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Painted exhaust pipes
Posted: Wed Dec 24, 2008 10:45 am
by philrock
I'm setting up a kart with twin Mc101s and RLV Blimp exhaust pipes. I'm thinking about painting the pipes black with engine paint - I've seen a few painted pipes on vintage karts, though never on a modern kart. It certainly would look better than bare heat-discolored steel, and it would spare me my ritual of dosing the pipes with WD-40 every time I come in off the track (the WD-40 gets all over everything, including the brakes).
The paint would certainly change the thermal situation, and I wondered if there might be some down side to it.
Comments, suggestions, paint recommendations, etc. would be appreciated.
Re: Painted exhaust pipes
Posted: Wed Dec 24, 2008 11:27 am
by Randy Forbes
Why not try this?
http://www.caswellplating.com/aids/tech ... ml#exhaust
It's a black satin finish that's also a thermal barrier.
Re: Painted exhaust pipes
Posted: Wed Dec 24, 2008 11:50 am
by Jeff Campbell
Black barbeque paint, works great, have used it for decades on pipes. I tried a colored one once, but it dis-colored and the oil cooking on it did not look great, a black colored paint hides all that.
I believe there is some evidence to support performance improvement from thermal barriers on the header pipe leading into the expansion pipe, but not so much so on the expansion chamber itself. A high temp fabric is available for wrapping header pipes to provide insulation (much better than an paint could do), but it doesn't look vintage of course. I'm sure if you ran a kart with an unpainted header-pipe, then painted them, nobody could tell the performance change when running on a track.
Jeff
Re: Painted exhaust pipes
Posted: Wed Dec 24, 2008 4:26 pm
by ted johnson
I used VHT brand high heat paint on expansion chambers for years. It is perfect. I used to paint a large area with yellow, blended into red, heat cure that in an old oven, then mask stars and spray the remainder flat black. After the star masks were removed, I heat cured the pipe again. After it cools, you can "buff" the pipe with coarse cloth and get a very nice semi sheen. The pipes last for years. In fact, I think my pal Charlie may still have one of my star-painted Blimps from the street race days. The stuff is available from most speed shops. Cheap and easy! Ted
Re: Painted exhaust pipes
Posted: Fri Dec 26, 2008 1:25 pm
by philrock
This is great news - thanks for all your help, guys.
Re: Painted exhaust pipes
Posted: Fri Dec 26, 2008 6:28 pm
by Brian Thomas
There was a post over on Bob's about why you should not put a finish on a pipe . Something about sonic waves and resonance .
Re: Painted exhaust pipes
Posted: Sat Dec 27, 2008 9:47 am
by ted johnson
Hi, Brian! I've run them both ways dozens of times and cannot tell one whit of difference. A heavy coating like powdercoat might cut power due to a resonance damping effect, but I'd be willing to bet that with a product like VHT or BBQ paint in thin coats, you will never know it's there, except it looks better

. I won lots of races against bigger engines (open 101 against BM-130's and B-Bombs) with a colored pipe! BTW, I'm still measuring Ramos; cylinder openings aren't easy. Ted