Braking Aluminum

[Bob La Londe]

I have a copy of Pollards aluminum boat building book, and I have read it.
It looks like he mostly plans on boats to be all cut pieces and welded.
That's great for big boats or even for some small boats, but braking seems
like it would make more sense if you have access to a brake big enough.
Some of the small boat designs (think shallow draft skinny water boats)
would really benefit from a mostly bent hull. Aluminum sheet can be had in
pieces large enough to make most of a hull out of one sheet. Some cutting
and welding is still needed obviously, but if you could brake the keel,
chines, and bottom of the transom only welding the front and the sides in
the back you would have an inherently stronger and more rigid boat for rough
service.

The problem of course is how do you brake a piece of metal that big?

Yeah I know a giant hydraulic brake would be a good answer for the
commercial boat builder once they have the capital for it, but how does the
backyard boat builder do it? Are they stuck with all cut and welded pieces,
or hauling their sheet to somebody with a giant brake to do it for them (if
there even is somebody with a brake big enough in the area that hires out)?

[Bob La Londe]

On Dec 30 2011, 6:15 pm, Bruce <bruceinbang...@gmail.com> wrote:

> Bob, you probably know this but sheet aluminum has a "grain" and
> bending with the grain is different then bending across the grain.
> Also aluminum bends are not sharp 90 degree bends but have a small
> radius and require a "bend allowance" for this radius. Depending on
> hardness of the aluminum you can make sharper bends across the grain
> then parallel with the grain (without cracking, that is :-)
>
> I would assume that you would have at least a bench brake, with say 36
> inch capacity,  if you were going to start building an aluminum boat,
> and depending of course on the design I would look around for a sheet
> metal business that might have a brake large enough to make any long
> bends as it will certainly make of a nicer looking finished project.
>
> I'm not really a tin-bender but I believe that there are brakes that
> will allow bending only part of a piece so that you can bends say 24
> inches then slide the work and another 24, etc. Try google "box and
> pan brake".
>
> You an bend aluminum sheet by clamping it to a male "mold" that has
> the correct angle and a radius for the allowance and then bending or
> hammering. Or you could build a "press brake" die which is a vee
> shaped female die and a matching vee shaped male die - with built in
> clearance - these will bend up to 90 degrees, or less, depending on
> how deep the male penetrates the female die.
>
> Lastly, (again as you may know) soft aluminum distorts extremely
> easily and it is easy to fall into the trap of bending something a bit
> wrong and thinking "Oh, I'll just straighten it out", only to discover
> that the aluminum just grew a little longer where you bent it.
>
> I suspect that bending up a pirogue might be fairly easy but one you
> your 900 HP Bass Boats will be a bit difficult.
>
> Oh. Yes, try to find a copy of "How to building a tin canoe" if you
> possibly can. It is a great boating book and does have instructions
> for building a boat out of galvanized iron :-)
> --
> Cheers,
>
> Bruce

Bruce,

Thanks. I will see if I can find a copy of that book. No this
application is not for a 900HP bass boat. LOL. Think 16-20 HP mud
motor. Purpose built shallow water brush country beaver dam jumping
mud boat. As light as possible and still make it home... mostly in
one piece.

P.S. The motor on my big bass boat only puts out somewhere between
250 and 270 at the prop shaft. (Depends on the temperature and
humidity.)

Bob

[Bob La Londe]

"Bruce" <brucein...@gmail.com> wrote in message
news:e8s1g7psi4phm9utq...@4ax.com...

> Bob, Obviously I was being a bit facetious with the 900 H.P. but after
> all I'm a guy that's sitting in my 8 ft. punt with the 2 H.P motor
> watching the bass boys roar by :-)
>

Oh! Well in that case I can brag about how fast my bass boat is... unless
one of those Bullet or Allison guys is within earshot. LOL.

Seriously. If conditions are ideal I can hit mid to high 70s (MPH), and I
can run 70+ under most conditions. I usually run in the mid 60s and my
motor sounds like its loafing. Same motor on a 20' Bullet will run high
80s, and on a 20' Allison they can hit 90. Faster on one of the old Allys,
but its to heavy for them.

Right now I want something that will do 15-20 with just me and my gear in
shallow stump infested beaver dam addled feeder streams. I can run them in
my canoe, but I have to get out and drag my canoe over the beaver dams. My
feet actually got wet out duck hunting yesterday. I couldn't take the cold
after 6 or 7 hours. Brrrrrrr.... It only warmed up to the low 70s (F)
yesterday. LOL. Actually it was a pretty nice day on the water wet feet
and all. Sadly I only plugged three of them pesky little entrees, and I
lost one in the brush. You should have seen me wading through the cat tails
chasing one little green wing teal that just wouldn't die.

Bob

[Bob La Londe]

"Bruce" <brucein...@gmail.com> wrote in message

news:84i4g7p3bt12fsc90...@4ax.com...

> It appears that you may be taking unfair advantage of the ducks....
> after all, they get their feet wet :-)
>
> But more seriously, don't you people use dogs?

