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From: Dave Baker
Newsgroups: rec.crafts.metalworking
Subject: Re: Engine Parts Cleaning
Date: 15 Apr 2000 23:45:49 GMT

> I am getting a cold tank (20 gallon) ready to clean a dismantled
>Subaru engine prior to rebuilding. Can someone recommend a great,safe
>cleaning solvent that will work well on aluminum and steel? Thanks in

You can buy purpose brewed decarbonising solutions for about £80 for 25 litres
over here. Or you do what I do and use methylene chloride at 1/3 the price
which all the custom stuff is based on anyway. Cover it with 4" of water seal
to stop it evaporating (the MC is more dense and stays under the water) and
make a decent cover to stop the cat/kids/significant other falling in.

Dissolves anything carbon based including valve stem seals, hands, pesky
neighbours etc etc. Handy for oven shelves and crudded up saucepans too - might
even make you popular with the SO if you clean the greasy oven bits once in a

Dave Baker at Puma Race Engines (London - England)  - specialist cylinder head
work, flow development and engine blueprinting. Web page at

From: Jerome Kimberlin <>
Newsgroups: rec.crafts.metalworking
Subject: Re: Engine Parts Cleaning, homemade hot vat?
Date: Sun, 16 Apr 2000 15:14:25 GMT

Dave Baker wrote:

> Just one - must have been damned good stuff if it removed corrosition :) I
> never have been able to find a solvent that shifted that.

Our hot-tank at the engine rebuilding shop where I worked used a
solution containing disodium EDTA to remove corrosion.  This was
for the cast iron blocks and heads.  I'm not sure if it was used
for the aluminum blocks and heads or not, but no reason why it
couldn't.  There was a time protocol written into the method.


From: (Don Wilkins)
Newsgroups: rec.crafts.metalworking
Subject: Re: Home Brew Wanted for Degreaser & Paintstripper
Date: Thu, 28 Oct 1999 14:51:39 GMT

On Thu, 28 Oct 1999 06:36:06 GMT, Robert Bastow <>

>Don Wilkins wrote:
>> On Wed, 27 Oct 1999 11:44:42 GMT, Robert Bastow <>
>> wrote:
>> >Hot, Soapy water!!
>> >
>> >No I am not kidding.  In this day and age of always seeking an easy out we often
>> >forget the best ways are often the simpest.
>> >
>> >It takes a heck of powerful (lethal) solvent to do what simple, hot
>> >soapy/alkaline water can do.
>> I agree but perhaps not alkaline water for aluminum. It depends on how
>> alkaline and how long.
>> My first thought was a power washer with a mild detergent.
>> Second thought was a basket and a trip to the car wash. Low overhead,
>> no inventory.
>Perhaps a bit better definition of soap and alkali and their relative roles in
>the washing process...
>"detergents" are commonly mixtures of a soap and an alkali..brighteners,
>deodorizers scents etc are also added for various purposes..not really relevant

"detergents" generally are considered to be synthetic compounds and I
wouldn't expect them to contain soap.

>Alkali..(Not Lye..but usually a sesquicarbonate or similar soda compound..even
>bi-carbonate which I use) This is what actually does the breaking
>down the grease that holds soil particles on or in the object or fabric thus
>allowing them to be flushed or more easily abraded away.
>Soap, in and of itself has no "Cleaning Power"  (surprised me too!)

I have a problem with that.

Soap is usually made by the hydrolysis of fat with either sodium or
potassium hydroxide.

(RCOO)3C3H5  + 3 NaOH  ---> 3RCOONa (soap)  + C3H5(OH)3 (glycerine)

Soap then consists of mixtures of compounds such as sodium stearate,
C17H35COONa,  sodium palmitate, C15H31COONa, sodium oleate,
C17H33COONa as well as the sodium salts of other fatty acids.

Soap functions as a cleaning agent by lowering the surface tension of
water and as an emulsifying agent to disperse oil and grease. A
disadvantage is the fact that heavy metal (metal content) ions form
greasy precipitates with those fatty acids.

