question about ceramic coatings

[Kurek, Larry]

For all concerned....we had an E-mail server conversion, so my "formal"
name has changed. However, just send to Lkurek at anl.gov and it'll make it
no matter what the server name is...

Now, to the question...

Yes, it is a good idea to coat the inside of the pipes...probably more
so than the outside. Reason being, the heat contained in the exhaust
goes as far as the coating, and is then retained. If you only coat the
outside...it will look pretty, and reduce your underhood temps, but the
pipe will burn out quickly. To coat the inside, you can use one of two
methods....I personally use a hybrid. You can flow coat them (pour a
couple of ounces in and swish it around), or pull a swab through. What I
do is flow coat them first, as this will ensure coverage, and then pull
a lightly compressed swab through to remove any excess. Works for me.
Oh, BTW, best if done on NEW pipes, since you have to ensure they are
clean to coat them. I usually etch the new pipes with HCl or H2SO4, then
coat them. With old pipes, you need to remove all traces of carbon as
well...

TTYL!

Larry

> -----Original Message-----
> From:	Chris Conlon [SMTP:synchris at ricochet.net]
> Sent:	Thursday, June 25, 1998 12:21 AM
> To:	'diy_efi at efi332.eng.ohio-state.edu'
> Subject:	question about ceramic coatings
> 
> Hi all,
> 
> I tried to send this reply to Larry <lkurek at smtpgate.anl.gov>, but the
> address doesn't seem to be good anymore. (Yeah, ok, I'm about a month
> behind on some things.) If Larry or anyone else has an answer, it'd be
> really appreciated.
> 
> ------ begin forwarded message
> 
> Hi Larry,
> 
> [CBC and/or other ceramic coatings]
> 
> > If they are applied too thick, then yes...they run a good chance of 
> > cracking and subsequently coming off. If the surface isn't properly 
> > prepared (sandblast finish) and completely free of grease/wax/oil, 
> > they coating WILL flake off. However, with all of the parts I have 
> > coated...they seem to last pretty well if applied correctly.
> >     
> > You don't want to dip the parts, even if you thin the coating...it 
> > would still be WAY too thick. What I have found that works best is
> an 
> > airbrush to apply the coating to a preheated part (150-175 degrees).
> 
> Would you have any suggestions about how to coat the *inside* of
> something like an exhaust manifold or pipes? Or would you suggest I
> not even try, & just coat the outside? I'd really like to DIY these
> coatings on a bunch of exhaust parts, but I haven't used this stuff
> before, just read about it.
> 
>    TIA,
>    Chris C.