rear window defogger wire repair

[dlb]

only 4 of the lines on my project car rear window defogger work so i'd like to try to fix the other ones. the FSM gives instructions on how to figure out approximately where the damage to the wire is, and then says to use a fine tip brush to apply "dupont paste #4817" to the break. does anyone have any idea if that paste is still available and where to find it, or better yet, what a more common type of suitable repair paste would be? i looked for the dupont stuff online and all i find are people giving instructions on using this paste for this particular job—no retail sources.

[MR2Di4]

I have used "defogger repair kits" before with mixed results. I can usually find them at NAPA and all they consist of is a little vial of copperish-colored repair fluid and a brush like what you'd find in a nail polish bottle. You have to clean the damaged area then apply an adhesive-backed paper strip with a slot cut out to the glass as a guide. The tricks is to apply a thin, even coat so your repair isn't a hot spot. Actually I need to do this on my Zombie T4 so maybe I'll put some pics in my work thread or make a separate guide...

MR2Di4

[marlinh]

You can also use masking tape instead of the paper they provide. Carefully peel it off after it has dried. I have never had a problem with the aftermarket stuff. Sometimes it is difficult to see all the breaks.

[dlb]

i got to this today. it's super easy but the repair kit is a total piece of crap. all you need for repairing the grid is the liquid and applicator brush. the alcohol prep pad left a film that the tape wouldn't stick to and the stencil you are supposed to use is about 3 times too wide. if you used the stencil you would wind up with huge thick portions where you repaired the grid so i used painter's tape instead and lined it up right next to the grid lines.

here are the many repaired spots.



this illustrates just how oversized the stencil is.



it says to wait 24 hours to test the defogger so i'll try it out tomorrow night.

[Highlander]

I've done this in the past using (as you did) painter's tape and conductive epoxy. The conductive epoxy is more expensive than the kit, but it's totally worth it as it won't flake off. I also used a small scrap of 1200 grit sandpaper with almost no pressure to expose the ends of the traces. IPA (Isopropyl Alcohol) works the best to clean the window and traces before applying the epoxy. I also used a pen to mark out on the tape exactly where the traces were broken so that I didn't FU and have to do it a second time .

[dlb]

HL, what is conductive epoxy and where can i find it? i also noticed that the repair fluid i used dries as a paste and looks like it could be rubbed off really easily so if there's something better i can use in the future, that's great.

[ARCHINSTL]

Is this what you mean? Apparently it's available at Radio Shack and similar places.
http://www.thinkgeek.com/product/b70c/
AKA "conductive glue."
Makes sense - I've wondered about the durability of the kit paste (cleaning back window with Windex, etc.).
Tom M.

[Highlander]

the carbon loaded glue might work, though I'm not so sure about its ability to resist the heat that is generated (really shouldn't be a problem, it just needs to be over 32F) , I'll check and see if I can find a manufacturer. What I use is a silver filled two part epoxy, its generally used in microelectronics. I'll search about and repost when I find a manufacturer and part number for you all.

Here's a link to Thorlabs, we use that around here when its just not feasible to solder components. Its pricey, but it doesn't dry up so you can use it for years to come:
http://www.thorlabs.us/newgrouppage9.cf ... oup_id=273
Hope that this helps, even if it doesn't its a starting point to find another manufacturer...