Very near miss

[Baldhead]

Yesterday morning I could smell burning plastic upstairs, this is what I found

My nearest and dearest had left one of her mirrors she uses on the windowsill, unfortunately the concave side was facing out towards the sky, yesterday was a very bright hot near cloudless day, I'm just glad I didn't go out because I'm certain there would have been a tremendous amount of fire damage.

I used to be a fireman and only once have I come across a fire which I believed started in this way.

I don't want to claim off my home insurance, I intend to smooth back the burnt area with an old chisel and fill and touch in the damaged area, but what type of filler and paint should I use?

Baldhead

 

[bugbear]

Scary; Thanks for the warning. I assume this is rare, since the mirror needs to be "focal length" away
from the target for the danger to occur.

BugBear

 

[Eric The Viking]

Thanks for posting this, Baldhead. The Domestic Controller also has one of those turnover, flat+convex mirrors and daughter #2 also borrows it. Both have south-facing bedroom windowsills.

I've warned everyone, but nobody has taken it seriously. I'll forward a link to your post.

On fixing it, some of that is possibly smoke scorching. To start with, I'd use a fine abrasive, like Autosol, to see what you can lift off. Wash with Meths (test it somewhere out of sight - it shouldn't attack the uPVC, but it might).

You might then build it back with a white car body filler (two part polyester, I think). I saw a clever trick on telly the other day, involving a thin polythene sheet pressed down over a repair while it set, to reduce the amount of finishing work afterwards. Can you clamp a smooth block on top of it with a polythene bag as a separator?

I fear you will struggle to exactly match the finish, but you might hide it well.

Also, I think uPVC dissolves in xylene, so a bit of white plumbing pipe might be dissolved to make a uPVC filler paste, but it's nasty stuff so best experiment outdoors. I use it as a degreaser, but I really don't like it. White spirit dissolves polystyrene excellently, but it's not quite the same chemistry.

I have a sister-in-law who's an organic chemist. I'll ask about solvents.

There may be something out there already, of course (glue/welder or repair putty), but the windows themselves are usually joined either with hot knives in the factory, or RF heating/welding.

E.

 

[cusimar9]

Blimey that was close then

 

[Eric The Viking]

Got a reply from my sister-in-law:

The trouble with uPVC is that it is largely non-stick (although the dirt pick up on my window frames is quite incredible - so maybe you need acidity as from the fall out of a nearby power station!)

There are proprietary paints out there for tricky surfaces - if there isn't one for uPVC, then something for tile paints might work. It's worth trying anything acrylic based - even acrylic art paint might work for touch up. There are acrylic-based adhesives, too. I think epoxy-based products would yellow and become brittle when exposed to UV, so keep away from those.

May be issues getting a gloss match - acrylic art paints tend to be matt, so you may get away with that and an egg-shell varnish over the top. Or, you can mix in your own filler - talc, perhaps, but check that it looks smooth enough before irrevocably applying it!

I should have said before: she's a coatings expert, rather than plastics specifically!

Might be helpful, as you did say you were planning to fill and paint over.

E.

 

[monkeybiter]

We've used T-cut on uPVC window blemishes with success, though yours may well be too deep. Perhaps worth a try.

 

[Jamesc]

Also, I think uPVC dissolves in xylene, so a bit of white plumbing pipe might be dissolved to make a uPVC filler paste, but it's nasty stuff so best experiment outdoors. I use it as a degreaser, but I really don't like it. White spirit dissolves polystyrene excellently, but it's not quite the same chemistry
E.

Many many moons ago when I was into plastic models (it was a long tome ago honest). We used to disolve pvc in brush restorer to make a filler that could be painted on. I don't know if the composition is still the same but it should be worth a try if you have some around.

James

 

[Eric The Viking]

Also, I think uPVC dissolves in xylene, so a bit of white plumbing pipe might be dissolved to make a uPVC filler paste, but it's nasty stuff so best experiment outdoors. I use it as a degreaser, but I really don't like it. White spirit dissolves polystyrene excellently, but it's not quite the same chemistry
E.

Many many moons ago when I was into plastic models (it was a long tome ago honest). We used to disolve pvc in brush restorer to make a filler that could be painted on. I don't know if the composition is still the same but it should be worth a try if you have some around.

James

If that does work, it's very useful indeed. Are you sure it wasn't polystyrene though?

 

[DeanN]

Konig do a great range in UPVC repair products - I went on one of their courses a few years ago, and was amazed at some of the repairs possible. A hard wax filler would be best, but there are a number of shades of white.