Before the days of the synthetic detergents many a housewife used soap
to clean and some in fact made their own using the ashes from the wood
stove and fat from the unfortunate (formally) livestock. Most or all
complained about the deposits left on the laundry but it did remove
the grease. The greasy deposits (insoluble heavy metal fatty acid
salts) were going to appear all the time because in most cases water
softeners were not in the home so the water usually contained enough
calcium (and probably iron) to cause the problem.

The harder the water the more the housewife bitched about the problem
until someone started making synthetic detergents.

A synthetic detergent on the other hand has the carboxylic acid
replaced with a sulfonic acid. The heavy metal salts of the sulfonic
acids are much more soluble.

2C17H35COONa  + Ca++ (e.g.) ---> (C17H35COO)2Ca (insoluble)

2C17H35OSO3Na  + Ca++ (e.g.) ---> (C17H35OSO3)2Ca (soluble)
synthetic detergent

>Its main purpose is to hold soil particles in suspension and prevent the
>redeposition of dirt on the objects being washed and as a "wetting"
>agent..allowing the water and other cleaning agents to get in closer contact
>with the soil.

Yes this is the way they work but soap does this the same way as the
synthetics. Soaps run into cleaning problems when the water is not
"soft". Synthetic detergents work OK in "hard" water.

<balance snipped>

From: "Barry L. Ornitz" <>
Newsgroups: rec.crafts.metalworking
Subject: Re: Home Brew Wanted for Degreaser & Paintstripper
Date: Wed, 27 Oct 1999 22:25:49 -0400

Andrew Roberts wrote in message ...
>Can someone help me out on a simple brew made up out of easy to
>find items that will clean and degrease.  It has to be able to
>used on aluminium and brass as well as other alloys.  I just want
>to chuck whatever in a tub full, and let it soak, then take it
>out and hose the 'brew' off.

For simple cleaning and degreasing, I second Robert Bastow's
suggestion of using soap and water.  I tend to like Dawn(r)
Dishwashing Detergent, but often use Tide(r) and other detergents
too.  These are safe and wash off easily.

For a quick degreasing of an already clean surface, say for
welding, wiping with paint thinner, naphtha, alcohol or acetone is
handy.  But remember these are quite flammable and nitrile gloves
would be a good idea when using them.  Avoid breathing the

Your recipe,
>Mix equal parts Kerosene, Automatic transmission Fluid, Mineral
>Spirits and Acetone.
is not a particularly good degreaser as the transmission fluid is
a light petroleum oil.  Washing this off will leave solvents to go
down the drain or on your lawn - not a good thing.

>I also would like a recipe to make paint stripper with similar
>requirements to the degreaser.

This is a far more complicated issue.  The proper paint stripper
to use depends highly on the paint.  Commercial methylene chloride
paint removers are as close as you can get to `universal' but I
doubt if they will be on the market for many more years.  Tri-
sodium phosphate and lye solutions work with some paints, but they
may attack some metals (especially lye and aluminum).  Acetone
will take off some lacquers.

Never even consider the use of conventional automobile brake
fluids.  These contain glycol ethers which are carcinogens (cause
cancer), teratogens (cause birth defects), and they specifically
attack the male reproductive system.

Stripping paint is hard work if done manually.  Put simply, any
chemical that is capable of doing this is capable of doing
considerable damage if used improperly (sometimes to the
underlying metal, but mainly to YOU).  So think before use.  Read
all the directions carefully and follow them.

        Barry L. Ornitz

Remove the NOSPAM before replying.

From: "Barry L. Ornitz" <>
Newsgroups: rec.crafts.metalworking
Subject: Re: Home Brew Wanted for Degreaser & Paintstripper
Date: Tue, 2 Nov 1999 17:17:41 -0500

Robert C. J. Bressler wrote in message ...
>if you want an excelent paint stripper try brack +AHs-sic+AH0- fluid that
>has been heated to boiling point

I cannot believe anyone would be so stupid as to try this.  Brake
fluids contain a mixture of glycol ethers.  As a class of
chemicals they are toxic (poisonous), carcinogenic (cause cancer),
teratogenic (cause birth defects), and they specifically attack
the male reproductive system, the eyes, the kidneys, and the

