Register now to get rid of these ads!

Hot Rods header dent removal

Discussion in 'The Hokey Ass Message Board' started by RmK57, Jan 1, 2015.

  1. RmK57
    Joined: Dec 31, 2008
    Posts: 1,826

    RmK57
    Member

    Has anyone used the heat and compressed air method of removing dents?
    How much air pressure would be a good starting point?
     
  2. Slopok
    Joined: Jan 30, 2012
    Posts: 2,659

    Slopok
    Member

    How about a welded stud puller?
     
  3. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,101

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    I don't think using compressed air for that is a feasible method, for several reasons.

    Either the dent puller mentioned in the above post....or heating the dent and shrinking it with a wet rag might help.

    Ray
     
  4. RmK57
    Joined: Dec 31, 2008
    Posts: 1,826

    RmK57
    Member

    Why wouldn't it be feasible? There slip together headers so I can work on a single tube at a time.
     

  5. SicSpeed
    Joined: Apr 23, 2014
    Posts: 653

    SicSpeed
    Member
    from Idaho

    I used to build my expansion chambers for my 2 stroke race bikes.
    Every once in a while a pipe would get smashed or dented. I have used air and heat. A rubber pipe plug on one end and I made up a plug with a Shrader valve. You only need a little heat, not cherry red or you can blow a hole or cause a bulge. Depending on the dent, mild dent I would start at 15 to 20 lbs. I have used much more ( 50)but I didn't feel safe . Heat at the crease. And wait a little before more air and heat. I made the pipes with 20ga and used a .000 welding tip
    I used a .00 for dent repair. An auto header is thick so maybe a 1 or .0
    tip. Take you time and don't hurry.


    Posted using the Full Custom H.A.M.B. App
     
    26 roadster and loudbang like this.
  6. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,101

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    Well, I'm not an engineer by trade...so my opinions are intuitive. That disclaimer made, I think it would take considerable psi (guessing 100 or more) to 'push' the dent, the smaller the dent the more psi required, I believe.
    So, how do you propose to seal the header tube to contain compressed air? How do you control the air pressure....when the dent 'moves' to prevent it stretching outward? How do you prevent it from blowing up?

    These are just some considerations that come to mind. You don't have to accept, or even like, my opinion. But I offered it because you asked. I may be incorrect, but I'd rather error on the side of caution with compressed air in a sheet metal tube. Too much like a pipe bomb to suit me.

    Ray
     
  7. Make up a mandrel the ID of the pipe and pull that through the dented portion. Applying heat at the dent would help.
     
  8. RmK57
    Joined: Dec 31, 2008
    Posts: 1,826

    RmK57
    Member

    what's a shrader valve? I can put 20 lbs. air into it and then keep the pressure with a ball valve.
     
  9. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 5,572

    Ebbsspeed
    ALLIANCE MEMBER

    This. Especially since you said they were slip together headers and can work one tube at a time.

    It's the correct term for what most would call a tire valve or air valve, used to inflate your tires. It's the nipple you put the hose on. (Hey, that sounds kinda kinky, not that there's anything wrong with that.)
     
    loudbang likes this.
  10. Joe H
    Joined: Feb 10, 2008
    Posts: 1,089

    Joe H
    Member

    It only takes 15 to 20 psi to push the dents out. I cap the collector ends and bolt both headers together with a gasket between them. One of the caps on the collector end has a air chuck with regulator. Use just enough heat and the dent will come right out. To much and it can bulge or blow out, just keep your face away from it. I have never had one blow out yet and I have done quit a few of them.

    This is pretty common repair on dirt bikes.

    joe
     
    loudbang and wraymen like this.
  11. RmK57
    Joined: Dec 31, 2008
    Posts: 1,826

    RmK57
    Member

    I can regulate the air pressure on the compressor and use a air hose fitting. I'll try it out and see what happens.


    Posted using the Full Custom H.A.M.B. App!
     
  12. Stu D Baker
    Joined: Mar 4, 2005
    Posts: 2,671

    Stu D Baker
    Member
    from Illinois

    ^^^^Please list me in your Last Will and Testament sir.
     
  13. metal man
    Joined: Dec 4, 2005
    Posts: 2,949

    metal man
    Member

    This sounds logical to me, having never done it. I've always just cut out the damaged area and T.I.G welded in a new section. It may sound like a lot of work, but I always have tubing and mandrel bends on hand and I can do it really fast.
    I have heard of guys putting water in the tube and freezing it with good results, but that seems risky to me (tube splitting)? Has anyone here used the freezing method?


