Using heat gun to defrost windows?

Red Squirrel

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May 24, 2003
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Is this a bad idea, could it cause damage? Would not use the highest setting, maybe 50 or 100C with fan full tilt and hold it far enough away.

I bought one for another project then I realized I could maybe use it in the morning to speed up window defrosting. Has anyone ever used one for this purpose before? My windows tend to frost both outside and inside. I normally just let the car run for a while to do a full window defrost but that's a huge waste of gas and money. The heat gun was on sale for like 30 bucks so it will pretty much pay itself in a few months.
 

Rubycon

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Aug 10, 2005
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How many watts?

WATTS important is how fast you move the nozzle. Park it in one spot for any period of time and you can fracture a pane. Keep it moving at all times!
 

Red Squirrel

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It has adjustable settings, think it goes from 50 to like 700C so I'd probably want to keep it at 50 and have the fan at full speed, and yeah keep moving it. I believe it's 12 amps but that's probably on the highest setting.
 

Rubycon

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LOL you're going to want the HIGHEST setting - just keep it moving!

Sounds like a hair dryer. ;)
 

Red Squirrel

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Figured I'd start low and work my way up until it works, but if highest is what is needed then I'll do that. And yeah it's basically like a blow dryer except this one can burn wood. Really I'd be curious to know how it works considering it uses the same amount of power as a blow dryer, guess it concentrates the heat more effectively.
 

Rubycon

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Figured I'd start low and work my way up until it works, but if highest is what is needed then I'll do that. And yeah it's basically like a blow dryer except this one can burn wood. Really I'd be curious to know how it works considering it uses the same amount of power as a blow dryer, guess it concentrates the heat more effectively.

Watt density is what determines air temperature rise and discharge. If you pack a lot of watts into a small area and move the air slower it will be hotter. If you partially cover the inlet on a 1.5kW blow dryer the air coming out can singe hair! Be warned though it will make the elements run much hotter and they are fused with a one shot (microtemp usually) that if opens renders the appliance inoperable. Some have a self resetting bimetal strip with a higher temp rating microtemp as a final safety, etc.

They're fun to play with and cheap and a good source of parts for other things too. :)
 

SSSnail

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Nov 29, 2006
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A bucket of warm water is much better (possibly the best method), it may be a bit messy but it'll clear up fast. As for the inside frost, warm it up.
 

iGas

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Feb 7, 2009
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I use a hot bottle/can of water and it has work very well for many years.
 

EightySix Four

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Jul 17, 2004
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Seriously? Warm/hot water on a frozen window? Now I'm from Texas and have never had a window frozen enough to require more than a 15 second scrape/windshield wipers to clear up, but I have always been told warm/hot water will crack/shatter glass.
 
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SSSnail

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Nov 29, 2006
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Seriously? Warm/hot water on a frozen window? Now I'm from Texas and have never had a window frozen enough to require more than a 15 second scrape/windshield wipers to clear up, but I have always been told warm/hot water will crack/shatter glass.

HOT water will, not warm water. Your auto glass is not your wine glass.
 
Mar 11, 2004
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Just put cardboard saturated with a water/vinegar mixture on your windshield the night before and you'll be fine.

Disclaimer: DO NOT ACTUALLY DO THIS.
 

DietDrThunder

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Apr 6, 2001
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You don't even need warm water, just warmer than freezing. My windshield was frozen when I went to leave work and I didn't have a scraper. I pulled my almost full water bottle out of my lunch box and poured it on the windshield while running the wipers. Cleared it off real quick.
 

Yowen

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Nov 22, 2004
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screw that... I dont wanna break my window, I am happy to do the cardboard thing or the scraper... Windshields dont like extreme temperatures and I imagine quick, possibly localized changes could be very bad. My windshield cracked once just sitting in a hot driveway.
 

StageLeft

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Hot glass made suddenly cold will crack it. Will cold glass made suddenly hot do the same thing? i suppose probably but perhaps there is a difference.
 

Yowen

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yeah, I had my car parked for like a week or so in the summer, in a hot driveway, I came back to a crack.
 

rh71

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Aug 28, 2001
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You don't even need warm water, just warmer than freezing. My windshield was frozen when I went to leave work and I didn't have a scraper. I pulled my almost full water bottle out of my lunch box and poured it on the windshield while running the wipers. Cleared it off real quick.

I think it's pretty cool that you have a lunch box. :awe:
 

SoulAssassin

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Feb 1, 2001
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I wouldn't do this. Do you know how much gas you burn in the 15 minutes it takes the car to warm up/defrost? I dunno either but it's next to nothing. You don't need to melt all the ice, just the part against the windshield and then it typically comes off in a sheet.
 

SearchMaster

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Jun 6, 2002
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When I try to use water to get the ice off, it usually ends up refreezing, and I live in the south. But it's probably another example of "you're doing it wrong" since I don't have to do it very often :)
 

herm0016

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Feb 26, 2005
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seems like pouring water over ice will melt it only untill the water freezes again, after it has all run into your engine compartment and cowl vents. just use a scraper or get a can of de-icer. the spray stuff works pretty well, usually just alcohol or glycol or some mix.
 

hanoverphist

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Dec 7, 2006
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Just put cardboard saturated with a water/vinegar mixture on your windshield the night before and you'll be fine.

Disclaimer: DO NOT ACTUALLY DO THIS.

ive never heard that one, what does it do


and i live in az, so frozen windshield to me means a fine layer of frost that will easily come off with a cold spurt from the hose.
 

Zargon

Lifer
Nov 3, 2009
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A bucket of warm water is much better (possibly the best method), it may be a bit messy but it'll clear up fast. As for the inside frost, warm it up.


bad idea.

that just makes a puddle of ice on your driveway and will also help your locks freeze etc when the warm water runs all over the car, then freezes


just turn the damn car on 10 minutes before you want to leave, not only will it defrost the windows, but the inside will be warm, and fleabag will come tell you that you are a moron and are ruining your cars engine


now I am not from WI or MINN or the UP, but it gets pretty damn cold in IL, its about 10 our if Im lucky right now.
 

Gibson486

Lifer
Aug 9, 2000
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Hot glass made suddenly cold will crack it. Will cold glass made suddenly hot do the same thing? i suppose probably but perhaps there is a difference.

yes...glass needs to expand close to a uniform rate. One extreme to another will crack it.
 

SSSnail

Lifer
Nov 29, 2006
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If you live anywhere that water will just freezes immediately when you pour it over the windshield to de-ice, you need to move to a warmer place.

And no, your windshield won't crack if you just pour luke warm water over it, if it does, you have shitty windshield and it's time to get another car.
 

EightySix Four

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Jul 17, 2004
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If you live anywhere that water will just freezes immediately when you pour it over the windshield to de-ice, you need to move to a warmer place.

And no, your windshield won't crack if you just pour luke warm water over it, if it does, you have shitty windshield and it's time to get another car.

C5 Corvette windshields are pretty easy to crack, they are thin to save weight and are also made a bit differently for the HUD.