toilet bowl cleanr hydrogen chloride to clean tank

otakar wrote:

If you put rocks into the tank, make sure that they are not any form of lime stone. They will react violently with HCL. I use a section of chain instead of rocks. But you should remove all the loose stuff first with just water and some Ammonia before you use the HCL to remove the rust. You should not require anything besides the HCL in the tank to do that.

Well, I'm SUPER glad I mentioned the tumbling media rocks, as I have NO idea if they have limestone. I'm so far from being a geologist I won't even gander a chance. I'm going with the chain.

As to the 'tile and grout cleaner, make sure it's got Phosporic Acid' -- let me ask you folks a question about that.

I tried Naval Jelly which is concentrated Phosphoric Acid, on a varnished-up H1-500 tank. It did NOT work at all. There was still much crud in the tank afterward, and I put a lot of naval jelly in there, left it in for several days, and each day at odd times I shook the sh*t out of that tank.

NO IMPROVEMENT. After several days I drained the naval jelly and flushed the H1-500 tank out with lots of water. No improvement.


Will the Hydrochloric acid work better? This kz900 tank is at least as bad as that H1 gas tank, and since Phosphoric acid failed in the H1 tank, I'm inclined to try something new.

The Muriatic Acid sold in your local hardware store is diluted HCL. You're fine using it straight. I think it's around 24%. At 20% HCL, I'd just use the toilet bowl cleaner he gave you. I use 15% HCL to strip the zinc off parts I'm replating. Just remember, if you decide to dilute it...ALWAYS ADD ACID TO WATER, NEVER ADD WATER TO ACID. It could cause a violent chemical reaction. Avoid the fumes and don't get it on your skin.

I use the Muriatic acid straight to get rid of the rust and once I flush the tank and neutralize it with Baking soda or Ammonia I use liquid Phosphoric acid like "Rust Mort" to Phosphate the tank and prevent it from rusting before I coat it.
Process;
1)Remove muck with Ammonia and a section of chain.
2)Flush tank with H2O two to three times.
3)Remove rust with Muriatic acid.
4)Flush tank with H2O Once
5)Rinse tank with Ammonia or Baking soda +H2O solution.
6)Flush with clear H2O.
7)Rinse with Phosphoric acid (Rust Mort)
8)Allow to dry thoroughly.
9)(optional) coat tank
10)The End

Thanks otakar and all.
This helps take all the pensiveness out of it.

btw, I'm going to use the Muriatic acid from the hardware store. Hard to believe that's a 20% solution (IF it is, I'm going to look again). It's enough to ruin your day just opening the cap.

...just did, it's 20-deg Baume HA 31.45%
Marketed for swimming pools and RV toilets. Brand "SMART". Got it at Home Depot. Gal jug was less than $5.

fwiw, everyone, this stuff should not be used indoors at all, IMO. The fumes alone will burn your lungs in no time.

Rather than looking for and purchasing Duponts' Delrin, which is probably pricey, then forming et al, thought I'd cut up an old Anti-Freeze bottle or such and find a sealant/glue to stick it on with. Any ideas what resists HCL?

While I'm here, if HCL takes chrome down to nickel, is that considered suitable for a re-chroming process. iow, re-chrome over nickel if it in good shape?

One more question...

If there's a lot of rust, is pressure any criteria?
That is, once all the holes are sealed up, any chance of blowout with HCL?

I'll probably use baking soda to neutralize, but wondered about the ammonia...

Is that just the household variety used for cleaning?
Some seem to be more of a soapy ammonia mix of some type.

Never heard of ammonia being a neutralizing agent like that.
Can it be used whenever one might also use baking soda?

KAHruzer wrote:

I'll probably use baking soda to neutralize, but wondered about the ammonia...

Is that just the household variety used for cleaning?
Some seem to be more of a soapy ammonia mix of some type.

Never heard of ammonia being a neutralizing agent like that.
Can it be used whenever one might also use baking soda?

I also was wondering about that, my chemistry is non-existent, I'm a software guy not a chemist, I had to take a chem class for my degree but really had to force myself. Worse than doing my taxes, cleaning out the 2nd story gutters, and breaking a car tire bead *combined.* Just wondering about using ammonia like that.

There's no reason to use ammonia or baking soda. If you flush with water you wont be left with any kind of harmful pH.

Using the "household" ammonia first is because it will remove most of the old "gunk" in the tank. Ammonia is not as strong or caustic as Sodium Hydroxide but is also a strong base. If you just flush with tap water the tank will rust quite quickly after the Muriatic acid bath.

I just did this with my tank not long ago.

I used some cork gasket material backed up with a piece of 1/8" plywood that I cut and drilled to fit over the fuel level sender hole. The cork held up just fine. I had some various rubber caps and plugs that worked well to seal up the filler and petcock tube. It will build up a small amount pressure when the tank is sealed so just let the pressure off from one of the caps once in a while.

I diluted the acid a bit, maybe not necessary, but at between 30% - 40% it is about as concentrated as it can be in liquid form. In college chemistry classes it is rare to see 4 molar HCL and 37% HCL is about 12 molar, very strong.

Also, I dumped the acid out of the tank into a 5 gallon bucket then neutralized it with baking soda, after that it is just water, normal table salt, and some carbon dioxide gas, plus whatever rust is in there. Add the baking soda slowly though because it does bubble up quickly (think vinegar & baking soda volcanoes x10).

After I rinsed with water a few times I sprayed the whole inside down with WD-40, then set up a hair dryer to dry out the inside. You could use the phosphoric acid (grout cleaner) like otakar said instead of WD-40. It leaves a rust resistant coating on the steel, but you should still dry out the tank with the hair dryer.

Be careful with the acid! I recommend doing this outside as the fumes are very strong. Also wear good rubber gloves, old clothes that cover up all of your skin, and goggles or safety glasses. I also recommend that you wear a respirator, this stuff can take your breath away.

If you get any on your skin wash well with soap and lots of water, most soap is slightly basic and will neutralized the acid and the water dilutes it. If you get some in your eye rinse it out with water for 15-20 minutes, then smack yourself upside the head for not wearing eye protection!

Wear some good rubber type gloves and long sleeve shirt, eye protection too.

Only last thing not covered would be volume.

I'm thinking dumping a whole gallon into the tank would be way too much. Anyone have a feel for how much might be needed?

Might even do two passes, just for that reason.

Besides, from what I've learned here, with Muriatic Acid, it's a minutes deal, not hours or overnight. I would think about a half hour with each dose, or position. Maybe by the time it's shifted around to each position, it could be a couple of hours, maybe less.