Anythingclose,anythingclose wrote:The reason I mentioned 160 degrees was because as I have been reading through the forums, from oldest to newest, I came across a topic wherein the inventor of the drystar came here for a little Q&A. In that thread, he mentioned that he wanted a tool with low heat because it was safer. He mentioned his tool only heated up to 160 degrees, and that while that wasn't enough to boil water, it certainly was enough to rapidly speed evaporation. Water will evaporate even at room temperature given enough time and a dry enough atmosphere surrounding it. The hotter/dryer the atmosphere is around it, the faster this will occur. While I don't know exactly what his intentions were when inventing the drystar, I believe he intended it not to boil the water necessarily, but instead to simply speed the evaporative process that would occur naturally in a dry/hot enough environment where no additional moisture was being introduced.
I have known Barry Slavin, the inventor of the Drystar moisture evaporator for a very long time, and I could have sworn that he was the one who told me that the secret of the tools performance was that it raised the water in the glass to boiling temperature or 212 degrees, which made sense to me as you can literally see it start to bubble inside the break for a couple of seconds before it disappears. However, I cannot find anything in writing from Mr. Slavin to prove that is what I was told, and I must confess that until today I did not perform any temperature testing on this tool myself. Today I did a few tests that provided some interesting results.
I used a high end infrared thermometer for my testing. First I checked the heating element and found that I could not get a consistent reading, but it did consistently reach temperatures well over 300 degrees and spiked to considerably higher than that. Next we checked the glass temperature and found it to be 69 degrees. The air temperature in our shop was also around 69 degrees. Following the instructions for the Delta Kits DS100 moisture evaporator (Drystar) we heated the element until it was red hot and then placed it on the glass directly over the repair for 20 seconds. Immediately after removing the tool from the glass we again checked the glass temperature and found it was only about 125 degrees and began cooling very rapidly. Within a 30 seconds the glass was under 100 degrees and within 2 minutes it was very close to the original temperature of 69 degrees. We repeated the test several times with similar results each time, but found that because of the transparency of the glass the readings were affected by whatever was behind the glass.
We then ran the same test again several times using a metal saw blade rather than the glass. While metal heats up and dissipates heat at a different rate than glass, we found that the results were similar but this time more consistent. We then ran the test on the saw blade starting with a glass temperature of 80 degrees, 100 degrees, 120 degrees, and finally 150 degrees. Normally I would warm the glass to a minimum of 80 degrees before using a moisture evaporator. Understandably, the starting temperature had a dramatic affect on the final temperature, so when we started with a temperature of 150 degrees the final temperature of the saw blade was over 215 degrees.
What we concluded from our testing was that there are far too many variables to accurately state that the Drystar heats the water in the damage to a certain temperature, but I would have to say that if you are starting with a glass temperature of 100 degrees or less your final glass temperature is probably closer to 160 degrees than it is to 212 degrees if limiting the application time to 20 seconds. That's not much hotter than a windshield that has been parked in the sun in Arizona on a 115 degree day which would explain how a break can be dry in a very short time after going through a car wash in a hot dry climate. Although it is possible to heat the water to 212 degrees with the Drystar, that is not the typical application and there is no need to do so as the water evaporates far before the glass ever reaches that temperature. Another variable is how close to sea level one is. Eugene is about 400' above sea level, so it stands to reason that someone working at 5000' above sea level would have to use even less heat to get the water in a break to evaporate.
Our testing did validate the claim that under normal conditions the inside of the glass will only be warm, not hot, to the touch when it is heated from the outside with a Drystar as recommended. Our testing also validated the claim that the outside glass cools very rapidly after removing the tool due to the fact that it is heating very rapidly and in a very small area.
In summary, when used in accordance with manufacturer instructions the Delta Kits DS100 moisture evaporator, or Drystar, does not heat the glass to a dangerously high temperature, but does heat the water in the break to a point in which it will evaporate within a matter of seconds, and does so in such a way that the glass cools to it's original temperature within a matter of minutes.
Thanks for setting me straight on this. I have been stating something for years that was not 100% accurate based on what I was told, rather than on verifiable test results. I know better than that and feel a bit foolish, but I don't think it has caused any harm other than I may have lost some sales because technicians were unnecessarily concerned about the excessive heat output of the DS100. Hopefully this data will be helpful to glass repair technicians who read the windshield repair forum. I know it will be helpful for me. Who said an old dog can't learn new tricks?
