Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, and 850 California Police models
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There are numerous approaches, techniques, and processes described on this page. Read through them and pick your favorite.
Plugs for the petcock holes
Thanks to Charlie Mullendore of Antietam Classic Cycle for the following recommendation:
The rubber plugs were purchased at the local Ace Hardware, any good hardware store should have them. I've seen them in the hardware section of the local Lowe's. You want the black rubber not cork ones. The [petcock] ones are 3⁄8 inch at the smaller end, 9⁄16 inch at the larger end.
Thanks to Hayden for the following recommendation:
For plugging the bottom of the tank, plastic peg spiles for cask beer are 13 mm diameter at the fat bit. Fuel tap theads are 12 mm which makes it a snug screw in fit. I went to a local beer brewer who gets them in boxes of 1000 - he just chucked over a handful.
Heat the spiles in hot water to soften and they screw right in.
Hardwood ones are available which should be ok, but softwood spiles are not as they are used to seal the barrel but vent gasses. Hardwood spiles do not breath and expand and seal the hole apparently.
Plastic peg spile for cask beer. Can be used to seal the petock holes on the bottom of the tank.
Photo courtesy of eBay auction.
Plastic peg spile for cask beer. Can be used to seal the petock holes on the bottom of the tank.
Charlie followed instructions he found online. Here are a few notes and several photos from Charlie....
You want Arm & Hammer Super Washing Soda which is normally found at the supermarket in the aisle with the laundry detergent. Comes in a yellow box. I bought two large (5 gallon?) plastic buckets to mix the solution in and to drain it back into when done. Used a large plastic cup to transfer the solution from the bucket to the tank.
I've had no recurrence of rust so far, but it is winter (low humidity) and I do keep the tank full as much as possible.
The rubber plugs were purchased at the local Ace Hardware, any good hardware store should have them. I've seen them in the hardware section of the local Lowe's. You want the black rubber not cork ones. The small ones are 3⁄8 inch at the smaller end, 9⁄16 inch at the larger end. The big one is 1.5 inch at the smaller end and 1.75 inch at the larger end. I used a 3⁄32 inch drill bit to make the holes in it for the sacrificial anode.
Following Charlie's lead, I now use this electrolysis technique prior to any coating. It works very well. Here are a couple notes from my personal experience.
If you cannot find the Arm & HammerSuper Washing Soda, just look in the pool section of your hardware store for Soda Ash (which is sodium carbonate). Soda ash is used to raise the pH level in swimming pools and is inexpensive.
I found coat hangers would disintegrate pretty quickly (I use a power supply). So, instead, I used bicycle hanging hooks (for hanging a bicycle from the rafters in a garage) that I purchased from the local hardware store inexpensively. It is really nothing more than a thick rod and they last a long time.
Keeping the tank in a horizontal position and filling it to the brim with the solution will still leave the underside of the top of the tank exposed. I found it necessary to carefully rotate the tank to ensure that all parts are submerged during electrolysis.
Electrolysis articles Charlie referenced from other websites:
Gas Tank Cleaning using Electrolysis
Removing Rust without Cutting it Open
Author: Chris Wantuck
Original URL (no longer available): http://www.secondchancegarage.com/public4/gas-tank-cleaning-1.cfm
We've all done it. We encounter a problem and run the usual phrase through our minds: There has to be a better way. One of the most important items in the restoration process of our classic car is ensuring that the fuel system will deliver a clean, reliable stream of fuel to the engine. That means the fuel tank has no debris like small stones, flakes of rust or other undesirable contaminants that can clog the fuel line or carburetor. Maybe it's a tank that is from a car that's a 40 year old barn find or it's a tank that was purchased at a flea market and it sat outside in the rain and snow for 20 years. In your heart you know that opening up the tank — either at a seam or using a die grinder and cutting a square hole — the tank will never be the same. It will still require crimping and resealing the seam or repairing the hole using common metal fabrication methods like Mig welding a patch and grinding it smooth. The tank could also be an exposed one like most cars of the teens through the twenties. These may require that the exterior has to be perfect. Looking for a replacement tank you may find one in equal or worse condition. Rarely will you ever find a NOS tank.
