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Dave WM

window defrost grid

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

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the trial wipe with glass cleaner and a paper towel worked well no effect. I get about 2 ohms per inch on the 1/16 stencil line.

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I am hoping that the remains of the old grid act as a good surface for applying the new paint. So far I have done test application on only smooth clean glass. The rough texture of the old grid may help with the stencil on new adhesion..

Edited by Dave WM

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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.

Think I did that right sound like enough power to warm the glass. can you check on this captO

oh and the stencil lines are about 50% wider than the orig at least from what remains. the stencil is for 1/16.

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.

Edited by Dave WM
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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.
Think I did that right sound like enough power to warm the glass. can you check on this captO
oh and the stencil lines are about 50% wider than the orig at least from what remains. the stencil is for 1/16.
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.


Nice work! That should definitely add some warmth!

And on glass removal, don’t even!!! Get a friend around with a face mask, you will kick yourself if you damage bodywork or drop the glass!!! Especially after that hard work!

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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.
Think I did that right sound like enough power to warm the glass. can you check on this captO
oh and the stencil lines are about 50% wider than the orig at least from what remains. the stencil is for 1/16.
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.


Nice work! That should definitely add some warmth!

And on glass removal, don’t even!!! Get a friend around with a face mask, you will kick yourself if you damage bodywork or drop the glass!!! Especially after that hard work!

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10 hours ago, Zup said:

That was lifted from frost fighters website.

Apparently there is no residual material after application---only the lines.

A purpose built grid that matches in lengths, spacing and element thickness should be as close to original as one is probably going to get and in my mind would likely be a better performer than a mix of old and repaired segments or a new conductive grid with irregular thickness (hence resistive) properties.

I appreciate your "do it myself" approach and applaud you for it. My only intent here is to see if there is interest in a quality one source solution that virtually anyone can purchase and install with a minimum of hassle and a maximum of performance.

So good to see you around Jim. Will miss seeing everyone at Zcon...I would be in for at least 2 grids, maybe 3

@Dave WM

I think I would want a solvant based product and in enough bulk to use a touch up spray gun

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

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5 hours ago, Dave WM said:

My biggest prob right now is trying to figure out how to remove the hatch by myself.

I'm sure others have succeeded at this task.  In my case, I used my engine hoist.  I wrapped the hatch using HF-quality cargo straps -- one strap along the vertical centreline, the other along the horizontal CL.  I used zip-ties at the crossover points so as to make sure that the straps didn't walk under load.  Lift cautiously.  Study the balance. Watch to ensure that nothing shifts.  Make sure in advance that you know where you're going to drop the hatch panel after removing it.  A set of movers' blankets is a good idea for protecting the hatch paint once in storage.

BTW, I successfully re-installed my hatch (a much bigger challenge, BTW) using the same process in reverse.

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3 minutes ago, Namerow said:

I'm sure others have succeeded at this task.  In my case, I used my engine hoist.  I wrapped the hatch using HF-quality cargo straps -- one strap along the vertical centreline, the other along the horizontal CL.  I used zip-ties at the crossover points so as to make sure that the straps didn't walk under load.  Lift cautiously.  Study the balance. Watch to ensure that nothing shifts.  Make sure in advance that you know where you're going to drop the hatch panel after removing it.  A set of movers' blankets is a good idea for protecting the hatch paint once in storage.

BTW, I successfully re-installed my hatch (a much bigger challenge, BTW) using the same process in reverse.

And masking tape on the roof around the hatch hole where the hatch might touch too. Hood is easy one man, hatch not so much...

Take the hatch strut off first. Not that I’ve ever forgotten to....

Edited by zKars
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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.

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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.       :geek: 

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.

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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!! 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!

 

3c150bc014763481e3e290f08459f154.jpg&key=2d0a4e2f58b8cb82fd98a560702309ea0b5df8344037ee33514594d7dcd8947d

 

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

 

86991fe093961b0014ca6fc7a4a66e52.jpg&key=b063d023467486a04d7d69a59a2495b7ab6653ff4f09cb883897b4b4f7077b38

 

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.

 

 

 

 

 

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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).

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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 by zKars
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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.

 

 

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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...

 

 

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