[Goober]

Hi bought a cheepy borescope for $20 about 2 years ago—I scratched the lens pretty bad, but it works better than nuttin

The attached pix are from an ‘86 TRX350 tank—showing the interior plumbing and the screens built onto them. First is the reserve pipe with the drain bolt removed; 2nd is the reserve intake screen 3rd is the plumbing that attaches to the petcock 4th is the bottom of the tank where water collected 5th shows the rust line.
Tank is not terribly rusty—you can see the some of the rust is flaking off in pretty thin pieces. I will use a vinegar soak and a pound of steel BBs to gently knock the rust off. Pics demonstrate the value of draining the tank annually and keeping it full to prevent condensation. Also important to use a flexible long handled small diameter bore brush to gently remove scale from the plumbing

The reason I use BBs is that they won’t damage the intake screens like bolts and other stuff people want to use. Even the polymer coatings that might work in straight draining tank might clog up these screens.

I checked the tank I cleaned two years ago—couldn’t take pics cuz the tank was full. I’ll drain it down maybe this weekend and show how well the soak worked.

 

[shadetree]

I never have noticed that screen in any of these models I have worked on ?, maybe they were removed ?..lol. I am just glad I got a plastic tank..no more rust !..lol. I am sure the pipes inside this plastic tank will rust over time ?, but as far as the tank itself ?, yeah..done with that !. wasn't cheap ?, but man, it sure beats dealing with trouble down the road !.

 

[Jeepwm69]

Hi bought a cheepy borescope for $20 about 2 years ago—I scratched the lens pretty bad, but it works better than nuttin

The attached pix are from an ‘86 TRX350 tank—showing the interior plumbing and the screens built onto them. First is the reserve pipe with the drain bolt removed; 2nd is the reserve intake screen 3rd is the plumbing that attaches to the petcock 4th is the bottom of the tank where water collected 5th shows the rust line.
Tank is not terribly rusty—you can see the some of the rust is flaking off in pretty thin pieces. I will use a vinegar soak and a pound of steel BBs to gently knock the rust off. Pics demonstrate the value of draining the tank annually and keeping it full to prevent condensation. Also important to use a flexible long handled small diameter bore brush to gently remove scale from the plumbing

The reason I use BBs is that they won’t damage the intake screens like bolts and other stuff people want to use. Even the polymer coatings that might work in straight draining tank might clog up these screens.

I checked the tank I cleaned two years ago—couldn’t take pics cuz the tank was full. I’ll drain it down maybe this weekend and show how well the soak worked.

What kind of solution do you use to prevent it from flash rusting after the vinegar. I know you said it was some kind of high PH hot tub stuff. What is it specifically?

 

[Goober]

Hi Jeep it was just some hydroxide solution probably potassium. Sodium Hydroxide solution like you used should have been good. Here’s what you and I may have done differently–you rinsed with water after the high pH rinse and I dried immediately with a hair dryer leaving the high pH residual

I would have thot the alcohol would be a good dryer but looks not to be.

The tank I did two years ago still looks great.

You can see by placement of the reserve fuel intake that unless we drain the tank periodically, condensate will continue to accumulate in the tank bottom til it rises to the reserve intake screen–unlike say a trx300 which you can run reserve from the bottom of the tank.

 

[retro]

I think you're onto something there Goober. Following with an alcohol rinse might be way too effective..? I'll try your method the next time I get a chance. Thanks for making this thread!

 

[Goober]

Thanks all for your interest. I pulled out my cement mixer. Will stop by Smallmart tomorrow for a couple gallons of vinegar and a pound or two of BBs. Then will run the descaling on Saturday.

 

[Goober]

I got a gallon of cleaning vinegar (6%) and a box of 6000 copperhead BBs: put in the rusty tank.
Taped the petcock holes and filler opening with aluminum tape; bubble wrapped tank and taped up in a cardboard box. Stuffed fed end out in my cement mixer in an off-axis orientation so the BBs would roll from front to back of the tank. let it ride for and hour and switched to end out for another hour.
Drained tank and removed BBs with a long handled magnet.
Mixed a gallon solution with 5 tbls of spa pH calcium hydroxide powder. Rinsed tank with that solution and poured out.
Dried tank with hair drier.
No flash rust.
I need to get some long pipe cleaners to ream out the fuel pipes. I would like to do it one more time but I’m pretty happy with the results

 

[retro]

Calcium Hydroxide? It works great doesn't it?! Thanks again Goober!

