RE: Hail damage
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RE: Hail damage - 7/1/2008 9:08:52 AM
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klrspz
Posts: 946
Joined: 9/30/2007
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Little bit of trolling to be done here::::
@nafango2:
actually if you use cold water, it will be more dense... In soft water, this procures a higher concentration of sodium; in harder water this has almost no effect. In hard water, you''ll still have the same amount of dissolved solids present regardless of temperature. boiling it for a while however reduces the concentration of the water, and leaves the deposits behind. so the more you boil water away, the more crap you are leaving in the water to be consumed.
for this among other reasons, i bought a filtration system for the entire house, which *naturally* softens the water (instead of how most systems infuse/dissolve salt into the water)
@01 vtec nc:
Actually that couldn''t be any more wrong.... really...
It''s been proven for HUNDREDS of years that cold water DOES NOT BOIL faster than warm water...
What HAS been proven, is that cold water reaches TOWARDS (but not yet boiling) 100F (boiling point of water) faster than water that is already 90F. Heat transfer is based on (among MANY MANY MANY things) the cardinal difference between the base temperatures...
I.E., 50F -> 100F would have 50 calories times the volume of grams of water to heat up; where the other 90F water would only have 10 of these same units to heat up.
Because of this, the thermal difference is made up faster in the colder water, however as it reaches closer to the 100F temperature - say the 90F range - it actually ends up equaling out.
Most people take either of these two sides:
1 - They just take it for granted, and think that cold water does boil faster...
2 - They think that since water boils at 100F, and the water is colder, it takes longer to heat up....
What most people don''t realize is that heat transfers are in no way LINEAR, and often change depending on the medium. In this case we''re talking water, so therefor the rate would be equal between both scenarios until similar heat has been achieved; however a piece of metal would rapidly change it''s density which would cause it to also change it''s thermal transference abilities. In the case of a car, surface area also has a huge play in that. This can be proven by running this exact experiment at home; you''ll see that the cold water gets very warm very fast, but they both will boil at the same time (or really damn close).
So if you only want warm water, this is a sure-proof way to get it there fast, but if you want boiling faster it''s actually best to start with lukewarm water. Cooling does NOT follow the same principle!!!!
Do some research, it''s all over the place!
On the same Accord (no pun intended), your statement about the compressed air is also completely opposite. It is USUALLY VITAL that you cool the area first in order to constrict the molecules in the metal. By heating them, you are forcing them apart, and causing them to move rapidly; thus it "pops" or pushes the dent out.. It is possible, however that doing as you stated would remove the dent, but you also have the unfortunate possibility of making it worse. it depends on the surface tension of the material, size and depth of dent, and the angled direction it''s facing.
For evidence of this, take an EMPTY aluminum can and submerge and boil it in water.. then take some very cold ice water and submerge the can in that... The can crushes itself... you want the exact opposite.
And also opposite, is that it works on large/wide shallow dents, not small (which are deep due to the low surface area) ones...
And LASTLY... you''re not changing volume of ANYTHING... the statement that follows is the most ridiculous one i''ve heard in a while:
quote:
But the compressed air thing is true; rapid change in volume = change in temperature.
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RE: Hail damage - 7/1/2008 11:00:34 AM
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01 vtec nc
Posts: 25
Joined: 6/26/2008
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wow, uh, sorry to offend you... Don''t know if it required such a flame, but ok. I was not making random claims, I''ll give you the boiling water point, there is no definite proof that either way boils faster or if they boil at the same time. As far as the compressed air goes, I did a little research, since it is all over the place; I found this and copied it here:
According to Boyle''s law, the pressure exerted by a given quantity of gas[link=http://www.answerbag.com/q_view/37186#][/link] increases as the volume of the gas decreases at a constant temperature. According to Charles''s law, at a constant pressure, the volume occupied by a given quantity of gas decreases as the temperature of the gas decreases. According to Avogadro''s principle, the volume occupied by a gas depends directly on the number of gas particles at a constant temperature and pressure. If all three of these laws are combined, the result is V= R*((nT)/P). R is the universal gas constant which is equal to 0.0821 L*atm/mol K (Kelvin). By multiplying both sides of this equation by P, the equation would become PV=nRT, the ideal gas law. Note: P=Pressure (atm), V=Volume (L), n=number of moles, and T= Temperature (Kelvin)).
