The Stovebolt Site Forums The Shop Area General Truck Talk Muriatic acid mix ratio?

Im getting ready to burn the crap outta my coes gas tank for the last time. I picked up 2 gallons of muriatic acid at 29% dilution. What kind of ratio have any of you experimented with?

I was thinking something like a cup of acid per a few gallons of water. I can always mix it stronger if need be, thought Id start out weaker...

Also what is a safe way to dispose of it? Can I dump it go out back if I dilute the hell out of it with water? I have no experience with this and dont want to end up killing my trees or pets. Will this eat through buckets if I need to bring it to the hazmat site?

Thanks in advance for any info, Jeff

Muriatic acid is Hydrochloric acid, which is the same as human stomach acid. You can dilute it with lots of water and it won't hurt a thing.

Make sure you rinse the tank out with water and then immediately fill it to the brim with gasoline, otherwise it will rust inside almost immediately.The acid sucks all the oils out of the metal and makes it rust fast.

Go slowly with this, Jeff. If you are starting at 29%, and going to add a cup (4 oz) to a couple gallons of water (256 oz each), you are going to have a mighty diluted solution. Plain ol' vinegar (acetic acid) from the grocery store is 5% right out of the bottle. I wish I could advise you what ratio to use, but I honestly have no experience with acid cleaning a fuel tank.

I bought some muriatic acid for a swimming pool just a weekend or two ago. I thought this was closer to the 98% purity. I'm confident it was LOTS more potent than 29%. Then again, I have no idea what product you bought. Mine goes for about $5/gallon, as a benchmark.

With acid, add the acid to water not the other way around. It won't dissolve plastic containers. (I live where the soil is VERY alkaline. If I dilute acid to a very low concentration and pour it on the lawn, the grass greens up!) Probably the safest approach is to sprinkle in some baking soda into your reclaim- it will react with the acid, and you'll end up with a type of salt water. This is safely transported and disposed.

I'm sure there are folks plenty more smart about this than I am. Allow them to weigh in and get the benefit of their opinion and experience.

Bill

I added it straight when I cleaned my 38's tank. After sloshing it around for about 5 minutes I poured in two gallons of strong soda water to kill the acid before dumping it out. Worked great but do it with a lot of fresh air, the fumes can kill. Wear old clothes and chemical resistant gloves. A drop of it'll eat holes in fabric and skin.

I personally wouldn't reccomend a first time user to work with muriatic without help. Gloves and eye protection are a must with muriatic acid, one drop splashed in your eye will do permanent damage. If you start out with a dilute solution you can always add more acid to it if it's not working fast enough. 32% is the strongest commercial muriatic acid you will find. You should use only plastic containers, it will attack metal ones. The easiest, safest and environmentally best disposal method is to dilute and pour onto limestone gravel. You can't make direct comparisons with acetic acid (vinegar), muriatic is many many times stronger. Muriatic will dissolve some things that acetic won't.

it woulda been 38% Bill

18% is used on steel

be afraid Jeff, and be safe , I'd dispose of it by returning for refund, and take the tank to a rad shop and let them clean it

Bill

Muriatic acid is hydrochloric acid... or HCl if you prefer. Pure HCl is a gas. The gas is "dissolved" in water to make a water solution of about 30% HCl in the water. This is generally referred to as concentrated hydrochloric acid (or muriatic acid if you buy it from the hareware store). It will be 95-99% pure, but still be only about 30% acid. Sound confusing? it is.

Start dilute and go stronger. I cleaned a bunch of stuff in a 2:1 mix of water to muriatic acid. That was probably stronger than I should have, but chemicals don't scare me. I only left it in there for about 5 minutes. Lots of bubbles! Do it outside and keep the fumes out of your eyes and nose. Rinse it off immediately after wards with lots of water. My pieces were small and I wiped them down then baked them in the oven for 30 minutes at 250 to remove any remaining water.

For disposal. Assuming your using the more dilute solution that you mention. Go to the store and buy a new box of Arm and Hammer baking soda. Bring it home to your wife and tell her that you are going to change out the old box in the freezer with this new box. Tell her you love her and you love her cooking and you just wanted to help her out. Don't tell her that you are going to take the old box and dump it in the dilute muriatic acid solution. There is no advantage to the old box in the freezer, but why not use it for your essentially disposal needs instead of the new box? Plus it'll keep you in good with the wife, so you can keep feeding your old truck habit.

The baking soda (sodium bicarbonate) is a weak base that will neutralize the strong acid. Dilute with lots of water and dump it down a drain or in a ditch.

38% is generall only available in lab grade acid, not likely to find many people that will sell to an individual and it will be close to $100/gal.

I appreciate all the response. Im not left with much choice in doing this myself. Ive called every radiator shop in the phone book and plenty more in Seattle and no one wants to do this. I spoke with a guy in West Seattle and the converstation went like this, "Its 200$ are you still interested?" Nope. He was the only person that even did this.

red58, that was the info I looked up to see what I should do. I do plan on wearing a few layers of disposable clothes, I have solvent gloves, respirator and goggles. I like all my senses and my wife wouldnt appreciate my disfigurement nor would I!

jhaa_lives, I do the cooking around here so no need to tell the wife anything!

I appreciate all the reiterance on safety! This is why I asked, as a search provided little to no info on proper procedure and disposal. And I know this stuff is NASTY.

