I finally tried electrolytic de-rusting and I like it. I tried it on
a sheet metal blower housing off a lawn mower and I was really
impressed with the results. The pitted areas of the metal were
blasted completely free of rust and the process removed most of the
paint as well.

The downside is that I now have a dead Harbor Freight battery
charger. I found a 24 V forklift battery charger that runs on 220 or
440 and will deliver 12.5/25 amps. the guy wants $20 so this might be
a good deal.

Is this a good candidate for making a dedicated power supply for an
electrolytic de-rusting set up?

I know that a cheapy little battery charger will work but I assume
that the forklift charger has much heavier internal components so it
should last.

I also understand that the power requirements to de-rust vary
depending on the surface area and the conductivity of the solution.
Would it be easy to tweak this charger to make it so I could dial in
an optimal setting?

Also, what sort of fuse or other safety should I be sure to build into
the supply?


Roger Shoaf

RS at work wrote:

I finally tried electrolytic de-rusting and I like it. I tried it on
a sheet metal blower housing off a lawn mower and I was really
impressed with the results. The pitted areas of the metal were
blasted completely free of rust and the process removed most of the
paint as well.

The downside is that I now have a dead Harbor Freight battery
charger. I found a 24 V forklift battery charger that runs on 220 or
440 and will deliver 12.5/25 amps. the guy wants $20 so this might be
a good deal.

If it actually works, then yes, it's a hell of a deal. (i.e., good.) :-)

Is this a good candidate for making a dedicated power supply for an
electrolytic de-rusting set up?

Yes, as long as you have control over the current delivered.

I know that a cheapy little battery charger will work but I assume
that the forklift charger has much heavier internal components so it
should last.

Agreed.

I also understand that the power requirements to de-rust vary
depending on the surface area and the conductivity of the solution.
Would it be easy to tweak this charger to make it so I could dial in
an optimal setting?

Only the seller can tell you that.

Also, what sort of fuse or other safety should I be sure to build into
the supply?

If it isn't already fused, breakered, or current limited, I'd say based
on the 25 Amp spec, a 30A slow-blow should be fine. When I worked for
the battery charger manufacturer a few years ago, they used fusible link
wire. :-)

Have Fun!
Rich

RS at work wrote:
I finally tried electrolytic de-rusting and I like it. I tried it on
a sheet metal blower housing off a lawn mower and I was really
impressed with the results. The pitted areas of the metal were
blasted completely free of rust and the process removed most of the
paint as well.

The downside is that I now have a dead Harbor Freight battery
charger. I found a 24 V forklift battery charger that runs on 220 or
440 and will deliver 12.5/25 amps. the guy wants $20 so this might be
a good deal.

Is this a good candidate for making a dedicated power supply for an
electrolytic de-rusting set up?

I know that a cheapy little battery charger will work but I assume
that the forklift charger has much heavier internal components so it
should last.

I also understand that the power requirements to de-rust vary
depending on the surface area and the conductivity of the solution.
Would it be easy to tweak this charger to make it so I could dial in
an optimal setting?

Also, what sort of fuse or other safety should I be sure to build into
the supply?


Roger Shoaf

What you want and need on the output is a "PWM controller" . Stands for
Pulse Width Modulation . Google that for more info , but the net result is
current/voltage control . I use one to control the temp of my 'lectric
motorcycle gloves . They are also commonly used to control DC motor speed .
Kits can be had fairly cheap , mine was around $35 including case . You can
also find them on eBay ...
As far as fusing , I'd think you'll rarely draw more than rated amps , say
fuse it for 15 with a 220 supply . I'd fuse it at the output of the PWM
though - unless your PWM is rated less than the supply's output spec , then
I' d fuse the input .
--
Snag
Learning keeps
you young !

"Snag" wrote in message
...
RS at work wrote:
I finally tried electrolytic de-rusting and I like it. I tried it on
a sheet metal blower housing off a lawn mower and I was really
impressed with the results. The pitted areas of the metal were
blasted completely free of rust and the process removed most of the
paint as well.

The downside is that I now have a dead Harbor Freight battery
charger. I found a 24 V forklift battery charger that runs on 220 or
440 and will deliver 12.5/25 amps. the guy wants $20 so this might be
a good deal.

