mesquite]

How do those windscreen fillers work then ? Do they work ? or is it just a fudge kind of thing ?

They're an epoxy resin based compound that will strengthen the glass.

However it does require that it's applied via a vacuum system to ensure that the resin penetrates right into the scratch or chip to achieve maximum strength. I don't know whether they do a vacuum system that would encompass the size scratch described. Even if they did it's as Stew said the scratch will still be visible lesser degree even after being treated

 

[Broch]

My parents had a scratch on the internal side of a double-glazing unit - I'm sorry to say that in the full sun the thermal gradient and the stress point caused by the scratch resulted in a crack up the full length of the large pane - it was never fixed and we sold the house with the cracked window

However, if you stop it early enough it may not happen. People like this offer a service but I've no idea how effective or expensive it is:

Magicman - Glass Repair - Hard Surface Repair Near Me. No1

Find our more about the wide range of repair services Magicman offer. Services include glass repair, tile repair, stone repair and lots more.

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[TLM]

No less than triple and more than a few quadruple, window glazing here.

 

[Paul_B]

There's double glazing and double glazing, it's not all the same? Before we got ours we looked at triple and it wasn't significantly better. Good double glazing design with thermal breaks, coatings on surfaces (right side of the window) and inert filler glass is a match for run of the mill triple gazing. It's all about the technical specs not the layers alone. According to the energy rating letters our windows were rated as the same as triple glazing by the same maker IIRC. Although colder countries do tend to have better designs than in the UK. For the UK good double glazing is probably as far as you need to go, especially when the building designs become the weak point for insulation.

New builds are getting close to passive house levels round here in the better developments but I suspect we're behind colder countries in this. We looked at a way of buying a new house cheaply to move into then rent our current house. That house was aiming at A rating overall but due to a few issues suspects it'll be a high B rating just below A rating. Quality of build was amazing right down to wall penetrations. For example if a pipe or cable passes through a wall or floor it had a special insulation piece to seal the hole from airflow. There's other details aimed at achieving a better energy rating. Inner door seals, AAA+10 windows or higher I can't recall exactly. Assuming we lived there for 5 or 10 years the energy savings would certainly add up.

Right now our house is 1900 design. Solid stone fronted with brick everywhere else. Cavity brick on the back walls. You can tell the stone walls are very cold in winter. Summer wind blows and doors shut round the house!!!