Inside a quick visual inspection shows an even coating of rust on the side walls and equal amounts on the baffles if your tank has those. If the car was put away 40 years ago with some gas still in the tank, it's a guarantee that there will be a layer of dried gas looking a lot like varnish or your grandmother's molasses. It will be thick, goop, and unlike molasses, no matter how long you wait with the tank upside down, it will not flow out. Adding an open flame heat to soften it is a dangerous proposition as fumes could still be ignited, even after more than 10 years of sitting to the open air. Methyl Ethyl Ketone (MEK) one of the active ingredients in most paint strippers will remove most of the thick varnish coating, but is an expensive proposition since several gallons could be needed. And MEK does not address the coating of rust. Photo 1 is a cross section diagram of a tank with both baffles and reserve chambers.
Photo 1 — A cross section diagram of a gas tank with baffles and reserve chambers. Not all tanks are this elaborate but it shows the various areas where rust can form which can't be seen from the filler neck or the opening where the gas tank sending unit is inserted.
Photo courtesy of Chris Wantuck.
Photo 1 — A cross section diagram of a gas tank with baffles and reserve chambers. Not all tanks are this elaborate but it shows the various areas where rust can form which can't be seen from the filler neck or the opening where the gas tank sending unit is inserted.
We're going to look at using electrolysis as a way to remove rust from gas tanks. Electrolysis is the passage of a direct electric current through an ionic substance that is either molten or dissolved in a suitable solvent, resulting in chemical reactions at the electrodes and separation of materials. In chemistry and manufacturing, electrolysis is a method of using a direct electric current (DC) to drive an otherwise non-spontaneous chemical reaction. Electrolysis is used commercially as a stage in the separation of elements from naturally occurring sources such as ores using an electrolytic cell. The technical definition of the voltage needed for electrolysis to occur is called the decomposition potential.
How it's done
You submerse the rusted part in a non metallic container (a plastic spackle bucket will do) with a solution of Sodium Carbonate or soda ash (Na2CO3), such as Arm & Hammer Washing soda found in the laundry section of your grocery store. Sodium Carbonate is also found in Hot tub chemical section of your local Home Store (Menards, Lowes, HD, etc.). Make sure you don't use baking soda, that's Sodium Bicarbonate (NaHCO3) which will not work.
The part to be cleaned is connected to the negative polarity of the direct current source and the Anode is a piece of steel such a Rebar used in concrete reinforcement. Several amps of Direct Current (DC) electricity from a battery charger or power supply will lift off the rust and deposit it to the Anode lead (Rebar). In hours or days, the part will be shed of the layers of rust and ready for the next step in refinishing.
Basically, we're using DC electricity from a power supply (battery charger) connected to the rusted part ,and a donor piece of ferrous (iron) metal immersed in a solution of water and Sodium Carbonate. The negative lead is connected to the rusted part and the positive lead is connected to the donor metal which will collect the rust deposits (Photo 2). The electrolyte solution (dissolved in regular water) and when the electricity flows, the rust is forced off the rusted part and mostly deposited onto the donor metal. Some rust particles are forced off, but fall into the container. The Electrolysis method for rust removal is not new, but this article examines its application for use in two cleaning gas tanks, one an automobile tank and the other a small gallon tank.
Gas tanks of the teens through the 1950's and even later can have a number of chambers created with the inclusion of baffles. Cleaning tanks with multiple baffles has traditionally been difficult and the electrolysis method is just one more tool in our arsenal of restoration methods. The difference here is that the metal tank is treated as the Cathode and it's filled with the electrolyte solution and the positive Anode that collects the rust deposit is suspended inside (Photo 3). And more importantly this is done without cutting open the tank!
Photo 2 — The basic diagram of Electrolysis rust removal. A non conductive container (5 gallon pail or Rubbermaid container) is filled with water, several tablespoons per gallon of Arm & Hammer brand powder washing soda laundry detergent, the rusted part (called the Cathode) connected to the negative lead of the direct current power and the Anode, the metal that will collect the rust while the electrolysis process is taking place.
Photo courtesy of Chris Wantuck.