Commercial methylene chloride paint strippers are dangerous
enough, fooling with brake fluid for this purpose is asking for

        Barry L. Ornitz

From: (Don Wilkins)
Newsgroups: rec.crafts.metalworking
Subject: Re: Slightly OT - How to break down cured RTV Sealant
Date: Mon, 19 Feb 2001 10:27:11 -0600

On Mon, 19 Feb 2001 04:14:13 GMT, Ted Edwards <>

>,;Don Wilkins wrote:
>,;> There is no way in hell that acetone is going to dissolve a
>,;> crosslinked RTV.
>,;I believe!  But gasoline seems to break down the bond to a substrate.
>,;As anyone knows who tried to use it for a carb gasket.  Don't ask.  :-)

It is correct.

Cross linked polymers may swell and/or soften with various solvents.
If the solvent can diffuse into the polymer then it may disrupt the
bonding between the polymer and the substrate so that the polymer can
be pulled loose or just let go due to the laws of unintended
consequences. Also if the "solvent" can attack that substrate bond at
the edges it may "unzip" the interface bonds but it will not dissolve
the crosslinked silicone.

From: (Don Wilkins)
Newsgroups: rec.crafts.metalworking
Subject: Re: Slightly OT - How to break down cured RTV Sealant
Date: Mon, 19 Feb 2001 10:27:08 -0600

On Sun, 18 Feb 2001 23:10:21 -0600, (Steve
Strickland) wrote:

>,;In article <>,
>,; (Don Wilkins) wrote:
>,;> On Sun, 18 Feb 2001 04:22:12 -0600, (Steve
>,;> Strickland) wrote:
>,;> >,;RTV dissolves in acetone.
>,;> There is no way in hell that acetone is going to dissolve a
>,;> crosslinked RTV.
>,;I use RTV to mount large optics to the tool holder. These are optics up to
>,;400 pounds each. I then use acetone to dissolve the RTV after the optic is
>,;ground and polished. The RTV is used straight out of the tube and the
>,;acetone is used straight out of the can. Has worked perfectly several
>,;hundred times without any trouble.
>,;Probably just about any ketone copolymer solvent would dissolve RTV.

Your last sentence may provide a clue to your astounding discovery (or
misunderstanding). You mention " ketone copolymer solvent". If you are
using a copolymer it ain't an RTV silicone even if it did come right
out of the tube.

There are a lot of silicone copolymers. Short lengths of silicone
polymer are inserted in the chains of other linear polymers, e.g.
polystyrene, for various reasons. Enhancing the flexibility, impact
resistance, etc are a couple improvements in the properties over
either polymer alone. Many of these copolymers will indeed dissolve in
solvents BUT they are not crosslinked and they are not RTV silicones.

I will stand by my original statement. After 50+ years as a research
chemist I may have forgotten some things but the problems in
dissolving crosslinked polymers isn't one of them. I didn't even go to
a reference book to reply to this.

If you persist however I do have a bottle of acetone and some
crosslinked RTV. I can assure you it won't dissolve. But I digress if
you were correct then all the original poster needs to do is run down
to the local hardware store and get some acetone or methylethylketone
and his problem is solved. Don't bet the farm on it working though.

From: (Don Wilkins)
Newsgroups: rec.crafts.metalworking
Subject: Re: Slightly OT - How to break down cured RTV Sealant
Date: Fri, 23 Feb 2001 19:25:15 -0600

On Thu, 22 Feb 2001 20:27:49 -0600, Mike Nash
<> wrote:

>,;I would suggest that you may be trying to remove EVA rather than RTV. I
>,;cannot tell you what the difference is, but this has come up on
>,; or before. It would seem
>,;that EVA was/is the preferred PV encapsulant.

Take some of the polymer and carefully burn it.  It is clear so there
probably is no filler. EVA (ethylene-vinyl acetate) will burn and not
leave a residue. RTV is difficult to burn and  leaves a residue....
white (SiO2) or black (SiC). If you get the black residue heat the
hell out of it to be certain you don't have carbon.

