@Pist-n-Broke, I like your thinking on welding just the inside of the tubes to the flange. I built some fenderwell Corvette headers that I brazed the outside of the tubes to the flange, after they were welded internally, as you say. I was going by some old thinking that the braze was supporting the tube better, and the brass acted like a shock absorber. They never leaked and actually looked pretty good with the fillet of the brass. Probably just an unnecessary step. I'm currently working on a lakes style, banger header. Stainless (304) with a megaphone. The material that I got for the cone is 16 ga. The bends that have the desired large radius are 18 ga. I can buy the bends with a tighter radius in 16 but have not found just what I'm looking for in that thickness. What do you think? Is 18 ga. sufficient? I realize that there is only .012" difference in wall thickness, but where do you draw the line?
I try at all times no matter the metal work not to mix material thickness. Have you shopped the S.P.D. Exhaust sight for what you need? On a low compression motor like a Banger 18ga. is probably just fine for it all. I'm assuming you rolled your own cone. I probably would have bought the S.S. sheet material in 18ga to match the bends.
I'll also throw this into the Hat. If you plan to put a Show Polish on your headers for looks and want them to stay that way and not turn Gold have them extrude honed to clean up the welds inside, then do a Ceramic coating just on the inside.
@Pist-n-Broke, Yes, I agree everything should be the same gauge. I just wanted confirmation that I was not overthinking it. Looking at the S.P.D. Exhaust website, they have exactly what I was looking for. In fact, they have a bend that might be even better than the one I had anticipated using. A little more measuring is needed. Glad you mentioned the ceramic coating for the inside of the pipes. I asked about it in post #26 in this thread. I'm assume that it would be best to polish everything before welding and then just having to repolish the HAZ after. When you weld the primary tubes inside the flange, do you purge the tube. Seems that the gas from the torch would be sufficient. I've read that coating the inside of headers really keeps the heat inside, which will be good for the big pipe running along side the body. (kinda like the Spaulding Bros. recreation that @Marty Strode built)
What we've learned about inside coatings is it extends the life of the pipe a ton. I have a customer with the same headers on his car I built over 20 years ago, and they are still airtight. That speaks pretty loud to me. Being I have caps with air fittings on them for pressure testing I do put 4 cf of argon into the each primary when welding the flange ends, sometimes even on the joints. I tend to do that on all tubing I weld. Cheap insurance especially on CM chassis stuff. If a guy is just Mig welding, it's probably a waste of gas. When it comes to polishing it depends on what's going on with each tube. Something real complex I would do each section pre weld. If it's kind of a strait run not so much. I also have a local shop that has a media tumbling tank that does wonders. Beats the heck out of a Buffing wheel, no stripes, no missed spots and you never run into the Nut on the end of the shaft.
Yeah, the guy that does my ceramic coating tumbles also. I'll give him a piece of ss tubing to experiment with.
Pist n Broke.... I'm going to have my headers ceramic coated when done. I want to make sure I understand. You recommend also ceramic coating the inside as well? Any idea how that is applied to the inside? Any idea of the cost? Are you involved in this for a living? Thanks for your input
Coop46; Yes, coating the inside reduces the heat saturation of the tube. This is what causes the S.S. to turn Gold. Lower heat, less discoloration. Works on Chrome plated pipe also, minimizes the amount of Blue. Cost is directly tied to length of pipe being coated. You do know the material used is a liquid, right? It's sprayed on the outside. I've been told it's poured through the inside to coat it there. No, I am in no way connected to any Coating Company except through my Wallet.
Got it. Figured it was sprayed but was wondering how they did the inside with out missing spots. I originally contacted jet coat and they gave me a price of 695.00. Just sent an email to see if the inside was included. Do you know who the gold standard vendor for coating is? Thanks again! And I hear you on the wallet connection....that's always the big one!
I don't know of a Gold Standard one to go to. I know $695oo sounds like a lot of money. When I think of what it would cost me to pay by the hour to build any good header system the coating cost seem like pocket change. I just know how it gives them a good long life and move on. I have sent plenty to Jet-Hot and been pleased. I will say their application has improved over the last 20 years. They have 2 plants, so shipping isn't bad. They always met the turnaround time for me. I'm lucky enough to have 2 choices in driving range and when dealing with Hand built anything, shipping is a big concern. I like standing face to face and shaking hands. Most all Ceramic coating product is on a level playing field, it's the application that seems to very. What I will tell you is I never install new coated headers on a brand-new motor that hasn't been run in and tuned. Most of my motors get fired and run in on a Dyno so the Tune up is spot on. A fuel lean or timing way off while doing a Cam run can damage the coatings. High Exhaust heat is the devil for the coatings and no coating company is going to stand behind your screw up. If you're going to do a first run-in, do it before coating the new exhaust. You'll be a lot happier. Any of the company's doing coatings will tell you their heat range. When you light it up with the new system on have a pyro gauge on hand and check each tube often till at total operating temp.
Don't care how cool they look....It is about increasing performance....If they don't do that then might as well leave the stock manifolds on them....
My headers are done and ceramic coated.....glad I built my own. Came out just like I wanted. Thanks to the guys who nudged me to build my own.
See there, we knew you could do it. Glad we convinced you. Next time you won't even hesitate. Yes, well done.
Thanks Man....when you first mentioned it I was like... what? Glad you nudged me and glad I saw it thru!
It might be much easier, and cheaper to find existing headers that have similar tube spacing, and simply chop the flanges off and weld on flanges for your little hemi. I've done this a couple times on builds and it makes building them way easier. I bet a set of BBC headers would be very close spacing, and easy to modify. Might consider the cheap Tri Five fenderwell Patriot headers that Speedway and others sell.
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