A guy wants me to repair his headers for his motorcycle. He told me they were ceramic coated aluminum. I figured no problem since they usually coat the inside and this weld was going on the outside. I jigged it up and hit the weld area with a s.s. wire wheel. I got to welding and things weren't looking right. After about an inch, I heard the familiar sound of a crack. My weld cracked right down the middle. So I chiseled it out and found holes under the filler. The weld fell off in chunks like I tried to weld to steel. What gives? Attached ImagesCommon sense in an uncommon degree is what the world calls wisdom.
Reply:are you shure there alum.and companys like jet coat do coat theinside and out
Reply:Its not aluminumIs it light? Is it magnetic?
Reply:Okay... I picked away at the coating with a knife on one of the flanges and found that it's either s.s. or ti. That's what I get for listening to the customer. I kinda wondered how they would use aluminum in a high heat application. I'm pretty sure it's s.s. I'm not sure if they would hide titanium with a coat of something.Common sense in an uncommon degree is what the world calls wisdom.
Reply:the way those holes look I would bet stainless, you can get stainless to take aluminum filler but you can hear it crack right after your done welding.Have we all gone mad?
Reply:The bad thing is that it turned this 30 minute job into a no-money 2 hour job with all the finish work I have to do now.Common sense in an uncommon degree is what the world calls wisdom.
Reply:It is possible and not a problem to weld on pipes that have been ceramic coated if you use a TIG, the puddle is kinda funny looking its almost like you are welding under the coating. I have always just used mild welding rod.
Reply:Titanium pipes would run a small fortune, it seems like he ought to know if he shelled out that kind of cash just for headers! I would guess other than Ti.http://en.wikipedia.org/wiki/TitaniumCity of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:Originally Posted by BrainfarthA guy wants me to repair his headers for his motorcycle. He told me they were ceramic coated aluminum.
Reply:I would also guess aluminized ceramic coating on steel, but not stainless. Lots of companies offer this. My welder just ground back the coating when welding on mine, then hit it with a little silver high-heat paint.
Reply:It must be s.s. because it's non magnetic. Kinda a shame they cover cover up stainless.Common sense in an uncommon degree is what the world calls wisdom.
Reply:ss gets ugly after awhile. theyre aluminized ss most likely...pruge em or theyll just keep cracking..actually his best bet would be replacing em cuz after ya burn thruthe coatin welding em theyre gonna be ugly and rusty..and they will spiderweb from the htg and cooling after the welding
Reply:The coating might be to try and keep a relatively uniform color to the header instead of having the heat-oxide rainbow colors on the stainless steel after the header heats up in use. Then the user or the detailer spends time rubbing and polishing the rainbow tinted stainless with stainless steel polish to get rid of the tint, until the next time the bike is used and the header turns rainbow colored again.So you TIG welded some aluminum filler onto a stainless steel part? You checked and found the headers were non-magnetic, but didn't you sort of say "Hmmm, this feels a bit heavy for a piece of aluminum?" Oooops.It -could- be coated titanium, for the same heat-tint reason as coated stainless steel. In which case you have an expensive mess on your hands. Yikes.Step one - verify WHAT the material actually is, and what alloy stainless it is if it actually is stainless. And the customer's say-so don't count at all, as you found out the hard way. Stainless or titanium will both require back-purging on the pipe.Please post follow-up pics and information about what went on and what you found out. This way maybe we can gain some experience from your experience. The best laid schemes ... Gang oft agley ...
Reply:Any chance that the aluminized coating inside and out would reduce the magnetic characteristics of steel? I was not aware that such a coating would adhere to stainless.
Reply:I heavily doubt they're titanium. The collector is MIG'd on.If I had to bet, they're probably carbon steel. Ceramic coating mild steel is usually the cost effective alternatives for manufacturers to keep a product looking good without the expense of stainless.
