Technical Fabbing headers at home. A few questions, best place to buy bends & and tips for best outcome.

Hell yea a good deal the collectors are almost worth the price of admission.

The headers on the Raven's roadster now ere made from a 15 dollar set if swap meet headers. They don't resemble the headers we started with at all and they certainly are not very scientific but they work real well, well enough that we had to richen the mixture which is what you are after, more or less.

If looking for swap meet headers I prefer either circle track headers or fender wells, if going circle track I really like offset chassis headers. they seem to have more then enough metal to work with.

 

I do headers often and use a bandsaw to make the primary cut, a belt sander to clean the cut and like P&Bnr I deburr the inside because when you fire the engine there'll be reversion and you don't want that trash getting sucked back into the cylinder. The tubes have to be very clean inside and out.
When figuring how to make a cut just figure the shortest possible cut across the tube, you don't want an angle cut or it'll be lemon shaped and won't mate right. You need to make the tightest fit possible, if you have a gap when welding the metal will move to fill that gap and you can't let the pipes move at all. I tack up one tube to the flange, then start the next tubes. I use that aluminum duct tape to hold 2 pieces together long enough to tack, I'll fit them and take them out to tack in a vice all pieces lift loose until everything is ready for tack.
I tack all tubes at the same time, I don't do complete welding on any tubes until I have all of them tacked - that helps to make them 'captive' and help minimize movement. The tubes can shift like crazy, you have to plan your welds so that the tacks etc work in your favor.
A couple pics of a set I just made, the drivers' side pic show the first tube welded to the flange and lakepipe, the 2nd pipe is tacked and setting in place, the 3rd pipe has been fitted and that aluminum tape I spoke of barely visible around the back side of the seam. That tube is ready to pull out and get tack welded. You can see how tight the seams need to be.
The other pic is the passenger side pipes going thru finishing.
Good luck.

 

Oj let me add to your post just a little bit, if I have two tubes that land to close together to get completely around the weld joint I make that joint up then install the tube. Think siamesed ports here. Then I install that part of the tube and work toward the collector taking as I go.

Listen to OJ here plan everything out ahead of your work and "THIMK" you don't want to paint yourself into a corner.

 

Lots of great fab work and advice. Thanks, fellas. I'm a few weeks out from starting this, but will report once I do.

Now, any primer threads on gas welding for dummies?

 

Tim, it was around three years ago and I do not have the members name any longer nor do I know if he is still a member on here after the upgrade.

 

Tim, I searched for this portaband saw article but could not find the one I was looking for, however I
did find one from Tudorfritz out in western NY that made his own and he may be able to share this info. Here is a pic of the one he has which is a duplicate of the one I use but with a Milwaukee unit. Hope this helps........Walt


Mine has a piece of L channel bolted to the bottom so I can clamp it in my vise.

 

Take a look at what http://www.hellsgatehotrods.com/ Has to offer. they sell several different kits and or individual bends.

On the mig vs Tig you can always think about tacking the headers together at home with the mig and when you get them the way you want them taking just the headers to your buddy's shop to weld them up with the tig.

 

Thank you very much. Yeah, I could fab up a table like that. Hhmmmm.

 

Great idea and what I think I would do. Plus, I've been itchy to do some TIG welding so this would be as good a time as any.

 

I gas weld, but there's no easy way to learn. Practice, practice, and more practice. Don't practice on your nice cut header tubes.

 

Get a pair of rt & lft avation snips and weld extentions to the handles for leverage. These can be used for minor trimming, then just a light kiss on the flat sander to square. anytime you use a flat sander on tubing it is imperitive to clean the tube inside because of the sanding slag imbeded into the material

 

To expand on Bruce's post above, I took about 5 minutes to show you what you can do with aviation snips. They work very well on "saddle joints". I didn't use the belt sander until the 5th photo. Another trick I use on butt joints during mock-up and tack welding is, using a stainless hose clamp to hold the joint together, drill at least two 5/16 holes on the center line of the clamp 180 degrees apart, for tack welding the joint. I didn't take the time to drill the holes in the clamp, but you get the idea. You can use a Harbor Freight step drill to make the holes.

 

If it hasn't been said yet...

Buying quality bends is worth it. If the tube is truly concentric through out the bend, it makes fitment much easier.

Also when doing headers, the portaband set up with a small table is clutch.

If the tube isn't perfectly concentric, it can be squeezed into shape. If worse comes to worse, small, and I mean SMALL, cuts can be made in the tube to pry it back into round, then weld up the relief cuts and deburr.

And I'm sure it's been covered, but if you're going stainless, purging is a must.

 

I don't know if anyone has mentioned this yet, but when you cut your bends to attach two pieces of tubing, always make your cut 90 degrees in relation to the spot where your cut is. In other words, always cut straight across the tube, not at an angle, the shortest cut possible. Doing this will insure that your tubes will match up the best for welding, and your bends won't have kinks. Hope that makes sense.

 

If you want to build 'em one time and forget it.....
http://www.burnsstainless.com/

 

Wondering what gauge every one is using? I am just getting ready to order up some bends and planning to use 18g. for the lighter weight.

 

I have used 16 gauge but I normally don't spend the money on it so while you are looking to save an ounce or two I am usually looking to save a dollar or two.

 

I bought one of these from the fab guys in NC. It literally changed the way I do things. Actually bought two more for friends. Highly recommended!

 

Couple of things to think about. I've bought a couple of boxes of the "Economy" pipes/bends. They were all different wall thickness and not all mandrel bent. Not really good for something you want to look right and last.

BTW, thicker is better. Easier to work with, lasts longer.

 

Flux core MIG will work, but it will be ugly and full of pin holes. Solid core MIG with gas will be cleaner. TIG will be even better if you're good at it. I've done flanges with MIG, but welding the bends ends up with a lot of grinding and re-welding to get rid of pinholes. I'd rather the TIG or gas.
The only tube benders good enough for headers are gonna be big, expensive hydraulic mandrel benders. That's a big investment unless you're building a few sets a week or something.

 

Marty just noticed your post. Good idea the wholes.

Makes me chuckle I once went to a friends house and he had both pipes for his bike held together with hose clamps he wanted to make sure that they were going to fit prior to welding.

 

I usually draw the curves I need in CorelDraw then I mark the tubes using a little fixture I built- squaring the tubes up on a disc sander. By drawing them first, you can get the joint right in the middle of the curve, makes matching the diameters easier. Tight joints are a must.

 

That's tits! Do you use the angles on the 'shoe' to center the tube?

 

Damn, another cool idea I'll forget the next time I go to do something

 

I've used the hose clamps with holes drilled in them too, can really be a help.

 

I agree with virtually everything that has been posted here. The last set of headers I built were from bends I purchased from Chassis Shop, which were stainless steel mandrels. I cut them on the metal bandsaw and deburred them with a 12" disc sander. I tacked them in place with a MIG with stainless wire, then did the full welding with a Miller Synchrowave 250 TIG. I couldn't imagine MIG welding a complete header. Which is not to say it couldn't be done, but it's certainly less than optimal. That being said, the bends will cost a small fortune, plus more time of yours than you can imagine, so if you can buy/modify a set of headers that are already made, it will be well worth it. In my mind, fully fabbing a set of headers is a last resort when you can't find something to fit, or if you have a performance or aesthetic objective that is paramount and time/money are no object.

 

I made these headers for my midget a few years ago. Most important tool was the band saw and the tubing notcher. These were gas welded. Instead of using random bends I used some 1.5" diameter donuts which I cut on the bandsaw to get the amount of curvature you need . Good for tight bends and consistency.

 

Part of my bend supply.