Tank Cleaning Questions

[Tracer]

I need to clean out the rust in my tank (81 GS1000GL). I've read through a number of previous posts about cleaning tanks and have some ideas now, but also some questions.

1. I'd like to start with putting a chain in the tank with some kerosene or diesel oil and shake it around awhile. But I'd like to remove the fuel guage float first. Any good ideas on how I can cover and seal the hole that this will create?

2. I read some posts indicating that some do the nuts & bolt/chain shake while the first step treatment (acid?) is in the tank. Am I reading those posts right? And if so, should I just skip the kerosene/diesel step above and do the shake with the first stage treatment?

3. Are there any particular brands/sources for cleaning tanks some of you might recommend? The last time I tried this with a GS850GL tank a few years back, I used some 2 step stuff from the local motorcycle/atv/boat, etc. shop here in town, and it it didn't impress me. The first step material didn't seem like acid at all, and seemed more like dish soap. Also, I'm not interested in doing the Kreem coating when I'm done. I just want to get the inside as shiny as possible.

4. In the end of the 850 tank cleaning, I took it to one of those power washing wand car wash places and washed out the inside of the tank by sticking the washing wand into all the nooks and crannies I could reach in the tank. Is that worth doing too, and if so, should I do it earlier than last?

Thanks everyone. Lovin' the site.

[Billy Ricks]

If it's badly rusted I would look into the POR-15 system. You get everything you need. A solution to clean any oily mess that might be in the tank, phosphoric acid to treat the rust, and a coating that is impervious to just about anything. If you just want to clean the rust out use phosphoric acid available at Home Depot. It's in the paint department and is sold as concrete etcher.

[catbed]

i used kbs-coatings.

[Nessism]

Most concrete cleaning products are muratic acid, not phosphoric acid. At least this is the case are the Lowe's near me. Muratic acid is very strong and will eat the regular metal, not just the rusted metal so be careful.

I recommend using Evapo-Rust or real phosphoric acid and a bag of aquarium rocks to get the rust out of your tank. You need to fabricate some plugs to cover the openings - aluminum plate and inner tube will seal the petcock and sending unit holes. To seal the main opening, I used a rubber plug from Lowe's and fashioned a hold down clamp to hold it in place. In either case, it will take a few days during which you need to rotate the tank to keep the inside wet. Worked well on a tank I did. Sealed off the metal with some caswell epoxy afterward. Por-15 sealer works well also.

[Billy Ricks]

Most concrete cleaning products are muratic acid, not phosphoric acid. At least this is the case are the Lowe's near me. Muratic acid is very strong and will eat the regular metal, not just the rusted metal so be careful.

I'll have to check the name of my phospho tomorrow. It is sold as concrete etcher at Home depot and is definitely phosphoric acid. I would have never used muriatic acid in my tank.

[ironsheik]

POR15 all the way. Absolutely fool-proof. Unless you have a LOT of rust, I would skip the rocks/bolts because getting them all out is really annoying. A chain would be a lot easier to remove. But seriously, the POR15 system worked great an only require about half a days work and then some drying time. Good luck.

Josh

[almarconi]

I guess it all depends on how bad the rust is. Both my bikes had been sitting for 10+ years without running and the tanks were both rusty. Before I did anything I would probe the metal on the tank to make sure it is not rusted through. In some cases, it is probably easier just to replace the tank with one that is solid. Assuming your tank has surface rust, the first thing I usually do is remove the petcock and other bits from the tank.
At this point you can either use electrolysis to remove the rust or clean/soak in acid. Electrolysis is a good method cause you pretty much just hook it up and let it run..doesn't require alot of labor. The electrolysis will not harm the good metal but will only remove the rust. If you want to use chemicals, I usually wash the tank first using a pressure washer to remove any large pieces of rust and other crud. Then I cover the petcock hole with a scrap piece of sheet metal (you should cover any other sender holes..etc). Fill the tank about 3/4 full with water and then add phosphoric acid. Make sure you wear gloves/goggles/apron so you don't get acid on yourself. I usually let this soak for a couple hours in the sun..hot water seems to work better. Make sure you don't put a cap on the tank or pressure will build up. After soaking, drain the tank. The rust should be gone and the metal should have a phosphate coating on it. Rinse the tank with the pressure washer again to get rid of any remaining rust. If the acid revealed some pinholes in the metal you can coat the tank with a tank coating. I like caswell epoxy. If no holes were found, I usually dump some acetone in the tank to remove any moisture and then coat the metal with some WD-40 to prevent flash rust. If you are going to use the tank right away you can fill the tank with gasoline.

[Tracer]

Wonderful and very helpful replies! I really appreciate it.

The rust appears to be surface rust. I don't think the bike was sitting too long (maybe a couple years before the last owner made a try at bringing the bike to life). Of course, a good cleaning will be the real test and will be more revealing.

Thanks again, and I feel more sure, and eager, to get on with the project!

[TheCafeKid]

Take it to a radiator shop....they can clean and etch it for a reasonable cost.