[TheForge] Sheet Metal Bender

[dan at irontreeworks.com]

Bruce,
   I don't want to make it myself.  I want someone to show up at my shop this
weekend and install my new side draft hood, fix the old Champion forge I got
for $100, and install a new chimney for free! :)

  However, this does not seem like a reasonable event, so I priced some stove
pipe.  I can get the 12" dia galvanized 24 gauge round ductwork from Menard's
pretty cheap.  I can't find anyone that sell/makes the plain black stove pipe
in 12 inch dia.  After what happened to Paw-PAw, I am alittle scared of
galvanized pipe close to the forge.  I have students in my shop, and I don't
want them hurt....soooo.....I thought stainless.  I looked into having some
made and found out that it would be over $600 for 12 feet.....so....if you
can't afford it....make it!

I thought stainless would withstand the elements.  I like the plywood circle
idea.  Seems easy.  I still think that using a slip roller would be the easiest
solution for the straight tube if I can find one to borrow this week.

Dan


Quoting Bruce Freeman <freemab222 at yahoo.com>:

> Daniel,
>
> First of all, why do you want to make this yourself?
> To have stainless steel instead of galvanized?  Or
> because stainless steel isn't available in 12"
> diameter?
>
> Next, correct me if I'm wrong, but isn't 24 gauge
> pretty light stuff?  Like you can easily flex it by
> hand?  If so, then bending pipe shouldn't be too
> difficult - roll it around a slightly undersized
> mandrel (maybe 10" or 11") and let it flex back to
> 12".  Lock seams are nice for the prefab stuff, but it
> would be a deal easier just to drill and pop-rivet the
> edges and ends.  Or even use self-drilling screws if
> you like them.
>
> Someone else advised 45 degree elbows, and I second
> that.  Whatever you choose, odd shapes can be made
> according to diagrams available in any text on sheet
> metal work. Visit a used_book store and peruse the
> contents.  The Audel's series should suffice, but
> there are text books for metal shops that are fine
> too.
>
> You can also fake it by means of a clever device Clay
> Spencer showed me, and which I've since used:  Imagine
> you want to make a pipe with a 12" diameter end on a
> vertical axis, and goes to a 12" diameter end on a
> 15-degree-off-vertical axis.  (Three of these would
> make a 45-degree bend.)  Construct a device as
> follows:  Cut two (~1/4") plywood circles, 12" in
> diameter.  Drill three holes in each, oversize for
> available threaded rod.  String the two circles on the
> threaded rods:  nut, washer, circle, washer nut, (then
> a lenght of threaded rod), nut, washer, other circle,
> washer, nut.  You'll end up with the two circles
> separated on the three threaded rods by some distance.
>  Now adjust the distance as you prefer, and adjust the
> angle to 15 degrees between the planes of the two
> circles.  You want the closest approach of the circles
> to be some reasonable amount (say 2") because this
> will be the narrowest sheet metal  you'll have.
>
> Now roll this pattern along a piece of paper, and it
> will describe a pattern to be used in cutting the
> sheet metal. When actually cutting the metal, be sure
> to leave tabs to overlap the next pipe section so that
> you can join them with rivets or screws.
>
> I have used this technique to develop a pattern for a
> side-draft hood of unusual shape, and found it worked
> quite well.
>
> Bruce
> NJ
>
> >>> "Daniel Kretchmar" <dan at irontreeworks.com>
> 9/18/2006 11:17 PM >>>
>
> Greetings,
>            I need 12" diameter chimmey pipe for my new
> side draft hood.  I
> looked into menards.  They have galvanized 12"  24
> gauge chimney.  I looked
> into having some custom stuff made but it's too
> costly.....so the next
> question is.....can I make it myself?
>
> What kind of bender would I need to make 12" diameter
> pipe/tubing out of 24
> gauge stainless steel?  I want to make it in 2 ft
> sections. which means
> investing in a crimper a bender.....and what about
> elbows?  I'll need two 90
> degree elbows.  How will I make them?
>
> Advice is appreciated
>
> Dan
>
>
> __________________________________________________
> Do You Yahoo!?
> Tired of spam?  Yahoo! Mail has the best spam protection around
> http://mail.yahoo.com
> _______________________________________________
> Manage membership or unsubscribe at:
> http://mailman.qth.net/mailman/listinfo/theforge
> theforge mail list group photo site is
> http://www.photoaccess.com
> Login:  blacksmithblacksmith at hotmail.com
> password:  anvil
> ___________
>
>
>




----------------------------------------------------------------
This message was sent using IMP, the Internet Messaging Program.