Reply:i had steel edelbrock headers on my dodge at first,, they had the fancy ti-tech ceramic coating on them... lasted about 4 months and started to rust... sold them and bought some gibson SS shorties.. they are severely discolored and ugly as hell.. some scale forming on the outside.. but no rust at all!!!moral of the story.. dont do drugs
Reply:What you have is a Buell Lightning exhaust, which is made from 304 stainless. I have an identical set without the ceramic coating.Richard TerryMarine engineer............. C'mon retirement!
Reply:Ti headers are getting very common; in fact, more than one stock sportbike have full Ti exhausts for weight savings. Like everything, once they get the process down, and enough material, the cost gets to an acceptable level. But I have never seen a coated set of Ti headers. Almost guaranteed they are SS.And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:Originally Posted by dieselbeefss gets ugly after awhile.
Reply
n my dirtbike when the mud is cooked onto it it gets pretty ugly
Reply:my nova headers are steal and ceramic Attached Images
Reply:Very nice Ed!!!And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:OK couldnt help myself, Jet Hot ceramic coated!
Reply:Motorcycle headers are chromed steel, stainless, or Ti.Ti is very common on the high performance street and MX bikes.
Reply:What's the deal with the plate on top of your intake? Is that some kind of restrictor deal for bracket racing?Common sense in an uncommon degree is what the world calls wisdom.its a heat plate helps keeps the bowls cooler Attached Images
Reply:To get back to the original post..There is no such thing as ALUMINUM HEADERS!!Can you say Melt? You guys are unbelievable!...zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:What about aluminum down pipes? 1600 deg turbos, haven't seen one melt yet. i'll be starting my exhaust from the hearders back shortly. .060 aluminum all the way back
Reply:stainless for sure. check twice weld once!only thing worse than an ugly woman is an ugly weld
Reply:Originally Posted by deboWhat about aluminum down pipes? 1600 deg turbos, haven't seen one melt yet. i'll be starting my exhaust from the hearders back shortly. .060 aluminum all the way back
Reply:why don't my pistons melt? would't the aluminum head melt @ the exhaust port? Everyone said the aluminum down pipe would melt to until someone tried it.Last edited by debo; 02-14-2009 at 06:59 PM.
Reply:Originally Posted by debowhy don't my pistons melt?
Reply:Originally Posted by zapsterWhat is the material between the heads and the turbo?...zap!
Reply:Originally Posted by deboThere stainless, but thats the standard. Just like I said Stainless Down pipes were always stainless. I think a .120 wall tube would live for a while. How long? I don't know.
Reply:Originally Posted by zapsterTo get back to the original post..There is no such thing as ALUMINUM HEADERS!!Can you say Melt? You guys are unbelievable!...zap!
Reply:Nice try..Those are WATER COOLED manifolds..NOT headers.Next!...zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Originally Posted by debowhy don't my pistons melt? would't the aluminum head melt @ the exhaust port? Everyone said the aluminum down pipe would melt to until someone tried it.
Reply:We did get it wrong one time. We used too hot of a spark plug on a 2 stroke and melted a hole through the dome of the piston.(Wiseco forged aluminum)
Reply:Cylinderhead is a big chunk o metal and contains water jackets. Pistons... several cooling mechanisms at work, heat is transfered to the bores via the rings (there's a trade off h//ere with ring placement), they're exposed to cool intake charge each cycle and in some cases the underside of the crown is cooled directly with oil[/QUOTE]Not to mention the Hyper eutectic nature of the alloys used for pistons enable them to resist forces that would otherwise render aluminum unsuitable for high pressure, high heat applications.Aluminum castings (356) used for exhaust manifolds have far greater cross section than a tubular structure made of .061" 6061. Aluminum is a great conductor of heat, but has a low melting point. Alloying the aluminum with manganese and silicone will increase the melting point and improve mechanical properties, but it will not increase cross sectional area. Cross section can be viewed as a method of buying time for aluminum to dissipate any heat build up. 6061 melts at around 1090 degrees F. What is the EGT of an internal combustion engine? What is the EGT of a turned up, hard working internal combustion engine? I'm sure I could include greater detail here, but hopefully you get the point.A cast aluminum exhaust manifold is not a thin wall tube intended to increase the efficiency with which exhaust gasses are extracted from an engine. They are primarily for saving weight.I guess the point here is that if it were practical to make header tubes out of thin wall aluminum tube, it would be done on a broad scale. Why pay mucho bucks for titanium when easy to weld, cheap to buy aluminum could be used instead?I'm with Zapster on this one.