Thanks again, Jeff

Jeff,
One last piece of advice. You'll probably have a garden hose hooked up anyway. Keep it within arms reach while you are working with the acid. That way in case you get some on yourself or any other place you don't want it, you can wash it off quickly. Getting it off quickly is the key to minimizing any effects.

Thanks for listening to the safety advice. I've worn safety glasses with side shields since the mid 60's and only had one small splash (something else, not HCl) and that one time probably saved my eye.

Jeff,

I pretty much followed this guy's routine when i did my tank.

http://www.ratwell.com/technical/FuelTankRestoration.html

Bob

OK here's another thing to watch for: My mother-in-law dropped a qt. glass bottle of 38% muriatic acid in her garage and it spilled all over the floor. We cleaned it up but for years (15 until she moved) all metal containers, tools, parts, etc. would rust pretty badly. You couldn't bring any metal into the garage without it rusting even though we cleaned the stuff up thoroughly.
I will be cleaning my gas tank another way. I will take the tank off my cement mixer and strap on the tank, add some sand and small crushed granite and turn it on. Hopefully this will clean it out. I wonder if anyone here has had experience making their own rotisserie for this kind of use.

brjr51 thanks for the link!

One of the searchs mentioned strapping it to your tractors tire and driving around for awhile. I dont have a tractor But I thought of making a little spit for it. Instead I opted for the bolt method and dumped in a few coffee cans of my old bolts and rolled it around about 200 times. The acid is for the final rust removal before sealing it up.

It would also be a good idea, in addition to the garden hose, to have a bucket of soda water handy for neutralizing any acid that may get splashed on you or something else you don't want it on. The hose will rinse off most of the acid, but the soda will neutralize anything the hose misses.
David

My recomendation is to go to HomeDepot and get some phosphoric acid metal prep from the paint department. It works well at removing rust and is not quite as caustic as the other. You still need to use the standard protection when using acids. Phosphoric acid is more steel friendly than Muriatic acid. Muriatic causes hydrogen embrittelment, phosphoric applies a phosphate coating.

Last time I talked to them, Mac's radiator in Portland did gas tanks regularly. That was 2 years ago, though.

Phosphoric acid is what is used in most tank coating "kits". It's slower but much more user friendly than muriatic acid. I used muriatic because it's available locally & dirt cheap. As noted by 4ontheFloor your tank will start rusting soon after treatment no matter what acid you use for the cleaning. Unfortunately keeping it filled with gas won't stop the rust because you can't keep it full. As you use the gas the level falls bringing moisture laden air into the tank. If you use an acid cleaner you'll need to coat the tank. You shouldn't have any problems with the coating sticking IF YOU FOLLOW INSTRUCTIONS. I've done several and have never had a problem. The coating I prefer is Red-Kote. I buy mine from the local Bumper to Bumper jobber but you can get it on line too.

After cleaning it I would coat with a tank sealer. I did it with mine and it hasn't rusted yet. The only thing that I would caution is the reaction between the sealer and any residual acid. I don't how resistant it would be against that and if it flakes of it can cause problems.
Also I found a container of this stuff in are basement always wondered what it was used for this stuff claims it can etch concrete. Sounds fun.

"Muriatic acid is Hydrochloric acid, which is the same as human stomach acid. You can dilute it with lots of water and it won't hurt a thing."

I say you just kill a bottle of Jack and then vomit into the tank. No messy chemicals, and you get a great ab workout.

That would be alcohol abuse

I have cleaned dirty tanks by just pouring in a bucket full of carefully selected 1/2 inch rocks ( just kidding, any clean gravel ), and agitating the tank. I have done this with the tank dry, but found I had better results when I added solvent.
Another method I have used with good results, is to use a solution of TSP, the same stuff used to clean concrete floors, also used by the radiator shop. It was also used in the engine shops to degrease engine blocks before rebuilding them. It is also used to remove paint. This takes less time with heat, but I would not do this unless the tank was completely submerged
When I worked on construction in the early 60's, ( before I got an edgication ) I used muriatic acid to wash brick walls on newly constructed buildings. I don't remember the strength of the product but it was an excellent cleaner. The only protection we had was the 5 ft of brush handle.
My first choice if I was going to use an acid, would be to see how expensive phosphoric acid is, and use that instead. It is commonly sold as Metal prep for etching metal before priming.
Bob

I bought some Muratic acid to adjust the ph level in my swimming pool. I said to my wife "It is downright scary what you can buy with $5". Handle it with the greatest care and use it outdoors only.
mv

My shop where I restore my cars had accumulated quite a bit of 'yuk' on the concrete floor. A neighbor advised me to use muratic acid straight on the floor and it would clean up like new. I cleaned an area about 12' x 30' with 2 gallons of muratic acid. He advised that I let it sit for awhile before washing it off. I did not dilute.

There are spots that cleaned pretty nicely. There are spots that didn't get clean. The push broom that I used to move this stuff around the floor only has about half of the bristles left. They're shorter now. That stuff stinks and I had to run out of the shop a number of times just to breathe.

It stripped the top layer of concrete off. I no longer have a smooth floor. And, worst of all it turned every piece of metal in my shop to rust. That includes my big stainless steel tool chest.

I don't want any more of that stuff around here.

This happens all the time. People give advice about dangerous things like muriatic acid where they don't know enough of the facts. Muriatic is not good at removing grease but it is good at dissolving and etching concrete. It also goes after clean fresh metal including stainless. Two gallons in an enclosed space is easily enough to cause breathing problems as your experience shows.