Theres a few tools that are handy; a bandsaw, beltsander, offset grinder with flapper disc and deburring tool. When you cut the tubing it will be full of trash, i roll the outside edge across the beltsander and do the inside edge with the deburring tool. The pics show typical cut and how clean the tube needs to be. Any trash left in the tube can go straight to the engine during a reversion pulse, so the tubes have to be spotless.
You need a good selection of tubing, i get different radius' as well for on good set of headers there'll be tubes inside of others and to do that you need different radius'. A nice thick flange with holes slightly larger than the od of the tube so you can stick the tube well into the flange and that helps hold it in place. Pick a tube to start with - picking the right tube can be a painful process but the hardest part is getting started. When you mark to cut the tube the cut must be square, the shortest possible distance across the tube. See pics 2 & 3, pic 2 with the exaggerated out of square cut will give you a tube mouth that is shaped like a lemon, you don't want that as welding lemons is a pita so makes all your cuts like pic 3. I cut and then true the cut on the beltsander, when cleaning the cut do not remove much material from the edge or it will be beveled and you'll habe a hard time welding because it is so thin. When i get good alignment i make a witness mark on the tubes and go to the bench. I use aluminum foil tape to join the tubes and align the witness mark, then tack. While the joint is still warm i pull the tape off - i use carb cleaner to wash the adhesive off the tubes as it will leave a stain on the pipes when you finish weld - BE CERTAIN YOU LET THAT CARB CLEANER DRY/EVAPORATE BEFOR WELDING it'll give off lethal type gasses if you weld too soon.
Gotta take a break when a buddy stops by to inspect your work and have a snack. The next pic is the tube we tacked on the bech is now tacked to the flange - 2 tacks at the flange, 12 and 3 o'clock will keep it from moving - and joined to the side pipe. Pic 3 shows the hole in the sidepipe for the 3rd header tube, tack that tube in place and it is ready for welding. Start the welds at the flange, when the tubes are welded to the flange then go to the other end and weld the collector, or in this case the sidepipe. With the 2 ends nailed down you can then weld the individual tubes without them moving. I have a vise that i just move around to wherever on the bench, it moved a lot making these pipes. I've been doing it for decades and i have never dropped it off the bench - i have a bigger vise that is bolted if i need it. Weld the seams and joints up and grind to taste - this set is not going on a ridler contender so i just hit the 'high' spots.
Finshing pictures. When making mutiple curves you cut the section of curve you need, don't try to angle cut the tube. I hold the two pieces of curved tubes in my hand and rotate them around until i get the alignment, give them a witness mark, tape them up and tack weld joining them to the fixed pieces. You really don't want to have more than 2 pieces taped. When you make the cuts and alignment the 2 pieces have to fit very tight, you have a welder not a calking gun to fill the gap. Tubing is cheap. Something i didn't show is finishing inside the flange, when the ouside is welded i ballpeen the tube ends inside of the flange opening, i ballpeen them back tight against the flange and run around them with a weld. Making headers is slow work and tedious, a good set will take a few days. The pipes in this example were quick and easy, they were tacked up in 4 or 5 hours and welded complete in another couple hours. Hope you find this useful, thanks oj
OJ, -Did you do the tacks with a MIG welder? -What about final welds? I know guys usually recommend OA welding because the bead isn't too brittle. I've seen them done with a TIG too. But can the final welds be MIG welded? Or are MIG welds too brittle and susceptible to cracking? Thanks!
tig welding usually is prefered, more penetration and less heat, but over time they all crack at some point. The heating, cooling cycle, vibration and stress from the engine and exhaust system all play a factor as does the fitt up and welder. Most all steels header tubing is 18 guage.
Thanks for the tutorial! I plan on trying my first set in the near future. I have the thick flanges and tubes ready. It's intimidating the first time. Cutting and tacking is hard to imagine/start. I will be trying it with a MIG for better or worse. I have the belt sander with a disc on one side and the angle grinder. Need a deburring tool...thanks for that advice.
I tig weld, you can mig weld and mimick the tig doing a 'penny-stitch'. I use 16ga metal but that 'trumpet' section was 18ga and a little thin. I took a few more pics and as soon as i fure out how i resized the other pics i'll post them. As far as cracking etc, that has more to do with how the finished header/exhaust system is supported than how the tubes are welded. If the motor has 'soft' mounts and the exhaust is more rigid than the motor then you'll have cracks.
Great tech OJ. One handy tool to make sure you get straight cuts is easy to make. Take one of the U bends youll be cutting and lay it on a piece of plywood. Screw down some "fences" made from wood scraps to hold the U bend from moving. One on top of the U and one on each side will usually do it. Now remove the bend and carefully measure to find the exact center of the bend radius. Run a screw into the center point and tie a string to it. Now when you put a U bend in the fixture, you can lay the string over the tube and pull it tight. This will always give you a line straight across the tube to make an accurate cut mark anywhere around the bend.
