<a href=showthread.php?s=&postid=11420216#post11420216 target=_blank>Originally posted</a> by dhnguyen
Nobody ever thought the Vortech would have caused THAT to J's tank and it did so....
Not really, at least by itself in my opinion. There were several causative factors involved and the heat from the pump was but one of them. Please understand I'm not trying to re-hash this but since the misinformation is still going around, I'll correct what I can to the best of my ability.
The factors include:
Tank itself: the tank itself is made thinner than most of it's size. 35" in overall height, 32+" inside is pushing the limits of what the 3/4" material should be expected to accommodate.
Tank material: the tank was made many yrs ago by a company that is long defunct so the material used can never be known, therefore it's physical properties are unknown so it's propensity to craze is also unknown. I'm not saying the material is extruded or anything else, I don't know - but it is a question mark. Since there is assumably little/no other crazing on the tank, I'm assuming it's good material but am not absolutely certain.
Heat from pump: I think heat is a factor as it is a stressor, simply put. Probably at the borderline of what is a tolerable working temp for the material. Any heat spikes would not be helping any.
Pump replacement on a crazed area: The affected area had some initial crazing. This was discovered and then the pump replaced in the same spot. It is far easier to aggravate an existing crazing problem than to start a new one since the area already has some fractures.
Quick explanation:
You cannot craze acrylic strictly from heat alone, you simply can't do it in a realistic fashion. If you apply heat to plain ol' acrylic, it will deform, soften, become pliable, bubble, fry, melt, then self ignite, but will not craze. We've all seen bowfront tanks and other thermoformed acrylic, it is heated to ~300F and yet doesn't craze. But, place the heat source on an area of acrylic that is already being pushed to it's potential and you can get the initial crazing. Replace the pump in the same spot for another year or so and the crazing problem grows to what it is now. There may be other contributing factors as well.
FWIW, this is just my opinion after reading as much of this as I could and saw there was some misinformation going around and thought I'd try to provide some insight.
Hope all is well,
James