- Can somone explain WHY positive first when jumping a car battery? - 12 Updates
- Vintage Radio Dial Cord Replacement - 4 Updates
| David Lesher <wb8foz@panix.com>: Jan 19 07:23PM You want the spark when disconnecting to be AWAY from the rapidly charging battery. So: Run the negative from frame to frame, and disconnect at the rescue car first. -- A host is a host from coast to coast...............wb8foz@panix.com & no one will talk to a host that's close.......................... Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433 |
| "Rod Speed" <rod.speed.aaa@gmail.com>: Jan 20 07:41AM +1100 David Lesher <wb8foz@panix.com> wrote > You want the spark when disconnecting to be AWAY from the > rapidly charging battery. There is no hydrogen when the once flat battery is being charged once the engine has started. |
| Peeler <trolltrap@valid.invalid>: Jan 19 09:45PM +0100 On Fri, 20 Jan 2023 07:41:53 +1100, cantankerous trolling geezer Rodent Speed, the auto-contradicting senile sociopath, blabbered, again: <FLUSH the abnormal trolling senile cretin's latest trollshit unread> -- Bod addressing abnormal senile quarreller Rodent Speed: "Do you practice arguing with yourself in an empty room?" MID: <g4ihlaFh5p5U2@mid.individual.net> |
| "Mighty✅ Wannabe✅" <@.>: Jan 19 04:28PM -0500 Rod Speed wrote on 1/19/2023 3:41 PM: > is being charged once the engine has started. >> So: Run the negative from frame to frame, >> and disconnect at the rescue car first. I real life scenario there is no danger of hydrogen accumulation under the hood because it is too airy inside the engine compartment. There will be danger of hydrogen accumulation if the lead-acid battery is confined inside a box, like underneath a motorized wheelchair. |
| scott@slp53.sl.home (Scott Lurndal): Jan 19 10:04PM >the hood because it is too airy inside the engine compartment. >There will be danger of hydrogen accumulation if the lead-acid battery >is confined inside a box, like underneath a motorized wheelchair. Then why do space launch vehicles use burners to ensure that any H2 that pools around the launch site is burned off before launch? Far more "airy" environment than any automobile engine compartment. |
| "Mighty✅ Wannabe✅" <@.>: Jan 19 05:48PM -0500 Scott Lurndal wrote on 1/19/2023 5:04 PM: >> is confined inside a box, like underneath a motorized wheelchair. > Then why do space launch vehicles use burners to ensure that any H2 > that pools around the launch site is burned off before launch? Have you actually seen a rocket launch? The launch rocket itself is a gigantic blowtorch which would have blown away or ignited "any H2 that pools around the launch site". Besides, H2 doesn't "poll around the launch site" because hydrogen is much lighter than air. Any leaked H2 would have risen up into the heavens. |
| scott@slp53.sl.home (Scott Lurndal): Jan 19 11:32PM >> Then why do space launch vehicles use burners to ensure that any H2 >> that pools around the launch site is burned off before launch? >Have you actually seen a rocket launch? Yes, and a shuttle landing as a guest at Edwards. Note that the SLS uses shuttle main engines. https://space.stackexchange.com/questions/35983/what-are-the-sparks-flying-at-the-bottom-of-ssmes-at-the-time-of-launch "At T minus 10 seconds, the "go for main engine start" command is issued by the GLS. (The GLS retains the capability to command main engine stop until just before the SRBs are ignited.) At this time flares are ignited under the main engines to burn away any residual gaseous hydrogen that may have collected in the vicinity of the main engine nozzles. A half second later, the flight computers order the opening of valves which allow the liquid hydrogen and oxygen to flow into the engine's turbopumps." |
| "Mighty✅ Wannabe✅" <@.>: Jan 19 07:02PM -0500 Scott Lurndal wrote on 1/19/2023 6:32 PM: > of the main engine nozzles. A half second later, the flight > computers order the opening of valves which allow the liquid > hydrogen and oxygen to flow into the engine's turbopumps." The person who wrote that is definitely not educated enough to know that hydrogen rises and won't stick around at the base of the rocket. That is the most laughable thing a person can say. The real reason for the flares shooting at the rocket nozzle is an insurance policy that in case the internal ignition mechanism failed to ignite the hydrogen fuel mixture, the flares will guarantee the hydrogen fuel will be ignited. Image if the hydrogen fuel mixture failed to ignite internally and there is no flare at the nozzle, the rocket will expel all the hydrogen fuel mixture while sitting on the launch pad. Image how big the fireball that will ensue when it does ignite by static charge or random spark one minute later. |
