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Rat Rod Nation builds => Rat Rod Tech Tips => Topic started by: miraclepieco on January 27, 2013, 01:03:32 AM

Title: Mandrel bent - just say NO!
Post by: miraclepieco on January 27, 2013, 01:03:32 AM
Another tech tip for keeping the RAT in RAT RODS:

As you know, I've been rebuilding my entire exhaust system from the heads back. If you consult any forum or body of experts, they will insist that you use "mandrel bent" tubing. Mandrel bent tubing is a constant diameter throughout the curvature of the tube. This makes it flow better as well as making it far easier to cut and weld sections together.  Of course mandrel bent tubing is much more expensive and harder to obtain. You probably can't find it at AutoZone.  However, if you don't use mandrel bent tubing, all the experts will turn up their noses at you.

Rat rods are works of art that break the rules. We build things cheap and we improvise. If street rodders are using mandrel bent, that's the LAST THING I want on my car.  So when building my headers and exhaust I specifically chose CRUSH BENT tubing. I was able to get it quickly and inexpensively from a neighborhood muffler shop, but it's also available at most any auto parts store. But the problem is, I needed to make some compound curves in my system, linking multiple curves together. How can you do that when the curves of crush bent tubing are smashed into oblong shapes? In the pics below you can see how the crushes elongate the tube so the end don't align.

No problem: just cut the tube where you want it, then whack the tube end with a hammer on its tall side. This will force it back round again. Also do it to the tube end you are welding it to until both are the same shape and can now be welded together.  The last two pics are of the sexy curve I made to match my tailpipe up to my stacks using this technique on crush bent tube.

Title: Re: Mandrel bent - just say NO!
Post by: lowboy on January 27, 2013, 06:50:01 AM
very kool i've been thinking about side pipes think ill go with the crush bends too 8) ;D
Title: Re: Mandrel bent - just say NO!
Post by: hotwheels on January 27, 2013, 07:32:06 AM
Hell yea, great tech tip.......
Title: Re: Mandrel bent - just say NO!
Post by: coony278 on January 27, 2013, 09:11:49 AM
Ahh man now you made feel bad , I used my bender to bend my headers and it doesnt crush bend , oh well guess mine will just have to lean towards hot rod. LOL that will never happen


 Great tip , it looks great !
Title: Re: Mandrel bent - just say NO!
Post by: Greybeards Customs on January 27, 2013, 01:46:14 PM
You can't go a single day with "bucking" the establishment  ... LOL !!  You are a man on the low cost mission ..... Good looking work .
Title: Re: Mandrel bent - just say NO!
Post by: miraclepieco on January 28, 2013, 12:31:43 AM
Ahh man now you made feel bad , I used my bender to bend my headers and it doesnt crush bend , oh well guess mine will just have to lean towards hot rod. LOL that will never happen

I'm sorry, I never intended to make anyone feel bad - I love your headers made from roll bars! I really wanted to encourage low-buck rodders to feel proud about their work and their cars against the onslaught of snobs who insist that one must use certain parts to be cool. To me, a rodder is coolest if he uses his ingenuity to devise a unique, low-cost solution - like you did!

You can't go a single day with "bucking" the establishment  ... LOL !!  You are a man on the low cost mission ..... Good looking work .

I do call myself a "militant" rat rodder!