Oops.

After finishing soldering my Very First model airplane fuel tank, I went
to do the last step of any soldering project -- cleaning off the flux.

Unfortunately, while I know that the flux I use yields to scrubbing with
hot soapy water, I don't know what -- if anything -- will just take it
off. I'm experimenting.

I've got some in each of four cups, with lacquer thinner, mineral
spirits, isopropyl alcohol, and plain drinking water. None of them seem
to be having any effect except the mineral spirits, which appears to be
separating it into two components.

In the mean time, I'm checking here to see if anyone has any pointers.
It's "Top Line Quality Soldering Paste Flux". Bought over thirty years
ago (I don't go through flux very fast). It looks like bearing grease,
& it sizzles when the iron touches it. Works great, but leaves a
residue which I don't want inside my engines!

So -- anyone happen to know if there's a common soldering flux that
contains calcium chloride and has this consistency, and if so how to
clean out the inside of an itty bitty fuel tank made with it? If all
else fails I'll run really hot water through it along with dishwashing
detergent -- but that doesn't leave me 100% confident.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

"Tim Wescott" wrote in message
...
So -- anyone happen to know if there's a common soldering flux that
contains calcium chloride and has this consistency, and if so how to
clean out the inside of an itty bitty fuel tank made with it? If all
else fails I'll run really hot water through it along with dishwashing
detergent -- but that doesn't leave me 100% confident.


Tim,

I am not sure exactly, but I might try two different things.

The first would be methylene chloride (Jasco paint remover.)

The second would be either lye or automatic dishwasher soap (cascade).

The latter might be the best choice as it should rinse clean.

I would test this on a couple of older copper pennies. Heat them and
slather some flux on till it sizzles and them let them cool then dunk them
in hot water and the alkaline solution of either the lye or the dishwashing
powder.

You might also do a test on some scrap copper pipe and fittings. This then
can be cut open after cleaning so you can judge how it will work on the
inside of your fuel tank

I use the dishwashing powder to soak nasty cleaning jobs like Pyrex roasting
pans that have that burned on grease that seems to defy all other ordinary
dishwashing attempts, and it works wonders, with no scrubbing needed.

I suspect that your flux residue is a lot like the burned on crud on the
baking dish

--

Roger Shoaf

About the time I had mastered getting the toothpaste back in the tube, then
they come up with this striped stuff.

Tim Wescott wrote:
Oops.

After finishing soldering my Very First model airplane fuel tank, I
went to do the last step of any soldering project -- cleaning off the
flux.
Unfortunately, while I know that the flux I use yields to scrubbing
with hot soapy water, I don't know what -- if anything -- will just
take it off. I'm experimenting.

I usually have good results with Berryman B-12 Chemtool for defluxing.

Jon

On Fri, 28 May 2010 05:48:01 -0700, "Jon Danniken"
wrote:

Tim Wescott wrote:
Oops.

After finishing soldering my Very First model airplane fuel tank, I
went to do the last step of any soldering project -- cleaning off the
flux.
Unfortunately, while I know that the flux I use yields to scrubbing
with hot soapy water, I don't know what -- if anything -- will just
take it off. I'm experimenting.

I usually have good results with Berryman B-12 Chemtool for defluxing.

Jon

That works????

Thanks! I try that!

Gunner

--


"First Law of Leftist Debate
The more you present a leftist with factual evidence
that is counter to his preconceived world view and the
more difficult it becomes for him to refute it without
losing face the chance of him calling you a racist, bigot,
homophobe approaches infinity.

This is despite the thread you are in having not mentioned
race or sexual preference in any way that is relevant to
the subject." Grey Ghost

On Thu, 27 May 2010 22:17:36 -0700, Tim Wescott
wrote:

Oops.

After finishing soldering my Very First model airplane fuel tank, I went
to do the last step of any soldering project -- cleaning off the flux.

