Topic: What's your favourite method of fuel tank de-rusting?

[JAG]

whatever you do, don't use muriatic acid.. It works wonders for about 10 minutes, and then it'll flash and the rust will all come back regardless of what you do to neutralize the acid - don't ask me how I know. lol

I've always wanted to try the electrolysis method, since science is cool and all, but I'm too impatient (If you need to see how impatient I am, read the first sentence again). 

[flybox1]

whatever you do, don't use muriatic acid.. It works wonders for about 10 minutes, and then it'll flash and the rust will all come back regardless of what you do to neutralize the acid - don't ask me how I know. lol

precisely why I like prep-n-etch.  Leaves a nice phosphorus coating which doesnt flash rust.
I'll rinse a tank 3-4 times with water, and then once with acetone.  finish w a dry out under a vac. 

[JWilde]

I promise you VINEGAR is the BEST esp if you heat it up a little before you pour it in.

[b52bombardier1]

Man . . . my tanks have all been horribly rusted, and varnished such that it has taken industrial strength chemistry, heat and days of agitation with nuts and bolts to get them clean.

I can't imagine a food grade substance like vinegar working. But hey, I'm here to learn.

Rick

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[flybox1]

Vinegar works.....slowly, its cheap, and it can be disposed of in the garden 

[JWilde]

Man . . . my tanks have all been horribly rusted, and varnished such that it has taken industrial strength chemistry, heat and days of agitation with nuts and bolts to get them clean.

I can't imagine a food grade substance like vinegar working. But hey, I'm here to learn.

Rick

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Its simple science and it works. My tank was SPOTLESS after I did it. See this video for vinegar/rust interaction

https://www.youtube.com/watch?v=TlcL_vHODkc

[b52bombardier1]

Very impressive.  I will certainly give that a try next time.

Rick

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[tkarahalios]

So I'm curious. If you use vinegar but can't get into the corners of the tank to agitate the rust will it still come off? Or will it just "reattach" itself after you drain the vinegar and flush the tank?

How would one agitate the rust to get it off when using vinegar?

[JWilde]

So I'm curious. If you use vinegar but can't get into the corners of the tank to agitate the rust will it still come off? Or will it just "reattach" itself after you drain the vinegar and flush the tank?

How would one agitate the rust to get it off when using vinegar?

You put a small link chain int eh tank an shake it around AND you keep it in different positions over a few days.

[tkarahalios]

You shake it around while it's full of vinegar?

[calj737]

When filled with vinegar, there is no need for further agitation. The chemical reaction covers completely all surfaces. Drain it, flush it to neutralize the vinegar, then either fill with gas/oil mix or treat with any of the previously mentioned products. Done, complete, very inexpensive. You want to use Distilled White Vinegar.

[chewbacca5000]

$9.39 Sherwin Williams wood bleach.  It nuked the rust and it has not come back.

http://www.sherwin-williams.com/homeowners/products/catalog/wood_bleach/


No hoping on left foot or reciting special incantations required.

interesting.   assuming you mixed it per instructions.
how bad was your rust and how long did you let it soak?
any issue with tank paint?

I can't take credit for it some other member looked up the key ingredient in espirt which is my favorite, but $34 per gallon.  I dumped the whole thing in there and filled up with hot water and let is soak for the better part of the day.  Rinsed it out and put some wood alcohol in there to soak up the water.

Turned the metal a grey color, but no more rust.  I used to sand the inside of the tank until it was bright and shiny, but got sick of that drill.  If did a ton of tank I would have a tumbler to agitate the tank.

[Terry in Australia]

Yep, most acids will remove rust. The wood bleach is Oxalic acid, Vinegar is Acetic acid, toilet bowl cleaner is Sulphuric acid, etc etc.

I've tried electrolysis (no, not for hair removal..........) and it's fun, quite messy, and needs to be done outside as it produces hydrogen gas, so if you're a smoker, or you use this method near a naked flame (heating furnace or hot water system with a pilot light etc) you could have quite the explosion to explain to your "other half", and having witnessed someone blowing themselves up many years ago when smoking over a truck battery that was charging, I wouldn't recommend it.

I have seen a U Tube clip of someone "tumbling" a tank full of nuts and bolts, he padded the outside of the tank with old towels then put it in a tumble dryer, and got some pretty good results, but the noise was horrendous, and once again, a good dose of Phosphoric acid would have done the job much easier. Horses for courses.  

[Lostboy Steve]

Yep, most acids will remove rust. The wood bleach is Oxalic acid, Vinegar is Acetic acid, toilet bowl cleaner is Sulphuric acid, etc etc.

I've tried electrolysis (no, not for hair removal..........) and it's fun, quite messy, and needs to be done outside as it produces hydrogen gas, so if you're a smoker, or you use this method near a naked flame (heating furnace or hot water system with a pilot light etc) you could have quite the explosion to explain to your "other half", and having witnessed someone blowing themselves up many years ago when smoking over a truck battery that was charging, I wouldn't recommend it.

I have seen a U Tube clip of someone "tumbling" a tank full of nuts and bolts, he padded the outside of the tank with old towels then put it in a tumble dryer, and got some pretty good results, but the noise was horrendous, and once again, a good dose of Phosphoric acid would have done the job much easier. Horses for courses.

Jesus Terry, you have some experiences. That must have been something.