Photo 2 — The basic diagram of Electrolysis rust removal. A non conductive container (5 gallon pail or Rubbermaid container) is filled with water, several tablespoons per gallon of Arm & Hammer brand powder washing soda laundry detergent, the rusted part (called the Cathode) connected to the negative lead of the direct current power and the Anode, the metal that will collect the rust while the electrolysis process is taking place.
Photo 3 — The basic diagram of the Electrolysis rust removal for gas tank cleaning. The tank is filled with Electrolyte solution of water and Sodium Carbonate and the Anode is suspended inside the tank before connecting the DC source.
Photo courtesy of Chris Wantuck.
Photo 3 — The basic diagram of the Electrolysis rust removal for gas tank cleaning. The tank is filled with Electrolyte solution of water and Sodium Carbonate and the Anode is suspended inside the tank before connecting the DC source.
The main components required to achieve electrolysis are:
An electrolyte: a substance containing free ions which are the carriers of electric current in the electrolyte. If the ions are not mobile, as in a solid salt then electrolysis cannot occur.
A direct current (DC) supply: provides the energy necessary to create or discharge the ions in the electrolyte. Electric current is carried by electrons in the external circuit.
Two electrodes: an electrical conductor which provides the physical interface between the electrical circuit providing the energy and the electrolyte. In our case the gas tank itself is one and the other is suspended inside the tank.
Photo 4 is the result of a tank project that went bad. A shop cut open this 1920's tank to reveal what was already known by the owner/restorer, that there were two vertical baffles inside that created three chambers. Additionally this tank was designed with two reserve chambers, along the bottom. Since the tank was already cut open and the damage done, the electrolysis process was applied albeit easier. A length of concrete rebar was used as the Anode cradled by scrap wooden blocks. Since electrolysis is so dependant on electricity, the rebar end was drilled and 14 gauge stranded wire was soldered into the hole (Photo 5). Photo 5 also shows the result of a few hours of the electrolysis process. The rusty Anode is easily cleaned using a small wire brush.
Photo 4 — This tragedy didn't have to occur. A 1920's era tank was cut open by a shop only to have the shop give up and return the tank to the customer in pieces. Since the tank was already cut open, the electrolysis cleaning was performed as outlined in this article.
Photo courtesy of Chris Wantuck.
Photo 4 — This tragedy didn't have to occur. A 1920's era tank was cut open by a shop only to have the shop give up and return the tank to the customer in pieces. Since the tank was already cut open, the electrolysis cleaning was performed as outlined in this article.
Photo 5 — Top: Rebar segment with a long length of stranded wire soldered into the end. The scrap wooden blocks act as insulators since the tank was already cut open. Bottom: The same Rebar after a few hours of electrolysis operation. The rust collected is easily removed using a small wire brush and a quick rinse in fresh water. As rust is formed on the Anode, the current draw will decrease. At 50 percent or less of the initial current is a good indicator of when the Anode requires cleaning.
Photo courtesy of Chris Wantuck.
Photo 5 — Top: Rebar segment with a long length of stranded wire soldered into the end. The scrap wooden blocks act as insulators since the tank was already cut open. Bottom: The same Rebar after a few hours of electrolysis operation. The rust collected is easily removed using a small wire brush and a quick rinse in fresh water. As rust is formed on the Anode, the current draw will decrease. At 50 percent or less of the initial current is a good indicator of when the Anode requires cleaning.
Another example of tank cleaning is this 5 gallon tank for a small portable generator (Photo 6). The generator was abandoned when the engine seized and they left the tank open to the weather. Photo 7 shows the condition of the tank's bottom surface where most of the rust had formed. Photo 8 is the flat stock steel Anode with stranded wire soldered to it. In this case a simple spring clamp kept the Anode suspended inside the tank, as low as possible without touching the bottom (Photo 9). Another possibility could have been to use vinyl tubing on the ends and/or tape or wire ties to make insulators on the tips of the Anode. What is important is to create an Anode that has as large of a surface area as possible. Simply dunking a wire in the electrolyte solution will collect rust quickly requiring cleaning every 5 minutes. Ingenuity is needed for your particular project and no two cases are alike. Photo 10 shows the Anode after a few hours of operation. Not all rust gets deposited onto the Anode as Photo 11 shows. Draining the solution from the tank into a bucket reveals the rust that got dislodged from the tank and was floating in the solution. Photo 12 shows the result after 10 hours of electrolysis cleaning. The tank was air dried, rinsed of Muriatic Acid followed by an application of a national name brand sealer and this tank was fit to be put back into service.