Unfortunately, while I know that the flux I use yields to scrubbing with
hot soapy water, I don't know what -- if anything -- will just take it
off. I'm experimenting.

Jeweler's pickle?
http://www.ganoksin.com/borisat/nena...ling-notes.htm

--
Ned Simmons

"Ned Simmons" wrote in message
...
On Thu, 27 May 2010 22:17:36 -0700, Tim Wescott
wrote:

Oops.

After finishing soldering my Very First model airplane fuel tank, I went
to do the last step of any soldering project -- cleaning off the flux.

Unfortunately, while I know that the flux I use yields to scrubbing with
hot soapy water, I don't know what -- if anything -- will just take it
off. I'm experimenting.

Jeweler's pickle?
http://www.ganoksin.com/borisat/nena...ling-notes.htm

--
Ned Simmons

Won't the acid be a problem? While not stated, I had assumed that the fuel
tank was made of copper or brass. If you look at the last part of the cited
article it indicated that the acid pickle eats copper.


--

Roger Shoaf

About the time I had mastered getting the toothpaste back in the tube, then
they come up with this striped stuff.

On Fri, 28 May 2010 07:25:11 -0700, "Roger Shoaf"
wrote:


"Ned Simmons" wrote in message
.. .
On Thu, 27 May 2010 22:17:36 -0700, Tim Wescott
wrote:

Oops.

After finishing soldering my Very First model airplane fuel tank, I went
to do the last step of any soldering project -- cleaning off the flux.

Unfortunately, while I know that the flux I use yields to scrubbing with
hot soapy water, I don't know what -- if anything -- will just take it
off. I'm experimenting.

Jeweler's pickle?
http://www.ganoksin.com/borisat/nena...ling-notes.htm

--
Ned Simmons

Won't the acid be a problem? While not stated, I had assumed that the fuel
tank was made of copper or brass. If you look at the last part of the cited
article it indicated that the acid pickle eats copper.

That paragraph is talking about the pickle plus peroxide. I've never
used that mix so I don't know how agressive it is, but copper or brass
can stay in the regular mix for hours with no apparent damage. This is
effective on brazing flux and I assume would work on soft solder flux,
though I've never tried it myself.

--
Ned Simmons

On Fri, 28 May 2010 11:04:31 -0400, Ned Simmons wrote:
On Fri, 28 May 2010 07:25:11 -0700, "Roger Shoaf" wrote:
"Ned Simmons" wrote
On Thu, 27 May 2010 22:17:36 -0700, Tim Wescott wrote:
....
After finishing soldering my Very First model airplane fuel tank, I
went to do the last step of any soldering project -- cleaning off the
flux.
....
Jeweler's pickle?
http://www.ganoksin.com/borisat/nena...ling-notes.htm
....
Won't the acid be a problem? While not stated, I had assumed that the
fuel tank was made of copper or brass. If you look at the last part of
the cited article it indicated that the acid pickle eats copper.

That paragraph is talking about the pickle plus peroxide. I've never
used that mix so I don't know how agressive it is, but copper or brass
can stay in the regular mix for hours with no apparent damage. This is
effective on brazing flux and I assume would work on soft solder flux,
though I've never tried it myself.

The question about copper or brass probably is moot because in later
posts, Tim said the tank is made of tin-plate steel sheet. (From a
"Dole chunk pineapple can" he said, but it seems to me other brands
or cuts of pineapple might work too.)

Anyway, HCl + H2O2 (which might be but probably isn't what the
ganoksin link refers to) is so aggressive that it's commonly used to
etch copper printed circuit boards. As noted in many web pages, eg
http://www.chemicalforums.com/index.php?topic=40738.0 , by itself
HCl doesn't attack copper, but CuO + 2HCl -- CuCl2 + H2O. Ie, when
copper is immersed in the mix, H2O2 keeps oxidizing Cu to CuO and HCl
keeps on forming copper chloride.