 

[fishfiles]

Sometimes you don't need a scope to see inside , but when you do get a tank beyond repair , don't ditch it , you can cut it and make a wall hanger , there is one hanging on the patio , a bird has had a nest in the back side of the tank every year since I hung it up , so the Honda tank still brings life

I did that electrolysis thing on a 300 tank one time , you take a plastic cap to fit over the fill hole and act as a isolator , drill a hole thru the top of the cap , a piece of wood would work for a cap , put a piece of all thread with a nut on each side the cap , fill the tank with a mixture of baking soda and water , hook a battery charger to the all thread and to the tank , I went for 3 amps , the all thread attracts the rust and becomes a corn dog looking thing , on the 3rd day when I done it , it ate thru the tank and leaked all the water all over the place and made a mess , the tank was too bad to start with , never did the electrolysis thing again

 

[Goober]

Ouch @fishfiles that’s a valuable lesson. I’ve heard of people using harsh acids and ruining their tanks too. I thot about using a copper plating technique to coat the bare metal instead of a Kreem-type coating, but was concerned I might get plating on the intake screens. That would be worth trying on a tank with a leak.

I was very surprised to see that the instructions on a Kreem kit suggested using nuts and bolts to aid in rust removal in a fuel tank. SMH.

I used the vinegar because it’s a weak acid and I feel I can manage the process better. I try to keep the time to a minimum—might’ve had better rust removal if I used more vinegar and more BBs. Actually had better results doing it twice—first to remove the scale and the second as a finishing step. Left the entire surface like brushed stainless.

I also don’t like using harsh acids or cleaning agents like MEK or acetone (Kreem kit suggestions).

Then using the spa solution to stabilize the bare metal—really liked the CaOH better than the KOH, @retro cuz of the cat-ion charge you get twice the hydroxyl groups using the calcium—lol something I read on the googles.
I will rinse out the residue with some fuel after I paint the tank.

 

[fishfiles]

I bring mine to the radiator shop , he soaks it in the tank over night , cut a small access hole in the bottom of the tank to better get it flushed out , he welds up the hole , and coats it with some thin red stuff , it is $90 for that job , well worth it ---it is $40+ for the Kreeme stuff and I have seen it come off

 

[Goober]

I had an old beer line cleaning brush I laid aside for reaming the fuel pipes now can’t find it grrrr

 

[fishfiles]

Plastic tanks like on my 450's are better in one way , they don't rust but worst in another as the threaded nuts molded into the plastic spin and ruin the tank ------- I think when they went to burning corn in the fuel , it caused a lot of problems ---now they are burning chicken pee in the diesel

 

[Goober]

Usually I clear the fuel lines before I acid wash the tank but couldn’t find my old 3/16 inch beer line brush. Unfortunately the reserve line had a very tight clog in it–couldn’t clear it.

Every time I ran a pipe cleaner into it I came up dirty with rust particles. tried a piece of copper wire–everything I had in the shop. No good. took a break and fixed a DWV plumbing leak and remembered my line cleaner–a long piece of flexible cable.

I took an old binding choke cable; cut it off to the length I thot needed. Poured cutting oil into the pipe. Mounted it to my drill. Took it slow as to not bind the cable–after 3 minutes of slow boring, got thru the clog!

So there’s another tank tool for you old TRX350 Outlaws; don’t press too hard or you’ll go thru the screens!

 

[Goober]

Ok I ran a second acid wash with 2 gallons of vinegar and all the BBs, but for half the time (1 hour). I recycled the first batch of material, mixing in new.

I think the greater volume resulted in longer contact time with the acid and more physical contact with the BBs on interior surfaces.

