Honda CB 550: Clean Tank with Toilet Bowl Cleaner

This is what I started with...

The new rack of carbs for my Honda CB 550 K are all set to go, cleaned and assembled with brand new rebuild kits.  The last project to tackle for the fuel delivery system is the tank.  This tank is not the worst I have seen, but it certainly has rust inside, and that should be remedied, before installing a sparkling rack of carbs.  No sense in clogging the jets with rust particles, after the time, frustration and misery it took to rebuild the carbs.

I have planned on stripping the paint off the tank as well, down to the bare metal, and leaving it that way.  The original, 35-year-old paint on the tank now is faded.  Although it looks sorta neat, I really wanted something a little more industrial looking, keeping the theme of the bike utilitarian, all black and metals.  I love all things metal, and this tank will look sweet with just the raw look.  There are some considerations for this process, such as whether to clear coat it or not, but that will be a decision for later.  For now, I just need to get the inside free of rust, and the outside free of paint.

I made a mistake here.  I decided to strip the tank first, before cleaning the inside.  My logic was that I didn’t want the stripper and sanding dust to get inside, once the interior was cleaned.  That turned out to be a very bad move, because the acid from the rust remover ended up tarnishing the tank, after I had spent hours getting it nice and shiny.  Lesson learned.

I borrowed a can of paint stripper from my friend.  I wasn’t sure if the normal, household stripper would work, but it was worth a shot, before I went out and spent $25 on Aircraft Stripper.  I got the old chemical resistant gloves on, and a shitty bristle paint brush, placed the tank over a large Tupperware storage bin, and slathered it on.  Remember to never use a foam brush, because these products will eat foam immediately.  Within seconds the stripper was working, the paint bubbling off the foundation.  The photo below shows the tank after only one coat of stripper, but it would end up taking 3-4 coats to get all the remaining residue off the tank.

First coat of stripper...

After all the coats of stripper, I then took it over to the bench, and began sanding down the steel.  I started with wet/dry 220 grit, making sure to keep both the paper and the surface extremely wet.  I sanded for what seemed like forever.  The tank was starting to look good, but I was getting tired, and then I remembered I had some special wheels that go on the air compressor powered die grinder.  Maybe this would cut the sanding time down?

“Who doesn’t want a shortcut to greatness?”                                                                                                                                                                                                                                                                                                                                                            Jeff Bridges: The Contender

I fired up the compressor with a 220 grit wheel (not wet/dry), and began working my way across the tank with fairly quick strokes, so as not to leave the cutting power in any one place too long.  The results were noticeable immediately, but the problem with this type of sanding is that it leaves lines in the metal, from uneven cuts.  I figured I could get the base sanding done this way, and then eliminate the lines with higher grit wet/dry paper later.  Below you can see the lines on the top, but the more even sanding, done by hand, on the sides.

Top after sanding wheel on the grinder...

My arm was aching and my fingers were twitching, so it seemed like a good time to call it a night.

Came back in the next morning and began the process of getting the top and one side completely uniform looking.  It was coming out decent, but I still had the back side to do.  The photo below shows what the tank looked like before I began the sanding.  At this point, the top and side were done, but I had yet to begin the second side.

Tank with Stripper Tarnish

I finished the second side, and was quite pleased with the look of the steel.  It was time to take on the rust inside the tank, and I began rounding up all the products I had purchased for this task.  Although it may seem odd, I was going to be using a technique involving a toilet bowl cleaner called The Works.  This has acid in it, like all toilet bowl cleaners, but at a higher concentrate than the ones we typically use at home.

Tune in next time for fun with acid cleaners and chemical reactions….

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