--
jiw

On 05/28/2010 07:25 AM, Roger Shoaf wrote:
"Ned wrote in message
...
On Thu, 27 May 2010 22:17:36 -0700, Tim
wrote:

Oops.

After finishing soldering my Very First model airplane fuel tank, I went
to do the last step of any soldering project -- cleaning off the flux.

Unfortunately, while I know that the flux I use yields to scrubbing with
hot soapy water, I don't know what -- if anything -- will just take it
off. I'm experimenting.

Jeweler's pickle?
http://www.ganoksin.com/borisat/nena...ling-notes.htm

--
Ned Simmons

Won't the acid be a problem? While not stated, I had assumed that the fuel
tank was made of copper or brass. If you look at the last part of the cited
article it indicated that the acid pickle eats copper.

Actually the tank is made out of poor-man's tinplate -- it's a Dole
chunk pineapple can, cut up and bent on a Harbor Fright brake.

So, if I use any pickling solution that'll eat steel, I want to not
leave things in there for long.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

"Tim Wescott" wrote in message
...
On 05/28/2010 07:25 AM, Roger Shoaf wrote:
"Ned wrote in message
...
On Thu, 27 May 2010 22:17:36 -0700, Tim
wrote:

Oops.

After finishing soldering my Very First model airplane fuel tank, I
went
to do the last step of any soldering project -- cleaning off the flux.

Unfortunately, while I know that the flux I use yields to scrubbing
with
hot soapy water, I don't know what -- if anything -- will just take it
off. I'm experimenting.

Jeweler's pickle?
http://www.ganoksin.com/borisat/nena...ling-notes.htm

--
Ned Simmons

Won't the acid be a problem? While not stated, I had assumed that the
fuel
tank was made of copper or brass. If you look at the last part of the
cited
article it indicated that the acid pickle eats copper.

Actually the tank is made out of poor-man's tinplate -- it's a Dole chunk
pineapple can, cut up and bent on a Harbor Fright brake.

So, if I use any pickling solution that'll eat steel, I want to not leave
things in there for long.

If you used a pineapple can, your problem might not be the flux residue.

Modern food cans have the interiors coated with a resin. It is difficult to
remove in the best case and it is impossible to remove after it gets
roasted.

If your problem is a crusty residue near the joint that thins out to a
transparent brown, then that is what you have.
When I need tinplate I scrounge it from gallon lacquer thinner cans. The
interior isn't usually coated and you can remove the paint on the exterior
with paint remover before you start working.

Paul K. Dickman

On 05/29/2010 10:34 AM, Paul K. Dickman wrote:
"Tim wrote in message
...
On 05/28/2010 07:25 AM, Roger Shoaf wrote:
"Ned wrote in message
...
On Thu, 27 May 2010 22:17:36 -0700, Tim
wrote:

Oops.

After finishing soldering my Very First model airplane fuel tank, I
went
to do the last step of any soldering project -- cleaning off the flux.

Unfortunately, while I know that the flux I use yields to scrubbing
with
hot soapy water, I don't know what -- if anything -- will just take it
off. I'm experimenting.

Jeweler's pickle?
http://www.ganoksin.com/borisat/nena...ling-notes.htm

--
Ned Simmons

Won't the acid be a problem? While not stated, I had assumed that the
fuel
tank was made of copper or brass. If you look at the last part of the
cited
article it indicated that the acid pickle eats copper.

Actually the tank is made out of poor-man's tinplate -- it's a Dole chunk
pineapple can, cut up and bent on a Harbor Fright brake.

So, if I use any pickling solution that'll eat steel, I want to not leave
things in there for long.

If you used a pineapple can, your problem might not be the flux residue.

Modern food cans have the interiors coated with a resin. It is difficult to
remove in the best case and it is impossible to remove after it gets
roasted.

If your problem is a crusty residue near the joint that thins out to a
transparent brown, then that is what you have.
When I need tinplate I scrounge it from gallon lacquer thinner cans. The
interior isn't usually coated and you can remove the paint on the exterior
with paint remover before you start working.