| "Rod Speed" <rod.speed.aaa@gmail.com>: Jan 20 12:31PM +1100 On Fri, 20 Jan 2023 08:28:30 +1100, Mighty✅ Wannabe✅ <.> wrote: >>> and disconnect at the rescue car first. > I real life scenario there is no danger of hydrogen accumulation under > the hood because it is too airy inside the engine compartment. In spades when the hood is opened to allow the positive jumper lead to be connected to the battery post. > There will be danger of hydrogen accumulation if the lead-acid battery > is confined inside a box, like underneath a motorized wheelchair. Not with modern sealed batterys which have a catalyst that recombines the gases back to water and which have the metal used in the plates which ensure that no hydrogen is produced when they are charged. |
| "Rod Speed" <rod.speed.aaa@gmail.com>: Jan 20 12:33PM +1100 On Fri, 20 Jan 2023 09:04:09 +1100, Scott Lurndal <scott@slp53.sl.home> wrote: >> is confined inside a box, like underneath a motorized wheelchair. > Then why do space launch vehicles use burners to ensure that any H2 > that pools around the launch site is burned off before launch? Because you get FAR more gaseous hydrogen in that situation. |
| "Rod Speed" <rod.speed.aaa@gmail.com>: Jan 20 12:37PM +1100 On Fri, 20 Jan 2023 10:32:26 +1100, Scott Lurndal <scott@slp53.sl.home> wrote: > of the main engine nozzles. A half second later, the flight > computers order the opening of valves which allow the liquid > hydrogen and oxygen to flow into the engine's turbopumps." And the important bit is the fact that the fuel is LIQUID HYDROGEN which can see lots of gaseous hydrogen around the area where the fuel will be ignited if there is any leak at all. |
| Peeler <trolltrap@valid.invalid>: Jan 20 09:40AM +0100 "Rod Speed is an entirely modern phenomenon. Essentially, Rod Speed is an insecure and worthless individual who has discovered he can enhance his own self-esteem in his own eyes by playing "the big, hard man" on the InterNet." https://www.pcreview.co.uk/threads/rod-speed-faq.2973853/ -- williamwright addressing Rodent Speed: "This is getting beyond ridiculous now. You're trying to prove black's white. You're arguing with someone who has been involved with the issues all his working life when you clearly have no knowledge at all. I think you're just being a pillock for the sake of it. You clearly don't actually believe your own words. You must have a very empty life, and a sad embittered soul. MID: <j08o6bFeqc1U1@mid.individual.net> |
| "Carlos E.R." <robin_listas@es.invalid>: Jan 19 06:11PM +0100 >> Peter, do you mean liquid "rosin" as used on violin bow strings? >> It actually is sold as a solid but I believe it is soluble in alcohol. Scrape some rosin shavings into iso-propyl and apply to the string. The alcohol will evaporate and leave the rosin in place. > Rosin is a band-aid and isn't required if it's strung properly and friction is mitigated. You can use virtually any non-stretching string of a similar diameter and it won't slip. On some radios, the string passes metal rods that are not pulleys, and there having friction would be bad. -- Cheers, Carlos. |
| "Peter W." <peterwieck33@gmail.com>: Jan 19 09:46AM -0800 > Rosin is a band-aid and isn't required if it's strung properly and friction is mitigated. You can use virtually any non-stretching string of a similar diameter and it won't slip. I will give a poor analogy to the reason for the Rosin - poor, because technology has changed over the last 20 years, or so. But for us Luddites: Those of us, who, back in the day, drove air-cooled VWs which we serviced ourselves for the most part, always used a wee bit of anti-seize on the spark-plugs to avoid head damage, and we adjusted torque accordingly. Most especially those of us who were *really cheap* and used un-plated plugs. Today, plugs are, for the most part, plated from the factory and anti-seize is not recommended by