Topic: Build Thread - The Aphid, 75 cb550F Super Sport

[BeSeeingYou]

That looks like pitting from the corrosion but it does not look deep.  There will be little bits or corrosion in the pits and that's harder to get out.  If you just paint over it it will come back.  One option would be to use a rust converter type coating that neutralizes it allowing you to prime and paint over it.  I have had good luck with this stuff on cars.  The other is to use muratic acid full strength applied with brush.  Work on one section at a time top to bottom.  Neutralize each section with baking soda water as soon as you are done working that section.  I have also used this method and it will get the pits clean.  You have to keep applying coats of acid keeping it wet.  It may take 10-15 minutes.  Do it outside and avoid the fumes.  

Jeez three posts get in while I am typing.  I guess if you are powdercoating this may not apply.

[Caaveman82]

That looks like pitting from the corrosion but it does not look deep.  There will be little bits or corrosion in the pits and that's harder to get out.  If you just paint over it it will come back.  One option would be to use a rust converter type coating that neutralizes it allowing you to prime and paint over it.  I have had good luck with this stuff on cars.  The other is to use muratic acid full strength applied with brush.  Work on one section at a time top to bottom.  Neutralize each section with baking soda water as soon as you are done working that section.  I have also used this method and it will get the pits clean.  You have to keep applying coats of acid keeping it wet.  It may take 10-15 minutes.  Do it outside and avoid the fumes.  

Where do I get me some of this acid? I know corrosion doesn't go away, its an organism like mold, but for metal.

[mick750F]

Okay here is the pictures of the rust.





The weapons in the war against terror, er rust.



Oh but hello, what's this?



I cannot tell if this is corrosion or if it's just in the casting. If it is corrosion, am I screwed or is there hope? Anyone have any advice?

   Jeebers man! Where'd you find that thing? Looks like it spent some time in salt water and then somewhere getting road salt kicked onto it's sorry ass. Personally, I'd walk away from that...far away, I'd suggest that you do too. In the second pic there are spots where it looks like there are holes through the tube. Care to guess what the inside of the frame might look like if there's been water and air and maybe salt having a jolly ol' time in there? Fourth pic is rust somebody treated, tubes are not cast. Walk away...walk away.

Mike

[BeSeeingYou]

That looks like pitting from the corrosion but it does not look deep.  There will be little bits or corrosion in the pits and that's harder to get out.  If you just paint over it it will come back.  One option would be to use a rust converter type coating that neutralizes it allowing you to prime and paint over it.  I have had good luck with this stuff on cars.  The other is to use muratic acid full strength applied with brush.  Work on one section at a time top to bottom.  Neutralize each section with baking soda water as soon as you are done working that section.  I have also used this method and it will get the pits clean.  You have to keep applying coats of acid keeping it wet.  It may take 10-15 minutes.  Do it outside and avoid the fumes.  

Where do I get me some of this acid? I know corrosion doesn't go away, its an organism like mold, but for metal.

Hardware store.  It's cheap maybe $7 a gallon.

[BeSeeingYou]

Mick makes a good point about what's going on inside the tubes.  WHERE was this bike stored?

[Industrial Cafe]

under the ocean.

[Caaveman82]

It was in my stupid garage hanging from the rafter but the damn thing was leaking water all winter. I had no idea till yesterday when I went to dig it out from the back. That last picture of the four was after I used the wire wheel on it. Man the last thing I can afford to do is buy a new frame. God dang it and other foul language.

[Industrial Cafe]

all that happened during storage? did you sand it down to the metal first or something?

[Caaveman82]

all that happened during storage? did you sand it down to the metal first or something?

Sand blasted it last winter... yes it all happened in my stupid garage.

[hosanna64]

have it sandblasted again and coat it with some por-15 or good etching primer.  it should be ok. 

[Industrial Cafe]

it just looks like surface rust to me. I don't think the inside of the pipes will be a problem.

Sand blasted it last winter... yes it all happened in my stupid garage.

after that info, what do you think mick?

[Caaveman82]

it just looks like surface rust to me. I don't think the inside of the pipes will be a problem.

Sand blasted it last winter... yes it all happened in my stupid garage.

after that info, what do you think mick?

It all happened this winter too, it was a wet winter here. Last fall it was still rust free. I knew I should have primed it at least.

[mick750F]

it just looks like surface rust to me. I don't think the inside of the pipes will be a problem.

Sand blasted it last winter... yes it all happened in my stupid garage.

after that info, what do you think mick?

   Like I said, there are spots in the 2nd pic that look like they rusted completely through to me, that can never be good. Is that the case Cavey? Can you tell us if those are in fact holes all the way through the frame? IMHO if they are then you are screwed.

   A few years ago when I was restoring/rebuilding my bike there was some minor surface rust on some of the frame welds, the bike had lived outside most of it's life though under cover. I painted anything that concerned me with POR-15 and haven't looked back. It was nothing like we're looking at here.

   All that happened in your garage?!?! Where's your garage man? Atlantis?

Mike

  

[Caaveman82]

Nope just Minnesota, we throw salt down like it is the cool thing to do.

I'll show you pictures of the same spot after cleaning it up.

Give me about five minutes here...

[Caaveman82]

No holes that are not supposed to be there, but in some spots where it is two pieces welded over top of eachother there is a little rust up there, but nothing like that first picture, more like oxidation than the other stuff.

