Again a GREAT video Skip !! Starting up your PA is similar to starting up an airplane 🙂 and it is NOT a boring movie. Some comments: -John has a very good point on the steel wool, i am sure thats the pollution. -Why not use LOW viscosity transformer oil, this oil has an excellent electrical insulating and is stable at high temperatures -Spring clips clamps for fuel tubes are very good, never had any problems. I am also using watercooling on my 70, 23 and 13cm SSPAs, i am very pleased with it. Have used oil cooling on my old 2 x 2C39BA PA for 23cm with very good results also, but changed to a SSPA years ago. 73s de Jac, PA3DZL
Hello Paul, yes the room is a must with this kind of setup.. My first shack was in two small rooms in an old farm house. I had to stand on my head to get at things like a typical ham shack.. I said to my wife when we move or buy a place I am taking over half the basement which I did, actually more like 3/4 of the basement ha ha.. Skip
Perhaps the source of the crud could be something chemical that slowly leaks out of the PVC tubing - a new, fresh ring of PVC hose from the shop often has a characteristic light smell of PVC. If whatever leaks out of the PVC is possible to smell, maybe it also dissolves into the water to some extent and gradually makes it more conductive. Silicone hoses might be better in this aspect.
No its mainly the High Voltage breaking down the water and dissimilar metals all mixed in, electrolysis etc.. Plus there is things that grow in the water when it has the air exposed to it in the tanks.. Microscopic stuff i have been told, then dust etc.. It all adds up... I just wonder why one cavity is so much worse than the other side and why just the two tubes.. Skip
@@VE6BGTHave you tried switching the order of the hoses around and watch if the problem somehow moves? Maybe the flow rate in the individual lines is not exactly equal due to some weird turbulence pattern forming in the manifolds. I experienced water doing strange stuff like that in heating systems: One radiator gets hotter than the other for no apparent reason. Anyway, very interesting to see the practical challenges of water cooling when High Voltage is involved. The big old broadcast transmitters that used 10kV or higher voltages and evaporative cooling must have been even more critical as far as water purity etc. is concerned...
The cleaning with steel wool that you did most likely left particles of steel embedded in the parts that you cleaned , these embedded particles will soon rust and discolor your water. I would recommend something like scotchbright pads instead. Loved the video though!
Good point John.. Thats something I never thought of.. It was done mostly on the outside of the copper tubing where as I used emery paper on the insides.. But I did use steel wool on the inside of the older water manifold.. Good thing I replaced that !! I wont do it with the new manifold next time.. But still why only is it real bad on one cavity and especially those two particular tubes?? Skip
Hello Pateick, well your speaking Greek to me now ha ha.. The thing is adding anything to the distilled water usually makes the water more conductive to the HV that is on the tubes and which the water is touching.. Not good.. I have to go back and look at the video and see if I mentioned this.. Your not the first person to comment on this.. Thanks, Skip
Ok I see what your saying.. Well I dont really know what all that is or where I would purchase it.. Probably for my small operation not worth it?? Skip
Maybe a water filter in the line to catch the crud might extend your teardown interval. That brown slime looks like metal eating bacteria. Perhaps a flush with vinegar or bleach would help.
Wow that was quick haha.. Well a filter of some kind would restrict water flow and cooling probably.. That's not the issue really, the crude build up is from the voltage reacting with the water and metals which break down the insulating property of the water.. The crude is the side effect from this reaction, normal actually.. The thing that puzzles me is why one cavity circuit is worse than the other side etc.. Then on that bad side these two tubes are the worst against all eight tubes.. One of those mysteries.. Skip
Wow that's a good idea.. That's a thought for sure.. I didnt want to move the tubes around yet but next time I will pay close attention to all this.. Maybe it's the manifold, being now I have a newer or different manifold, I will have to really look at this.. Thanks.. Skip
Hello David, no I cant use any kind of additive due to the fact that the fluid comes in contact with the High Voltage (1600 VDC) on the brass water jackets on the tubes.. Antifreeze or any other additive would make the water really conductive and the HV would really leak or short out to ground. Thats why distilled water is used.. Its conductive properties are a lot better than ordinary water, especially my water here at my house that is real hard full of chemicals, it would be a dead short ha ha.. There was this silicone based fluid that was really non conductive but the price was just enormous, would have cost me thousands of dollars to use back then.. Distilled water has been the fluid used by all of us crazy amplifier builders.. Skip
@@VE6BGT What about mineral oil? You can buy it cheap in gallon jugs from farm stores. It is non-conductive. It's a much better insulator than water. It is used as a coolant in high voltage power transformers and dummy loads.
I guess the thing that has some other hams concerned about with mineral oil is that its flammable. I have been talking with another ham here about it again today and I just might get some and do some side experiments.. I have extra pumps and can try things to see what it would be like.. Something to think about for sure.. I know I have used mineral oil in RF dummy loads before instead of old transformer oil with PCB in it !! Something to think about.. Thanks, Skip@@stargazer7644
