tima's DIY RCM
- Thread starter tima
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Hmm, another question. I noticed that after a while, the fluid in the tank gets lower than when I started. So some evaporation I guess. I’ll eventually need to top it off, before I run it through a filter, or I’ll no longer be able to reach the inner grooves. So I’ll be diluting the original concentration. At what point of “topping off” do I effectively have no idea of what cleaning strength I’m left with?
And doesn’t this make batch filtration risky, since there is some additional loss as well using this method?
And doesn’t this make batch filtration risky, since there is some additional loss as well using this method?
You could make up solution in, say, a one gallon jug with the same percentage concentration as used in your tank. Use that to top off.
What do you mean by batch filtration?
Great idea! Thanks.
I have a secondary tank - not nearly as sophisticated as what you’ve got, that I will pump the fluid into, from the USC tank. Unfortunately the pump on it can only handle a 5 micron filter. But I also have a 1 micron filter for the USC that I can place in the tank. I figure, run the fluid into the holding tank and the through the 5 micron filter (I know, won’t do much, but it’ll at least do something). Then back into the USC tank, crank up the 1 micron filter, then hope the result will be good enough to keep cranking away.
As the fluid evaporates the Tergitol 15-S-9 concentrates, remember the 15-S-9 is non-volatile. However, the IPA is volatile. But recall what is said in the book:
VIII.8.8 Alcohol Evaporative Losses: Ethanol and IPA at low concentrations (<50%) are not azeotropes and can evaporate separately from water; and this is quite evident when reviewing the applicable vapor-liquid equilibrium diagram that when boiling shows the vapor vs the liquid concentration. At low concentrations, the alcohol vapor concentration is much higher than the liquid concentration. At higher concentrations when an azeotrope forms, the alcohol concentration in the liquid and vapor are the same. For those that may use Ethanol or IPA at low concentrations in an ultrasonic tank (use only at concentrations that are not flammable); over a period of time, the alcohol will evaporate from the water faster than the water evaporating. Unless the alcohol concentration is monitored (alcohol hydrometers are available), the concentration will drop if the tank bath life is extended.
Absent you buying an isopropyl alcohol hydrometer, what @tima recommends is the best you can do. Also, there will be some drag-out of 15-S-9 so over time it's concentration will also decrease overtime. Ultimately, what @tima recommends with a preprepared gallon is about the best you can do.
As far as batch filtration, there should be no loss of IPA or 15-S-9 from that process other than fluid that is not returned.
Note that while I said to refresh at 10-ppm TDS, that is pretty much a maximum. If the fluid starts to become cloudy, before you reach 10-ppm, you waited too long. In which case 5 or 7-ppm will be better. There are no hard & fast rules here - common sense and visual inspection are expected. The quality of the filters you are using are mostly unknown, so experience will guide you into what will be best for 'your process'.
I do not use IPA and I do not use an alcohol hydrometer. If you want to buy one - this 0-50% version should tell you if you are in the ballpark VWR® Isopropyl Alcohol Hydrometers, Traceable to NIST | VWR noting that the smallest graduation is 1% and the accuracy is +/-1%. Note that alcohol hydrometers are calibrated to the specific type of alcohol and the ranges are 0-50% and 50-100%. The practicality of the 0-50% hydrometer for very low concentration is debatable.
Yes, I can see where a 0/50 scale might make looking at a 2.5% concentration somewhat iffy. But hey, what's a few extra dollars? After all, we're on WBF!
You did not find that post because I do not own an alcohol hydrometer! After I stopped using Ilfotol and switched to Tergitol I stopped using IPA. For a while Neil cautioned away from IPA largely for safety / flammibility reasons -- although I had no problems with it when I was using it. His caution still stands.
Only with my last water replacement a few days ago did I add a 2% concentration of 99% IPA. We'll see how that goes. Granted it absorbs into the air over time but unless I find a dramatic difference with and without it, I"m not not going to get into topping off IPA.
Degassing wash and rinse tanks after fresh change of water. Both Elma P120 and S120 include a degas feature.
"Dissolved Gases & Degas: Fluids exposed to air will absorb air and the solubility of air in
water is inversely proportional with temperature and can decrease by about 25% between
20°C/68°F and 40°C/104°F. Air that is dissolved in the fluid will interfere with cavitation.
As the cavitation bubble forms, the dissolved air in the fluid migrates into the cavitation
bubble preventing maximum cavitation intensity when the cavitation bubble collapses. The
degas process operates the ultrasonics with a tank of fresh liquid to remove some or most
of the dissolved air. Degas efficiency is dependent on frequency, power and volume. Low
frequency 40-kHz and less can take 30 minutes or more to fully degas a large tank, while
80 kHz and greater can accomplish degas in as little as 5 minutes. During the degas process, bubbles may be seen rising in the fluid; the fluid may go from cloudy to clear; there may be a change in sound; and the surface can change to smooth with just a slight rippling effect caused by the ultrasonics."