Is this a good candidate for making a dedicated power supply for an
electrolytic de-rusting set up?

I know that a cheapy little battery charger will work but I assume
that the forklift charger has much heavier internal components so it
should last.

I also understand that the power requirements to de-rust vary
depending on the surface area and the conductivity of the solution.
Would it be easy to tweak this charger to make it so I could dial in
an optimal setting?

Also, what sort of fuse or other safety should I be sure to build into
the supply?


Roger Shoaf

What you want and need on the output is a "PWM controller" . Stands for
Pulse Width Modulation . Google that for more info , but the net result is
current/voltage control . I use one to control the temp of my 'lectric
motorcycle gloves . They are also commonly used to control DC motor speed
. Kits can be had fairly cheap , mine was around $35 including case . You
can also find them on eBay ...
As far as fusing , I'd think you'll rarely draw more than rated amps ,
say fuse it for 15 with a 220 supply . I'd fuse it at the output of the
PWM though - unless your PWM is rated less than the supply's output spec ,
then I' d fuse the input .
--
Snag
Learning keeps
you young !

I've been using a no-name charger for "wand" derusting for ten years. (Ted
Edwards' recipe:

http://www.metalworking.com/dropbox/...es/E-CLEAN.TXT


I blew a fuse once when I slipped and touched the probe to the work
(actually, my piece of cotton batting wore through).

At first I put my big Variac in front of the charger to fine-tune the
amperage, but I soon found it wasn't necessary.

--
Ed Huntress

On Apr 23, 2:44*pm, RS at work wrote:
...
Would it be easy to tweak this charger to make it so I could dial in
an optimal setting?
...
Roger Shoaf

If you can find a surplus Variac or Powerstat you can make an
adjustable supply from a transformer and rectifier. A built-in current
meter is useful. You can clip on an external voltmeter because its
leads don't have to pass high current and it isn't nearly as hazardous
if a lead clip falls off.

I don't think this will work with an automatic charger unless it's
blown and you are salvaging only the transformer and rectifier.

jsw

The downside is that I now have a dead Harbor Freight battery
charger.

All you need is a charger that isn't a complete piece of crap (horrible
fright being a near-guarantee of a complete pice of crap barring the
occasional planetary alignment - so killing that is an upside if you get
a better replacement.)

Use weaker solution or more distance between electrodes or a smaller
electrode if you are pulling too many amps for the charger.

I use my regular charger (don't recall the brand, but not Chinese) and
have had no trouble in 20 years - I can switch that one to 6V if it gets
too excited on 12V.

--
Cats, coffee, chocolate...vices to live by

On Sat, 23 Apr 2011 18:40:15 -0400, Ecnerwal
wrote:

The downside is that I now have a dead Harbor Freight battery
charger.

All you need is a charger that isn't a complete piece of crap (horrible
fright being a near-guarantee of a complete pice of crap barring the
occasional planetary alignment - so killing that is an upside if you get
a better replacement.)

Use weaker solution or more distance between electrodes or a smaller
electrode if you are pulling too many amps for the charger.

I use my regular charger (don't recall the brand, but not Chinese) and
have had no trouble in 20 years - I can switch that one to 6V if it gets
too excited on 12V.

Ive used electrolytic derusting for a number of years now..and I try to
keep my voltage below 5 volts. Higher than that..and I find excessive
pitting.

Just a heads up.

Gunner, with a 40 amp 5vt DC supply as his power source

--
"If I say two plus two is four and a Democrat says two plus two is eight,
it's not a partial victory for me when we agree that two plus two is
six. " Jonah Goldberg (modified)

"Snag" wrote in message
...
RS at work wrote:
I finally tried electrolytic de-rusting and I like it. I tried it on
a sheet metal blower housing off a lawn mower and I was really
impressed with the results. The pitted areas of the metal were
blasted completely free of rust and the process removed most of the
paint as well.

The downside is that I now have a dead Harbor Freight battery
charger. I found a 24 V forklift battery charger that runs on 220 or
440 and will deliver 12.5/25 amps. the guy wants $20 so this might be
a good deal.

Is this a good candidate for making a dedicated power supply for an
electrolytic de-rusting set up?

