Guest Anonymous Posted November 18, 2001 Share Posted November 18, 2001 Hey guys, has anyone tried heating a header and bending it? I want to get a little more clearance with mine and was thinking about heating all the tubes and tweaking them in just a bit. Anyone ever try that? Jon Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 18, 2001 Share Posted November 18, 2001 Nope, haven't tried it but I'd like to. I have a MAC shorty header that according to the prevous posts by scca and others will wind up pointing directly into the firewall. I don't have the motor in the hole yet but I suspect when I do I'll be disappointed by my plans on using the header that I have on my donor Mustang.... -Dan used Dynomax block huggers which cost $200 Canadian...quality questionable... -SCCA used ceramic coated flowtechs...happy with them? Where did you get them in our fair country? _Firebern used passenger manifold from 1964 Comet (how easy is that to come across) and a driver's side F150 manifold... _HP tech tried FRPP street rod block huggers in an old post...(still out there HP tech??...still working on this project or did you give up?) _Alsil says in an old post that you can use Hedman or Hooker block huggers...has anyone done this? _Comments appreciated by all Quote Link to comment Share on other sites More sharing options...
ZROSSA Posted November 18, 2001 Share Posted November 18, 2001 I may be way of the wall here but I had a conversation with a old employee of mine years ago who said he made motor bike headers buy getting the length he wanted and then sealed the ends after filling them with sand, then heated and bent them to the shape he wanted. It seems remotely possable if you took great care in the bending process to not crimp the tubes. i wonder how the F1 and Indy guys make there headers? Thre doesnt seem to be any joins. Douglas Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 18, 2001 Share Posted November 18, 2001 this is the basic process for doing sand bends on headers 1 weld a piece of scrap pipe of the same diameter as the headers to the end you want to mount in your vice. 2 Then use a coarse sand (the finer the longer it takes to fill), plug one end with a ball of moist newspaper, then start syphoning sand into the headers. Do a kilo or so at a time and gently tap the sides of the headers with a soft piece of wood like pine to settle the sand properly. Continue that process until you cant put anymore sand in. Then get a second ball of paper and hammer it in so it cant pop out. 3 Mount the headers in the vice and clamp down hard, (this is why you weld extra pipe on because it will be distorted badly). 4 Heat the area at which you wish to bend until bright red and apply moderate pressure in the direction you wish to bend, all the time keeping the heat on it. (If you have to put a heap of pressure on it to bend the metal it isnt hot enough, and you will be stretching and weakening the grain to much). Keep going until you get the dessired result. (You can change the direction of the bends in the tube within an inch or two of each other if the heat is applied in the correct manner). 5 Once the desired result is achieved cut the scrap pipe off and remove all of the sand. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 18, 2001 Share Posted November 18, 2001 Thanks for the info. BTW I have Hooker Blockhuggers. Jon Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 18, 2001 Share Posted November 18, 2001 Nice post robZilla. Thanks. Quote Link to comment Share on other sites More sharing options...
ZROSSA Posted November 18, 2001 Share Posted November 18, 2001 Good on ya Robzilla, How good a bend can you get? Can they be made as good as mandrel bends? This could make getting equal length header much easier. Cheers Douglas Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 20, 2001 Share Posted November 20, 2001 Thanks guys, The bends can be as good if not better than some forms of mandrel bending, ie. it doesnt shrink the diameter of the tube where its bent as some mandrel benders do. But it does take some time and practice to get the technique right. I've only done a few practice bends on scrap pipe, after my wood work teacher (long story) showed me the basic procedure. I've just found an old article about it as well, it sais to tap the sand down after each bend as it gets loose again and push the paper wad down further, if you dont you may get ripples in the pipe. Also it sais to use dry sand, which i didnt worry about but had i though about it i would have, because you dont want a build up of steam blowing the wad out and spraying red hot sand down your back! The guy doing the bending in the article used a piece of wire bent into the basic shape he wanted as a template as well. Quote Link to comment Share on other sites More sharing options...
Owen Posted November 20, 2001 Share Posted November 20, 2001 Sounds like something I'd like to try one day! Can I use a propane torch to heat the pipe? BTW, I have Hooker ceramic coated block huggers too. Tried the Dynomax block huggers first but found it impossible to screw the spark plugs in. Owen Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 21, 2001 Share Posted November 21, 2001 I also used the Hooker block huggers and had the same issues. I cut a wedge of material out of the inside of the radius on all four tubes and bent it over and rewelded it. A little time with the grinders and you can't see the change from either inside the tubes or out. Works great. GrinZ Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 21, 2001 Share Posted November 21, 2001 You can use whatever gas/fuel you've got but LPG/oxy mix is best as its cheaper than oxy/accetelyne, and heats the metal fairly fast, Its all i use for cutting and heating, I only use accetelyne for welding, also use the biggest tip you can get (preferably a big cutting torch) as you have to heat a wide area and keep it red hot whilst bending. Quote Link to comment Share on other sites More sharing options...