This tank looks great on the inside; when I get ready to use it will rinse out any calcium hydroxide residue with a little fuel

 

[Jeepwm69]

I got a gallon of cleaning vinegar (6%) and a box of 6000 copperhead BBs: put in the rusty tank.
Taped the petcock holes and filler opening with aluminum tape; bubble wrapped tank and taped up in a cardboard box. Stuffed fed end out in my cement mixer in an off-axis orientation so the BBs would roll from front to back of the tank. let it ride for and hour and switched to end out for another hour.
Drained tank and removed BBs with a long handled magnet.
Mixed a gallon solution with 5 tbls of spa pH calcium hydroxide powder. Rinsed tank with that solution and poured out.
Dried tank with hair drier.
No flash rust.
I need to get some long pipe cleaners to ream out the fuel pipes. I would like to do it one more time but I’m pretty happy with the results

I'll have to try that calcium hydroxide out. I have a couple of 300 tanks and a couple of 350D tanks that need a good cleaning!

 

[Jeepwm69]

Sooo, yesterday I finally got some wrench time in and discovered that a previously clean 300 tank is now full of rust. A friend of mine bought a new tank that was clean when he got it, but if I had to guess the seller had just done a vinegar bath so now it's full of light scale again. I have vinegar on hand. Is this the stuff I need to use after the vinegar, and if so, do I add 1 teaspoon per gallon or do I need to mix it stronger?

https://www.homesciencetools.com/pr...MIg4X6o4uE3wIVjrrACh28iQkPEAQYAiABEgJsN_D_BwE

 

[Goober]

Hi Jeep
Yeah that material should work I would use 2-6 tablespoons (3 teaspoon/tablespoon) per gal. the reason I make it extra strong is that some of the limewater will be neutralized by residual acid (vinegar) left in the tank. Slightly stronger solution in this case is better than slightly weaker.

Have a hair dryer ready. After the vinegar rinse I empty the tank through the drain or petcock hole. try to get all the BBs out with a magnet. Rinse with that high pH solution, empty, then start drying. Roll that tank occasionally to get remaining BBs and water moving.

If you use a heat gun beware that you don’t get it so hot you blister the paint

When mixing acids and bases always add the pure mix to water, rather than adding water to the pure mix. The chemistry rule is “Always Add Acid” TO water.

Here’s my tank now

 

[Jeepwm69]

Hi Jeep
Yeah that material should work I would use 2-6 tablespoons (3 teaspoon/tablespoon) per gal. the reason I make it extra strong is that some of the limewater will be neutralized by residual acid (vinegar) left in the tank. Slightly stronger solution in this case is better than slightly weaker.

Have a hair dryer ready. After the vinegar rinse I empty the tank through the drain or petcock hole. try to get all the BBs out with a magnet. Rinse with that high pH solution, empty, then start drying. Roll that tank occasionally to get remaining BBs and water moving.

If you use a heat gun beware that you don’t get it so hot you blister the paint

When mixing acids and bases always add the pure mix to water, rather than adding water to the pure mix. The chemistry rule is “Always Add Acid” TO water.

Here’s my tank now

Looks like the inside of the tank is clean now. Gotta dump the vinegar, and then based on what you said here I should flush the tank a big, then fill it with clean water and add the calcium hydroxide, slosh it around a bit? Should I let it sit at all with that solution in it, or just slosh it around for 30-45 seconds and then dump it and hit it with the hairdryer?

Just wondering how long it will take the solution to neutralize the vinegar....

 

[Goober]

Hi Jeep
Yeah that material should work I would use 2-6 tablespoons (3 teaspoon/tablespoon) per gal. the reason I make it extra strong is that some of the limewater will be neutralized by residual acid (vinegar) left in the tank. Slightly stronger solution in this case is better than slightly weaker.

Have a hair dryer ready. After the vinegar rinse I empty the tank through the drain or petcock hole. try to get all the BBs out with a magnet. Rinse with that high pH solution, empty, then start drying. Roll that tank occasionally to get remaining BBs and water moving.

If you use a heat gun beware that you don’t get it so hot you blister the paint

When mixing acids and bases always add the pure mix to water, rather than adding water to the pure mix. The chemistry rule is “Always Add Acid” TO water.

Here’s my tank now

Looks like the inside of the tank is clean now. Gotta dump the vinegar, and then based on what you said here I should flush the tank a big, then fill it with clean water and add the calcium hydroxide, slosh it around a bit? Should I let it sit at all with that solution in it, or just slosh it around for 30-45 seconds and then dump it and hit it with the hairdryer?

Just wondering how long it will take the solution to neutralize the vinegar....

Yup no need for a water rinse just vinegar, remove BBs, high pH solution and slosh it for a minute then dump out and dry