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Post by johnbirmingham on Dec 21, 2005 11:42:49 GMT
Just when I need it most the H R W has failed !I've checked there's 12v across it . It seems as if the conducters stuck to the glass have slightly decomposed although I can see no breaks.Some genius must surely have invented a metalic "paint" to overcome this . Any ideas or sugestions ? Please ,P L E A S E don't say change the window! John
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Post by Deleted on Dec 21, 2005 12:42:19 GMT
John,
I havn't found a way of repairing the window, but you can buy HRW strips that you apply to the glass. They don't work awfully well (but then neither did the original) but they do clear the condensation off eventually. Much better than replacing the window and far cheaper.
good luck!
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Post by RichardF on Dec 21, 2005 13:14:13 GMT
John, there is definitley a conducting paint available specifically for heated rear windows where the element is accessible. I believe Frost sell it (if my memory serves me). I can check my latest catalogue when I get home this evening. However, as you say, the hard bit is locating the break. Just checked their web site www.frost.co.uk and found it under "electrical", page 3, item code E178, £11.50 incl vat. RichardF Southampton |
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Post by Deleted on Dec 21, 2005 13:54:17 GMT
John and Richard It is sometimes possible to find these small bottles of silver conductive paint in Halfords or your local car accessory shops. Marketed by the name "GRANVILLE" electrical circuit paint repair kit. Only a small bottle but it goes a long way, can be used to repair broken printed circuit board track too!! Also available from Maplin Electronics: www.maplin.co.uk/Free_UK_Delivery/Electrically_Conductive__Silver_Paint_36275/Electrically_Conductive__Silver_Paint_36275.htm ELECTRICALLY CONDUCTIVE SILVER PAINT Simple to apply Highly conductive Tough surface film Supplied in a 3g phial Drys in 15 to 30 minutes Pure silver is used in the formulation to give excellent conductive properties and a hard resilient surface film. Typical applications include making electrical connections on circuit boards, providing radio frequency interference shielding, repairing broken track on PCBs, repairing demisters on car rear windows, bonding wires together, conductive ink and many more. Once applied the paint will last for many years and after opening will last for at least 2 years in the bottle. only £6.99 inc VAT !! Adrian |
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Post by Deleted on Dec 21, 2005 13:55:19 GMT
May be worth checking the earth end of the HRW circuit is making good contact too!
12 volts going in won't do much if the circuit is not properly earthed.
Good Luck
Adrian
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Post by Phil Nottingham on Dec 21, 2005 16:37:35 GMT
I assume you have the later modern orange element type as opposed the ultra modern earlier version with built in wires.
If it is the orange wire (you need to carefully scrape the orange paint off the silver strip) type the silver paint option does work well but if its the contact terminal strip thats broken off its less successful as you have to use the quick set epoxy glue as well to hold it position
Halfords did sell this but all the usual mail order electrical places usually have some
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Post by dorsetflyer on Dec 21, 2005 20:16:26 GMT
Breaks in the orange version are very often caused by the use of abrasive cleaners when cleaning the inside of the glass. Also if you have a ring on your finger it's so very easy to scratch the surface sufficiently to cause a break.
The use of silver loaded paint has been used in the electric/electronics industry for over thirty years now and very successfully to.
If it's the fine wire within the glass I don't know of a way of doing any repairs to that.
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Post by johnbirmingham on Dec 23, 2005 0:11:09 GMT
This is the first time I've used this site and am delighted to have had so many useful replies .Mine is indeed the orange type (I thought it was gold ! ) . I'll get down to Maplins to-morrow and will let you know the results . Thanks a lot to all of you . John .
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Post by Phil Nottingham on Dec 23, 2005 16:08:59 GMT
;)Good and you are welcome to use it again!
Keep us up to date with the outcome.
Tell us more about your car
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Post by johnbirmingham on Jan 19, 2006 16:02:03 GMT
I've got hold of the paint Adrian mentioned,Maplins had it as "Leitsilber".It works OK and conducts better if blow-dried with a hair drier.Scraping the existing varnish off to make contact with the"elemert"is a bit tricky Phil -I seem to be causing more damage in the process.Thinners doesn't seem to touch it.I persevere with an aluminium scraper! There are many breaks in each bar so I can't believe it "fused"-I'm beginning to wonder if parking for long periods with last year's very hot sun on it has caused the failure.Still,it is 34yrs old. I've owned her for 30 of those,only doing about 3000m a yearand almost trouble free.I could go on and on about her,Phil,but I don't think this is the slot to do it. Thanks again lads, John.