>,;Mawdeeb wrote:
>,;> Experiments so far have not been to good. Gasoline (petrol) had no effect
>,;> on this stuff after 2 hours. Acetone/MEK did finally start to break down
>,;> the bond between the silicone and the fibreglass backing after 8 to 10
>,;> hours of soaking with one major drawback. As the silicone lifts at the
>,;> edges it cracks the solar cell all to hell.  What ever this silicone is, it
>,;> is tough stuff. I'm in the process of cutting out each cell with a rotozip
>,;> ( wicked tool on fibreglass)  and I'll explore some other options like
>,;> heating the bath to accelerate the chemical action. I also going to try a
>,;> talk to the local 3M rep that sells silicones and epoxies to the company I
>,;> work for and see if he has any other ideas.
>,;> Thanks to all who responded
>,;> Jim Vrzal
>,;> Holiday,Fl.
>,;> Mawdeeb <> wrote in article
>,;> <01c09977$70b2d520$f11d88d8@mawdeeb>...
>,;> > Greetings Netizens -
>,;> >
>,;> > I have an unusual salvage problem. I acquired 3 Solar panels (electric)
>,;> > that each have damaged cells.
>,;> > My goal is to salvage the remaining good cells and rebuild two panels.
>,;> > Problem is the cells are potted into
>,;> > clear silicone (RTV) sealant. Need to chemically soften up the silicone
>,;> > and
>,;> > break the surface seal without damaging
>,;> > the cells underneath.
>,;> >
>,;> > Tried so far -
>,;> > Paint stripper - swelled edges but nothing further
>,;> > Goof Off - wetted surface but no penetration
>,;> > Break clean - no effect
>,;> > PB blaster - no effect
>,;> >
>,;> >
>,;> > Any other ideas?
>,;> >
>,;> > I have thought of the freon vapor degeaser tank ,but no one around here
>,;> > has
>,;> > those any more.
>,;> >
>,;> > TIA
>,;> >
>,;> > Jim Vrzal
>,;> > Holiday, Fl.
>,;> >

From: (Don Wilkins)
Newsgroups: rec.crafts.metalworking
Subject: Re: Slightly OT - How to break down cured RTV Sealant
Date: Sat, 24 Feb 2001 07:29:44 -0600

On Fri, 23 Feb 2001 22:40:12 -0600, "Tim" <>

>,;> Take some of the polymer and carefully burn it.  It is clear so there
>,;> probably is no filler. EVA (ethylene-vinyl acetate) will burn and not
>,;> leave a residue. RTV is difficult to burn and  leaves a residue....
>,;> white (SiO2) or black (SiC). If you get the black residue heat the
>,;> hell out of it to be certain you don't have carbon.
>,;You should also mention the smell thus produced
>,;(not like inhaling such is a good idea).

I don't use the smell test on any combustion products.

>,;Is the silicone sold in calking-gun tubes (or whatever
>,;else for that matter) for sealant/adhesive EVA?

There are dozens (or more) types of products sold in caulking gun
tubes. Some are silicones some are other polymers and some are
silicone-copolymers. You need to read the label and hope that it is
descriptive of what is in the tube.

The original poster has a clear polymer. It probably but not
necessarily is a silicone. Some one suggested it might be EVA. My
comment was to enable the original poster to determine if that
specific polymer was an EVA or a silicone. The test is not absolutely
definitive but works most of the time. If there is a filler that has
the same refractive index as the polymer (unlikely) then you can get a
residue and thus a false positive.

>,;The "A" appears to be for acetate, and on curing,
>,;that stuff smells (heavily) of vinegar, so...?

See above ...EVA = (ethylene-vinyl acetate).

So...? Some RTVs release acetic acid when they cure and the "acetate"
in EVA refers to acetoxy groups distributed along the polymer chain
not to the presence of acetic acid.

>,;But it can't be EVA because you say it doesn't leave
>,;a residue, yet this stuff (BTW) burns orange (flame)
>,;and leaves white residue.

You aren't the original poster so I don't know what "it" or "this
stuff" refers too. Orange color arises from carbon radicals in the

I don't mind discussing some of this if it is of general interest but
the original scope of the post concerned a specific piece of purchased
junk. If we start talking about two different pieces of junk in the
same thread someone will probably get confused (I being one of them).

