I recently sanded down my exhaust header as the chrome had gone off color from running lean.   I looked through the forums and picked up the proper grit sandpaper,  acetone to clean the sanded header well,  tack clothed it,  then applied primer,  matte black paint,  and a coat of clear for a slight satin shine.   I don't have an oven to cure it in and the can had instructions for an on bike curing.   Idle at ten minutes,  cool for twenty.   Idle for twenty minutes,  cool twenty minutes,  finally,  ride your bike normal for 30 minutes,  let cool,  and your done (hooray...)  Well I had my pipes looking amazing and right from the start the curing went bad.   Before I even could cure them I had to get the exhaust on,  well when I tighten the header on,  the uncured paint that had force applied from both ends cracked,  or at least for was smashed,  causing an improper seal, though not my main concern as it's covered up,  I'd prefer my whole painted header remain looking great no matter where the paint is.

The major issue though was despite having followed the instructions on the can,  within the first ten minutes of curing,  the paint at only the ends of each side I applied paint to started to turn grey,  back to a darker version of the primer,  so I don't know if it was burning the paint off,  as the was a good bit of snow,  but I read that's to be expected.   Well I went ahead and did all three steps and at the end of it I basically had a foot in the center where it remained looking great,  and on each side from then on it faded slightly grey,  and very quickly was just the primer color.   I spoke to a friend who does automotive painting and read up some more and from it I've gathered that the time between primer and the color on terms of letting it dry needs to be more like at least a day.   Also upon having taken the pipes off to try again,  like I mentioned earlier,  the paint around the head of the header that fits the gasket was completely bare metal at the corners and definitely looked bad on the level parts that the pressure of attaching it was applied to.  

So I didn't strip it as I feel I did a good job of at least sanding it and there is 95% off it covered in a cured VHT paint.   So I wet sanded the header evenly till all was perfectly smooth,  regardless of the color I was at  and applied three coats of primer again,  but I waited twenty minutes between coats instead of the recommended ten,  and then let it dry for two days.   I then sanded the primer with a very fine 1000 grit sand paper till the primer was no longer shiny (at the advise of my painter friend)  and today I applied 3 coats of the matte black.   Well I had some issues with the paint being applied evenly,  so I ended up with some nasty ripples in the paint.   Oh well...   So  this is where I currently am.   I just waited about 6 hours and with different grits I lightly sanded the troubled areas so it's one again smooth and it's still all black,  I didn't go very hard.   I did run out of paint though,  so tomorrow I plan on buying one more can of the matte black and applying either one light then one heavy,  or just two light coats of the black (if you think I should do otherwise please let me know!!!)  and I will follow a few hours later with two coats of the clear VHT for a nice satin finish.   I originally did just the one,  but I'm worried it will burn off....  

So,  that long explanation leads me to the main purpose of this thread.   How can I cure this without firstly burning off paint as my only main option is to do it on the bike.   But before I even do that,  is there some way for me to maybe cure the end of the header so once it's smashed in there the paint doesn't just get crushed right off?   I've read of using a heat gun but I have one and I put out to the painted area I had to sand down earlier and it just made it revert back to a liquid almost.   A more logical,  but precisely executed thing I could do which I've read works is to take a blow torch at one end and let it cure that way.   Now I imagine this would not be a flame to the paint approach,  but rather taking the torch and have the header pointed directly up so the head applied goes through it like normal,  and from some distance hold the torch upwards towards the header until the desired temperature is reached,  or just doing that off and on slowly heating it then letting it cool etc...   I'm just not very sure of how I'm supposed to make this work without at the very least compromising that portion of the header where it connects to the bike.   Granted,  no one will see it,  but I am anal about things being perfect and I've seen others do it on YouTube without this problem and I will be getting those and results darnit!   Lol,  ok,  so others on this forum have mentioned that for the rest of the curing process to just take it crazy slow,  like ten seconds on at first and then cool five minutes,  and slowly work up from there.   It can't really be that tedious can it?   If so,  VHT is going to get an ear full from me on the misrepresentation of how to apply their product.    I'm already pissed I have to buy another can of black just for our what,  1.5-2 foot header?   Granted I'm doing it a second time,  but if they'd give more details about ways to cure then this wouldn't be a problem....   So please any help as to how I can make this look the way it does before I cure,  after I cure?  Also any suggestions on my previous question about how I plan to finish the painting process would be much appreciated!