 

[Ed Bray]

Konig do a great range in UPVC repair products - I went on one of their courses a few years ago, and was amazed at some of the repairs possible. A hard wax filler would be best, but there are a number of shades of white.

To be pedantic, there aren't. White is white, black is black and anything else is a tone of another colour.

 

[DeanN]

OK. Just pointing out that white isn't necessarily white where uPVC is concerned.

 

[Eric The Viking]

Konig do a great range in UPVC repair products - I went on one of their courses a few years ago, and was amazed at some of the repairs possible. A hard wax filler would be best, but there are a number of shades of white.

To be pedantic, there aren't. White is white, black is black and anything else is a tone of another colour.

To be very pedantic: google "colour temperature" (or "color temperature") and "mired shift".

White, like the other colours, really depends on both the context and the perception of the observer. About the only 'standard' white is #ffffff in RGB (hex), but even that presupposes a colour curve of one sort or another.

Sorry but life (and white) isn't that simple ;-).

 

[Phil Pascoe]

There is a paint manufacturer in the USA that offers over 5000 shades of white, so I've read.

 

[Baldhead]

Thanks for posting this, Baldhead. The Domestic Controller also has one of those turnover, flat+convex mirrors and daughter #2 also borrows it. Both have south-facing bedroom windowsills.

That's the same type of mirror that caused this damage, ours is about 8" in diameter, and also a south facing window, hopefully now you wife and daughters will be careful where they leave their mirrors!

Scary; Thanks for the warning. I assume this is rare, since the mirror needs to be "focal length" away
from the target for the danger to occur.

BugBear

In 24 years as an operation fireman (now retired) I've only come across something like this on one occasion, we blamed a fishbowl on the windowsil setting fire to the curtains! I tend to agree about the "focal length" thing but on that bases I can't understand how there is two definite areas of seperate ignition? wish I'd paid more attention to all those boring fire prevention/investigation lectures.

A big thanks to you all for your help and suggestions, and also to Eric's sister in law. If you ever have a problem with 'anything' you can bet your bottom dollar someone on this site can help or knows someone who can.

Cheers guys.

Baldhead

 

[Benchwayze]

Just glue a strip of plastic moulding to the frame right to the top, covering the whole upright. It's only you who probably know it's there!
Just a suggestion BH. 8)

The two spots of burning are probably due to the fact that the mirror will likely be silvered on the rear of the glass. Thus you are getting a 'double' focal length, due to refraction through the glass.) Just a guess, because I know parabolic telescope mirrors are slivered directly on the 'business' side, to avoid double-images, when 'stargazing'. HTH

John

 

[Eric The Viking]

I have a sneaky feeling it's because when the sun goes behind something (a cloud?) it stopped burning, something like this:

 

[Benchwayze]

I have a sneaky feeling it's because when the sun goes behind something (a cloud?) it stopped burning, something like this:

Yes. Considering the space between each spot; and the angle of the sun also might have something to do with the fact that one is higher than the other.
I dunno really! :mrgreen:

 

[woodfarmer]

I had a similar thing with one of those lamps with a magnifying glass attached. Left it o na workbench in front of a window in summer . as luck would have it the light from the sun went through the magnifier straight onto some wrapping paper. for days every afternoon I would smell burning..... wasn't until I tidies up the workbench I realised what it was when I found the burnt paper.

 

[Lons]

Hi

You can get a PVCu solvent cleaner for less than a fiver. (Go to the little plastics shop on the road up from the "elephant pub " ? in Ashington, JTF on Tyne Tunnel trad est and I've seen it in Yorkshire trading in Cramlingon as well. give me a ring or drop in and I'll give you some if you wish - and a coffee :lol: ) You can also get small gap filler in a tube and they might be able to advise on repair.

It's highly unlikely that annoying as it is, the PVCu would have started a fire as if my memory serves it's a class 1 self extinguishing material (might be wrong of course) It would have melted / burned a hole in it though.

I'm sure the missus has learned her lesson.

Cheers
Bob

PS
Morrisons Glass ( ASDA roundabout) is worth a call in if you can't find it.

 

[rafezetter]

Having worked in selling uPVC stuff I can say there are touch up pens - much like for cars, available for white and most of the other uPVC foiled colours. smooth it down, maybe T-cut as someone mentioned and if it's still not to your liking, you can try a pen.

The body filler smoothing trick is very good - I've used it myself but I would advise something more like an old credit / store nectar card or maybe one of those clear plastic a4 wallets, as a plastic bag is almost impossible to get crease free.