It's not showing that at all -- I chose those cans because they're
obviously galvanized on the inside. They certainly soldered up like
there's nothing in between the solder and the can. All of the other tin
cans that we go through are obviously coated with some sort of plastic,
which I'd have to clean off, and which may not leave me with a nice
surface to which to solder.

I'm mostly concerned with leaving acid residue inside my nice model
airplane motors after running them with a tank made with this flux.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

On May 27, 11:17*pm, Tim Wescott wrote:
Oops.

After finishing soldering my Very First model airplane fuel tank, I went
to do the last step of any soldering project -- cleaning off the flux.

Unfortunately, while I know that the flux I use yields to scrubbing with
hot soapy water, I don't know what -- if anything -- will just take it
off. *I'm experimenting.

I've got some in each of four cups, with lacquer thinner, mineral
spirits, isopropyl alcohol, and plain drinking water. *None of them seem
to be having any effect except the mineral spirits, which appears to be
separating it into two components.

In the mean time, I'm checking here to see if anyone has any pointers.
It's "Top Line Quality Soldering Paste Flux". *Bought over thirty years
ago (I don't go through flux very fast). *It looks like bearing grease,
& it sizzles when the iron touches it. *Works great, but leaves a
residue which I don't want inside my engines!

So -- anyone happen to know if there's a common soldering flux that
contains calcium chloride and has this consistency, and if so how to
clean out the inside of an itty bitty fuel tank made with it? *If all
else fails I'll run really hot water through it along with dishwashing
detergent -- but that doesn't leave me 100% confident.

--
Tim Wescott
Control system and signal processing consultingwww.wescottdesign.com

Acid flux uses zinc chloride and should be washable with water. Rosin
flux can be taken off with alcohol or some really active dishwasher
detergent. Ammonium chloride flux comes off with hot water. Have
never seen any flux with calcium chloride in it, sounds like it would
turn into rock when heated. Try some vinegar. I would have used some
electrical soldering paste, myself.

Stan

On 05/28/2010 09:12 AM, wrote:
On May 27, 11:17 pm, Tim wrote:
Oops.

After finishing soldering my Very First model airplane fuel tank, I went
to do the last step of any soldering project -- cleaning off the flux.

Unfortunately, while I know that the flux I use yields to scrubbing with
hot soapy water, I don't know what -- if anything -- will just take it
off. I'm experimenting.

I've got some in each of four cups, with lacquer thinner, mineral
spirits, isopropyl alcohol, and plain drinking water. None of them seem
to be having any effect except the mineral spirits, which appears to be
separating it into two components.

In the mean time, I'm checking here to see if anyone has any pointers.
It's "Top Line Quality Soldering Paste Flux". Bought over thirty years
ago (I don't go through flux very fast). It looks like bearing grease,
& it sizzles when the iron touches it. Works great, but leaves a
residue which I don't want inside my engines!

So -- anyone happen to know if there's a common soldering flux that
contains calcium chloride and has this consistency, and if so how to
clean out the inside of an itty bitty fuel tank made with it? If all
else fails I'll run really hot water through it along with dishwashing
detergent -- but that doesn't leave me 100% confident.

--
Tim Wescott
Control system and signal processing consultingwww.wescottdesign.com

Acid flux uses zinc chloride and should be washable with water. Rosin
flux can be taken off with alcohol or some really active dishwasher
detergent. Ammonium chloride flux comes off with hot water. Have
never seen any flux with calcium chloride in it, sounds like it would
turn into rock when heated. Try some vinegar. I would have used some
electrical soldering paste, myself.

Dangit, it is zinc chloride. I let half a minute pass between reading
what's in it and writing it in a post, and look what happens.

But it's in some sort of greasy carrier that resists water.

