Re: Extracting a buggered knob grubscrew

Chuck Harris <cfharris@...>

I like PBBlaster, but one thing I have noticed is any
bolt/nut I use PBBlaster on, will be badly corroded the
next time I visit it. I would recommend washing it away

The acetone in Ed's Red will be gone before you can say
Bob's your uncle. Its sole and only purpose is to bring
the transmission fluid into the threads, or under the
copper/lead fouling in the case of guns. It evaporates
very, very quickly.

-Chuck Harris

- wrote:

You don't have to bath it in oil but a good PENETRATING oil will creep.
But I agree with you that there are good ready made solvents that won't
harm the plastics and my preference would be to use one of them instead of
something that I don't know would be safe.

I have a 5 gallon can of home made Ed Red's sitting in my garage. Great
stuff! But I used PB Blaster to loosen the set screws on my 576. A tiny
drop applied with a toothpick is all that is needed.

On Mon, Feb 8, 2021 at 10:09 AM Chuck Harris <> wrote:

You don't have to bathe the entire knob in the stuff, you know.

Kroil, PBBlaster, and other penetrating oils contain good stuff
that I wouldn't want to soak a plastic knob in either.

The Acetone/ATF mixture, is based on a homemade gun cleaner known
as Ed's Red, and has been shown to beat all of the commercial
penetrating oils at reducing fastener breakaway torque, when applied
to the exposed threaded area of the fastener.

But, YMMV.

-Chuck Harris

- wrote:
That's a good mix for working on mechanical stuff but I don't think
be willing to try Acetone on a Tektronix knob or painted surface. ATF
by itself is a good penetrating oil and is *probably* safe and effective.
But I still wouldn't use it on anything that is irreplaceable until I
that it was safe.

On Mon, Feb 8, 2021 at 12:15 AM Frank DuVal via <corvairduval=> wrote:

Kroil is excellent.

But also try 50/50 mix of ATF and Acetone. That's any automatic
transmission fluid and Acetone.

Of course if you have to buy a quart of fluid and a quart of Acetone,
one can of Kroil may be cheaper if available locally.

Frank DuVal

On 2/2/2021 4:44 PM, JJ wrote:
I used a drop of Kroil on a 7000 plugin knob set screw when it was
That stuff never lets me down. Of course, you need to use it before you
strip the screw head! And, you need to be patient - like a few drops
an 8 hour period. Be careful that you don't get the stuff on the face
Tek instrument - it will likely take the print off. But, just about
anything other than a lightly water damped cloth will take the print
Tek instrument.


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