Neil Antin, "Precision Aqueous Cleaning of Vinyl Records, 3rd Edition"
section XIV.2.1, pp152-153
"Dissolved Gases & Degas: Fluids exposed to air will absorb air and the solubility of air in
water is inversely proportional with temperature and can decrease by about 25% between
20°C/68°F and 40°C/104°F. Air that is dissolved in the fluid will interfere with cavitation.
As the cavitation bubble forms, the dissolved air in the fluid migrates into the cavitation
bubble preventing maximum cavitation intensity when the cavitation bubble collapses. The
degas process operates the ultrasonics with a tank of fresh liquid to remove some or most
of the dissolved air. Degas efficiency is dependent on frequency, power and volume. Low
frequency 40-kHz and less can take 30 minutes or more to fully degas a large tank, while
80 kHz and greater can accomplish degas in as little as 5 minutes. During the degas process, bubbles may be seen rising in the fluid; the fluid may go from cloudy to clear; there may be a change in sound; and the surface can change to smooth with just a slight rippling effect caused by the ultrasonics."
Neil Antin, "Precision Aqueous Cleaning of Vinyl Records, 3rd Edition"
section XIV.2.1, pp152-153
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Note: The above may not be the current version. This version is the same as the printed version my meter has - COM100_usersguide2015_p1_8 (qcsupply.com). The difference is the calibration procedure. Make sure to check the printed version provided with your meter.
@tima, @Neil.Antin, here the question. I’ve cleaned about 70 records and the COM-100 is reading 3.1. Figure it’s time to clean the bath, but here’s what it looks like right now. Is all this crud “normal”?
Tony,
I am curious to see what @tima has to say about his own observations, but I suspect some or most of the problem is how you are filtering. Assuming you're using the Isonic 1-micron filter that attaches to the side of the tank, it only draws suction from tank depth mid-way, and I do not know if the suction is behind or below the device. Whatever the location, it is not optimum for picking heavy particles that drop to the tank bottom. Also, if the suction and discharge are close together there is risk of the it just short-circuiting the fluid with filter half-life much longer than calculated. In comparison, DIY filter systems draw suction from the tank drain so they would be better at filtering heavier type of debris. Additionally, the pump discharge is position away from the suction to prevent just short-circuiting of the fluid. But I am curious to see what @tima has seen with his system that uses the DIY pump/filter arrangement.
Take care,
Neil
PS/Please recall when I mentioned the Isonic filter I did so only to advise of its existence making no claim to its effectiveness.
Neil, I may not have been clear. I haven’t filtered yet. I was wondering if this looks “about normal” before filtering, and as supported by number of records cleaned and the CDM-100 reading.
Tony,
There is no normal since the condition of the records is variable. But detritus settling to the bottom of the tank if you do not filter is normal - you can search over at Turntables | Audiokarma Home Audio Stereo Discussion Forums where not many filter their tanks, and you will read and see similar.
As far as TDS with the COM-100, note that @tima has just started using it also, but it is normal to increase after cleaning records. Is your reading 'normal' for 70-records, there is no normal, since there is nornal record - they are different to some degree. Additionally, the tank just exposed to the ambient air will result in some increase in TDS, and how much is variable based on your environment. Unless you have reason to suspect the reading of the COM-100 - just check your unused DIW to see if it close to what it was before starting - otherwise believe your indications.
Otherwise, do you have any feedback on the most important item - how do your records sound?
Take care,
Neil
It's fairly simple - if you don't filter the water in your wash tank it will continue to get dirtier.
Your photo looks what I imagine as normal for an unfiltered tank that probably needs its water changed. I assume your 3.1 is ppm for TDS. But what I see in your photo are undisolved solids and- given that I'd say the tank is overdue for a water change..
When I started my original DIY RCM project I started with a filter, so I've not seen such as you show. Actually my original idea was to keep the tank water so clean by filtering that I would not need to do a rinse. I did pretty well according to my original TDS measuring tool, but my standards got higher and I bought a rinse tank along with a better filter and larger cannister for my wash tank. I moved my original filter to the rinse tank. I think that was the right move and now I endorse ultrasonic rinsing.
I cleaned a batch of 6 and a batch of 5 records back-to-back two days ago. I took measurements a day after that session. My wash tank with its 0.2 micron (absolute) filter measured 1.6ppm and 3.4µS conductivity. (I estimate that is an 0.9 ppm increase from a fresh tank with new solution.) The rinse tank with its 0.35 micron (nominal) filter measured 0.6ppm and 1.5µS. From that I presume there is very little particle carry-over on records from wash to rinse. On both tanks the drain feeding the filter is on the bottom of the tank at one end. Fwiw I never see undisolved solids at the bottom of either tank. How dirty are the records to start with is another factor.
Starting out typically means refining your system as you go -- at least it did from me. I think you're off to a good start and congratulate you on your efforts.
edit: I"m not familiar with the physical iSonic tank. I'm gathering from what Neil wrote that the filter input is midway into the tank. Is that correct? If so, my speculation is that will take in water but not vacuum particles settled on the tank bottom.
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