So, PV=nRT means Pressure * volume = numberber of moles * 0.0821 * Temperature.
Without getting into too much detail, let''s say that temperature is directly proportional to pressure and volume.
When volume (the can) is constant and pressure decreases, the temperature also decreases. Look at it this way: PV=T
For example (omitting the units should avoid further confusion), P= 10, V= 10, T= 100
10 * 10 = 100.
Let''s lower the pressure to 8. P= 8 V=10 (again, this is constant), T= 80.
8 * 10 = 80.
The same works in reverse. When the can is a constant size, increasing the pressure increases the temperature.
PV=T
We''ll start the with the same ammounts:
P=10, V=10, T= 100
10 * 10 = 100
Let''s raise the pressure to 120.
P=120, V= 10, T= 1200
120 * 10 = 1200
On the issue with the dents in the accord: both ways should work equally well, when the molecules are spread apart like when it is hot and you cool it quickly, the molecules will suddenly constrict and "pull" the dent out. It is not going to make it worse because it is going to take more pressure to push the dent in and bend more metal than pull it out and fight the force of unoccupied space.
Apparently you already know how it works when you do it the other way around so I won''t go to the bother of explaining it other than the fact that you are then pushing the dent out instead of pulling it.
_____________________________
2001 Accord EX 3.0 VTEC (My new baby)
1987 Camaro IROC-Z28 5.0 TPI (Currently for sale $3500)
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RE: Hail damage - 7/1/2008 11:26:26 AM
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01 vtec nc
Posts: 25
Joined: 6/26/2008
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Oh and klrspz, I don''t know why you felt the need to flame me with faulty information, but if you had done some of the research you are so fond of you would have found quite a few articles, pictures, and even videos of people doing this dry ice dent removal with little to no problems.
Saying that, this is not the perfect solution, klrspz idea of cooling first and then heating might work better for some dents, I don''t know, I have NOT done the research and won''t make claims on something I don''t know. Either way, this method seems to work well with small to medium size hail dents; there was a very small change in the tiny dents, and I didn''t have any dents big enough to test the method on them.
Oh and it didn''t hurt my paint or clear coat at all, when it got cold, it discolored and I kind of freaked out, but after like 20 seconds it went back to its perfect shine.
_____________________________
2001 Accord EX 3.0 VTEC (My new baby)
1987 Camaro IROC-Z28 5.0 TPI (Currently for sale $3500)
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RE: Hail damage - 7/1/2008 1:01:00 PM
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klrspz
Posts: 946
Joined: 9/30/2007
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Actually, I didn''t flame you, i was pointing out your inaccuracies... there''s a difference... I''ll try to keep this to pointing out facts and NOT flaming
Also, you didn''t offend me or anyone, I just wanted to point out some facts...
In regards to the volume thing, I misread what you were talking about; i thought you were talking about the volume of the panel on the car... in that respect, you have to understand how silly that sounds... my bad.
Anyway, I didn''t flame you with faulty information in fact, it''s science...
It''s not only more logical to consider that cold water can''t boil faster, but is indeed scientifically proven countless times that it is in fact a FALSE CONCEPT that cold water boils faster than warm... It''s proven, over and over.. You can easily try the experiment at your home..
You can even invest tens of thousands of dollars into thermodynamic tools it would require to mathematically prove it as well... Not only have I done it with such high-end equipment, but you can find the information free-flowing on the Intarwebs. This is called Physics 101, and is usually the first or second lab experiment you do after class... Something along the order of "Watch Mr. Wizard" type difficulty.
