De-rusting a fixed tank, the saga continues. Evaporust.

Ken F /

Oct 27, 2019 07:32PM

So I thought I would start a new thread to let folks know what I found. I am far from an expert but maybe folks can learn from my experience.

So after emptying the fuel, it was apparent that my 1978 moby 50V tank was pretty darn rusty. When I put my finger in the tank and felt around I could feel a significant crust and not just surface rust.

I did two vinegar treatments for 24 hours each, and flushed with DI water, but I was not satisfied with the results. So I picked up a gallon of Evaporust and treated the tank for about 30 hours (only at about 65 degrees though) and dumped the results into a large pan. I strained this for reusing. FYI: I recommend a cloth (old t shirt) strainer and not just a normal funnel strainer to get the smallest bits.

After emptying I looked in the tank and was really impressed with the results. But on emptying I flushed with a bit of DI water and could tell right away there was a blockage on the lower end. Thus I went out and did the garden hose flush and HOLY COW, the amount of stuff that came out was amazing.

So if I have only one piece of advise... if you have a really bad fixed tank then you need a considerable flush after the treatment. I ended up turning the bike over and flushing from the bottom. I had to do this on high for at least 5 minutes before things really ran clear. I just can't see doing that with DI water or anything else. You need pressure and volume. And compressed air did not do it, I tried. I had to use the water.

After it was done I used the air gun to dry the tank out, then I put the treatment back in. I am not sure if this is necessary but given the amount that came out I wanted to be safe. I will let it sit another 24 hours and then repeat the flush. If things look good I will dry with air and fog it with carb cleaner (I hope this is ok, if not please let me know).

For those folks who are not sure about Evaporust, I can tell you it does work. I can't imagine a tank so bad that it would not work. Get your gallon from Tractor Supply and not an auto parts store, you will save at least 25%.

Well finger crossed. When its over I am going to run an in-line filter just to be safe and see what else might come out.

Best, Ken

Re: De-rusting a fixed tank, the saga continues. Evaporust.

Don Ohio /

don45640

Oct 27, 2019 07:41PM

Thanks for the advice!

Re: De-rusting a fixed tank, the saga continues. Evaporust.

P D /

pdcomm

Oct 28, 2019 09:59AM

Carb cleaner will likely remove any type protectant that may be on the metal .

Better to use a spray oil or just slosh some 2t oil around in the tank .

Re: De-rusting a fixed tank, the saga continues. Evaporust.

Rebel Moby /

rebelmoby

Oct 28, 2019 10:00AM

Excellent Ken. I do vinegar if it is only a little surface rust, a couple of gallons is cheap.

Evaporust (and similar products) work by chelation, the fluid bonds with oxidized iron only and keeps it in suspension, so all you have left is iron. Good suggestion t buy a gallon, because if you get a smaller jug and try to cut it with water, the evaporust will bond with the oxidized iron in water and weaken it more than just the diluted volume you have added of water.

You can use it to clean any steel or steel alloy tools and parts, pour it into a tub or bucket and give the stuff a soaking. Also if you use this or similar on any high carbon steels, keep in mind that it will not bond to the carbon, so the steel will have a darkened finish to it (or even be quite blackened) due to the carbon content.

Evaporust can be reused until it is saturated with iron oxide and can no longer absorb any more rust. Basically keep it in a sealed container and it will work until it stops working, then purchase more.

I would suggest to rinse the tank with kerosene, diesel or heating oil if it is going to sit a while before you fill her up. You need something oily to cling to the walls so it will not surface rust again.

Re: De-rusting a fixed tank, the saga continues. Evaporust.

Brandon Weiss (Detective brandon to you) /

mopedallday

Oct 28, 2019 04:46PM

Evaporust is incredible. The trick is to prep though. To really let it work its magic, you need to degrease/flush whatever tank you're putting it in before you soak it.

If I can, I like to throw some 1 inch drywall screws into the tank and shake it around with some very hot water/degreaser mix. Obviously you cant really do that with tank frames unless you strip them down so they're light enough. I've found all the sharp points and spirals of the screws to work wonders at scraping alot of rust off the tank walls, and breaking up large bits so they can be flushed out easily. Then, you pour in the evaporust.

That said, I did once treat a crusty moby tank with evaporust without prepping it, left it in for like 2 days. Came out spotless.

Re: De-rusting a fixed tank, the saga continues. Evaporust.

Ken F /

drken OP

Oct 28, 2019 06:07PM

I fogged with a really good spray of wd 40. Ok or bad move?

Re: De-rusting a fixed tank, the saga continues. Evaporust.

P D /

pdcomm

Oct 28, 2019 07:08PM

> Ken Filchak Wrote:

> -------------------------------------------------------

> I fogged with a really good spray of wd 40. Ok or bad move?

Should work . I'd cap it to keep any possible moisture out , until you're ready to use it full time .

MOPED ARMY

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