Condition inside the gas tank

Make sure you flush it out real good and coat the inside with something or it will flash rust fairly quickly.

bluej58 wrote:
Make sure you flush it out real good and coat the inside with something or it will flash rust fairly quickly.

The phosphoric acid solution create a zinc layer on the iron surface = no flash rust after you flush out other acids like HCL (hydrochloric acid) or H2SO4 (sulfuric acid).

Thank you, I understand hot water stabilize the acid.

1.
How much in total liquid should I have in the tank? I don’t want to fill up the whole tank because you need oxygen? So I need to rool the tank around all the time to weet the surface or?

2.
How long time shall I have it in the tank, to next day?

No, gordone hot water or/and heat will accelarate the acid reaction.
1 Liter of your 75% phosphoric acid mixed with 2 Liter of hot water is ok.
Shake and roll the tank every 10 minutes for an hour should be okay.
But it is more importent to degrease the inner tank surface before you can use any acid to react against the rust inside.

Scirocco wrote: No, gordone hot water or/and heat will accelarate the acid reaction.
1 Liter of your 75% phosphoric acid mixed with 2 Liter of hot water is ok.
Shake and roll the tank every 10 minutes for an hour should be okay.
But it is more importent to degrease the inner tank surface before you can use any acid to react against the rust inside.

I understand, thank you !

1. What is the best to use for degrease and not damage the paint on the outside?

2. What do I use to remove the acid after, alot of fresh water ?

3. Dry the tank with hair dryier

4. Spray alot of WD40 inside and turn it around, and the tank is ready for a new season later?

5. When season start clean it with some gas....

6. Fill it up with fresh gas ?

Hot soapy water and a vigorous shake followed by a good rise of clean water should break down and remove the oils in your tank.

I would use the same procedure to remove the acid.

A hair dryer works well

I use Marvel Mystery Oil mixed with gas ,
it's 2 main ingredients are as per Wiki;
Petroleum Distillates (Hydrotreated Heavy Naphthenic) also known as mineral oil, 60-100%[2]
Petroleum Distillates (Stoddard Solvent) also known as white spirit, 10-30%[2]

I like WD-40 for combating oxidation on aluminum but I know it is a rust inhibitor too, they have never released the formula (trade secret) but wiki says this:
The German version of the mandatory EU safety sheet lists the following safety-relevant ingredients:
60–80% hydrogen-treated heavy naphtha (a petroleum product used in wick-type cigarette lighters)
1–5% carbon dioxide

Lastly, flush out with fresh gas when ready to use

Good luck!

After draining the acid rinse with water with a garden hose. Shake out as much water you can then dump half a spray can of wd40. Turn the tank around so you cover the entire inside of the tank. Shake out. Then heat with a hair dryer through the filler cap and tank sander hole and turn the tank around so that the water is not left sitting in one spot. Heat, turn, heat turn until no water is present approx 30 min. Don't use a heat gun as it will heat the paint to much.
I usually start with usual degreaser and a hand full of dry wall screws and shake the tank for a good 15 min and rinse before I fill it up with acid.

Brgds Anders

When I use phosphoric acid, shall I only weet the surface so alot of oxsygen willaccess the surface?

Said another way, is there a good point to not kerp the surface under water/acid?

Better to have only 0,5liter instead of 2 liter?
And just rull the tank around each 10min for a ahour?

You want to keep the surface wet at all times. If you don't want to purchase a huge quantity be sure to shake the tank every few minutes for an hour or so and the tank should be clean by then. You can also dilute the phosphate and it will work fine, just slower.

Nessism wrote: You want to keep the surface wet at all times. If you don't want to purchase a huge quantity be sure to shake the tank every few minutes for an hour or so and the tank should be clean by then. You can also dilute the phosphate and it will work fine, just slower.

Just to avoid I misunderstand something, can I just fill the tank completely full and let it stay for 1 hour ?
Or do only want to have the surface wett, so 2 liter is a good number ?

I`m planning to use hot water with the acid, then the effect increase ?

I`m planning to use hot water with the acid, then the effect increase ?

dilute the acid with water will extended the time.
2 liter acid is good and let the tank swim into your bathtub filled with hot water, shake and turn the tank every few minutes for an hour.

Scirocco wrote:

I`m planning to use hot water with the acid, then the effect increase ?

dilute the acid with water will extended the time.
2 liter acid is good and let the tank swim into your bathtub filled with hot water, shake and turn the tank every few minutes for an hour.

The acid has a concentration 70%, need to use som water to get it down to 30%, was planning to use hot water todo that ?