Image no longer available, but leaving the caption for reference. Photo 6 — This tank on a portable generator was left open to the weather and a healthy film of rust collected inside.
Photo courtesy of Chris Wantuck.
Image no longer available, but leaving the caption for reference. Photo 6 — This tank on a portable generator was left open to the weather and a healthy film of rust collected inside.
Image no longer available, but leaving the caption for reference. Photo 7 — Close up view of the inside of the generator gas tank. Rust has formed and started to leach into the metal surface. The Electrolysis process will clean both surface and crevices.
Photo courtesy of Chris Wantuck.
Image no longer available, but leaving the caption for reference. Photo 7 — Close up view of the inside of the generator gas tank. Rust has formed and started to leach into the metal surface. The Electrolysis process will clean both surface and crevices.
Image no longer available, but leaving the caption for reference. Photo 8 — Anode is a segment of flat steel stock with a stranded wire soldered to it.
Photo courtesy of Chris Wantuck.
Image no longer available, but leaving the caption for reference. Photo 8 — Anode is a segment of flat steel stock with a stranded wire soldered to it.
Image no longer available, but leaving the caption for reference. Photo 9 — A simple spring camp suspends the Anode by its green stranded wire in the tank just above the bottom to prevent shorting out. The electrical spring clip on the flange is the Cathode (negative) connection. A better connection would have been on the tanks flange away from where gas may form.
Photo courtesy of Chris Wantuck.
Image no longer available, but leaving the caption for reference. Photo 9 — A simple spring camp suspends the Anode by its green stranded wire in the tank just above the bottom to prevent shorting out. The electrical spring clip on the flange is the Cathode (negative) connection. A better connection would have been on the tanks flange away from where gas may form.
Image no longer available, but leaving the caption for reference. Photo 10 — After a few hours of Electrolysis, rust is forming on the Anode. A small wire brush easily cleans it off and is put back into the tank for more cleaning.
Photo courtesy of Chris Wantuck.
Image no longer available, but leaving the caption for reference. Photo 10 — After a few hours of Electrolysis, rust is forming on the Anode. A small wire brush easily cleans it off and is put back into the tank for more cleaning.
Image no longer available, but leaving the caption for reference. Photo 11 — Not all the rust removed from the tank's inside is collected onto the Anode. Here the electrolyte solution was drained into a bucket and strained for the picture to show the amount.
Photo courtesy of Chris Wantuck.
Image no longer available, but leaving the caption for reference. Photo 11 — Not all the rust removed from the tank's inside is collected onto the Anode. Here the electrolyte solution was drained into a bucket and strained for the picture to show the amount.
Image no longer available, but leaving the caption for reference. Photo 12 — The same generator gas tank after the electrolysis cleaning procedure was applied. Notice how it pulled the rust from the pit holes and crevices.
Photo courtesy of Chris Wantuck.
Image no longer available, but leaving the caption for reference. Photo 12 — The same generator gas tank after the electrolysis cleaning procedure was applied. Notice how it pulled the rust from the pit holes and crevices.
Anodes (Electrodes) of ferrous metal, or graphite material are widely used. Choice of the suitable electrode depends on shape and method of suspension. Do not use stainless steel as an Anode.
Notes:
An important note on safety. Electrolysis creates Hydrogen Gas while the current is flowing and can be flammable or dangerous if inhaled. Perform this cleaning in a well ventilated area and disconnect the power source and wait 3 minutes for vapors to escape. Always disconnect the wire leads away from the area where the electrolysis is taking place. This is the reason why long leads are connected to the Anode and the tank.
It doesn't take much Sodium Carbonate (Arm & Hammer detergent) to make the electrolysis to work. Two or three tablespoons per gallon are enough. Adding more to the solution doesn't accelerate the process. The solution should periodically be replaced, say every 8-10 hours. Since rinsing with hot water is a part of the cleaning, start with a fresh solution each time after rinsing. The cost of the washing soda is low, so replacing the solution is no big deal.
