I can't offer much in the way of advice on welding - I am now building a 20'
W Atkin design in aluminum; cutting and fitting the pieces myself, and
hiring a local pro to do the welding. Pictures and discussion on the Yahoo
AtkinBoats site
http://groups.yahoo.com/group/AtkinBoats/ (registration
required).
1/8" can be welded, but it isn't easy. But for smaller boats, it is still
pretty heavy - about the same as 3/4" plywood. Use 5000 series (5083 or
5086 for salt water) and 6061 for angles, pipe, and extrusions (6063 if you
can find it).
Build yourself a little skiff or dinghy for practice. It will come in
handy, and last forever with zero maintenance. Around here standard sheets
seem to be 6'x20', and you could build a nice narrow little skiff from one
sheet. There are all kinds of nice plywood designs out there that can be
adapted to metal.
And pick up Pollard's book, and Gerr's "Boat Strength".
Sal's Dad
"Bob La Londe" wrote in message
.. .
"imagineero" wrote in message
ps.com...
I do a fair job with my little MIG welder on any kind of steel. I've
got a
gas bottle and flow regulator for stainless. That takes a little more
work
to get jsut right. I do heavy steel stock with my cracker box AC
welder,
but the best welder I ever used for heavy stock was a Hobart DC stick
welder. Wow talk about smooth.
Hi there,
Ive been a full time welder for about 5 years now, and a tinkerer most
of my life before that. I spent a year doing contract work stick
welding trawlers but in the last year and a half most of my work has
been aluminum; big tip trailers, and aluminum plate boats.
Here's my 2 cents worth... I dont think it really makes too much of a
difference what alloy you go with, particularly for fresh water. Just
go with something that isnt too hard. We use 5083 marine alloy, but a
lot of the 5000 series alloys are suitable. You'd do well to decide
early on if you want to go for a 'plate' boat or a 'pressed' boat.
There was a lot of great stuff in your post. Thanks. I was thinking more
along the lines of pressed, although actual structural bending or forming
was not part of my plan for the main hull design. Wrapping and flexing
would be more accurate. Plate would be way to heavy for some of the
smaller designs I have in mind. I was thinking to basically light bend
most of the sheets using .125 for most things and creating structural ribs
out of top hat bent sheet. I figured to use some 1/4" plate for a
slightly different design than most modern production boats for increased
ridgidity for stringers and knee bracing as well as rear corner gunnel to
transom bracing so that the boat will actually standup to the horsepower
that the CG formula says is appropriate for the design. Most production
boats flex to much and begin to get stress fractures when run with their
max rated HP even after only a couple years.
Your comments on welding the thinner sheet have made me step back and
reconsider. I had hoped to avoid stitch and glue even though it is much
easier, because of the extreme heat and dry conditions where I live. I
have read all about encapsulation etc, and I have also seen real boats.
Wood just does not hold up in the desert no matter what you do to it. Now
your comments about the difficulties of welding sheet aluminum make me
reconsider that approach as well. I suppose the thing to do is get some
sheet and a gas bottle and see what I can do.
You are right in that I have a cheap MIG (with only 2 heat settings).
Usually I use flux core except for stainless because its just faster to do
a small repair weld. My business can justify the expense of a better MIG
welder, although an autodarkeneing shield is probably going to come first.
I know the duty cycle of the one I have is abysmal. This one mostly gets
used for minor fabrication for my business. I probably can't justify top
of the line. Anything over a couple thousand would be pretty hard to
justify.
Anyway, thanks for your suggestions regarding a local boat builder. Its a
great idea, except as far as I know there aren't any. The nearest would
be about 180 miles in either direction. I probably need a better MIG
anyway, so I guess I'll go hunt up another gas bottle and pick up some
scraps from Mike and see what I can do.
--
Bob La Londe
Fishing Arizona & The Colorado River
Fishing Forums & Contests
http://www.YumaBassMan.com
--
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