Topic: Painting the inside of the fenders?

[DiscoEd]

I have removed the rear fender and been working on cleaning it up. The chrome on the outside is in reasonable condition and will look well when polished. On the inside there is some tar and rust. It's not severe but it's ugly. I'm wondering what the oppinions are...

1.) Should I clean the inside up and paint it?
2.) Should I clean the inside up and just wax it?
3.) Should I just not even worry about the inside of the fenders at all and find something else to work on?

Regards,
DiscoEd

[Bob Wessner]

I think the biggest problem with putting some sort of "surface" on the inside is; a) you really have to convert/seal previous rust or your just sealing it in and if there is any trapped moisture, it will keep doing its thing, and b) whatever you use has to stand up to being seriously abraded by a stream of spray and sand if you ride on wet pavement, think sandblasting. I do recall reading somewhere where someone had used some pretty tuff stuff to coat the inner sides of the fenders. I might try to find it again. So far I'm using the keep it clean as best I can method.

[Raul CB750K1]

I plan to do something with my mudguards/fenders too. My idea is to use phosphoric acid (the one used to de-rust gas tanks). Suppousedly, a treated surface become rust-resistant, so I will apply sparingly with a brush and, in theory, the inner side would become rust resistant.

Raul

[KB02]

If you're going to paint it anything, use that rubberized undercoating stuff. Once you get it cleaned up, that will just help protect it.

[DiscoEd]

I plan to do something with my mudguards/fenders too. My idea is to use phosphoric acid (the one used to de-rust gas tanks). Suppousedly, a treated surface become rust-resistant, so I will apply sparingly with a brush and, in theory, the inner side would become rust resistant.

Raul

Raul,
I saw something similar to this stuff yesterday. Darn, I can't seem to remember the name of it. Anyway, it was some kind of green  looking liquid phosphoric something. I did read the label and it made it sound like it would chemically convert the rust in to chromium something. It also said that it would leave a black TACKY coating on the metal which would then be ready for the application of primer.

So, I'd becareful with whatever you use. I'd definetly stay clear of the chrome with that stuff that I saw. If I can find out the name I'll update my post here.

Regards,
DiscoEd

[Bodain]

I did mine...

Remove all rust with Muratic Acid.
Neutralize acid
Paint with anything.

[DiscoEd]

I think the biggest problem with putting some sort of "surface" on the inside is; a) you really have to convert/seal previous rust or your just sealing it in and if there is any trapped moisture, it will keep doing its thing, and b) whatever you use has to stand up to being seriously abraded by a stream of spray and sand if you ride on wet pavement, think sandblasting. I do recall reading somewhere where someone had used some pretty tuff stuff to coat the inner sides of the fenders. I might try to find it again. So far I'm using the keep it clean as best I can method.

Bob,
Yes, excellent point. I could imagine making things worse by trapping rust and moisture under some type of coating. Perhaps for now, I'll just clean it up the fenders and wax them on the inside.

I'm still trying to figure out if there is some kind of nutralizer available that won't "kill" the chrome.

Regards,
DiscoEd

[DiscoEd]

I did mine...

Remove all rust with Muratic Acid.
Neutralize acid
Paint with anything.

Bodain,
Does the Muratic effect the chrome? (Of course I'll assume leaving it too long on anything could be bad.)

Regards,
DiscoEd

[mrblasty]

A product name You could look out for is this stuff called rustmort it is made by a company called SEM.
Takes 24 hours to convert rust and washes off with water, It can be purchased at autobody supply houses and possibly well stocked hardware stores.
I am sure it is one of the acids that have been mentioned already.
After You get it rust free, use rubberized under coating/chip guard and layer on three or four coats, 3M makes on of the more durable versions, this stuff will build up thick and is paintable.
Good luck

[stevej]

Has anyone tried silver Hamerite,did it work?It can apparently cover rust and is at least a silver colour so shouldnt look too obviouse.

[TwoTired]

 The fender insides get blasted by stones and debris picked up by the tire and flung onto the fenders.  Part of the reason why they are there.  Whatever you put there is going to be worn away, chip, or scratch eventually.  Wax is very thin and not very durable.  In fact it will sublimate off the surface in about 6 mos to a year.  And, soap and water generally remove it quickly.

The tar deposits actually impedes rust.  I suppose you could make a case for leaving it there as a preservation technique.

Eastwood sells a product called Oxisolve, I have use on steel surfaces that chemically removes rust and leaves a zinc phosphate coating.

The zinc coating is sacrificial, meaning it will chemically convert prior to nearby steel and is an excellent preservative.  Zinc Chromate can also be used, but the rust must be removed first for best preservative effect.  And, breathing the spray is bad for you if you don't brush it on.

