Car door mirror heating pads

[Dave Plowman (News)]

Just as an update having seen some different makes, it appears some are made out of copper clad Kapton, which is a thin flexible plastic sheet, suitable for high temperatures, made by DuPont. The copper cladding is etched into the element - rather like a PCB - and then laminated with a second layer of plain Kapton. This sounds like it would be suitable for a small production run - I know of several others who'd like replacement elements. I've found a couple of suppliers of this stuff in the UK but not had any replies to my e-mails.

Anyone have details of this process and suggestions for a supplier?

[Mr Harry]

If there is sufficient space withing the mirror housing, mount a couple of 12v bulbs in there. You will probably need to paint the bulbs to prevent the light coming around the edge of the miorror glass.

harry

[Dave Plowman (News)]

What you need for efficient demisting, etc, is a good even heating source since glass is a very poor conductor. And bulbs don't provide this.

[Andrew Gabriel]

Glueing 10 or so resistors on the back of the mirror would be good enough.

[Mr Harry]

It certainly de-ices them

harry

[Dave Plowman (News)]

Not enough room. The mirror is glued to a back plate which has a cutout for the heating element and that cutout is only about 1mm deep. There would be room for resistance wire, but making such a thing doesn't appear easy. While etching a PCB type will be - if I can find a source of the material I've mentioned.

[Tony Williams]

Sounds like a bit of a no-hoper Dave. All the cars I've had recently have heated the wing mirrors by piping some of the warm air from the passenger compartment vents, through the door, and out behind the mirror. Would that be an easier mod?

[Dave Plowman (News)]

Interesting. Difficult to do on this car as the mirror is mounted on the window frame so not much space for an air tube of an adequate size - although it does have air ducted into the doors for side window demisting.

I've had a quote from a US firm to make the required elements in silicone.

They'd cost 6.30 gbp each - but with a one off tooling charge of 250 gbp.

[Tournifreak]

I've used these guys in a professional capacity:

do a range of off-the-shelf heaters but also custom to you design

- size, resistance etc.

Basicly the process is as you describe. Etched resistive material (not exaclty sure what) sandwiched between two layers of Kapton.

I found them helpful, flexible and relatively cheap. (I needed 10,000) but my application was much smaller and higher precision than yours.

Regards, Jon.

[dingbat]

Why not just buy replacement glass, with a heater element already on it ?

[Dave Plowman (News)]

Just what I needed. Thanks, Jon.

[Dave Plowman (News)]

I suppose you've not seen the whole thread. It's for an older car, and new heated replacements aren't available anymore. Un-heated ones are, though, and are identical apart from the heating element. So it would be simply a matter of removing the mounting frame which is held in place with double sided tape, inserting the element, and glueing back together.

[dingbat]

So bodge it. Find something else that's practically the right size.

Failing that, buy a big one and grind it down.

[Dave Plowman (News)]

That's a possibility that occurred to me since BMW E39 ones are only slightly oversize - and incorporate a 'blind spot' section. However, they're of the order of 40 quid each.