Hey guys, I've got another question about dealing with RUST!!!

I got these mufflers on ebay for my bike, but they have a good deal of surface rust that needs to be addressed before I put them on.

Anyway, they have two parts I guess you could say: a black painted pipe, which is rusty on the outside and a little bit on the inside; and an apparently aluminum can, which is alright on the outside, but the baffles on the inside are all rusty.
I'm not positive that the can is aluminum, since I don't know much about anything, but I think it is. I can tell you that the cans aren't magnetic and the pipes are.

Anyway,

Here are some pictures:


Here's where it would attach to the common collector:


Here's where the black pipe and the aluminum can meet:






Now here is a look at the inside. It was pretty tricky to get these pictures to turn out!

This is from the back end. You can see the rusty baffles down there.


Here you can kind of see some light surface rust on the inside of the pipe


And finally here's a view from the back, which didn't turn out as well, but you can see the rusty baffles anyway



SO ANYHOW, that's the situation. I'd like to at least get all the rust off the outside and repaint so it looks halfway decent before I install them.

What do you guys think of that rust on the inside? I imagine it will only get worse if I ignore it, so what can I do? Is there some chemical I can spray in there to neatralize it or something?

PART 2: I'm also thinking about painting the aluminum part black as well, because I think it would look better all black. Is the procedure for painting on aluminum any different than painting on steel?

I have ruled out getting this stuff ceramic-coated because I'm on a tight budget.

Now, here are the supplies I have at home so far:
A sandblaster and plenty of blasting grit for it
A little can of POR-15 Black Velvet High-Temp Paint
A quart of POR-15 Solvent (to dilute the paint)

What else will I need for this little project?

And guys, it's safe to assume I don't know what I'm doing, because this is the first time I've done something like this!

Thanks a lot for any help guys!!!

-Chris

I'd say you are on the right track. Make sure you scuff the aluminum a little to help the paint adhere. The best thing to use is a maroon scotchbrite pad.

I wouldn't worry about the rust on the inside, but that's just me. You'll be screwed if you pull it apart and the baffles all fall apart when you are blasting them. Plus, any paint that you can apply will probably burn off eventually on the inside. Good Luck!

That's kinda what I was thinking, but I wasn't sure. It just seems kind of wrong to leave all that rust! I think I heard something like a radiator shop could flush all that crap out, but I'm not sure. Anyone know anything about that?

Also, should I prime this stuff before I paint? If that's the case, I'll need some kind of high-temp primer, won't I? The instructions on the Black Velvet don't say anything about primer, so I haven't bought any yet.

I would expect there's no primer, but call POR. They'll tell you exactly what to do.

You could just paint as much of the inside as you can. It won't hurt anything and will make it look better.

I mentioned this to one of my engineering teachers at school, and he said to keep in mind that if I use some chemicals to take all the rust off the baffles, it would remove a little bit of material, which could change the back pressure. He wasn't sure if it would actually make a big difference though.

I didn't even think of that. What do you guys think?

Ok I called POR-15, and the guy told me I should just sand blast everything on the outside to bare metal, and go over the aluminum part a little bit to rough it up, and then paint directly on the metal. He said Black Velvet isn't a rust preventative paint, so I can't put it straight on rust like regular POR-15. He also said don't use any kind of primer or Metal-Ready or anything, just paint on the bare metal.

I asked about the inside, and he said he's seen people sand blast the inside to get the rust out, and then soak a sponge in paint and pull it through. Has anyone tried anything like this? I don't know how I could sandblast the inside of a muffler without taking it apart, do you?

The paint won't change the back pressure much, if anything. Nothing worth worrying about.

You would probaby have to pull it apart to sandblast the inside. You could just shoot sand in and hope for the best.

Another dude told me you can get some spray cans of stuff that neutralizes rust, and that would at least stop it from getting worse in there. He didn't know the name of the stuff though. Anyone know what I'm talking about?

I'm gonna go check out the auto paint store tomorrow on the way to the parents' house to get to work!

Ok, I went to the paint store, and they said the stuff they had for neutralizing rust doesn't stand up to high temperatures, so I'd be better off just leaving the baffles as they are.

But anyway, I got to work after I got home and made some decent progress!


This is what I got done today:

I started by sandblasing the major rust spots and loose paint off


If you were ever curious, this is what a sand blasting encolsure looks like in rural Wisconsin:


I made a stylish doo rag out of mom's dish towel to keep some of the sand from going down the back of my shirt



Anyway, after getting the easy crap off, my dad busted out this awesome goop that loosens the paint right up! And it smells good too!




After glopping this stuff on, you have to let it work for like a half hour


Then I was able to scrape a lot more paint off with a plastic putty knife!


After repeating that a couple times, we washed the goop off and I was able sand blast the remaining paint and rust away.

My dad rigged up a board to hang the stuff from


Rather than watching the bare metal rust again while it warms up enough to paint (it was pretty cold outside), I used this heat gun to warm them up quickly


Ooooh, here is the stuff


And on it goes...


Looking pretty good


Here's one done, it looks kind of a weird color, but it's actually black


And here's two done!


The paint is actually not very glossy, but I think it's partly because we painted on pretty rough metal. Anyway, we'll give it another coat later and see where it's at. If it's not shiny by then, I'll spray some glossier stuff on!

I didn't do the aluminum parts today, but I'm still thinking I'd rather paint them than polish them up. We'll see, I'll decide tomorrow!

The insides are going to rust no matter what you do it. Your mufflers baffles aren't made of stainless.

ALL mufflers draw in moisture as they cool off. The higher humidity you have. The more water it will draw. Thats is in part why mufflers rust out. They retain water as they cool, mix that with the corrosives in the exhaust mixture... Add some heat..... VOILA.... Crapped out muffler.

Underneath the perforated baffles in your muffler....... There is probably a layer of fiberglass or stainless baffling material. If you get the internals of the baffle wet while starting and running an engine. You will blow out the baffling material immediately. Wet fiberglass blows out FAST. Stainless wool baffling lasts much longer.

I don't believe the rust you have will hamper performance at all. All the loose rust will blow out after it gets hot and you drive it some miles... especially if you run it hard a couple of times.

If you are bound and determined to get the rust out of the inside of muffler.

Go here: Best Rust Remover I have ever used

Buy it.... use it.... And you will be a happy camper.

Cheers,

Clayton

Looking Good!!!

Does the Black Velvet require any kind of heat to set up? Is that when the gloss comes in?

It says it reaches it's full hardness after it's been exposed to 350 degrees I think

or maybe 300

anyway, we'll try heating them up tomorrow

OK! I got some more work done this morning!

First I used the heat gun and a razor blade to get the old decals off.

I didn't have any scotchbrite pads to rough up the aluminum, but a few more minutes with the sandblaster and it was ready to go!


I put a nice coat of Black Velvet on both cans




The flash made these two look really wierd, but it's actually all black, and that end is cover nicely




Now I have to let it dry for a few hours. The instructions say after the paint is dry, I can re-coat after it's been heated to 400 degrees. So that will be the next step!

Well I cured the paint in the oven!

Luckily mom is out of town for the weekend, otherwise we never would have gotten away with this!


Bake at 400 degrees until impenetrable black finish is attained!


Dinner's ready guys!!!!!!!!


I'm back at my apartment now, so no more work for this weekend. My mission for the week is to find some gloss black paint to put over this stuff, and maybe find some new decals to put on the cans when I'm all done.

Next weekend's goal are:
1. Finish painting the mufflers
2. Get the old mufflers and common collector off without breaking anything
3. Sand blast and paint the collector
4. Put everything back together with the new pipes!

Hopefully it'll all work!!!