If I can't find a good cheap process to wash this stuff off I'll
probably get some liquid flux that I know will rinse off easier.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

Grease - acid - need a strong base. Base will take off the oil/grease.
It will nuke the acid.

Strong stuff in the house - sodium hydroxide IIRC.

Strong soap and the like would work.

Martin

Martin H. Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
"Our Republic and the Press will Rise or Fall Together": Joseph Pulitzer
TSRA: Endowed; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal.
NRA Second Amendment Task Force Charter Charter Founder
IHMSA and NRA Metallic Silhouette maker & member. http://lufkinced.com/

On 5/28/2010 1:31 PM, Tim Wescott wrote:
On 05/28/2010 09:12 AM, wrote:
On May 27, 11:17 pm, Tim wrote:
Oops.

After finishing soldering my Very First model airplane fuel tank, I went
to do the last step of any soldering project -- cleaning off the flux.

Unfortunately, while I know that the flux I use yields to scrubbing with
hot soapy water, I don't know what -- if anything -- will just take it
off. I'm experimenting.

I've got some in each of four cups, with lacquer thinner, mineral
spirits, isopropyl alcohol, and plain drinking water. None of them seem
to be having any effect except the mineral spirits, which appears to be
separating it into two components.

In the mean time, I'm checking here to see if anyone has any pointers.
It's "Top Line Quality Soldering Paste Flux". Bought over thirty years
ago (I don't go through flux very fast). It looks like bearing grease,
& it sizzles when the iron touches it. Works great, but leaves a
residue which I don't want inside my engines!

So -- anyone happen to know if there's a common soldering flux that
contains calcium chloride and has this consistency, and if so how to
clean out the inside of an itty bitty fuel tank made with it? If all
else fails I'll run really hot water through it along with dishwashing
detergent -- but that doesn't leave me 100% confident.

--
Tim Wescott
Control system and signal processing consultingwww.wescottdesign.com

Acid flux uses zinc chloride and should be washable with water. Rosin
flux can be taken off with alcohol or some really active dishwasher
detergent. Ammonium chloride flux comes off with hot water. Have
never seen any flux with calcium chloride in it, sounds like it would
turn into rock when heated. Try some vinegar. I would have used some
electrical soldering paste, myself.

Dangit, it is zinc chloride. I let half a minute pass between reading
what's in it and writing it in a post, and look what happens.

But it's in some sort of greasy carrier that resists water.

If I can't find a good cheap process to wash this stuff off I'll
probably get some liquid flux that I know will rinse off easier.

On May 27, 10:17*pm, Tim Wescott wrote:
Oops.

After finishing soldering my Very First model airplane fuel tank, I went
to do the last step of any soldering project -- cleaning off the flux.

Unfortunately, while I know that the flux I use yields to scrubbing with
hot soapy water, I don't know what -- if anything -- will just take it
off. *I'm experimenting.

I've got some in each of four cups, with lacquer thinner, mineral
spirits, isopropyl alcohol, and plain drinking water. *None of them seem
to be having any effect except the mineral spirits, which appears to be
separating it into two components.

In the mean time, I'm checking here to see if anyone has any pointers.
It's "Top Line Quality Soldering Paste Flux". *Bought over thirty years
ago (I don't go through flux very fast). *It looks like bearing grease,
& it sizzles when the iron touches it. *Works great, but leaves a
residue which I don't want inside my engines!

So -- anyone happen to know if there's a common soldering flux that
contains calcium chloride and has this consistency, and if so how to
clean out the inside of an itty bitty fuel tank made with it? *If all
else fails I'll run really hot water through it along with dishwashing
detergent -- but that doesn't leave me 100% confident.

--
Tim Wescott
Control system and signal processing consultingwww.wescottdesign.com

I think I have a couple of cans of that stuff. Grease mixed with zinc
chloride. Dad used to make the flux by dissolving zinc in hydrochloric
acid (muratic acid). The grease is supposed to burn off with the
soldering heat, but usually never does. I have never used the stuff on
something that I could not get into to wipe out, so can't help there.