Reply:Those downpipes appear to be in a drag application. They actually may be a form of aluminized steel, but maybe they are aluminum. The only reason that you may be able to do that is because the amount of time that the engine is making really high temp exhaust is very short and a failure downstream of the turbo would have minimal consequence (unless it starts a fire). That would probably be impossible to do in anything but drag racing.There is a form of marine header that is aluminum, but it is a jacketed aiuminum, water cooled setup. Keith Eickert is the brand and they are a true header, just not the classic "tube" construction.Engine pistons don't melt because they just don't get hot enough. Detonation and preigntion/timing/fuel issues can melt pistons because they increase the rate of heat transfer to the pistons and subsequently overheat/melt them.All in all, I have never seen or heard of an aluminum headpipe/header exhaust for a gasoline engine that isn't water cooled. Model airplane engines do run an aluminum header that is air cooled, but they are a whole different story.Rene
Reply:Originally Posted by debowhy don't my pistons melt? would't the aluminum head melt @ the exhaust port? Everyone said the aluminum down pipe would melt to until someone tried it.
Reply:Originally Posted by zapsterThat's a good question.. But answer MY question..What is the material between the heads and the turbo?...zap!
Reply:I did question what he had told me for a second. But I figured the ceramic coating had something to do with the heat issues so I didn't give it another thought. Yeah.. I got suckered on that deal. As for the finished product, I had to purge the pipe, weld up the holes and grind/sand them back down. Then I stuck my tungsten out 3/4" and slapped a nice cosmetic weld all the way around. Unfortunately I forgot the purge was still on and dropped 80% of an argon bottle on the ground.Common sense in an uncommon degree is what the world calls wisdom.
Reply:just figured I would throw it out there that there are plenty of guys on honda-tech running aluminum downpipes, and exhausts. Some of them have had issues with the downpipes, but I have not heard of one heat related failure after the downpipe/header.
Reply:EGT's can drop significantly by the time it reaches the downpipe. You'll see 1200+ EGT temps at the exhaust ports, but some of that dissipates by the time it hits the downpipe, which also has a much larger cooling surface area. With aluminum, you've also got strength issues as it approaches the higher temperatures, and considerable fatigue issues, particularly with the weight of a turbo setup hanging off of it.
Reply:There *are* ceramic lined aluminum "headers" for lack of a better term. Experiment done by Toyota among others for racing, but it was found that Titanium or Inconel would be just as light. As far as exhaust ports melting, they have on high output air cooled engines. Porsche uses a cast in ceramic insert in the last versions of their turbo air cooled engine.
Reply:1963 Pontiac 421 aluminum headers.
Reply:Originally Posted by debo1963 Pontiac 421 aluminum headers.
Reply:I did manage to find this: HEADERS ARE JET-HOT CERAMIC COATED INSIDE AND OUT IN A POLISHED ALUMINUM FINISH on this site: http://turbochargedpower.com/Turbo%20Headers.htm They seem to be more common that what I had first thought.Common sense in an uncommon degree is what the world calls wisdom.
Reply:Originally Posted by BrainfarthI did manage to find this: HEADERS ARE JET-HOT CERAMIC COATED INSIDE AND OUT IN A POLISHED ALUMINUM FINISH on this site: http://turbochargedpower.com/Turbo%20Headers.htm They seem to be more common that what I had first thought.