[Grnrngr]

http://www.skybryte.com/

This stuff works great also. I'd hit the worst spots with the wire wheel and if they're no worse than the piece you already did, it's probably OK. Where the tubes are completely sealed, its unlikely to have rusted inside. If there are holes, you could cut out that section and weld in a new piece. It's not an organism, it's a naturally occuring process when any bare metal is exposed to oxygen, unless there's a hole that allows air (and more importantly here, water) into the inside of the tube, there should be no rust inside. Definitely give all the welds a serious once over tho....

[Caaveman82]

Good deal, I was getting nervous there for a second. I really didn't want to buy a new frame lol.

It looked really bad but it wasn't too bad, came off fairly easy with the wire wheel.

[the technological J]

i heard a home remedy about lemon juice getting rid of rust though i have never tried it

[BeSeeingYou]

I thought from the look of it maybe you rescued it from Minnehaha Creek.   If it was fine last fall it should not have suffered to much over the winter.  The road salt should not be an issue but the coloration in the first photo is a bit strange.  It was damp here this winter and several times when I went out to the garage the bikes were covered in condensation.

[TyMatthews]

i heard a home remedy about lemon juice getting rid of rust though i have never tried it

The most effective way to dissolve rust... iron oxide... is with phosphoric acid:

http://en.wikipedia.org/wiki/Phosphoric_acid#Rust_removal

This converts iron oxide into iron phosphate (ferric phosphate), which prevents further surface corrosion by inhibiting oxidation of the remaining iron, also known as "passivation".  You can then scrub the ferric phosphate off immediately before painting or powder coating to get back to raw metal.

You can buy phosphoric acid from Home Depot:

http://www.homedepot.com/h_d1/N-5yc1vZ1xgl/R-100672861/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053

It's not very toxic... after all, Coke has phosphoric acid in it.  Naval Jelly also contains phosphoric acid, albeit in a slightly different form.  There are likely many other name brand solutions whose active ingredient is phosphoric acid.  They're just clever disguises and scents for what's really useful... the acid!  You neutralize the acid with some baking soda, and can then dispose of it down the drain.

Lemon juice contains citric acid, which does not offer the same passivation route as phosphoric acid.  Citric acid serves as a chelating agent with iron; that is, it binds to iron in the same sort of way that hemoglobin in your blood binds to iron.  Once bound, the citric acid/iron chelate is whisked away into solution.  In the end, you're actually removing iron from the surface, not forming a protective coating.  Careful preparations of citric acid are used in the stainless steel industry to passivate the surface of their products.  This works because the citric acid pulls away surface iron, thereby enriching the surface with chromium oxide and nickel oxide, which in turn passivate and prevent iron from oxidizing beneath the surface layer. 

So unless you have stainless steel, or know you have a large amount of chromium and nickel in your steel, citric acid on raw steel will just etch it, and not provide any real protective coating.  That is, you could use citric acid to remove rust, but you'd have to paint/prep it immediately, because as soon as you stop you're left with raw iron on the surface, which will begin oxidizing back into rust before you've even put your towel down.

[Caaveman82]

Thank you guys, I think I can get this thing under control now. I will finish busting the rust and then clean it and throw a coat of primer on it.

[traveler]

Nothing works as well as sand at HIGH psi being administered to it!  (Sandblasting).

Seriously, do it....you will be glad!  Then POWDERCOAT the frame and swingarm.

You will be glad you did it later.  Even if there was rust that survived the sandblasting, powdercoating is soo thick, and once it is melted down, it seals the frame....without air, rust is dead.

I have never seen a CB frame that hasn't been redone, that dosen't have rust on it....Honda put all their money and energies into the motor....everything else was done on the cheap to keep prices down....that is why the factory chrome is crap, paint is crap (outside the tank and side covers) etc, etc.

~Joe

[Caaveman82]

Nothing works as well as sand at HIGH psi being administered to it!  (Sandblasting).

Seriously, do it....you will be glad!  Then POWDERCOAT the frame and swingarm.

You will be glad you did it later.  Even if there was rust that survived the sandblasting, powdercoating is soo thick, and once it is melted down, it seals the frame....without air, rust is dead.

I have never seen a CB frame that hasn't been redone, that dosen't have rust on it....Honda put all their money and energies into the motor....everything else was done on the cheap to keep prices down....that is why the factory chrome is crap, paint is crap (outside the tank and side covers) etc, etc.

~Joe

Yes normal oxidization is easily delt with but corrosion is really bad stuff. I used to work at a wheel shop where we refinished aluminum wheels, I even have a thread on it some where in the open forum, and corrosion could bot be killed even with tig welding. We would basically grind the spots out with a cut off wheel and then weld a new bead on there and I'd cut it down on the lathe.

[traveler]

Makes sense, but your frame is made of Carbon Steel, which rusts, not corrodes....Sandblasting is still the way to go.....but it's your call.

I'm just passing on what has worked for me.

~Joe

[Caaveman82]

Makes sense, but your frame is made of Carbon Steel, which rusts, not corrodes....Sandblasting is still the way to go.....but it's your call.

I'm just passing on what has worked for me.

~Joe

I appreciate it man. I am going to use some rust removal stuff then see if my old boss will let me use the blaster after hours, then I will throw a coat of primer on it and send it to HT.