Paul

On May 27, 10:17*pm, Tim Wescott wrote:

It's "Top Line Quality Soldering Paste Flux". *Bought over thirty years
ago (I don't go through flux very fast). *It looks like bearing grease,
& it sizzles when the iron touches it. *Works great, but leaves a
residue

The paste flux used for plumbing is ZnCl2 in a vehicle of petroleum
jelly.
If that's what you have, any waterless hand cleaner will loosen it,
and you can flush with water. It's inconvenient to do this inside
a finished tank, so consider tinning the seam bits, cleaning the
flux off, then pressing together and heating without any extra flux.

Boiling water rinse is a good starting step. When most of the
petroleum jelly is dissolved, the ZnCl2 will dissolve in water.

On 05/28/2010 10:03 AM, whit3rd wrote:
On May 27, 10:17 pm, Tim wrote:

It's "Top Line Quality Soldering Paste Flux". Bought over thirty years
ago (I don't go through flux very fast). It looks like bearing grease,
& it sizzles when the iron touches it. Works great, but leaves a
residue

The paste flux used for plumbing is ZnCl2 in a vehicle of petroleum
jelly.
If that's what you have, any waterless hand cleaner will loosen it,
and you can flush with water. It's inconvenient to do this inside
a finished tank, so consider tinning the seam bits, cleaning the
flux off, then pressing together and heating without any extra flux.

Boiling water rinse is a good starting step. When most of the
petroleum jelly is dissolved, the ZnCl2 will dissolve in water.

That sounds exactly like what I have, except that it's brown instead of
the clear you'd expect from petroleum jelly.

I think I'll try hot, then boiling water with hand dishwashing
detergent, then hot and boiling water with Cascade if the hand stuff
doesn't do the job.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

On May 28, 11:35*am, Tim Wescott wrote:

I think I'll try hot, then boiling water with hand dishwashing
detergent, then hot and boiling water with Cascade if the hand stuff
doesn't do the job.

Petroleum jelly, like heavy grease, doesn't (in my experience)
emulsify well with normal detergents; it's easy to get loose
with whatever is in waterless hand cleaner, though.
I've also used the waterless hand cleaner mixed with water
(it turns milky) in an ultrasonic cleaner, it's a good degrease
solution. The water is key to getting rid of that ZnCl2, or
you could just use mineral spirits.

On Fri, 28 May 2010 12:14:36 -0700 (PDT), whit3rd wrote:

On May 28, 11:35*am, Tim Wescott wrote:

I think I'll try hot, then boiling water with hand dishwashing
detergent, then hot and boiling water with Cascade if the hand stuff
doesn't do the job.

Petroleum jelly, like heavy grease, doesn't (in my experience)
emulsify well with normal detergents; it's easy to get loose
with whatever is in waterless hand cleaner, though.
I've also used the waterless hand cleaner mixed with water
(it turns milky) in an ultrasonic cleaner, it's a good degrease
solution. The water is key to getting rid of that ZnCl2, or
you could just use mineral spirits.

2K paint thinners (not pure acetone) will dissolve both petroleum jelly and
tallow (which is a decent flux).


I was using some last weekend for the job and found it better than the other
solvents I had to hand.


Mark Rand
RTFM

"Tim Wescott" wrote in message
...
Oops.

After finishing soldering my Very First model airplane fuel tank, I went
to do the last step of any soldering project -- cleaning off the flux.

Unfortunately, while I know that the flux I use yields to scrubbing with
hot soapy water, I don't know what -- if anything -- will just take it
off. I'm experimenting.

I've got some in each of four cups, with lacquer thinner, mineral
spirits, isopropyl alcohol, and plain drinking water. None of them seem
to be having any effect except the mineral spirits, which appears to be
separating it into two components.