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Post by Phil Nottingham on Jan 19, 2006 16:11:02 GMT
It is essential to remove sufficient of the orange paint, varnish or whatever it is but its that or nothing.
Any paint subjected to heating up and cooling down whether original paint or not cannot be realistically expected to last 30 years without cracking and it this that could cause the silver element to separate.
Even secondhand screens where the element has hardly ever been used may still quickly fail.
The earlier fine metal type back screen (like modern cars) fails and these were never very good as took a long time to heat up.
Please go on and on - someone else would make a change from me
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Post by stantondavies on Jan 19, 2006 19:09:21 GMT
I don't have the luxury of a HRW, but find that opening the quarter-lights works very well in keeping the mist away. Useful whilst you are finding a 'permanent' cure.
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Post by Phil Nottingham on Jan 19, 2006 20:11:41 GMT
I find the same on the Coupe although it also extracts the warm air!
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Post by stantondavies on Jan 19, 2006 20:50:32 GMT
The heater's up to it!
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Post by dorsetflyer on Jan 20, 2006 20:34:56 GMT
Trying to scrape it off will only makes thing worse.
The best thing is a Fibreglass Eraser. Should be obtainable from artist shops etc.
This is what I have used in the past cleaning electrical contacts etc. One word of warning though watch out for tiny splinters of glassfibre getting in your fingers they are a sod to get out. Use a pair of rubber gloves.
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Post by Phil Nottingham on Jan 21, 2006 9:20:38 GMT
That sounds a very good idea - I never heard such items existed!
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Post by dorsetflyer on Jan 21, 2006 15:45:24 GMT
I forgot to mention that they can also be bought from a good Hobby/Model shop.
I first used them in the early 60's in the drawing office. They were used to carefully remove ink from linen or plastic based (copies of earlier drawings which had to be modified) drawings.
Careful usage of these only removed the ink etc and did not destroy the subsurface.
So mine didn't cost me anything. The only thing I have had to buy is the box of glassfibre refills.
They were ideal in the modelling field and also the electrical side of things, like corroded brass and copper etc. Can also be used for preparing either of these for soldering without the use of solder flux.
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Post by johnbirmingham on Jan 22, 2006 22:56:51 GMT
Thanks for your encouragement Phil,I've been at it again to-day.It's nice to know that I don't suffer alone! John; I hadn't thought of the glassfibre "rubber"; will give it a try. Thanks , John.
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Post by johnbirmingham on Feb 19, 2006 12:45:35 GMT
Sucess at last ! It was great to see the frost dissapear off the glass and although it didn't start melting in the old evenly spread pattern,the hot spots showed up to useful effect. I'll try a few more dabs of silver on those later.
When I'd finally got continuity it looked quite a mess (Michealangelo had it easy , lying on his back in comfort, painting on plaster - not so funny sitting on your own legs on the back seat painting on glass with an adverse camber,Mike ! ) I was able to tidy it up quite well using a flexible straight edge to guide a scraper. The silver paint in the phial settles out very quickly so I found it best ,after a good shake, to use it from the hollow of the inverted bung. That way the brush reached the good stuff every time.
Thanks lads,to all who replied ; and to those with the same problem -- get out there and suffer too . John
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Post by dorsetflyer on Feb 21, 2006 21:48:35 GMT
Very pleased you had success in getting the HRW working again. I can guess what its like trying to work at that awkward angle, especially if you have wobbly hands trying to paint the silver loaded paint on.
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Post by John Stacey on Feb 27, 2006 16:24:16 GMT
John,
I tried the conducting paint, it is very awkward to apply because of the angle of the coupe rear screen. Finding the break is very difficult. Eventually I routed hot air from the rear heater using the space behind the seat back to get into the boot. From there through a demist nozell from a mini/allegro making a slot in the buffer on the parcel shelf. It took a few hours but it does work well.
John Stacey (Bristol)
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