[R-390] Alodine and hexavalent chromium

Thu Jan 13 16:51:10 EST 2005

I may try masking.  If I can work with the guy at the plater, then it would be worth it.

He said it would be about $40 to for 8 parts.  Sounded like it wasn't set in stone and a few back panels wouldn't run it up much past $50.  Worth it to me to have these looking good again.

Be sure to wash down that hot-n-sour soup with a little wasabe. :P

Barry(III) - N4BUQ

>Oh OK, yeah the chemical stripping only takes care of  the surface,
>scratches and pitting need sanding or grinding to clean up.
>Out of curiosity how much is the plater charging for how many parts? Might
>need to go this route someday.
>
>The rear panel work that I did was a couple of years ago and the radio isn't
>in front of me now so I can't take a peek, but as I recall the damage was
>only in one area on one side (I think the inside) , where some kind of
>corrosive gook had seriously damaged and discolored an area.
>
>The lettering in the back was in good condition and I didn't want to mess
>with it or take on a re-lettering job so basically what I did was mask it,
>or possibly even masked the entire back side with ordinary masking tape
>which worked very well while I did the metal prep and Alodining. Anything
>that can keep the surface dry for several minutes will work as a mask, and
>for masking small areas wax or crayons would probably work well.
>
>(Arggg, did you ever have hot and sour soup go down the wrong pipe?, you
>should have seen what just happened the monitor!)
>=:^0
>John
>
>
>> The reason I wanted to wet-sand the pieces is they weren't in really great
>shape.  Scratches, small oxidized patches, etc., made me want to get them in
>physically better condition before any surface finishes.
>>
>> The center shelf seemed to have a rough texture about it that I wasn't
>sure would come out if just chemically stripped.  I got a lot of the old
>finish off and it went down the sink.  I assume there wasn't enough of
>anything in that to be a hazard.  As someone else mentioned, once it has
>dried and done its thing, it isn't as hazardous as when in liquid form.
>>
>> As I said, the local place is quite reasonable and I'd rather someone do
>it right than have me messing it up on top of creating a potential
>biohazard.  There's a lot of things I can do, but some things I'd just
>rather leave to the pros.
>>
>> You mention you did a back panel.  Did the process destroy the lettering?
>I assume it did.  What did you (if anything) about that?
>>
>> Thanks to all for the kind responses and advice.
>>
>> Barry(III) - N4BUQ
>>
>> >After Alodine is applied and dried I believe it's totally safe (as long
>as
>> >you don't eat it). It is commonly used as a surface finish on all kinds
>of
>> >aluminum parts or as a surface prep for painted aluminum to increase
>paint
>> >adhesion, like on the R-39x dial bezel. It is a very, very thin coating,
>> >usually 0.5 to 3 thousands of an inch, and is easily removed by sanding
>or
>> >by phosphoric acid metal prep solution or a lye bath as Hank suggested.
>> >
>> >If you are sending your pieces to an Alodiner are you sure you need to
>> >remove what's already there?; they will probably throw the parts in an
>acid
>> >bath first thing.
>> >
>> >It IS something you can do at home, but aside from the cost of buying a
>> >gallon and having it shipped, you need to practice a bit to get the
>coating
>> >to be uniform and the correct thickness to match the other parts. (longer
>> >soak or brushing = heavier coat = darker color). If you screw up the part
>> >you can always throw it back in the lye bath and start over :^) I've done
>> >the R-390 IF coil cans, dial bezels, and a back panel with good results,
>but
>> >it's not something I'd want to do frequently.
>> >
>> >For *small* quantities of the stuff that are used for home projects I
>> >wouldn't worry about disposal issues, but please don't throw the used
>stuff
>> >on the ground. You definitely want to wear gloves to protect your skin
>(and
>> >to keep hand oils off the prepped part), and it can permanently stain
>> >anything it touches.
>> >
>> >John
>> >
>> >----- Original Message ----- 
>> >From: <N4BUQ at aol.com>
>> >To: <R-390 at mailman.qth.net>
>> >Sent: Thursday, January 13, 2005 11:48 AM
>> >Subject: [R-390] Alodine and hexavalent chromium
>> >
>> >
>> >> I've been doing a bit more looking into getting the panels for my
>R390A's
>> >re-alodined. Turns out this stuff is hazardous as it contains hexavalent
>> >chromium (chrome?). Around here, you have to dispose of this stuff
>properly
>> >so I might not be trying this at home after all. Fortunately I've found a
>> >place that will do the lot of parts for a reasonable price.
>> >>
>> >> This got me to wondering how hazardous it is to remove this coating. Is
>> >it safe to wet-sand the parts to remove the old coating? Is the amount of
>> >coating removed so small that it is insignificant?
>> >>
>> >> Just wondering...
>> >>
>> >> Barry - N4BUQ
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