The Arm & Hammer brand washing soda seems to work best, though it's not the only source of Sodium Carbonate. Hot tub and pool supply are also sources for sodium carbonate.
The Anode's size and surface area makes a difference. The greater the surface area, the more rust will be deposited on it. A piece of steel rebar works and may fit into narrow passages, but its round shape limits the surface area requiring you to change it often. Consider other shapes like 1/8 inch think cold rolled 1 X 2 or pipe/rod that is bent or curved to fit your situation. Solder the lead wire to the Anode to make the best electrical connection. You can be creative in its shape to suit your particular needs and add insulators at the ends. It's important to prevent the Anode from touching the gas tank directly.
Watch the ammeter on the DC power source. When the ammeter drops below 50 percent of the start value, the Anode needs to be cleaned. If your power source doesn't have a meter, check the Anode every 2-3 hours. Better yet, have a spare Anode handy and swap them.
The closer the Anode is to the rusted area, the better the electrolysis. Move the Anode around from one portion of the tank to another every few hours. You may have to repeat an area for heavily rusted areas.
Make a good connection of the negative lead to the tank to a section to where gasses won't be escaping. A little spring clip may not be enough. A small C clamp or Vise grip pliers onto a sanded area should make a good connection.
A benefit of Electrolysis is that it heats the electrolyte and may warm the contaminates to allow them to pour out during rinsing.
You're not limited to a single power source. Multiples power sources can be employed to accelerate the cleaning process. Don't let the Anodes touch each other.
You can apply the Electrolysis cleaning to your project tank before or after being boiled out by a local shop (sometimes radiator shops offer that service) to remove any lingering contaminates. Typically boiling out doesn't remove heavy rust only surface debris. Apply sealers following the instructions of that vendor. Paint the exterior appropriate for your project.
At the conclusion of the cleaning process, inspect your tank for structural integrity at the bottom, top, sides, and the baffles. Check for pin holes in the bottom and all sides, a common occurrence for tanks that have had old fuel sitting for long periods of time. Also make a determination if the tank is structurally sound as rust and corrosion may have thinned the metal. Using a bright light inside the tank in a dark room is one method to reveal pin holes. Apply some common sense on whether your tank is still a good candidate, if you should seek a better replacement, or have it repaired. Soldering small holes on the tank's exterior may be needed along with the sloshing sealer to address small pin holes.
Motorcycle Gas Tank Rust Removal
Author: 4strokeengine.org
Original URL (no longer available): https://www.motorcyclezombies.com/rebuild-tune-motorcycle/carbs-fuel-air/remove-rust-gas-tank/
If the classic motorcycle you're rebuilding has been sitting for a long time, chances are good that there will be some rust inside the gas tank.
There are a number of ways to remove rust from metal, but given the limited access and difficult angles/crevices inside an old motorcycle's gas tank, one of the easiest methods is electrolytic rust removal - especially for removing rust from the inside of the gas tank.
Electrolysis is one of the best ways to remove rust from a motorcycle gas tank.
Materials needed for electrolysis rust removal:
Scrap nuts and bolts.
Arm & Hammer Washing Soda (not baking soda).
Bendable steel or iron rod to be used as the sacrificial anode (do not use stainless steel as it will omit toxin during the process).
Battery charger/tender.
You'll also need a working battery if you're using an automatic battery charger. In this case, you'd route the tender to the batter and run clamps from the battery to the tank and anode.
Scrap wood, tennis ball, tape, etc. to hold the sacrificial anode in place.
A plastic bucket or two.
Water.
Functional petcock or something to plug the petcock holes.
Image no longer available, but leaving the caption for reference. For automatic chargers, you'll need to route your hookups from a battery to your tank set up. Manual chargers can connect directly to the tank. Click to expand.
Photo courtesy of motorcyclezombies.com.
Image no longer available, but leaving the caption for reference. For automatic chargers, you'll need to route your hookups from a battery to your tank set up. Manual chargers can connect directly to the tank. Click to expand.
How to set up your motorcycle gas tank for electrolysis rust removal:
Place some loose nuts and bolts inside the old gas tank and shake them around to loosen some of the rust. Dump them out after a few good shakes.