In Thermal Physics (thermodynamics, kinetics, etc) [which my minor in Physics happens to be specialized in; as well as E&M], heating a cooled item and cooling a heated item are completely different, and require completely different things to occur. Sure the end result is technically the same in terms of the thermodynamics, but the kinetics and stat. mech''s behind it are not even close in magnitude. You can''t say that heating up water to a gas and bringing it back to water are near the same thing, there''s so much going on there. There are so many statistical things you have to consider... AND, you have micro and macro states that define what''s truly happening at any given moment (think instant velocity). It could certainly play a big role in terms of how effective or damaging these techniques could provide... However without proper equipment, specific stats at hand, and the time/effort to put into it you MIGHT be right that it doesn''t matter in the order... However, in the right scenario, it means all the world.
I not only have a Majors in MATH, BUSINESS, and COMPUTER SCIENCE, but I have a minor in Physics. I''m not trying to be a dick, nor am I trying to be difficult; but apparently you were butt-hurt about the facts I presented... So much so that you thought it wise to present a formula. I know you didn''t come up with it on your own and copy/pasted it, but the original author remove parameters from it without any stated assumptions.. And BTW in this equation, PV ≠ T; but rather PV/nR = T; there''s a HUUUUUGE difference there. I''m not an engineer, but they''d surely argue that all day and night with you.
Also, that proves it to be non-linear in multiple ways, again going to thermal stats. In your examples you''re unstated assumption that your gas contains the same number of moles during use; which is not the case. Your "mole usage" will be at a different rate than that of the pressure in the system. Hence why (and you probably didn''t have any clue to this) this is called the "Ideal gas law" as it''s ideal to find out the real values of a hypothetical mechanical state of a gas. In the stated reference above, he actually ignores the fact that there are about 3 other formulas involved to actually derive to his final equation, all of which are very important.
If I have offended you, then I apologize; however I know I''m right so there''s no point in arguing over the internet.
I merely wanted to point out the boiling water tid-bit, and to inform you of the science about what is gong on.
What brought me in closer with some people on this forum, as well as the forum in general, is the attention to details and the accuracy of information portrayed is very important to us. We don''t like half-assed answers (unless we''re kidding around) and we certainly don''t like to guess.. i could be speaking for more people than I should, but this is how I -definitely- am.
Now, back on topic after all that....
If YOU would have read, I''ve never stated that it doesn''t work, or will not work...
In fact, I''m the one who first posted links to said video in this thread. I know it''s done, I''ve seen it done; I know it *can* work.
Also, you don''t state exactly which technique you attempted.
And also can you circle your dents in your pictures? I can''t make out what''s a dent and what''s a shadow of a curve or reflection... also since they aren''t directly associated with eachother I can''t tell which goes with which.
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Silver '03 Honda Accord LX i4
My Car
Accord Link Collection
Wiki I'm Starting - http://hondaaccord.wikidot.com
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RE: Hail damage - 7/5/2008 12:41:52 PM
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01 vtec nc
Posts: 25
Joined: 6/26/2008
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A little update; I didn''t take the time to check up on the dents. It seems they have popped back, when the car heated back up in the sun. No worse, just the same as they were before. I don''t think the car was hot enough before I did it. I could have also kept the ice on for longer.
I think this would work if someone wanted to take the time do it right. I just have a couple hundred dents and hate spending that much time.
_____________________________
2001 Accord EX 3.0 VTEC (My new baby)
1987 Camaro IROC-Z28 5.0 TPI (Currently for sale $3500)
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RE: Hail damage - 7/6/2008 10:07:30 AM
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dksix
Posts: 6
Joined: 7/4/2008
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I don''t think the pops a dent will work on dents that small . I''ve only used on one , but the smallest puller base in the kit I got was 1" . I looks to that the puller would have to be small enough to fit down in the dent for it to pull it out . I could be wrong , like I said just used it once .
BTW , I don''t know if hot or cold water freezes faster , but I''ve found that if I put hot water in my ice trays the cubes come out without breaking and they break when filled with cold water . And that''s information I can use , lol . six
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91 Accord LX Coupe
First Honda & First FWD
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