[R-390] Removing MFP

[Al Parker]

Hi Perrier, et al,
	This is a very timely subject for me.  I'm working at/on an 
SP-600-JX-28/R-620, that was MFP'd, and is pretty cruddy.  It has the 
large square side panels which gave even more area to clean, and as you 
say, there's MFP on everything, I've been chipping away at solder 
terminals to get it off so I can remove/re-solder, or even just get a 
meter probe on them and make connection.
	I have a can of Never Dull Wadding, so did a little experimenting this 
AM.  Took the turret cover as a trial, as it's relatively small, with 
some difficult areas as the s/n tag, and the ground post.  Using your 
wadding approach took about 10 minutes to get the horizontal surface 
almost clean.  I wasn't sure if the fluid it's soaked in was doing much, 
and put a wad of the stuff on a side panel area that was pretty thick 
with MFP, and let it sit under some pressure for about 10 min.  It may 
have softened the stuff a little.  I've left it on another spot and will 
go back after lunch to see the result.
	But, after wiping a surface with the wadding, I used some extra fine 
steel wool on it and it came off very easily.  I know, there are folks 
that wouldn't let steel wool anywhere near a radio, and I rarely do, but 
I think this is a safe application.  Many pieces can/will be removed 
before cleaning.  It'd still be nice to find a solvent, but I know it's 
been looked for before with no results that I can remember.
	No matter how you do it with the wadding or steel wool, the black grimy 
stuff needs to be removed, so you can see how it's going.  Just wipe it 
off with a rag, it'll help keep the wadding or the steel wool a bit 
cleaner.  But it'll get all over your hands, rubber gloves might be 
good, just for cleanliness, the black stuff must be fine MFP and 
aluminum oxide, it's hard to wash off your fingers, gets in the creases.
	It's still going to take a while to get this rcvr cleaned up, but 
hopefully it'll be worth it.  It has some interesting design differences 
from the run of the mill SP-600's.  You can take a look at it as it was 
when I got it, over a yr ago 
<http://www.boatanchors.org/SP-600-JX-28.htm> I will get more info up 
there on it's features soon.
73,

Al, W8UT
www.boatanchors.org
www.hammarlund.info

"There is nothing -- absolutely nothing -- half so much
worth doing as simply messing about in boats"
Ratty, to Mole

On 3/24/2012 10:51 PM, Perry Sandeen wrote:
>
> Some of the BA’s we have/get were coated with MFP which causes several problems.
>
> Background.
> A long time ago the US military found it had a problem in some situations with mold and/or fungus thriving inside electronic equipment so they developed a spray material that was applied to combat the problem. It is a brownish looking material on wires and solder joints and adds a somewhat golden look to aluminum chassis parts
>
> Our current problems with MFP
> Wires and terminals coated with MFP makes repair difficult as the wires become stiff and tend to glue together in wire harnesses.  Sometimes adding to the problem is the spray coating was very heavy.
>
> Terminals covered with MFP must be scraped clean before soldering or one gets an ugly residue.  Scraping the stuff off can be difficult.  I’ve found that a stainless steel cuticle pusher, about $4 at beauty supply stores, sharpened a bit on a grinding wheel worked best for me.  I tried using a Xacto knife.  For me in many cases the blade was too large or wasn’t good for prying, but then it wasn’t designed to pry.
>
> I had no success with either alcohol or acetone.  A list member suggested AFAICR, Goof-Off.  I tried it but it didn’t work on the MFP. I’m still looking for a chemical cure that isn’t a carcinogen.
>
> Removing MFP from aluminum parts.
> For removing the stuff from chassis parts thanks to Walter Wilson, I learned of an automotive product called NEVER-DULL by Eagle One.  It is about $5 for a 5 oz. and comes is a round metal can.
>
> It is a bit of a strange product.  It seems to be cotton wading moistened with a faint kerosene-like odor fluid.  To use it, one pulls out a wad and then rubs the MFP coated metal.  The wading turns black in color as you rub.  You keep moving the wadding around until the whole piece is black. The results are spectacular.  Now the downside is that this takes a great deal of time and can be expensive.  To do both sides of one R390A side panel might consume a whole can and several hours.
>
> Somewhat faster (relatively speaking) and considerably cheaper was using a product marketed by Turtle Wax called POLISHING COMPOUND&  scratch remover.  It is a white cream with some abrasive in it so the finished shine was a bit duller than using NEVER DULL.  I have yet to try using NEVER DULL as a final polisher for metal done with polishing compound.
>
> For very heavy MFP or corrosion I used The Turtle Wax product rubbing compound. This is a rust colored paste that removed MFP fairly rapidly.  It is about the same price as the polishing compound but leaves a duller finish.
>
> The level of finish “shine” desired is totally subjective.  The amount of MFP applied seems to very greatly.  My best advice is to try any or all of these products in an inconspicuous place and see how they work in your particular situation.
>
> A final note.  I also tried these products on an old plain SP-600 side panel and got the same results.  IMNSHO, I believe any BA metal polished with these products makes for a very good looking radio.
>
> Still on the to-do list is to see if front panel paint can be shined up with the NEVER DULL or the polishing compound. I personally wouldn’t use rubbing compound on a painted surface because it is so aggressive.
>
> Perhaps others would share their experiences.
>
> Regards,
>
> Perrier
>
> ______________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:R-390 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html