I lost the post but I believe it was mentioned that the surface was
"hazed" and thus substantially decreasing the output. If this is the
reason for removing the polymer it might solve the problem by putting
a new layer of the same polymer on top of the hazed surface. If the
refractive index matches it will eliminate the "haze"

From: "Barry L. Ornitz" <>
Newsgroups: rec.crafts.metalworking
Subject: Re: solvent toxicity
Keywords: Stoddard Solvent, toxicity, mineral spirits, degreaser
Date: Sat, 11 Sep 1999 00:16:25 -0400

Dan Clarke wrote in message <>...
>  I dunk my hands in my solvent tank when cleaning parts all the
>time.  They may be wet for 3 or so hours off and on in a day.
>The days may add up to 6 in a  month.

I don't mean to be intentionally insulting to Dan, but this is a
good example of why OSHA is necessary.  I cannot believe someone
could be so foolish.

>  I used to buy Stoddard solvent from my petroleum supplier,
>which was supposed to be safe. Now he carries mineral spirits,
>instead, which he says is safe but which irritates my hands
>more. I found mineral spirits  in a paint store with a lable
>that lists benzene as an ingredient.

Maybe it is time to soak the vendor's head overnight in the tank.

>  Is mineral spirits all the same?  How toxic is it to use as I
>do ?  What about the water based cleaning solutions I see
>advertised for use in parts cleaners?
>  Thanks ahead,
>  Dan

To begin, Stoddard solvent is a type of refined kerosene.  It is
composed of a mixture of hydrocarbons, mainly in the C-10 to C-15
range, as determined by a particular boiling point range.
Typically less than a few percent of the hydrocarbons are
`aromatics'.  This is the chemical term, not related to smell,
that has to do with the presence of benzene-ring chemical groups
in the molecular structure of the hydrocarbons.  Such aromatics
are known carcinogens - they cause cancer.  Gasoline, for
example, contains large amount of aromatics.  Because Stoddard
solvent contains only small amounts of aromatics, exposure to it
is generally not believed to cause cancer.  Stoddard solvent is
the main ingredient in many products such as WD-40.

However, Stoddard solvent is not without its risks.  Ingestion is
naturally quite dangerous with a few ounces causing death.
Breathing the vapors is bad enough, however.  They can cause
dizziness and euphoria (a solvent high) at low levels with higher
levels causing unconsciousness.  Some symptoms of exposure are
coughing, difficult breathing, throat irritation, and chest
pain.  The vapors are considered a central nervous system
depressant.  Long term exposure to vapors can cause what is
called Painter's Syndrome - a result of central nervous system
damage.  While short term skin contact is generally not too
dangerous, Stoddard solvent can dissolve the fat from the skin
leading to extreme irritation and dermatitis.  Long term
exposure, however, can cause liver and kidney damage, blood
changes, and as mentioned earlier nervous system damage.

Mineral spirits today are generally similar to Stoddard solvent,
but are not so closely refined and they may contain a higher
aromatic content.  Thus long-term exposure to mineral spirits may
be more dangerous.  Be careful of the nomenclature on labels,
however, as the word `benzin' is used by the British as a general
term for light solvents, much as they use the word petrol for
what we call gasoline.  Benzene is rarely found today in
commercial products in its pure form because of its cancer
forming properties.

As many others have pointed out, the modern water-based
degreasers are far safer to use than Stoddard solvent.  If you
must continue to use a hydrocarbon-based degreaser, PLEASE use
proper gloves.  Simple latex gloves are not adequate for these
solvents.  Instead use gloves rated for solvent use.  Typically
these are acrylonitrile-butadiene polymers (Buna-N synthetic
rubber).  These are sold inexpensively in many hardware stores.
Look for the term `solvent resistant' when buying them.

I would advise anyone exposed to as much solvents as Dan has, to
seek medical testing.  While many of the short term effects of
exposure to Stoddard solvent will go away, kidney and nervous
system damage does not.

        Barry L. Ornitz

        (replace the `-at-' with the symbol when replying)

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