Painting Chrome

[Cobia]

Hi,
Anybody have suggestions about prepping chrome for painting it? The exhaust manifolds on my XJ are in pretty sad condition with surface rust on the inside bend of the top where they bolt on. Don't want to let them go so far where they rust through, so I'm thinking about painting them. But I was told that it's hard to get paint or the ceramic coating/paint to stick to the chrome w/out sanding it off. Sounds like a lot of work. Any ideas or shortcuts to accomplish this? I'm only painting the manifold, the chrome on the muffler is still good so I intend to keep it original.
Gracias, Amigos.

[TADracer]

Here is my two cents.

I have been through this before and have found that short of having a chrome shop remove the chrome (which is something many do not want to do) the only way to really get ceramic paint to stick to chrome reliably is to thoroughly blast the pipes with 100 or 120 grit Aluminum Oxide blasting media. Like every other paint job, the preparation is the most important step.

White Aluminum Oxide granules have an angular shape that will remove the rusting and leave the chrome surface with a microscopic 'tooth' so the coating will adhere. Silica blasting media is OK too but will not produce as good a 'tooth' as the aluminum Oxide. Stay away from glass beads and slag based media as their shape may actually close up the surface of the metal and the paint may not properly adhere. If you have access to a blasting cabinet then that is perfect. I did not so I used a cheap blasting gun from Harbor Freight and blasted the parts in my back yard.

Use clean flannel work gloves to handle the parts after blasting and then clean the parts with Acetone or Laquer Thinner before applying the paint coating. Apply the paint coating as soon as possible after blasting so that no surface oxidation happens to end up under your coating. If you are applying a ceramic coating that needs to heat cure, curing on the bike is OK but it is best to cure the pipes in your oven if they will fit (and if SWMBO will not kick you out of the house). Highest temp your oven will go for about an hour will do the trick.

[fredintoon]

Silicosis anyone?

Hi Cobia,
if you decide to DIY the sandblasting fer chrissake wear a real good breathing mask. Sandblasting debris will rip your lungs out.

[Cobia]

All good advice!!!

Thanks guys.

It will probably be a back yard project with no oven baking allowed. Will have to cook them in the Florida sun and on the bike.

There are no chemicals that will accomplish the surface prep?

[Da-Bubble]

I used a cheap sand blaster in my back yard. And I bought $3 per 50lb bag play sand from home depot then sifted it through a screen to take out the pebbles. Worked great. As for baking the finish on; paint the pipes with ceramic header paint, let it dry for an hour put them on the bike and start it up. Let it run for a few minutes then let them cool. Do this three or four times and it'll be a tough finish!

Good Luck!

[MrOzz]

I painted my headers. Here is the fourm link to it. Before and after pics included.

http://www.xs11.com/forum/showthread.php?t=19582


Ozz

[Cobia]

Thanks for the thread Ozz. What did you finally end up using? The tedious hassle is the blasting of the chrome off.
Thanks

[MrOzz]

To get the crome off I sand blasted, sanded with paper, used a grinder (mostly cause of pitting). It takes time but I was happy with the results. Make sure to use a resperator and protective eye wear.


Hope this helps,

Ozz

[TopCatGr58]

Hey Robert/Cobia,

I used a 3M fiber grinding disc on a drill to roughen up the rusted pitted chrome on my old front and rear fenders, and then used a metal etching/converting primer, and then the base/color coats and clear. You saw the results, didn't bother taking it down to NO CHROME! YMMV!
T.C.

[Cobia]

Yeah, TC

Yours looks great and I'm not even going for the shiny look, I just want to paint the exhaust pipes with the flat black ceramic stuff!!
What kind of "etching/converting primer" did you use?

[selfmade]

check the caswell plating forum for the right method. I usually will just use simple green to make a first to third pass cleaning. and then Sand with a 180 to break the surface and then sand with 320 and prime. On the pipes you can use a regular etch primer. You do not have to use a phosphate coating such as rust mort. Then just spray as per the directions. Let sit overa 2-3 hr span and put on bike. after that run the bike for 15min. 3 times and it should be fine.

[MrOzz]

On the pipes you can use a regular etch primer...

Is the etch primer good for the heat of the headers and pipes? From my understanding you need a good high heat primer like the VHT Header paint, if not the paint will come off the headers.

The etch primer will work for cromed items like the handle bars, fenders trim pieces.


Ozz

[selfmade]

the etch primer will not be affectted by the heat...or atleast should not. I have yet to have any problems. It acts as a bonder for the new paint to go on to. It will not work if the surface of the chrome is not scuffed. The reason chrome is so shinny is due to the lack of porosity from the metal. That is great for a finsihed surface but not for a bonding surface.

[selfmade]

http://www.longislandcustoms.com/tec...ver_chrome.php

here is a good write-up

[Cobia]

Good information, Thanks

Hey Guys,
This is really good information that will be usefull to us all. I'll keep you posted on the progress and effectiveness. Plan to start it in about a week or two, after I seal the tank and detail my '80G. Engine and carbs are getting reall gummy from the dripping, so it's time to "git r' done".
Keep the info flowing.