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Basic blister tech!

Discussion in 'The Hokey Ass Message Board' started by X38, Mar 26, 2008.

  1. From a basic hot rodder - and my first tech post.

    I need some hood clearance for a project and the most expedient solution was...blisters! Hammerforming into a block of wood is about as tricky as I get, so I thought I'd give it a go.

    First off was to determine the size I needed then make a cardboard template and buck of the shape. Once I found a suitable sized hunk of wood, I used the template to transfer the shape.

    Start digging! As I chiseled away I used the buck to check on depth and form progress.

    With the hammerform shaped, I cut out a piece of MDF the same shape as the blister to clamp some sheetmetal to the hammerform.

    With everything securely clamped I started banging away with a drift to define the edge and followed that with a peening hammer to get the basic shape and depth. With the bilster roughed in I went back to various drifts to tune the shape.

    Once freed from the form, ta-da, a really rough blister, complete with woodgrain.

    Some simple dolly work and a bit of filing and there it is, one blister!

    Hope this helps some fellow HAMBers, but as the saying goes, If I can, anyone can.

    Attached Files:

  2. panhead_pete
    Joined: Feb 22, 2006
    Posts: 2,689


    Cool !!!!!!!!!!!!I gotta try that!
  3. tdoty
    Joined: Jun 21, 2006
    Posts: 821


    Yep, that's hammerforming. Not much for woodcarving? Instead of a seperate buck, carve a blister like the one you want out of foam and use it to make a female "mold" out of fiberglass reinforced filler (kitty hair) and some 1/4" rod to hold it together. The fiberglass filler will take quite a beating.

    Good show, X38!

    Tim D.
  4. I wish! I don't even think I could make the wooden part. You might as well have waved a wand and made that piece. I've got to spend some time learning metal work, that shit really scares me. Awesome job!

  5. striper
    Joined: Mar 22, 2005
    Posts: 4,498


    Where's it going?
  6. TomH
    Joined: Oct 21, 2003
    Posts: 1,253


    What gauge aluminum did you use and did you anneal it??
  7. That's neat. I've done some simple stuff but nothing like that. Thanks
  8. Flipper
    Joined: May 10, 2003
    Posts: 3,333

    from Kentucky

    So does the shape of the blister come from thinning the metal? or did the metal that was originally beyond the hole get pulled down into the hole and then get smoothed out?

    I'm curious how deep you can make a form using this technique.
  9. The shape comes from thinning the metal, like any stamping. Holding the part, feeling it, you wouldn't know it was thinned.

    Not aluminum.

    They're going on Deuce hood sides Striper.
  10. What thickness was the metal you started with?
  11. fiat128
    Joined: Jun 26, 2006
    Posts: 1,427

    from El Paso TX

    What does "not aluminum" mean, is it steel?
  12. The Hank
    Joined: Mar 18, 2008
    Posts: 779

    The Hank
    from CO

    was that 16 or 18 G steel ?
  13. FiddyFour
    Joined: Dec 31, 2004
    Posts: 9,008


    looks to be 20 or 22 gauge to me... nice work
  14. alchemy
    Joined: Sep 27, 2002
    Posts: 16,840


    Why not just clamp the whole hood side to the buck and hammer away? Save you from welding and warping.
  15. FiddyFour
    Joined: Dec 31, 2004
    Posts: 9,008


    you'd need some seriously large clamps to pull that off unless you drilled holes in the hoodsides to bolt it together, then you still need to weld in the holes...
  16. publicenemy1925
    Joined: Feb 4, 2007
    Posts: 3,187

    from OKC, OK

    Very nice indeed. What hammers did you use?
  17. pimpin paint
    Joined: May 31, 2005
    Posts: 4,937

    pimpin paint
    from so cal


    A great showing of metalshaping skill, there Tony!

    It's funny how everyone thinks that one needs a lot of big money
    tools to shape metal, nope, just simple tools used skillfully.

    Again, a good show.

    Swankey Devils C.C.

    "Meanwhile, back aboard The Tainted Pork"
  18. Goztrider
    Joined: Feb 17, 2007
    Posts: 3,066

    from Tulsa, OK

    This is the kind of idea that I posted about a few days ago in another thread. That is really cool stuff and a neat idea.
  19. scootermcrad
    Joined: Sep 20, 2005
    Posts: 12,372


    AWESOME! Great tech and I will use it since I have plans for at least three blisters! Thanks for sharing!
  20. Jeff Norwell
    Joined: Aug 20, 2003
    Posts: 13,271

    Jeff Norwell
    Staff Member

  21. JAWS
    Joined: Jul 22, 2005
    Posts: 1,846


    Show off.....:D
  22. To answer some questions, yes it's steel, .6 or 20 gauge I think.

    Here are the weapons used to bang it out.

    I haven't done the second one yet, it's clamped and ready to go so I'll take some pix of it with all the really crude hammerwork to give a better idea of the process.

    And thanks for the positive comments. All my wife said was "are you making an easter egg mould?"

    Attached Files:

  23. swifty
    Joined: Dec 25, 2005
    Posts: 1,799


    Only engines needing blisters on a 32 hood are Arduns, Polys and Hemis then when I re-read your roadster build post and saw the dyno figures I guessed it was a Hemi and a big one at that. What adapter and trans are you using?

  24. Swifty, I wish. Here's the miserable truth. A US supplier set up a chassis with a SBC and T5 mounts. They now know that while TH350 and T5 trannies share the same mount, the T5 is an inch further back!!! The net result was the engine was/is too far forward and the water pump pulley touched the radiator and the hood hit the Speedway rams horns. To move the engine back meant redoing basically everything including all the mounts, chassis x member, tailshaft, firewall, trans hump... etc etc.

    Obviously it can't simply be taken back to them to fix.

    So, to solve this situation in the most expedient way, the rad is moving 3/4" forward, hood is being lengthened the same amount and blisters will provide the necessary exhaust clearance. It's the left side that's the worst (furthest forward head), but both sides have to match.

    I wish there was a better reason.
  25. swifty
    Joined: Dec 25, 2005
    Posts: 1,799



    You could solve one problem by not running the hood sides but I guess that wrecks the theme of the car
    I am interested in the fact that you will only have 3/4" of clearance from the pulley to the radiator as that is all I have on my 32 and I thought I was cutting it fine. I guess that we have both had to make do with what we had.

    Is it going to be a highboy?
  26. Swifty it will be a hiboy and definitely will have hood sides.
  27. You shoulda left the woodgrain on it! :)

    Swifty - I heard once, that an inch is as good as a mile. Surely 3/4 of a mile is enough space between the pulley and radiator? If it's not going to move, it won't hit. :)
  28. wethebmx
    Joined: May 30, 2006
    Posts: 244

    from walnut, ca

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