[R-390] My 2 cents regarding cleaning RF decks

[wa4aos at aol.com]

Hi Tish,
    
I have a Sharper Tec 5 gallon Ultrasonic cleaner. One of those $1500 commercial units that will take the solvent temp up to 140F.
    
When I bought this cleaner I had hoped to dunk the nose of the entire RF decks from R 390 and R 390A's into the bath and clean without removing the gears.
I had several badly damaged RF decks that were NOT candidates for resurrection to test with.  
    
I tried Purple Power first and had disastrous results. At 140F the Aluminum face plate on front of an R390A RF deck turned black in less
 than 20 minutes. The brass gears became tarnished and Hash marks for alignment as well as the serial number info disappeared..
    
Next I tried Simple Green and had similar results but not as bad. The gears did start to tarnish and the Aluminum plate did start to turn dark.
The hash marks held up a little better but were starting to fade.
    
I have not checked the PH of those cleaners but my guess is they are alkaline and that probably accounted for the Aluminum reaction. 
Not being a chemist, I am not sure what happened with the brass. 
    
Now I use a Toluene based cleaner called RS 8 that I bought from Sharper Tec, the company that made my cleaner; It cost $200 for 5 gallons. I heat the tank up until it reaches
 100F and put my basket of gears and parts  in the soup with gears removed and the RF electronics chassis removed from the RF frame of a 390A RF deck. Yes, with a little
work, I remove the gear frame from the chassis containing the electronics and put the frame in the cleaner.. It would be difficult if not impossible to take the frame completely apart since the hash
mark cams are pressed onto the frame and provide the alignment foundation of the entire deck. 
    
Even though I still remove the gears I am additionally able to clean all of the shafts, cams and fittings that are permanently attached to the frame.
I have done this enough times that I can take the RF deck apart down to the frame and put it back together in about an hour and a half, less cleaning time, Once I have pulled the RF deck from a 390A. It is more
work but afterwards, I know ALL of the grime and crud is fully removed from places on the frame that are impossible to reach otherwise; just because it's difficult to reach parts of the RF deck 
does not mean there is not crud there as well 
 First time I pulled the 39OA deck apart, down to the frame and re assembled it, 
I spend about 6 to 7 hours figuring out how to do everything; that was with many digital pics I took to help reverse my steps.
    
I have had no reactions with the toluene product but I don't leave the parts in the cleaner more than 30 minutes at 100F.That seems to be the maximum time required for a very good cleaning with my cleaner.
    
73,
Glenn Scott WA4AOS
DSM Labs