 |
 |
|
|
| :: The
Quiet Corner |
Sponsorship:
Some trade banners space is available on the right hand side and affiliate
program banners can be replaced.
See
rate card.
Madness:
The Lord's Prayer contains 56 words, the Ten Commandments 297, the
American Declaration of Independence 1,300 - but the EU directive on duck
eggs contains
26,911...
Remember:
"The good you do comes back to you, sometimes when you need it most,
sometimes when you least expect it"
Communicate:
Promote yourself, your business and enhance your professional reputation
for FREE at:
DoubleGlazingWeb.Info
|
|
|
|
Frame Materials:
PVCu
Off colour?
What to do about Pinking?
The problem of discoloration of PVC-U does exist but is very rare, and I believe it is caused
more by an accident, in an odd bad batch, rather than by deliberately including recycled or 'regrind' plastic in a mix.
If you have windows or doors that suffer 'pinking' you will readily know that the framework is at fault and no amount of elbow grease will make it better. Usually only parts of the frame are affected, with some white and some off-colour.
There was a particular problem with one well-known profile manufacturer in the second half of the 1990s and a number of its trade customers are in the 'piggy in the middle' situation of an unhappy homeowner and their at-fault material supplier. This places the blameless window-fitting company in an awkward situation, as the supplier proposes that they mask up and spray all the windows on site with a special compound to make them white again. The problem with this remedy is twofold:
| 1) |
The process (which is used to make coloured windows) is not best suited to outside conditions and is best performed in factory conditions. |
| 2) |
The window company has the embarrassment of being out there for all the world to see, apparently ‘respraying’ its 'new' windows - definitely not good for business. |
The funny thing about real 'pinking' is that it seems to have nothing to do with ultraviolet light stability, because the Sun tends to 'bleach out' the discoloration; in fact the problem shows up worst on the north side where there is less direct sunlight.
 Notice that the openers have started to go a pinkybrown against the framework, which has kept its
whiteness. This is NOT due to premature degrading of the vents in the PVC-U by ultraviolet light because of added regrind or recycled plastic, but
far more likely to be caused by a bad batch of stabiliser in the mix. This is also proved by the fact that windows facing north show more of the problem, as windows facing south are actually being bleached back to white by bright sunlight!
I am fairly sure that the extruders of this would have just had a bad batch, and that a sales pitch of ‘unlike other makes, we use only virgin 'A'-grade material’ is almost all cobblers and meant to scare you into buying their make. |
| |
 The problem of pinking is not confined to just the framework of some PVC-U windows and doors, but
could also affect trims, bay poles and other parts of an installation. This photo shows a plastic Georgian grille (between the glass), which has degraded and discoloured since originally fitted by Zenith around 11 years ago (according to Mrs T. of
Rayleigh, Essex, the homeowner).
I took this photo on 28th November 2001 after the owner of the property ordered all-new replacement sealed units from me. My Georgian grille is white polyester-coated
aluminium, and so will not suffer this problem. |
|
So what can you do if you have frames that are pinking, then?
Well, now you can get out the paintbrush and just repaint them if your supplier is of no help, see
PVC-U colours and finishes and
repainting.
Or get the experts out to do the job for you: Go to the Kolorbond
website.
Please be aware that the problem of profile discoloration is nowhere near as widespread as some salespeople make out, and it does not matter whom you buy your new windows from, as it can happen if there is a bad mix with a particular type of titanium dioxide (Ti02). Tests indicate that it is the photoactivity properties of the Ti02 used that cause the problem. Pinking seems to occur sooner and with higher intensity with high photoactive Ti02, and formulations made with low photoactive Ti02 do not show the same signs of pinking. No significant link has been identified between pinking and the other parameters such as fillers, impact modifiers and type of resin. Although no effect has been noted either as a
result of the type of lead stabiliser used, I rather think that one day all lead- and tin-based stabilisers will be outlawed by the EC, and calcium zinc-based stabilisers are the way of the future. Analysis of pinked samples has been carried out by what is called the XPS technique, which stands for X-ray Photoelectron Spectroscopy of surface analysis. The analysis has demonstrated the photoactivity of the Ti02 to be the main influence in the pinking phenomenon, and it is fair to assume that it is the Ti02 interacts with the stabiliser to oxidise it.
Prospective customers often ask me, ‘Are your windows and doors made from recycled plastic?’ or, ‘Do your windows and doors contain any recycled plastic?’ Straight away I suspect that some dodgy 'double-glazing salesman' has given them the dubious line about how pure their window system is, compared with most of their competitors’, which go off-colour. Just another sales tactic. See
Can I believe the salesperson?
Years ago when a car 'pinked', the ignition was too far retarded, the compression was too high or cheap petrol was being used, and the trouble was 'pre-ignition', which happened when the engine was put on load. I'm showing my age now, and you didn't really want to know all that, did you?
Read a lot more about this on my other related page
called Regrind.
|
|