VHT rattlecans have been garbage since the 1990s.

Rustoleum BBQ paint cures well, but plan to recoat it every 2-3 years. If you get tired of black, you can also get white, silver or bronze BBQ paints. No primer required...

1000 grit primer sanding? You aren't shooting House of Kolor ultra thin almost impossible to use base-clear catalyzed urethane... 320 grit on primer at the absolute finest, 150 grit would be better. VHT is like pressurized mud, it doesn't flow worth a hoot and needs a pretty fierce mechanical bite to stay in place.

So here is my header,  all ready to be cured....  How it stays looking so nice.

old_rider wrote on 04/20/14 at 22:33:20:


That's the best option at this point. Cure it from the outside in and the inside out at the same time. You have got to let it solvent out gas for a couple days before you heat cycle it on the engine. The heater and dryer will speed that process up.

FWIW, ALL rattlecan exhaust paint sucks...

Realistically, you sanded to fine and you applied the paint to a cold pipe. Once it has heat cycled a couple times, if it looks funky, get the pipe warm to the touch and then coat it again. AFTER scrubbing the whole thing with an acetone soaked green or red scotch brite pad.

Dave wrote on 04/21/14 at 03:58:42:


In hindsight I wish I'd just had my header sandblasted which I could have done for like $10 and our header is what,  like 2 feet so like they would just charge $30 assuming it was stripped of the chrome to their satisfaction as they say there is an additional charge for stripping chrome,  but shipping from Houston to them in a decent time with proper packaging,  that's what would be the deal breaker.   What I should have just done was gone to Polydyn here in Houston,  dropped it off.   They told me it'd be a week and cost just $70.   You'd think in Houston there would be more than one company that does ceramic coating,  but nope,  just these guys.   Now I've gone and spent probably about $50 for all the paints,  chemicals,  sanding pads and tack cloths etc...  not to mention at least ten hours of just fiddling with it.   If this doesn't work in just dropping it off there,  I just didn't before because my bike is my only form of transportation and I can't be without that for a week,  but semester is up in a few weeks so well see...   I hope this just takes and u can spend that money on a new Mikuni VM36 carburetor,  and a UFO.   Scratch that,  I have fiberglassing to do!   Spend money so I can fabricate new parts...

I used whatever AutoZone sells--HIGH TEMP Rustoleum or Duplicolor for primer and color. Any way, they were around $20 for primer and paint. Use rough grit paper and plenty of elbow grease. Clamping in a vice and beltsander helped on long runs. Tear paper into 1" or 2" and get inside curve like shining shoes. No curing. Just wait about ten minutes between coats. Ride after an hour or two. Cheap, simple, and it works.  

So after many days of letting my paint dry and going over the outside with my heat gun for about 30-45 minutes 4 times I've finally got my exhaust back on the bike.   I'm currently waiting for it to cool,  I've gotten up to about 5 minutes of running,  starting with 30 seconds and then add a minute after every 20 minutes of cooling,  along with using my heat gun for the outside as its running and so far so good...   I don't want to jinx myself but it looks like it's going to finally take.   No bubbling,  chipping,  or cracking and it's gotten hot enough that the smoke has started.   While I was waiting for my paint to dry I contacted VHT about what happened and they offered me a refund.   I don't know if I'm going to take it I guess I'll just have to see how this turns out,  but if I had the option of just getting this done professionally at Polydyn here in Houston I'd of just done that.   Would have been $70 and that includes stripping the chrome so the fact I've spent about $50 -  $60 just for a DIY paint job is rather upsetting.   Even if it does stay,  and it does look great,  I can see areas where it's not 100% smooth and being as anal as I am that kinda stuff gets under my skin...   OK well here is a pic of what it's looking like now,  I'll post another when I finish curing.   I will probably end up taking it off and try to smooth out as much as I can after this,  but for now I'm pretty happy with my work.

Well I jinxed myself.   Overall 95% has held up but the very top part has began to fade very very slightly.   As long as it remains black I'll be ok but if it reverts back to a primer grey I'm gonna lose it...