manufacturers any longer. Similarly back in the day VW also used lug bolts, and there was a 'whole thing' on anti-seize on the threads (not the bearing face) of the bolt. Again, not so much today due to improved technologies and plating processes. Getting back to Rosin - the OP is starting with a vintage German radio - and as I have noted on occasion, the Germans never use one part where three-or-more will do better. So, restringing such a beast is one of more troublesome tasks in the vintage radio hobby. Even getting the chassis out of the case/cabinet is a massive PITA. So, the idea is to do it once and get another 50-75 years out of the effort. The things that mess up dial mechanisms: a) Age: The pulleys wear, the springs (if any) wear, and the bearings wear such that the pulleys wobble. b) Dust and airborne crud contaminate the system causing additional friction, or slippage. c) And many hobbyists rely on their memory rather than looking for a diagram when re-stringing. There are few absolute cures for a) - I have found that going to the next higher (or two) string gauges can help for two reasons: A greater bearing surface, so less tension is required, and therefore less wobble. And the string centerline is further from the edge of the pulley - again, less wobble. Replace the springs, of course. Dust and crud can be cleaned - in fact a radio from a smoker environment will not see the display in our house until absolutely thoroughly cleaned. Most will be rejected prior to purchase in any case. And, there are sources for stringing diagrams, even for many/most Euro radios. Further, the generic diagrams are useful to find similar configurations. I need to repeat HAND MATTERS! And may German radios tune from Right-to-Left - matters even more! What the rosin does best is reduce the amount of tension required on the string, and together with the slightly larger diameter increase the friction without increasing wear. And if simple Dacron is used, that first application is well-and-truly life-time. The analogy that comes to mind is the fiber core of elevator ropes - as a reservoir for lubricants - the Dacron acts as a reservoir for the rosin and does not spread it all over the place as a sticky mess - a little goes a long way. Yes, I keep high-tack PTFE-impregnated synthetic oil for bearings and such - it is emphatically non-conductive, and stays where-put, does not oxidize and does not turn to varnish even in warm environments. NEVER graphite as it is a conductor, and can 'track' even if by accident. Horrible stuff in an electronic environment, especially with tubes involved. It is a process - and if done carefully, those next 50 years are a near certainty. Peter Wieck Melrose Park, PA |
| Allodoxaphobia <trepidation@example.net>: Jan 19 06:20PM > Rosin is a band-aid and isn't required if it's strung properly and > friction is mitigated. You can use virtually any non-stretching > string of a similar diameter and it won't slip. I've often thought waxed dental floss might be a solution for dial cord. But I never had a opportunity to employ it. Jonesy -- Marvin L Jones | Marvin | W3DHJ.net | linux 38.238N 104.547W | @ jonz.net | Jonesy | FreeBSD * Killfiling google & XXXXbanter.com: jonz.net/ng.htm |
| "Peter W." <peterwieck33@gmail.com>: Jan 19 11:33AM -0800 > I've often thought waxed dental floss might be a solution > for dial cord. But I never had a opportunity to employ it. Not quite as bad as graphite, but approaching that state. Once-upon-a-time dental floss was made from silk, and could be doubled or tripled to make a reasonable, stretch-resistant cord. Silk, like nacre feels smooth, to the touch, but creates considerable friction when tight - while not being overly abrasive. Today the crap is made, primarily, from PTFE, and is flat, not round. It is also highly abrasive and will cut through soft aluminum pulleys and sheaves if made tight enough not to slip. Since it has a very low surface area, and PTFE is a naturally slippery material, and because the surface is textured to catch tartar but still slip easily, it is altogether nasty in that application. Not to mention that as landfill, it can last hundreds of years. Worse, if burnt, the POC are deadly to felines and Avian species. Peter Wieck Melrose Park, PA |
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