Set up your sacrificial steel anode so that it will extend into the gas tank without touching the sides.
Make sure there is enough metal sticking outside of the tank that you can clamp the charger to.
Use wood/old tennis ball/tape/etc. to keep the steel anode in place.
It must not touch the sides of the gas tank or the process won't work.
In a large bucket mix enough water and washing soda to fill your tank.
Use about a tablespoon of washing soda to every gallon of water. Stir until the washing soda has dissolved.
Pour the dissolved washing soda mixture into your gas tank.
Make sure the petcock or plug you used is not leaking.
Grab your battery charger (and a battery if using an automatic charger).
Attach the positive lead from your manual charger (or battery for automatic charger) to the sacrificial anode.
Attach the negative clamp to metal on the tank - the mounts can work.
Plug in your battery tender.
Double check that the anode has not moved to touch the tank.
If it has, adjust it so it will stay suspended inside the solution.
Let the gas tank and tender sit for a few hours.
Unplug the charger, unhook the positive/negative leads, and remove the sacrificial anode.
If done correctly, there should be a good build up of rust that has transferred from the tank to the anode.
Scrape of the rust so that the sacrificial anode is clean and repeat the process until you are satisfied with the rust removal.
Drain the solution when you're finished and swish some denatured alcohol around the tank.
For automatic chargers, you'll need to route your hookups from a battery to your tank set up. Manual chargers can connect directly to the tank. Suspend the sacrificial anode in the tank so that it doesn't touch the sides (Tennis balls are useful here).
Removing rust from parts seems to be something I need to do way too often. I came across this electrolysis rust removal method while researching the best way to remove rust from a motorcycle gas tank. I didn't want to purchase a gas tank sealer kit and found out as long as your tank isn't rusted through, there is no need to seal it. Electrolysis rust removal is really easy to do and kind of fun as well. Before I get into this rust removal technique, there is one very important thing you need to know.
DO NOT USE STAINLESS STEEL FOR ANY PART OF THIS PROCESS! Using stainless steel as your sacrificial electrode will create the "Erin Brockovich" poison. Mkay, nuff said there. The other rule of thumb is in regards to the polarity. Your PART is ALWAYS NEGATIVE and the sacrifical steel is always positive. Get the polarity backwards and your part will quickly rust and deteriorate!
OK, here's what you need for elecrolysis rust removal
Battery charger
LAUNDRY soda (not baking soda)
Tap water
Sacrifical steel electrode (soft steel part that attracts the rust, remember NO Stainless Steel)
Something to suspend the sacrifical electrode in the water (the electrode must not be touching the gas tank)
By the way, the electrolysis rust removal process can be used on almost any metal part, it doesn't have to be a gas tank. You can suspend your part in the soda water instead of filling your part with it. For example you could line a bucket with tin and suspend you're rusty metal part in the bucket (remember no matter how you do it, you're part is always connected to the negative cable from the battery charger). The rust removal works on kind of a line of sight principle, so if you're sacrificial electrode isn't in the line of sight of a certain area of your part, the rust likely won't be removed from that area. Also the more surface area on the electrode the better, but as you will see in my test below, a smaller electrode will work, it's just not optimal. Please remember, the sacrificial electrode can't be touching you're part, only the soda water.
Exhibit A, the rusty gas tank from my old Harley Davidson Sportster. As you can see the metal inside the tank is rusted and dirty looking. This is typical of a gas tank that has sat for a while without fuel in it. I removed the petcock from the rusty fuel tank and plugged the hole with a rubber stopper.
Exhibit A, the rusty gas tank from my old Harley Davidson Sportster. As you can see the metal inside the tank is rusted and dirty looking. This is typical of a gas tank that has sat for a while without fuel in it. I removed the petcock from the rusty fuel tank and plugged the hole with a rubber stopper.
I used this ibolt for my electrode since it was handy in the garage. Most bolts like this have a zinc coating, I sanded the zinc off the round end a bit with a scotch brite pad. When I do this again, I will use a longer piece of soft metal as the electrode, bend it such so it goes down inside along the side of the gas tank (without touching the tank), and then stop an switch it so to do each side of the tank for a while (remember line of sight).