Guest JAMIE T Posted November 21, 2001 Share Posted November 21, 2001 Hmm. I have heard of doing this before. Do you think it would work with thicker tubing(i.e. Roll bar tubing) 1 5/8" .125" wall thickness? I'm thinking to use one of those Northern or Harbor Freight hydraulic tubing bender, fill tube with sand, heat and bend. sounds like it should work O.k. Jamie Quote Link to comment Share on other sites More sharing options...
jeromio Posted November 21, 2001 Share Posted November 21, 2001 Don't get the regular hydraulic bender. You can use that to make slight bends, but nothing over 30 degrees or so. After seeing this site, http://www.blindchickenracing.com/tools/Tube%20Bender/Tubingbender.htm, that someone here posted, I really wish I'dve done something like what these guys did. That link they have to ProTools has lots of nifty stuff. Roll bar tubing, at least the thick wall DOM stuff that I got, is VERY expensive. Kinking it SUCKS. What I've done is to buy some 90 elbows that I'll spot in place and then get my friend to Tig in properly once everything is all setup. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 21, 2001 Share Posted November 21, 2001 You should have no problems bending roll bar tubing, as long as its hot enough it should bend no worrys, getting a mate to keep it glowing red whilst you bend it should make the job a bit easier. The guy in the article i found said that when he begun his apprenticeship with the navy he helped bend 12 inch pressure pipes with wall thicknesses of a quarter inch . Using an oil burner for the heat and block and tackle to apply the bending pressure, they also had to make them accurate enough that with multiple bends they would match up to flanges at either end, so anything is possible i guess. Quote Link to comment Share on other sites More sharing options...
jeromio Posted November 21, 2001 Share Posted November 21, 2001 I'm not a metal expert, but I would be somewhat worried that heat bending rollbar tubing would weaken it somewhat. When I talked to my welder friend about the troubles I was having (cold) bending the DOM tubing, he suggested buying the Els (the 1 3/4 ones for the truck were on sale, and the 1 5/8 for the car were not - WAY expensive). So I said, Great, then I can just weld 'em up - easy. And he said, With your Mig? No. You'll heat up the metal too much and weaken it. Spot them in place, then bring them to me and I can do such and such and mumbo metal so and so or something. Anyway, he knows what he's talking about and I don't. Next time I see him I'll ask him about this hot bending thing. Quote Link to comment Share on other sites More sharing options...
Guest JAMIE T Posted November 22, 2001 Share Posted November 22, 2001 How does SCCA/NHRA, etc... feel about welded Els. I don't think they allow such things. They also prohibit grinding of welds. Thats why chassis shops have got you by the cojones. I have 1 5/8" DOM that I will take to the chassis shop to have them bend it. The guy said to bend a piece of brake line to the shape I want and he can bend it(the DOM). I am a welder by trade so I will weld it in myself. Jamie Quote Link to comment Share on other sites More sharing options...
Z-TARD Posted November 22, 2001 Share Posted November 22, 2001 Heating the pipe to bend it should not weaken it appreciably provided that you dont get it to hot. If it goes beyond red hot and starts turning yellow, carbon molecules begin escaping out of the steel, you can tell when this happens because the steel will have a boiled look to it when it cools. As far MIG vs TIG for heat input, Tig welding puts a far greater amount of heat into the metal being welded because of slower speed at which it welds, and because of the polarity used. TIG welding has the negative terminal going to the electrode (torch), and the positive going to the metal being welded, this places approx. 70% of the heat generated by the current into the metal being welded. MIG uses the opposite polarity, placing most of the heat into the weld wire, which is why it burns up so fast while welding. Either method can be used for roll bars, although TIG, if done properly will look a lot neater, and will normaly be much stronger because it penetrates more deeply into the material being welded. Just my two cents worth. Quote Link to comment Share on other sites More sharing options...
Z-TARD Posted November 22, 2001 Share Posted November 22, 2001 Heating the pipe to bend it should not weaken it appreciably provided that you dont get it to hot. If it goes beyond red hot and starts turning yellow, carbon molecules begin escaping out of the steel, you can tell when this happens because the steel will have a boiled look to it when it cools. As far MIG vs TIG for heat input, Tig welding puts a far greater amount of heat into the metal being welded because of slower speed at which it welds, and because of the polarity used. TIG welding has the negative terminal going to the electrode (torch), and the positive going to the metal being welded, this places approx. 70% of the heat generated by the current into the metal being welded. MIG uses the opposite polarity, placing most of the heat into the weld wire, which is why it burns up so fast while welding. Either method can be used for roll bars, although TIG, if done properly will look a lot neater, and will normaly be much stronger because it penetrates more deeply into the material being welded. Just my two cents worth. Quote Link to comment Share on other sites More sharing options...
jeromio Posted November 22, 2001 Share Posted November 22, 2001 Well, as I said, I ain't gots the knowledge. Just something to look into and be aware of. Also, my understanding (again, obviously incomplete and potentially flawed) was that the key to Tig was the tungsten electrode, not the polarity. For instance, I can very easily switch the polarity on my Mig. I'm sure that changes the properties of the welding, but in my limited experimentation with this, I couldn't tell. But either way it wasn't tig welding. I agree, the welded Els are not the ideal solution, but I am confident that the end result will be strong enough. This welder dude is crazy anal retentive. Has an almost unhealthy attention to detail. And I may have also misconstrued what his point about the Mig weld strength issue was - I kinda glazed over as he went into detail. Hell, it may have been as simple as he didn't want to have me pull up to his shop with the completed cage and have to look at my ugly welds Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 22, 2001 Share Posted November 22, 2001 I'm not sure I agree with better penetration in TIG welding. Even thin sheet tig'ed doesn't get as good a penetration as gas welding or even mig with a spool gun. Tig has the advantage on sheetmetal of having a very small heat affected zone which means less warpage. Mig is up from there, and finally gas welding which does affect about 4-6 times the area from the heat of welding it than mig or tig. If a guy has access to a large tig, and has the time to do the seams (it'll take quite a while) and is skilled at tig welding then its a good way to go and of course looks beautiful, but mig'ed it'll be nearly as strong (way over the task asked of it) and much faster. For thicker materials thats how I'd do it anyway, but thats my opinion and only fits one model. Me. Regards, Lone Quote Link to comment Share on other sites More sharing options...
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