[Terry in Australia]

The battery explosion? The noise was just like a shotgun discharging, a cloud of colored plastic shrapnel flew past my cousin and I and the poor stupid bastaard staggered out with his face torn up by plastic shrapnel and battery acid.

All we could do was hit him with the garden hose to wash the acid off, then drove him up to the hospital to get his face stitched up. He looked like Frankenstein's monster for a few weeks, but amazingly, he had no permanent injuries, he must have blinked just at the right time, because both his eyes were OK, he was very lucky.

My cousin wasn't too happy though, he'd just bought that truck battery, and he'd warned the victim about smoking near it only a few minutes before the explosion. Some people need to learn by personal experience, I guess?

[JWilde]

You shake it around while it's full of vinegar?

Yes. You HAVE to in order to clear off the flaking rust. This is based on experience.   When you brush your teeth you dont just put toothpaste on and let it sit, you BRUSH to get the cleaning action going. When you put a small chain inside the tank and shake it, you loosed the rust which assists vinegar in derusting the tank I did it and my tank was pristine inside. Here is a video from someone else in agreement

[Lostboy Steve]

Christ... That is insane. Ive a big old mudding tire explode in person... The belts could have cut someone in half, lucky no one was standing near it.

[grcamna2]

Kleen strip prep n etch.  $15.
5 hours of soaking and turning...

Photo taken during drying after a few water rinses and an acetone gargle.

flybox,
Will the prep n etch flash rust after you use it? what's the best way to use it ?

[flybox1]

It will, but very slowly.  I guess it depends on your humidity
My PnE bath was about 2 hours.
Shook and rotated the tank every 15 minutes.  Water rinsed/shake 4-5 times.
1 pint acetone, shaken, not stirred, and then on the vac for 15 minutes to dry.
If you were hanging in the dry AZ heat with toytuff, you could go a week+ without worry.
Up here in the PNW, the humidity will get after it, and after a day or two, without fogging the insides, yeah, rust will set in.
I fogged mine w MMO, and it still looks good inside.  I dont have a filler cap as i'm prepping for paint.

Here is a 'before' PnE treatment.  Not bad to start with, but much better after.

[calj737]

Fly - I always fill my tanks with PnE, then swirl it really well, then let dehydrate overnight. In the AM, theres a lovely little gray hue over the interior and its ready for gas (or usually with me, Caswell). I do use some Acetone prior to PnE, but per the label, some moisture present doesn't bother it.

As for agitating Vinegar to get it to work, its untrue that it is necessary. For demonstration purposes, fill a cup with vinegar and drop a rusty socket or piece of metal in. The cup will foam very quickly which is the chemical reaction at work. Once the foaming subsides, the acid is now attacking the metal, not the rust. Remove the piece, rinse with water and you'll see the difference.

Now, would agitating or brushing help? Sure, but theres no practical method to filling a tank full of nearly 5 gallons of chemical, then sealing it, and agitating it. If you do drop in nuts, bolts, screws, chains, or neighbor's kids, then you can't fill the tank full and you lose the benefit of constant immersion.

Many ways to skin this cat, and lots of techniques. Vinegar is the cheapest chemical method, electrolysis (if you have the gear) is probably cheaper still.

Good luck-

[JWilde]

As for agitating Vinegar to get it to work, its untrue that it is necessary. For demonstration purposes, fill a cup with vinegar and drop a rusty socket or piece of metal in. The cup will foam very quickly which is the chemical reaction at work. Once the foaming subsides, the acid is now attacking the metal, not the rust. Remove the piece, rinse with water and you'll see the difference.

I tried it at the suggestion of someone I respect. It worked. Lots of flakes of rust came out. I can only say many others have said it worked for them and suggested the same.

At least ppl have come away with lots of options from this post. I suppose, in this case, many paths may lead to the goal.

[Lostboy Steve]

In fairness, depending on how bad the rust is...

I usually put a bit of lacquer thinner in the tank with a chain or whatever and slosh that around. This breaks up any varnish or loose rust. Then use whatever method you prefer. The vinegar will work alone, the chain is for the loose stuff, I get it. Again most of the bad tanks I've gotten have a good sludge in them that lacquer thinner or acetone will eat up and vinegar will not.

[Terry in Australia]

Yep, regardless of which method you use, agitating will work better than not. The POR-15 kits and even the old Kreem kits came with Phosphoric acid, the most effective commercial rust remover, and their instructions called for agitating the tank, so if you're using an acid as weak as vinegar, agitating is pretty much a necessity unless it's just very light surface rust. Cheers, Terry.

[Rookster]

One issue with vinegar is if you just fill the tank and leave it, the areas with no rust are exposed to an acid that will attack steel.  A tank full of vinegar that is sitting for a few days is just asking for pin holes where the metal is the thinnest.  It works and is cheap but you are much better off with a vinegar slosh and some drywall screws for a shorter interval than a sitting vinegar tank.  Phosphoric acid is the better choice as it will not attack the bare steel and leaves a protective coating behind.

Scott

[grcamna2]

One issue with vinegar is if you just fill the tank and leave it, the areas with no rust are exposed to an acid that will attack steel.  A tank full of vinegar that is sitting for a few days is just asking for pin holes where the metal is the thinnest.  It works and is cheap but you are much better off with a vinegar slosh and some drywall screws for a shorter interval than a sitting vinegar tank.  Phosphoric acid is the better choice as it will not attack the bare steel and leaves a protective coating behind.

Scott

Good to know.