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Thread: tips for custom headers
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08-31-2006 #1Registered User
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tips for custom headers
i gotta question for any of you who have made there own headers or have seen it done. i wanted to know if you guys have any tips to make it easier or cleaner. i can tig good beads, laps, and t joints, but i tried welding an extra piece of exhaust i had lyring around to a flat piece of steel, and well it wasnt so great. i had to keep turning the plate and stopping my beads, of the 2 or so inch diameter pipe, ide say theres a good 1/2 inch of decent bead. how do you guys do it and make it look good?
67 Camaro SS 383 this winter. squeezin by summer.
97 camaro Z28 30th anniversary bolt ons.
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08-31-2006 #2how do you guys do it and make it look good?
but i tried welding an extra piece of exhaust i had lyring around to a flat piece of steel,
Some tips:
For butt welds, grind your tungsten to a very sharp point. Say around 20º and don't put a flat on it. That will widen the puddle and give you better directional control. It will also lessen penetration to a slight extent.
What size tungsten are you using? 1/16" tends to be best on the butt welds, but I'm finding that 3/32" 2% Lanthanated works well on everything. Its only fault is that it can be hard to start.
What size filler were you using? .035" works best for most people on the butt welds, and maybe .045" on the fillets.
If you have a pulser, use it on the butt welds. Try 50-75pps, 75% peak time and 10% background.
Don't try to go further around the tube than is comfortable. Lots of well done starts/stops looks a lot better than long but shaky welds.
To improve dexterity, at night when watching TV or whatever, spend 15 minutes with a 10lb dumbbell. Move it in a hap hazzard fasion...pretty hard to describe here. Roll your wrist up, down, side to side and radially. It looks stupid but it works.
If you're building stainless headers, purging the tubes is a MUST. The picture I attached is of 2"x.065" 304 tube, butt weld with no edge prep, and purged.
If mild steel, sand off all mill scale within 1/2" of the joint. This is not optional. And don't grind it off as it's too easy to get the tube too thin and drop through unexpectedly when welding.
Consistent, full pen welds are a must. As much expansion and contraction as headers go through, any stress raiser is a bad bad thing.
There's three schools of thought concerning how to weld the tubes to the flange. 1) Weld all the way around. Critics say this over constrains the tube (especially with stainless) and will create cracks over time. Proponents say it's more support for all that weight hanging off the flange. 2) Run two 1/2"-3/4" welds top and bottom. Basically the opposite arguments of #1. 3) Braze. Proponents say that brazing moves with the tube as it expands/contracts but still gives the gusset effect of an all around fillet. I like #3 but never do it simply because I have no desire to learn how to do brazing. I've allways used #2 and have good results, although #1 is done by a lot of well known header builders with good results too.
Make yourself a fixture for cutting the U-bends. Look at the second attached picture and I'm sure you can figure out how it works.
Do it right and form the first tube to match the profile of the port. Don't just leave it round and weld it to the outside of the flange because it's easy. You need to make a male mandrel out of wood or metal that matches the port in the flange, minus tube wall thickness. The goal is to form the end of the tube so the mandrel you made just slides into the tube the distance of however thick your flanges are, minus 1/8". That will leave you a lap weld on the inside of the flange to weld the tube to.
There's lots more but that's all I have for tonight.
-Matt
Welders: The only people that think a co-worker catching on fire is funny.
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08-31-2006 #3Registered User- Join Date
- Jun 2006
- Location
- rochester, NY
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- 12
Originally Posted by Matt@Lateral Dynamics
Awesome help! im definately going to do a lot more practice before i start making my own headers and using em. like you said if im gonna do em, i gotta do em right.
and lastly the welder, and all the steel i use etc. is supplied by my school. can i get a good/decent tig welder under 2 grand? (i browsed some other posts and that seems to be about what im gonna spend) Im a college student so money isnt exactly something i have much of right now.67 Camaro SS 383 this winter. squeezin by summer.
97 camaro Z28 30th anniversary bolt ons.
08-31-2006 #4For future reference, in the reply screen, you'll see a quote bubble looking thing in the grey toolbar. Click that and it'll write the quote code for you. This is a lot easier for posters after you that want to quote you. (Like me)
For clarification, when I say to grind your tungsten at 20º, that is the included angle, and is very sharp. Just 20º from having no grind at all.
If you want to spend less than 2k then you're not going to get a pulser, but I'll explain anyway.
The pulser does just like it sounds: pulses the amperage output. Variables are:
PPS (pulses per second)
Peak time - The time the arc spends at full amperage within one pulse. A percentage.
Background amperage - The amperage output whenever the cycle is not at peak amperage. A percentage.
So my example above would be 50-75 pulses per second. The arc would spend 75% of its time at peak amperage within one pulse cycle, and it would go down to 10% of peak amperage for the remainder of the cycle.
Pulsers are NOT for making welds "pretty". They are for lowering overall heat input, although in some cases they can be used for autogenious (fusion) welds on stainless.-Matt
Welders: The only people that think a co-worker catching on fire is funny.
09-01-2006 #5