I know that a cheapy little battery charger will work but I assume
that the forklift charger has much heavier internal components so it
should last.

I also understand that the power requirements to de-rust vary
depending on the surface area and the conductivity of the solution.
Would it be easy to tweak this charger to make it so I could dial in
an optimal setting?

Also, what sort of fuse or other safety should I be sure to build into
the supply?


Roger Shoaf

What you want and need on the output is a "PWM controller" . Stands for
Pulse Width Modulation . Google that for more info , but the net result is
current/voltage control . I use one to control the temp of my 'lectric
motorcycle gloves . They are also commonly used to control DC motor speed
. Kits can be had fairly cheap , mine was around $35 including case . You
can also find them on eBay ...
As far as fusing , I'd think you'll rarely draw more than rated amps ,
say fuse it for 15 with a 220 supply . I'd fuse it at the output of the
PWM though - unless your PWM is rated less than the supply's output spec ,
then I' d fuse the input .
--
Snag
Learning keeps
you young !

A linear adjustable current regulator is not difficult to build.

I think there's a research project in the PWM idea.
Does it work as well as continuous current?
Does it work better?
Is high voltage (current), low duty cycle an advantage?
A quick Google search didn't find any data.
Mikek

Gunner Asch wrote:
On Sat, 23 Apr 2011 18:40:15 -0400, Ecnerwal
wrote:

The downside is that I now have a dead Harbor Freight battery
charger.
All you need is a charger that isn't a complete piece of crap (horrible
fright being a near-guarantee of a complete pice of crap barring the
occasional planetary alignment - so killing that is an upside if you get
a better replacement.)

Use weaker solution or more distance between electrodes or a smaller
electrode if you are pulling too many amps for the charger.

I use my regular charger (don't recall the brand, but not Chinese) and
have had no trouble in 20 years - I can switch that one to 6V if it gets
too excited on 12V.

Ive used electrolytic derusting for a number of years now..and I try to
keep my voltage below 5 volts. Higher than that..and I find excessive
pitting.

Just a heads up.

Gunner, with a 40 amp 5vt DC supply as his power source



You want a low voltage high current source. The reason being that you
need more currant the larger the item gets AND the stronger you make the
brine.

The normal method is to fill the tank with water, add in the parts, then
start adding the magic powder. Watch your amp meter while doing this and
stop adding powder when the meter stops climbing. This is saturation
point for that part. It is also the point at which the best cleaning
takes place. The problem is that it is also hard to adjust the mix once
you have it set. So what I generally do is to put in a mid sized part,
then mix, then just accept that smaller parts will need to be watched
and larger ones will take more time.

--
Steve W.

The place to find out more about a forklift charger is from the
manufacturer, if the model isn't too old.
I've looked up several brands/models, and the basic schematics/wiring
diagrams (and jumper settings) were available online.

Old F-L chargers vary considerably from newer charger models.

Any of them can likely be modified for other purposes (spot/resistance
welding, arc welders etc) with some additional control circuitry that
replaces the original controller.

Newer charger controllers are microprocessor/firmware driven (the circuit
board may only be about 3x3"), and unless you really know electronic design,
it's likely to be much easier to just replace the controller with something
that's much more simple, but also reliable and safe.

--
WB
..........


"RS at work" wrote in message
...
I finally tried electrolytic de-rusting and I like it. I tried it on
a sheet metal blower housing off a lawn mower and I was really
impressed with the results. The pitted areas of the metal were
blasted completely free of rust and the process removed most of the
paint as well.

The downside is that I now have a dead Harbor Freight battery
charger. I found a 24 V forklift battery charger that runs on 220 or
440 and will deliver 12.5/25 amps. the guy wants $20 so this might be
a good deal.

Is this a good candidate for making a dedicated power supply for an
electrolytic de-rusting set up?

I know that a cheapy little battery charger will work but I assume
that the forklift charger has much heavier internal components so it
should last.

I also understand that the power requirements to de-rust vary
depending on the surface area and the conductivity of the solution.
Would it be easy to tweak this charger to make it so I could dial in
an optimal setting?

Also, what sort of fuse or other safety should I be sure to build into
the supply?


Roger Shoaf