Cleaning out rusty steel fuel tanks

[maico490]

This actually relates to a metal fuel tank on a Honda generator at work but many older chainsaws have steel tanks so still has relevance on this site.
This generator has not been used much and when we needed it for a job the other day the tank had a good half inch of water under the very old fuel and was as rusty as an anchor. I ended up putting 12 24mm bolts in it and rattling them around for about an hour then rubbed what I could reach of the top with emery tape. I then blasted what I could get at of the bottom of the tank with a hot water pressure washer.
At the end of this(about 2 hours) it was definitely a lot cleaner but a long way from perfect. It started with half a pull and ran fine for a whole day.
My question is what do the rest of you do when you get one of these? Is there an easier way for instance involving chemicals?

 

[davefr]

You had the right idea with the bolts however I like to use bulk drywall screws. (they're very sharp). Then shake the hell out of the tank. Once it's clean line it with something like POR fuel tank liner.

I'd only do this on steel tanks where no replacement is available.

 

[superfire]

gas tank idea

ball bearings and bbs and paint thinner for light rust. heavy rust spot blaster with fine dust blasting agent and take some time metal fatigue could be ever present..opcorn: opcorn:

 

[maico490]

You had the right idea with the bolts however I like to use bulk drywall screws. (they're very sharp). Then shake the hell out of the tank. Once it's clean line it with something like POR fuel tank liner.

I'd only do this on steel tanks where no replacement is available.

Good call on the screws. I didn't think of it at the time but sharp and hard would have to be good. I'll do some asking around on the fuel tank liners that are available over here in the UK.

 

[mattinky]

There's a product called Kreem for rusty steel tanks, it's a 3-part system, cleans out the rust and lines the tank. You can get it from any motorcycle dealer. I've used it on a ton of rusty vintage dirt bike tanks and it works great

 

[RAYINTOMBALL]

There's a product called Kreem for rusty steel tanks, it's a 3-part system, cleans out the rust and lines the tank. You can get it from any motorcycle dealer. I've used it on a ton of rusty vintage dirt bike tanks and it works great

+1 On the Kreem. Used it on a rusty Ford 8n fuel tank about a year ago and everything is fine.,

 

[blsnelling]

I don't like the idea of coating a tank unless it's a last resort. It's just something to come loose and clog things up years down the road. On the other hand, it does work when you need it. I had a classic 1981 Honda Z1R tank done like that at a radiator shop. It was really messed up and there was no way to get it clean enough. I had to have them coat it a second time since I wasn't happy with the first coat, but it turned out good and worked great.

I recently had a generator with a 5HP Briggs engine and the bare steel fuel tank. It only had surface rust in it but had clogged the pickup tube. I simply rinsed it out for the time being and put it back together. I'd like to get the tiny remants of surface rust off of the steel. I read several sites that tell how to use acid, maybe Muratic or some other acid, to eat it clean. You then have to rinse with a caustic solution, then rinse well with water, and finally rinse well with alcohol to absorb and remaining water. It should work for mild surface rust. It was bare to begin with, so it should be good as new. I thought I'd finish by filling the tank with 100LL fuel since it's an emergency generator, sump pump, and is rarely ran.

 

[maico490]

Thanks Brad. Good to see you are up and posting so soon. I hope your recovery continues. Mike

 

[mattinky]

I don't like the idea of coating a tank unless it's a last resort. It's just something to come loose and clog things up years down the road. On the other hand, it does work when you need it. I had a classic 1981 Honda Z1R tank done like that at a radiator shop. It was really messed up and there was no way to get it clean enough. I had to have them coat it a second time since I wasn't happy with the first coat, but it turned out good and worked great.

I recently had a generator with a 5HP Briggs engine and the bare steel fuel tank. It only had surface rust in it but had clogged the pickup tube. I simply rinsed it out for the time being and put it back together. I'd like to get the tiny remants of surface rust off of the steel. I read several sites that tell how to use acid, maybe Muratic or some other acid, to eat it clean. You then have to rinse with a caustic solution, then rinse well with water, and finally rinse well with alcohol to absorb and remaining water. It should work for mild surface rust. It was bare to begin with, so it should be good as new. I thought I'd finish by filling the tank with 100LL fuel since it's an emergency generator, sump pump, and is rarely ran.

I don't know about radiator shops, but using the Kreem kit I mentioned I have NEVER had it come loose or cause any problems whatsoever, even years down the road

 

[blsnelling]

Thanks Brad. Good to see you are up and posting so soon. I hope your recovery continues. Mike

My wife brought the laptop today and I'm on the hospitals wireless network

 

[blsnelling]

I don't know about radiator shops, but using the Kreem kit I mentioned I have NEVER had it come loose or cause any problems whatsoever, even years down the road

That's good to hear. How much does it run and how much will one kit do?

 

[The Lorax]

I had to clean my metal RMX250 (Japanese street legal) tank out.
I got a big handful of pea gravel and put some water in with it and shook it and rinsed it x6 then when the water was clear when I rinsed it out I just left it dry with a good slosh of WD 40 to displace the water.
I have never used that Kreem stuff, seen it advertised but as I am now running premix I don't have any problems with rust coming back.
I think the pea gravel cleans the best as it is slightly abrasive not just sharp.
Maybe try the screws then the pea gravel?

