I cannot answer all of your questions, in part because I am not mixing any solution for my ultrasonic for the reason stated above (I use a KL machine right now).
One issue I see as a potential hazard is the flash point of isopropyl even diluted, given the vapor. I believe that the chemistry suggests it should be below 3% of overall volume for the temperature you are achieving (Note, i am not a chemist so this should be checked). Is 3 ounces of alcohol in 6 liters really a 50/1 ratio? My maths suggested it was about 5% but there is a reason I didn’t major in math- somebody check me here.
Alcohol will work as a solvent, I’m not sure how effective it is as as surfactant (to break surface tension of the water, which is the goal). I believe one of its long time values in record cleaning generally is that it evaporates quickly. For effective formulae, you should read Rushton Paul’s article if you haven’t; there are others, including a formula Tima (Tim Ackerman adopted) that is posted on my blog; others, including @terry9 (who does have a scientific background) can offer more on the chemistry they have found effective and also weigh in on whether I’m being a nervous nelly about the amount of alcohol being used.
In general record cleaning- whether ultrasonic or conventional- the main points are effectiveness of the solution/method and the ability to remove the solution from the record, once done. I do know old school record cleaning folks that used Photoflo and no rinse. My impression is that it leaves a residue as do most of these chemicals and cleaners. That’s why I employ a rinse step. (Even though I’m not using chemistry in my ultrasonic, if I have a record that I’m especially concerned with, I will, once removed from the ultrasonic bath, do a rinse step using reagent grade water and point nozzle vacuum system (Monks or Loricraft- which doesn’t have the same issues as wand or velvet ’lips’ type RCMs)).
You said you just want "good enough" and don’t want to go all white lab coat-- there are some who say vacuuming after ultrasonic defeats the whole purpose of US cleaning given the potential for contamination and static caused by some conventional RCMs. You have to make a choice here- by experimenting with the chemistry- Tima does not do a rinse step using his brew (which I think is an adaptation of the London Jazz Collector mixture meant for conventional cleaning); others, like @@terry9, @slaw might be able to tell you what their experience is. But I think first stop is Rush Paul’s article if you haven’t read it.
Number of records per load- this has also been calculated- is in the original diyaudio thread and has been verified independently by other’s empirical experience-- I can give you links to some of this if you can’t find it but for a smallish bath it’s more like 2 records at a time with space in between.
There is good proof that a filter goes a long way- again, not to rely on what I publish but Tima did a follow up on his results using a filter-- pretty much the same one outlined in the diyaudio one that Rush adapted- and there was a lot of crap picked up by the filter. See [url]http://thevinylpress.com/record-cleaning-timas-diy-ultrasonic-rcm-followup-1/[/url] How long can you go before changing the water without a filter? I don’t know. Part of it depends on how much crap there is on the records to begin with I guess. (I pre-clean, so less of an issue).
One issue I see as a potential hazard is the flash point of isopropyl even diluted, given the vapor. I believe that the chemistry suggests it should be below 3% of overall volume for the temperature you are achieving (Note, i am not a chemist so this should be checked). Is 3 ounces of alcohol in 6 liters really a 50/1 ratio? My maths suggested it was about 5% but there is a reason I didn’t major in math- somebody check me here.
Alcohol will work as a solvent, I’m not sure how effective it is as as surfactant (to break surface tension of the water, which is the goal). I believe one of its long time values in record cleaning generally is that it evaporates quickly. For effective formulae, you should read Rushton Paul’s article if you haven’t; there are others, including a formula Tima (Tim Ackerman adopted) that is posted on my blog; others, including @terry9 (who does have a scientific background) can offer more on the chemistry they have found effective and also weigh in on whether I’m being a nervous nelly about the amount of alcohol being used.
In general record cleaning- whether ultrasonic or conventional- the main points are effectiveness of the solution/method and the ability to remove the solution from the record, once done. I do know old school record cleaning folks that used Photoflo and no rinse. My impression is that it leaves a residue as do most of these chemicals and cleaners. That’s why I employ a rinse step. (Even though I’m not using chemistry in my ultrasonic, if I have a record that I’m especially concerned with, I will, once removed from the ultrasonic bath, do a rinse step using reagent grade water and point nozzle vacuum system (Monks or Loricraft- which doesn’t have the same issues as wand or velvet ’lips’ type RCMs)).
You said you just want "good enough" and don’t want to go all white lab coat-- there are some who say vacuuming after ultrasonic defeats the whole purpose of US cleaning given the potential for contamination and static caused by some conventional RCMs. You have to make a choice here- by experimenting with the chemistry- Tima does not do a rinse step using his brew (which I think is an adaptation of the London Jazz Collector mixture meant for conventional cleaning); others, like @@terry9, @slaw might be able to tell you what their experience is. But I think first stop is Rush Paul’s article if you haven’t read it.
Number of records per load- this has also been calculated- is in the original diyaudio thread and has been verified independently by other’s empirical experience-- I can give you links to some of this if you can’t find it but for a smallish bath it’s more like 2 records at a time with space in between.
There is good proof that a filter goes a long way- again, not to rely on what I publish but Tima did a follow up on his results using a filter-- pretty much the same one outlined in the diyaudio one that Rush adapted- and there was a lot of crap picked up by the filter. See [url]http://thevinylpress.com/record-cleaning-timas-diy-ultrasonic-rcm-followup-1/[/url] How long can you go before changing the water without a filter? I don’t know. Part of it depends on how much crap there is on the records to begin with I guess. (I pre-clean, so less of an issue).