QuestionQUESTION: G'day! I've been told that when welding plastics, there can be NO moisture in the area to be welded. Does "NO" mean 0%, or maybe 2, 4, 10%?
ANSWER: Dear Michael, I suppose you know that welding is accomplished by using the same polymer(in this case Polypropylene)and not sealants, putties, glues or adhesives of any sort. So, it does not matter to have some moisture around cracks, as water will vaporize when using the 40 watts soldering iron which according to experience, may reach up to 230º celsius. This is true welding. Just add more PP in the affected area and then some EVA on top (hot melt glue)if our concern is a cold water tank.Thank you.
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QUESTION: Actually I'm primarily using an Extrusion Welder, with the Extrudate @ 500degF, & the Heat blanket at 260 deg Celcius. Then at the tighter areas, an Injection welder set to 285 Celcius. I HAVE found in the past that w/ the Injection unit, even at THAT heat --- moisture will prevent a true fusion. As I recall the moisture was Visible. Perhaps that's IT then, .... as long as it's not VISIBLE? You see, when I 1st began routing out the old weld.... suddenly, I could see a few drops of moisture coming up out of the crack(where the 2 -- 3/4" thick walls met at 90deg).
AnswerHi Michael,according to my experience, this does not seem to be an automotive application. A 3/4" wall thickness is far from ordinary in car plastics.May be Im not qualified to offer a professional application. However, I understand you have plenty of good tools (have you tried hot air with the Leister gun nozzle?). I would suggest to ask for assistance in Wegener for instance,At info@wegenerwelding.de I am sure they will be glad to help you.I will appreciate if you let me know the final results of your project.
good luck, Octavio.