I used this ibolt for my electrode since it was handy in the garage. Most bolts like this have a zinc coating, I sanded the zinc off the round end a bit with a scotch brite pad. When I do this again, I will use a longer piece of soft metal as the electrode, bend it such so it goes down inside along the side of the gas tank (without touching the tank), and then stop an switch it so to do each side of the tank for a while (remember line of sight).
I found this black plastic thing in the garage, it already had a hole in it and looked like it would work perfectly to hold the ibolt in the tank so I decided to use it. You can pretty much use anything that doesn't conduct electricity for this. We are removing rust from a gas tank, it doesn't have to be pretty :-)
I found this black plastic thing in the garage, it already had a hole in it and looked like it would work perfectly to hold the ibolt in the tank so I decided to use it. You can pretty much use anything that doesn't conduct electricity for this. We are removing rust from a gas tank, it doesn't have to be pretty :-)
After filling the gas tank with warm water, I added approximately 1/4 cup of LAUNDRY soda. Just to recap, laundry soda is different from baking soda. You can find laundry soda at most grocery stores. More isn't better here, about a 1/4 cup will do just fine. Here I am lowering the sacrifical electrode into the soda water mixture. We're almost ready to start removing rust!
After filling the gas tank with warm water, I added approximately 1/4 cup of LAUNDRY soda. Just to recap, laundry soda is different from baking soda. You can find laundry soda at most grocery stores. More isn't better here, about a 1/4 cup will do just fine. Here I am lowering the sacrifical electrode into the soda water mixture. We're almost ready to start removing rust!
Remember POSITIVE on the electrode, NEGATIVE on you're part. Connect the terminals before you plug in the battery charger. I put the black tape on just to hold it in place. In no way do you want to seal the gas tank. do this in a well ventilated area and let the gasses escape out the top.
Remember POSITIVE on the electrode, NEGATIVE on you're part. Connect the terminals before you plug in the battery charger. I put the black tape on just to hold it in place. In no way do you want to seal the gas tank. do this in a well ventilated area and let the gasses escape out the top.
With the battery charger plugged in and set at 6 Amps, the rust removal process is drawing about 2 Amps here. I left it on for about 50 minutes on this first run. I would have left it longer but I had to go do something else and didn't want to leave it sit there unattended.
With the battery charger plugged in and set at 6 Amps, the rust removal process is drawing about 2 Amps here. I left it on for about 50 minutes on this first run. I would have left it longer but I had to go do something else and didn't want to leave it sit there unattended.
Look at the soup in the gas tank after just 50 minutes! I dumped out the muck in the tank and rinsed it out really good with water. Next I used a heat gun to blow inside the tank until it was dry. I finished by spraying WD40 all over inside the tank. After just a 50 minute run with this small electrode, the tank was quite a bit cleaner on the inside. Success!
Look at the soup in the gas tank after just 50 minutes! I dumped out the muck in the tank and rinsed it out really good with water. Next I used a heat gun to blow inside the tank until it was dry. I finished by spraying WD40 all over inside the tank. After just a 50 minute run with this small electrode, the tank was quite a bit cleaner on the inside. Success!
Thanks to Charlie Mullendore of Antietam Classic Cycle for sending me this information via persona email. In Charlie's own words:
Just a quick note. Needed to remove some light rust from the inside of the latest customer's Eldo tank. Didn't want to go through the whole electrolysis process and couldn't find any milkstone remover locally. Did find a gallon of Evapo-Rust, so I thought I'd give it a try.
Since it was only a gallon, I had to rotate the tank to a different position every few hours. Did this for two days, then drained the Evapo-Rust, rinsed it out with water, then flushed with 92% isopropyl alcohol and dried it with the heat gun. The Evapo-Rust did an excellent job - the metal was clean and rust free. Another nice thing is it's reusable.
Horticultural molasses
Thanks to Ken Giese for providing the following information on the old Yahoo! Loopframe_Guzzi news group (which has now moved to Groups.io).