In the mean time, I'm checking here to see if anyone has any pointers.
It's "Top Line Quality Soldering Paste Flux". Bought over thirty years
ago (I don't go through flux very fast). It looks like bearing grease,
& it sizzles when the iron touches it. Works great, but leaves a
residue which I don't want inside my engines!

So -- anyone happen to know if there's a common soldering flux that
contains calcium chloride and has this consistency, and if so how to
clean out the inside of an itty bitty fuel tank made with it? If all
else fails I'll run really hot water through it along with dishwashing
detergent -- but that doesn't leave me 100% confident.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

30 years ago we used to use 1,1,1 TCE which dissolved & removed
the flux in short order. It's outlawed now but if you have any in a dusty
corner ...
Art

On Thu, 27 May 2010 22:17:36 -0700, Tim Wescott
wrote:

Oops.

After finishing soldering my Very First model airplane fuel tank, I went
to do the last step of any soldering project -- cleaning off the flux.

Unfortunately, while I know that the flux I use yields to scrubbing with
hot soapy water, I don't know what -- if anything -- will just take it
off. I'm experimenting.

I've got some in each of four cups, with lacquer thinner, mineral
spirits, isopropyl alcohol, and plain drinking water. None of them seem
to be having any effect except the mineral spirits, which appears to be
separating it into two components.

In the mean time, I'm checking here to see if anyone has any pointers.
It's "Top Line Quality Soldering Paste Flux". Bought over thirty years
ago (I don't go through flux very fast). It looks like bearing grease,
& it sizzles when the iron touches it. Works great, but leaves a
residue which I don't want inside my engines!

So -- anyone happen to know if there's a common soldering flux that
contains calcium chloride and has this consistency, and if so how to
clean out the inside of an itty bitty fuel tank made with it? If all
else fails I'll run really hot water through it along with dishwashing
detergent -- but that doesn't leave me 100% confident.

You are removing zinc chloride and vaseline. Try brake cleaner to
cut the vaseline. If it's real heavy, use gasoline or perhaps
napththa for gross cleaning, then brake cleaner for the solvent
stage. Then I'd use a good proprietary alkalai metal cleaner as from
Birchwood Casey or Caswell, or make your own with TSP and sodium
carbonate or sodium hydroxide. Some add some sodium silicate but I
don't think it's necessary. These steps should result in metal that
is chemically and waterbreak clean, suitable for plating.

Since it's itty bitty, I'd at least try a run in my HF ultrasonic
cleaner with their pretty good cleaning stuff heated to 160F or so.
That doesn't always work but it gets 'er done surprisingly often.

On May 28, 1:17*am, Tim Wescott wrote:
Oops.

After finishing soldering my Very First model airplane fuel tank, I went
to do the last step of any soldering project -- cleaning off the flux.

Unfortunately, while I know that the flux I use yields to scrubbing with
hot soapy water, I don't know what -- if anything -- will just take it
off. *I'm experimenting.

I've got some in each of four cups, with lacquer thinner, mineral
spirits, isopropyl alcohol, and plain drinking water. *None of them seem
to be having any effect except the mineral spirits, which appears to be
separating it into two components.

In the mean time, I'm checking here to see if anyone has any pointers.
It's "Top Line Quality Soldering Paste Flux". *Bought over thirty years
ago (I don't go through flux very fast). *It looks like bearing grease,
& it sizzles when the iron touches it. *Works great, but leaves a
residue which I don't want inside my engines!

So -- anyone happen to know if there's a common soldering flux that
contains calcium chloride and has this consistency, and if so how to
clean out the inside of an itty bitty fuel tank made with it? *If all
else fails I'll run really hot water through it along with dishwashing
detergent -- but that doesn't leave me 100% confident.

--
Tim Wescott
Control system and signal processing consultingwww.wescottdesign.com

Model airplane fuel tank, right? How about using some of your nitro/
alcohol fuel to clean the tank? That stuff is a mighty active solvent.
Besides, anything the fuel doesn't remove isn't going to be a problem
later.