Eastwood also sells a one step rust encapsulator in red, black, silver, and clear.   The clear you can tint for a wide range of colors.  It is very tough and durable once cured.  I put it on pretty thick and it took a long time to harden.  Much of that may have been because it was inside a tube and hard to aerate, though.  They also have a rubberized undercoating that might bounce off a lott of the debris smacking it inside the fenders.

http://www.eastwoodco.com

Cheers,

[CharlieVT]

I use a product call Rust Convertor or similar product called Extend. Both come in spray on or paint on form. Wire brush the rust to get rid of the loose stuff and spray on the Rust Convertor. Let it dry and the paint over it. I have had very good luck with this stuff and it is quick and easy. 

[Bodain]

I did mine...

Remove all rust with Muratic Acid.
Neutralize acid
Paint with anything.

Bodain,
Does the Muratic effect the chrome? (Of course I'll assume leaving it too long on anything could be bad.)

YEP... I learned that the hard way. You don't want the acid to even touch shiney chrome.
My rear fender looks pretty bad now because when I was using the muratic acid to remove rust from the inner fender.
I was kinda sloppy and got it on the chrome. It's a definite no no...



Regards,
DiscoEd

[Geeto67]

por15 paint over rust. easy, works great in the car world. Its only downfall is sunlight breaks it down but under the fender it won;t get much of that.

[Glenn Stauffer]

por15 paint over rust. easy, works great in the car world. Its only downfall is sunlight breaks it down but under the fender it won;t get much of that.

That's kind of what I did, but I used Eastwood's Corroless .  You just need to chip off any loose rust, wire brush it, then paint it.  Afterwards, you could use a auto chassis paint to provide a good durable chip-resistant finish.  Chassis paint is available in a number of different colors; I used silver.  I'd avoid acids since you could mar the chrome on the upper side of the fender if you are not super careful.  In my experience paints like POR15 or Corroless bond much better than most of the consumer grade rust converters.

--Glenn

[DiscoEd]

O.k. So here is what I'm thinking....
I've got to do this on the cheap so I can't be ordering all kinds of exotic stuff from around the globe right now...

I've already cleaned up the inside of the fender some with a wire brush, got a bit more work to do there. Anyway, I read in another post about tank cleaning about this stuff called "The Works". It's suposed to contain phosphoric acid. I'm wondering if I was to very carefully apply this to the inside of the fender if this would nutralize the rust. Then I was thinking that I could apply some self etching primer to the inside of the fender and then coat it with the 3M rubberized undercoating.

What's the oppinions about giving this a try?

Regards,
DiscoEd

[Bob Wessner]

I read in another post about tank cleaning about this stuff called "The Works". It's supposed to contain phosphoric acid

Just used some in a drain. Don't know if this changes anything for you, but "The Works" uses hydrochloric acid, not phosphoric acid.

[MRieck]

You could tape the chrome and bead blast the surface.

[Zane]

I thought I was going a bit overboard by wanting to paint the insides of my mudgaurds.  So I'm glad you brought the subject up D.E.  I'll watch with interest.  (So far my efforts have produced poor to embarrasingly poor results, unfortunately.)

And thx Two Tired, for the Eastwood link.  Neat outfit.

[DiscoEd]

I thought I was going a bit overboard by wanting to paint the insides of my mudgaurds.  So I'm glad you brought the subject up D.E.  I'll watch with interest.  (So far my efforts have produced poor to embarrasingly poor results, unfortunately.)

And thx Two Tired, for the Eastwood link.  Neat outfit.

Zane,
 What have your efforts been so far? Just so others don't go down the same path.

DiscoEd

[mcpuffett]

hi, you could wire brush the inside of the mudguard to get all the loose and flakey stuff then underseal it  thats what i do.  mick.

[Zane]

I masked off the chrome very well.  I bead blasted then cleaned with acetone.  Then I washed with soap and water and hot air dried (I don't have any hair, but I do have a hair dryer).  Then I sprayed on a light coat of epoxy appliance enamel.  (I've had great results with this stuff before, in the black.  I heat the can a touch, apply a number of lightish coats, bake it at 70C for 30 to 45 minutes, cure it in warmish air for a week, then cover it with either gloss or matte clear laquer.  (I know laquer generally does cover enamel, but it works great with this stuff - especially on plastic.   It's really good and strong when I do that - as in my glossy black rack will take high stretch metal bungee cord hooks and not mark and on the plastic you can't hardly sandblast if off when it's cured and dried properly.)