I picked up a gallon of horticultural molasses at a feed store. The 850 T has a collar inside the fill hole which REALLY limits access and sight angles. Top to bottom filling really appealed to me considering the top of the tank was probably where the bulk of the rust was. I forgot to mention that I rinsed the tank out first with soap and water to loosen things up. I also shook some bb's around. A real hassle getting them out as the filler hole collar leaves drainage to the petcock holes. Plugged up those holes and filled ‘er up.
Nothing happened for a few days (molasses is a long process) but about the 3rd day I noticed the solution was draining out the top onto the floor. Topped it back up and even more on the floor the next day. Then it started burping every once in awhile. Obviously some sort of chemical reaction. I decided to put the cap back on and shake it up in case of settling. Wow. When I opened the cap it exploded out like a shook up cola bottle. What a mess, so a word to the wise. All said I let it set for about 10 days, drained it and rinsed with water. Bare metal. I was impressed!
After it dried, I sloshed around some phosphoric acid to prevent rusting until I add gasoline. Figure I can treat the tank again in a few years if desired rather than add a sealer.
Update:
My yearlong, slow restoration project is nearly complete; meaning that blasted tank sat with nothing in it and rusted again! Not bad, but more than flash rust. The phosphoric acid treatment only lasts so long by itself. So, this time I sealed it with POR-15 after researching the product and corresponding with their service dept. I again got the rust out with molasses. I didn't buy their kit, just the sealer. Terrific product. Yes, if the bike was ready to ride I could have just filled it with gas and been done with it as originally intended. Interestingly, POR-15 thought I'd be ok naked with a full tank of gas. But with the next step of painting and a planned Oct launch I like knowing it's sealed.
Moyer Fuel Tank Renu
Thanks to Lannis Selz for providing the following information on the old Yahoo! Loopframe_Guzzi news group (which has now moved to Groups.io). In Lannis' own words:
After years of fighting fuel tanks, trying to clean old braze out of seams to get a clean weld, experimenting with sealers, trying to figure out how to get the old sealer out (because it never seems to hold), I found Moyers Fuel Tank Renu and will never go back.
Having a known-good fuel tank is important to me, I hate leaks, I hate fires, I hate little stringers of goo in my jets stopping me in the rain on a long trip. And since it's something you only have to do ONCE per fuel tank if it's done right, it's worth it.
Moyers takes your tank, plasma-cuts the bottom out of it, bakes it at 800° F to burn all the old goop and solder out, fixes all the seams and leaks with MIG or TIG welds as needed, straightens it out, welds it back up, grinds and handworks the seam so you can't see it, seals it with some sort of red sealer that never quits, gives the outside a coat of primer, and sends it back. My last tank was USD $290.00 for this treatment; I've never had one leak or fail after all this...
Milkstone remover is sold in gallons and is very reasonably priced - about USD $7.00. Use about 1⁄3 gallon, and then fill the tank with water to the very top. Let it sit for a day or so (in the sun helps a little), empty it, rinse it, and dry it with a heat gun and a little alcohol. The phosphate leaves a coating to inhibit rust. The solution also can be re-used. Just filter the crud out, and bottle it up.
You can get milkstone remover at Tractor Supply Company. Dairy farmers use it to clean their milking equipment.
I have mixed it 50:50 for the really rusty stuff. You just have to be more careful if you are trying to preserve original paint. More dilute mix just takes longer. After use it I filter it through a fine screen and re-use.
I can get a gallon of phosphoric acid for about USD $7.00 at the local farm store. Its labeled as pipeline cleaner or milkstone remover.
Works good as a rust remover but don't get it anywhere near aluminum. That includes the petcock. It will eat that away in a couple of days. For badly rusted tanks I will fill it with a mix of the acid and water and let it sit. Sometimes I will put some nuts and bolts or a length of chain it it to knock some of the stuff loose. Every time I walk by it I'll give it a shake.
POR-15
In Gregory Bender's own words:
The fuel tank on my Ambassador was showing signs of rust on the inside. So, prior to having it painted, I used a several stage system designed to (1) remove gum, sludge, and varnish, (2) remove rust and prepare the tank for the sealer, (3) seal the tank against any further damage. The kit worked great and I've had no problems. The kit even came with a patch for repairing holes or weak areas, but I did not use it and cannot attest to it's ability. I purchased the entire kit from a company called POR-15. They call it a cycle fuel tank repair kit.
