window defrost grid

[SteveJ]

6 hours ago, Dave WM said:

My plan is to remove the hatch for better access, then do one line and confirm the resistance. My biggest prob right now is trying to figure out how to remove the hatch by myself. maybe the boss can help, but sometimes that does not go well. maybe rig up a carrier that loops around the top and bottom and use the cherry picker to hold it while I remove the hinge bolts.

Another reason you should consider the Dawson County/Forsyth County option. There are plenty of good Z people who would be willing to lend a hand.

[Captain Obvious]

7 hours ago, Dave WM said:

2 ohms per inch X 34 inch per line=68 ohms per line, 16 lines in P = 68/16= 4.25 ohms, 12v/4.25r=2.8 amps,2.8*12=34 watts.

The math looks good to me.        

That said, however...  I cannot attest to any potential GIGO factors with the original inputs though. What's the fuse value? And they run a relay for the defroster, right?  I've seen them switch 3A loads without a relay... Seems a little fishy.

[AK260]

I would think a good buffing compound and a  rotary buffer would take care of the lines

 

That is a great idea! It also worries me that it may leave swirl marks behind. I have a spare rear screen, so I will have a go on that one at some point in the winter. There is a part of me that wonders if you would ever notice the 2cm difference in defroster height if the lines were totally rubbed out and frost fighter installed!?

 

 

And masking tape on the roof around the hatch hole where the hatch might touch too.

 

Masking it is great advice!! [emoji106] Just one word of caution, masking tape is EVIL stuff especially if you leave it on the car for any length of time. Ask me how I know! This is what happened when I peeled off the tape just below the rear plate a few days after I was doing some work in that area!

 

 

Another time, it had a really weird reaction with the paint that looked like Yellowstone park and took 2 months to disappear by itself!

 

 

Frog tape I have found works best

 

Indoor painting and decorating for sharp lines and no paint bleed https://www.amazon.co.uk/dp/B007AS07UI/ref=cm_sw_r_cp_api_i_CRhwFbV5PW1MB

 

 

Finally, I found adding and old duvet cover provided a level of padding / protection that tape alone wouldn’t.

 

 

 

 

 

[Dave WM]

14 hours ago, SteveJ said:

Another reason you should consider the Dawson County/Forsyth County option. There are plenty of good Z people who would be willing to lend a hand.

I made a run to blue ridge area over the weekend, gosh it nice up there, noon it was 78 and dry, MUCH nicer that cen fla.  I will be looking in Dawson area next. prob just by myself this time, will scout for boss and see If I think she will like it (trips are hard on her).

[Dave WM]

I assume you unbolt from the shell leaving the hinge on the hatch?

[zKars]

3 hours ago, Dave WM said:

I assume you unbolt from the shell leaving the hinge on the hatch?

No!  Get the hatch to hinge bolts out. No hatch line up on re-install. Getting tight flat head Philips screws out might be a bit of a pain, but use a ratchet with a power bit, not a screw driver. 

Edited September 9, 2020 by zKars

[Racer X]

On 9/8/2020 at 11:48 AM, AK260 said:

Agreed! Completely!! The question is, just how does one get the silk printing off? It’s very hardy stuff! ?

The Frost Fighter website says to us a razor blade, and that it will leave a shadow of the old lines.

I would think using some cerium oxide and a felt glass buffing pad on a buffer should clean up any residual grid material, and leave a nicely polished glass surface. I've used the cerium oxide and felt buffer pad to clean light scratches from windshield wipers, and the scratches left on side windows from rolling up and down while rubbing against a dirty outer squeegee rubber.

 

 

[ensys]

I think (an admittedly tentative version of "believe") that the hatch glass is not a simple barrel curvature, so that if one were to draw a straight line on a piece of paper (as in the role used by FrostFighter), one could not get a "horizontal" transfer without warping the paper.

Just a speculation...

 

 

[Matthew Abate]

A couple of thoughts I had while reading through this thread:

• Can we can an inventory of all of the materials tried so far (stencil tape, various paints, etc.) and a review of their efficacy?
• I can't look right now, but I think maybe the OEM grid has a slight curve to it that makes the lines look straight on the curved glass. If I am correct, then the Frost Fighter may pose a slight problem in looking correct.
• Has anyone done a masking test to see which tapes do the best job? I am intrigued by the cellophane tape idea mentioned earlier.

One thing I have been considering is recreating the grid in software, having a vinyl sticker mask made from that, and airbrushing the paint on after I apply the vinyl sticker. Then I won't need to remove the grid that is there. I just need to find. the best paint. However making the mask with tape might be faster and cheaper. If I make the vinyl sticker it could be reproduced and distributed.

Another thing I am trying to find is a company that does these restorations. I would much rather take it to a pro to have restored. My grid is about 20% missing due to a sticker that pulled it off when I removed it.

I am considering tinting my glass after I fix the grid in order to protect it. My car is a resto-mod with a bunch of non-reversible changes, so factory original isn't a concern for me. Those who are worried about the paint coming off from cleaning might consider this. (I am also considering buffing the grid off and adding a third brake light).

Last thought, take a look at the electric guitar world. Conductive paint is used to lower interference in the pickups to get a cleaner sound: https://www.stewmac.com/electronics/shielding/conductive-shielding-paint.html

Edited January 24, 2021 by Matthew Abate

[grannyknot]

I spent a lot of time using the conductive paint technique to try and get mine working and finally threw in the towel, such fiddly work.

Now now I have 30% tint film on the glass and a working defroster grid probably would not be a good thing for it,  I'm sure you have seen what happens over time with that combination. 

[Matthew Abate]

14 minutes ago, grannyknot said:

Now now I have 30% tint film on the glass and a working defroster grid probably would not be a good thing for it,  I'm sure you have seen what happens over time with that combination. 

True, but new cars have this, so it must be possible. Maybe it's up to the place that does the tinting.

[Mark Maras]

 I removed the tint film from our Subaru. The film used on the rear, over the defroster, was much thinner than the tint film used on the side windows.