Now, theres a slick method, just make a fixture for each radius and you'll be in business. Heres' a couple more pics, they show how well the tubes came out with just a minimal touch with a flapper disc. This is a customers' car and cost is a gorilla in a small room here - these could have been stainless with flawless finish but they are not. What these are is what you guys can make and this is how they'll look.
Nice job! Any pointers on the weld where it gets tight? Longer tungsten? More heat? More filler? Higher cover gas pressure? Thanks.
In tight spots I usually add some additional shielding around the weld area, tape or cardboard and then extend the tungsten and start the argon flowing without striking an arc and hold the torch such that the gas quenches the to be welded area then strike the arc and go at it. You can also buy extended weld cups that work but adding a little shielding and then quenching the area with argon before you strike the arc works for me. Rex
Good question. To do the tight inside i have high heat anyway, the argon is 6lbs, and i'll extend the toungsten a little. I use the mass of the metal to control the heat, the lower tube is thicker (the upper tube has been gound to fit and the inside edges are thinner) so i get the lower tube hot enough to 'park' a blob of metal and then 'pull' it around with the heat and i also make short arcs with the tip to move metal from the low tube to the upper tube. These pics might help explain: the first example is a square cut butt joint, the tubes are cut square, cleaned and tightly fitted - you don't want any air gaps. The first 2 pics show the prepped tube, ready to be taped together; 2nd pic is the tubes tacked. The 3rd pic is the weld seam on the joint, i have left it high. The 4th pic is where i have made a 2nd pass over that seam and the seam is about gone, i hate grinding. The 5th pic is where i finished welding the tube by fuzing them together, no or very little filler is used. The stain to the left of the weld is from the tape, i didn't clean the adhesive off the metal from the tape so that you can see what happens.
This set shows the welding inside an angle, i didn;t make a severe angle because it would be hard to show the technique. For those of you doing a roll cage this is done a million times for the diagonals. The first pic shows the angle of the tube in a vise so you can work it with an offset grinder, fishmouthing can be the subject of another thread and there is a lot of technique involved. The 2nd pic is the trial fit - it has to be tight. The 3rd pic i have it tacked and the typical length of the toungsten is shown. The 4th pic i have made the electrode a little longer (if the angle were more severe i would make it longer yet, you can go out quite a ways, 3/4" or so. I have tried different lenses etc and they just block your vision). If you look past the electrode you can see that i have 'parked' some metal from the other side, while the metal is nice and hot i begin at the metal and 'pull' it around. The 5th pic is where i have pulled it around. And completed the weld in the 6th pic. I want to point out that my heat is much higher than you'd think, around 125amps and i work very quickly. I used to do it at about 50-60amps and try to be more fussy with the weld appearance. Since i have only one eye working i have given up on 'pretty' welding as my electrode is in the puddle about half the time and now i focus on doing the weld with the least amout of effort and work. Thanks oj
For the tight spots on headers or roll cages I use a gas lens on my tig torch. It replaces the standard collet holder and cup. It has a built in screen that creates a long column of argon that allows you to extend the tungstun 3/4" out of the cup. They should be available at any welding supply house.
One tip for us cheapskates is to look at rough used headers for flanges. They wanted 75 bucks for the 2 flanges. I bought a used set for 50 bucks and recycled the flanges. A trip through the bead blaster and they were as good as new. Enough for a couple of U bends. I have more time than money.
They are dirt cheap and will move some metal, i have used them to go to the next hole size on thin aluminum - just whittle a bigger hole.
Nice headers! This thread reminds me when i was fabricating upsweep pipes for my shovelhead few yrs ago.. I bought a DIY header-kit for that upsweep project.Those DIY pipes looked like pretty much same than the stuff you have used.
I learned to braze them, as you suggest, thinking the brass would support the headers better. The problem was if they cracked then you can't come behind the braze and tig weld - i don't think you could mig either. I think some of the oldr books reccommended braze but i haven't seen that done in a long time.
We are building a set of headers right now and I can tell you it is a lot more work than you can ever imagine. The fitting and checking and rechecking is what takes the most time. Not to mention a zillion trips to the belt sander to take a bit off and then trying it for fit once more. It is a game of fractions of an inch. Now I see why headers are not cheap to buy. Don
I tig weld my headers with a Gas Lense, also i use 1mm tungstens which do a much better job. Regarding the cracking issue i havn't had one crack since i started tig welding them, not so brittle. I also weld my flanges on the inside, looks neater.
Just built a set for my 455 Buick. Couldn't find used flanges or order from the normal places, so I ordered a set of flanges from Noxious Customs off the web. They were thicker than most flanges, which made them much easier to weld, and they fit perfect. Price with shipping was really reasonable, less than a set of used headers.
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