 

[bobc]

I had to clean my metal RMX250 (Japanese street legal) tank out.
I got a big handful of pea gravel and put some water in with it and shook it and rinsed it x6 then when the water was clear when I rinsed it out I just left it dry with a good slosh of WD 40 to displace the water.
I have never used that Kreem stuff, seen it advertised but as I am now running premix I don't have any problems with rust coming back.
I think the pea gravel cleans the best as it is slightly abrasive not just sharp.
Maybe try the screws then the pea gravel?

X2 on the gravel it works greate and if there is any leaks you can always solder them. The Kreem stuff works well too.

 

[CharlieG]

I use the reverse electrolysis method- pretty neat and does a great job without caustic waste. Costs next to nothing, also. Google it to see how you can do it

 

[Lakeside53]

Better living though chemistry...

The reverse electrolysis works great, but it will remove the paint and toast any aluminum or brass tank fittings. If you don't have that concern, it's very easy. I just used the process to remove rust from a precision lead screw - one ounce of lye (sodium hydroxide) per gallon of water, a sacrificial anode which is piece of old steel (positive connection) and your part connected as the cathode (negative connection. The only problem with derusting the insides of the fuel tank is that you really need to insert an anode down into it without touching the tank. A cheap (not too smart though... it might fault by knowing you're not connected to a battery!) battery charger works great. Be very carefull with the lye - it's nasty stuff... drain cleaner... You can used baking soda or washing soda, but they aren't anywhere near a good.


The lead screw...

A super safe and amazingly effective way is to use a product called "evapo-rust". It's neutral PH and totally safe. Clean any grease off/out first, then put in the evapo-rust. Leave it overnight if its real cruddy and it will be spotless nett day. Only rust is affected... no base metal will be removed or converted. Paint is unaffected unless it contains iron oxide). The maybe some back material on the surface - that's just carbon from the rusted steel - it wipes off. One word of caution - it immediately removes black/blue oxide finishes on steel - like gun blue... so if you want the finish, only treat the actual area that's rusted.

I just restored a lathe that has sat in a wet basement for 30 years, putting several hundred parts through an evapo-rust dip. I used maybe 1/2 gallon total.

Here's a bunch of pics end to end... the mill is in a sub folder.

http://s238.photobucket.com/albums/ff150/lakeside53/Emco v10P rebuild/


Here's a critical part that could not be abraded in any way - the spindle both inside and out. The inside turned out "perfect".

The threads had been "immersed" with a wet sponge - not the best. A second application make them close to prefect. The spindle was invered (entire lathe) and then filled with evapo-rust. I didn't want to use electrolysis inside the spindle because of the possibility of hydrogen enbrittlment of the hardened steel.


Don't be too quick to throw the old product out. I used and reused all the old leftovers (even wrung out rags back into the container) on my tools - recovered rulers I hadn't been able to read the scales on for 20 years. I soaked entire cast iron assemblies and electric motor - removed all rust, nothing else. I sprayed the internal sections of the derusted cast iron (not painted) with a heavy coat of LPS-3.


Check out here : http://www.evapo-rust.com/photos/

You can buy it at Harbor Freight (and other places)... $19 a gallon.


There's a few other eco/user -friendly products out there.. most are slightly acidic. Evapo-rust is about as benign as is possible.

 

[Rookie1]

Lake I cangt see pics. Is my puter messed up?

 

[super3]

This actually relates to a metal fuel tank on a Honda generator at work but many older chainsaws have steel tanks so still has relevance on this site.
This generator has not been used much and when we needed it for a job the other day the tank had a good half inch of water under the very old fuel and was as rusty as an anchor. I ended up putting 12 24mm bolts in it and rattling them around for about an hour then rubbed what I could reach of the top with emery tape. I then blasted what I could get at of the bottom of the tank with a hot water pressure washer.
At the end of this(about 2 hours) it was definitely a lot cleaner but a long way from perfect. It started with half a pull and ran fine for a whole day.
My question is what do the rest of you do when you get one of these? Is there an easier way for instance involving chemicals?

I used a product called Rusteco an my motorcycle tanks with excellent results.Does not harm paint in any way.

removes all the oxygen from the rust and leaves a black crust that you just preasure wash off,dry out tank with air and you have brand new metal.

Best product on the market in my oppinion but a little pricey.Still a whole lot cheaper than replacing a custom paint job.

I bought a 5 gal container and done it myself but you could send them the tank and get it done cheaper.

I did not want to chance getting paint job screwed up in transit

 

[Lakeside53]

Lake I cangt see pics. Is my puter messed up?

No, I was... check now

 

[Lakeside53]

One more sequence using evaporust.

Change gears frozen in place by rusted portion where they contact, and due to expanding rust on the shaft ends.

After degreasing, immersion in evapo-rust for a few hours to remove the rust, and a little assembly work:

13 bearings and 100 hours of work over three weeks (doesn't leave time for anything else!) and you get one of these (I now have two identical units)... The wife thinks I should sell one, but I'm happy to just look at it for a week or two

BTW... assemblies that are frozen together - like gear clusters or even bearings on shafts - don't try to get them apart the hard way- you'll likely cause damage; just degrease in diluted "hot" purple cleaner, wash off in hot water, then soak them for a day or two in evapo-rust... Once the rust is gone they will come apart like "normal". It works best above 70F, and barely works at 60F. Heating it to 120 seems to make it "come alive".


The QC gearbox had 1/2 inch of rusted crud in the bottom..... it and the internal gears now look and work like new. Luckily the gears weren't in the water, but the bearings sure crusted up.

 

[mattinky]

That's good to hear. How much does it run and how much will one kit do?

It's about $30, one kit will do a large motorcycle tank