    Posted using the Full Custom H.A.M.B. App!
     
  14. By golly, I never thought that 15-20 psi would do it. I also was assuming above a 100psi. I learned something already this year. LOL
    My idea was to use a steel ball that would just roll into the tube, then tap around the dent, letting the inertia push the dent out. Like hammering off dolly!
     
    loudbang likes this.
  15. SicSpeed
    Joined: Apr 23, 2014
    Posts: 653

    SicSpeed
    Member
    from Idaho

    The term for a valve that is in your car tire is Shrader valve




    Posted using the Full Custom H.A.M.B. App
     
  16. Fopelaez
    Joined: Sep 24, 2010
    Posts: 275

    Fopelaez
    Member

    Every day is school day!
     
    1927graham likes this.
  17. Bonneville Avanti Dan
    Joined: Jan 21, 2011
    Posts: 243

    Bonneville Avanti Dan
    Member
    from California

    I used the water/freeze method on the zoomies on the Avanti. Got a deep dent and just added some water and tipped it so the water was sitting where the dent was. Friend had a chest style freezer and in it went overnight. Next morning no dent and no damage. Let it thaw and it was as good as new. I think I have pictures of the before and after. Much safer than compressed air. Just saying.
     
    stillrunners likes this.
  18. metal man
    Joined: Dec 4, 2005
    Posts: 2,949

    metal man
    Member

    I guess if you leave space in the tube for expansion , the water will expand along the length of the tube instead of splitting the tube.


    Posted using the Full Custom H.A.M.B. App!
     
  19. JimSibley
    Joined: Jan 21, 2004
    Posts: 3,397

    JimSibley
    Member

    I do it all of the time. It also works good on gas tanks or anything else you can compress air in.


    Posted using the Full Custom H.A.M.B. App!
     
  20. stimpy
    Joined: Apr 16, 2006
    Posts: 3,547

    stimpy

    I used the screw and blow torch method screw in the dent then red hot and pull out with a pair of pliers . then weld the hole up from the screw , if it was real bad and could get with my steel rods I would work from the inside out , if it was real bad replacing the section often had to do .
     
  21. unkledaddy
    Joined: Jul 21, 2006
    Posts: 2,865

    unkledaddy
    Member

    We used to use the freeze method on enduro bike tanks and expansion chambers with great success.
     
  22. aaggie
    Joined: Nov 21, 2009
    Posts: 2,531

    aaggie
    ALLIANCE MEMBER

    I have repaired a lot of motorcycle exhaust pipes by drilling a hole in the back side opposite the dent then inserting a drift punch in the hole and knocking the dent out from the back. After the dent is out just weld up the hole.
     
    26 roadster likes this.
  23. 26 roadster
    Joined: Apr 21, 2008
    Posts: 2,015

    26 roadster
    Member

    I will try this, I have used 1.5" ball bearing and it work but only marginally.
     
  24. toreadorxlt
    Joined: Feb 27, 2008
    Posts: 733

    toreadorxlt
    Member
    from Nashua, NH

    this looks intriguing.
     

  25. A single pipe would not be as bad as far as sealing it as say a 4 tube header with a collector. It could be done but I would not do it my self.

    I have use d dent puller to remove dents from a header, that was before the day of the welded stud, drilled a hole and screwed that bugger in then give it a yank. Weld the hole shut and your done-ish.
     
  26. hotroddonnie
    Joined: Apr 28, 2011
    Posts: 243

    hotroddonnie
    Member

    That's what I was thinking!
     
  27. RmK57
    Joined: Dec 31, 2008
    Posts: 1,826

    RmK57
    Member

    I ended up drilling a hole through the backside of the dent and tapping it out with a punch. The dent was small, about an inch square but with sharp crease. Turned out great.
    Brazed the hole I drilled and called it done.

    Thanks for the ideas.

    Randy


    Posted using the Full Custom H.A.M.B. App!
     
  28. #30 ball bearing, Prestone and a rag.
    At the most 20 psi, we just used a rag stuffed in the collector and rags stuffed in the primarys, heated the spot and applied air. A couple of trial hits with air and the dents come out.
     

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.