So I thought I would use the "Stainless Steel" appliance epoxy and do the same as above (with the black), and see how it worked.  It's time intensive (drying wise anyway) but it's economical and has been technically pretty good so far.  And where I live I sure have lots of time becasue the weather's not good for riding currently.

So enough with the defensive stuff - I used the "Steel" paint the same way as I use the black.  It was really weird.  It kinda curdlled or separated or something - it was like the pigment separated.  After a second of spray it fuzzed up on the metal and had these little black flecks going on (kinda neat, but not for this project unfortunately).

So I emailed Rustoleum.  They had a guy call within two hours.  He left me a lengthy voicemail (I was out, sandblasting this first, botched attempt off) and said a few things i found interesting.  He said they get occassional bad cans out there, which sort of surprised me and then he talked about the obvious - that it was the prep with sandblasting was the problem.  He left his name and number and I'll call him Monday. (I did try spraying some other steel too, and it wasn't as bad, but as the paint built up it started the same oddball contortion.

So I tried again, and got a better result, but still not at all like their other epoxy at all.  So I'm regrouping, and trying to imagine a "better way".  In that direction - I like the rear, plastic mudguard thingy on my bike.  I wonder if it would be possible to cover the inside of the metal mudguard(s) with something similar?  (If you did that though, you'd still have to protect the metal between the steel and the plastic from rusting, somehow.)

I wouldn't be spending so much time on this right now if I could actually ride outside these days.  But I like my little machine so much I'd really like to preserve it as best I can.  I also read where the little rear, metal mudguard on these little 400fours is difficult to replace - and expensive.

I was thinking of trying some clear stuff I put on my (bare concrete) floor - it really seems to wear and protect extremely well.

So I'm leaning towards a clear, thick protective finish of some sort (and I don't care if I have to brush it on, since you can see very little of it) or towards making an inner shell of some sort out of something really durable and easy to clean.  And a third possibilty is one of those gun coatings I mentioned in an earlier post.  They look sort of neat.  By the way, I emailed Brownell's and asked if their coatings were resistant to corrosive type brake fluids.  I didn't expect an answer but they not only got back to me, they told me that the employees at Brownells who have motorcycles (quite a few, I guess) use that stuff on their bikes a lot.  And it is resistant to corrosive types of brake fluids.  I wish I could get a can as easily as United States people can get it - I'd try it for sure.


So I've come clean - just sort of embarrassed I guess.  Thanks for asking though.  I can sometimes do stuff the hard way, for sure.  (It's a bit of a perfectionist streak too I guess.)  Simply brushing off the metal and and then sealing it sounds reasonably sound too....

[TwoTired]

If preservation is your primary goal, consider Zinc Chromate paint, at least for an underbase.

Aircraft maintenence supply outfits carry this stuff. 
http://www.aircraftspruce.com/menus/cs/paint.html
for example.
We've got some pretty old airplanes in the GA fleet and preservation in key to keeping them flying safely.

I've got a 72 CB500 that had the inside of the fender zinc chromated (only).  There is NO rust under there.  Now, the bike hasn't been in service and has been sitting for the last 15 years or so.  So, there aren't any stone chips, either.  But, the zinc chromate is sacrificial in that it reacts with oxidizing attacks BEFORE the steel does. So, just having it nearby the exposed steel site, delays the onset of rust.
It's kind of a hideous green or yellow.  So, if the looks are important you can over coat it with a color more to your liking.

Something to consider. 

Cheers,

[loonymoon]

I used car underseal containing something called waxoyl on the inside of my front mudguard. I took the mudguard off, brushed it up to remove most of the loose corrosion and then coated it with the underseal. It contains a rust inhibitor and is also quite rubbery and flexible and so should also protect from stones and flying debris. I didn't bother to paint over it and so far it's been absolutely fine (I put it on probably 5 years ago or so..)..

[DiscoEd]

I used car underseal containing something called waxoyl on the inside of my front mudguard. I took the mudguard off, brushed it up to remove most of the loose corrosion and then coated it with the underseal. It contains a rust inhibitor and is also quite rubbery and flexible and so should also protect from stones and flying debris. I didn't bother to paint over it and so far it's been absolutely fine (I put it on probably 5 years ago or so..)..

Hmmm...I wonder if this is the same Waxoyl they put on the underside of Land Rovers? That seems to be pretty good stuff. With the stuff they put on the land rovers, you wouldn't want to paint over it. It really is a hard wax with various additives. It does last a long time but may need occasional touch ups.

http://www.roversnorth.com/RRD04/RRD04_92_96/RRD04_page96.htm

Regards,
DiscoEd