I don't have the time and patience (mostly the time) to keep a good dog. A
couple of my buddies have dogs, but only one that will work at hunting (the
buddy not the dog), and he lost his dog a few months ago to some kind of
arterial disease. He is making plenty of noise about me helping him train
the new puppy though. He's pretty worked up about it. Losing the old dog,
and about getting the new puppy. He picks it up this weekend.

Its going to be pretty hard to top his old dog though. Last summer we
boated into some back waters to do some fishing and we were wading back even
further were the boat wouldn't go. I has in some chest deep water fishing
when Hunter (my buddy's dog) decided I should not be there. He swam circles
around me trying to herd me to the bank. When I wouldn't cooperate he swam
over to the bank, grabbed a big stick in his mouth, came back, and tried to
get me to grab onto it. It was pretty cool. I was fine, but I hurried up
to shallow water so he wouldn't exhaust himself trying to rescue me. LOL.

Bob La Londe
P.S. I live in the desert. LOL.

[Bob La Londe]

"Bruce" <brucein...@gmail.com> wrote in message

news:8tn5g7poha5028p8h...@4ax.com...
> On Mon, 2 Jan 2012 18:36:17 -0700, "Bob La Londe" <no...@none.com>

> Somehow from reading you posts I had assumed that you were from
> Georgia, Alabama or maybe S. Louisiana :=)

Dey's got alligators, water moccasins, an' snappin' turtles in dem places.
You wouldn't find me in the water there, no way, no how. Probably have a
hard time getting me in a small boat there.

<G>

[Bob La Londe]

"Bob La Londe" <no...@none.com> wrote in message
news:tuHMq.14246$Uj1....@newsfe20.iad...

Reminds of the first time I took one of my buddies from North Carolina
backwater fishing here. The water had fallen while we were fishing and the
boat wouldn't make it over a couple shallow spots in the channel to get back
to where we launched. I was familiar with the area so I just stepped off
the front of the boat into the water and dragged it over the shallow spots.
He just about freaked out. They have some of those nasty aggressive bitey
poisonous critters that hang out in the water were he grew up.

We are getting a little off topic aren't we... LOL. To bring it back on
topic, I just welded in a patch on that boat.

[chaniarts]

there's a lot of good knowledge in rec.crafts.metalworking that might
help with this topic.

[Pete Keillor]

On Tue, 3 Jan 2012 11:08:18 -0700, "Bob La Londe" <no...@none.com>

Oh, when the alligators would ease into the water, I'd ease out.
Growing up on a rice farm, killing water moccasins was an almost daily
occurrence. I was only struck good once, on my rubber boot. They
strike hard when you're standing on them.

My grandmother drove a stepside Chevy and had keys to most reservoirs
around. Raised her own minnows and fished almost every day until her
stroke at 80. There was a 13' alligator at the little res she named
"George". Talked to him while she fished. He was so used to her, he
would just lie there sunning. She didn't wade, fished off the bank.
Grandma died about 1990. Great lady, and a hell of a shot.

Pete Keillor

[Bob La Londe]

"chaniarts" <chan...@nospam.yahoo.com> wrote in message
news:je24e9$pk9$1...@dont-email.me...

Thanks. I am a regular in that group, and I got some feedback on this topic
there too.

[Bob La Londe]

"Bruce" <brucein...@gmail.com> wrote in message

news:hv47g79l63gcm4d8c...@4ax.com...

> On Tue, 3 Jan 2012 11:13:20 -0700, "Bob La Londe" <no...@none.com>
> wrote:
>
>>"Bob La Londe" <no...@none.com> wrote in message
>>news:tuHMq.14246$Uj1....@newsfe20.iad...
>

>>We are getting a little off topic aren't we... LOL. To bring it back on
>>topic, I just welded in a patch on that boat.
>

> Had a buddy that bid on a job to repair some rental boats; lot of
> welding. Got the bid and went out and stick welded them all, at a rate
> that others had bid for TIG welding. Said the owner got made about it
> :-)

I didn't know it was possible/practical to stick weld aluminum. I do it
with a MIG machine and straight argon gas. One of my buddies has a more
expensive pulse MIG, and he can weld about twice as efficiently with it.
Certainly its faster than TIG.


> I really hate welding flat aluminum as it warps so bad.

There are tricks. I'm just a hack metal sprayer, but the big one is to make
lots of spaced tack welds when joining sheets and then work back and forth
fill between the tacks, so you aren't building to much heat in any one area.
A pulse MIG is more forgiving in this area, but alas I just have a regular
MIG. Another trick for some problem spots is to stack tack welds. It looks
like it was welded with a TIG that way. The big thing though is brushing
off the oxidized coating with a stainless brush and cleaning any oil off the
metal with alcohol or acetone. Getting back to Pollard. Lots of people
will weld aluminum on a backing of some kind, but I don't know anybody who
welds, back chips, and back welds like he suggests except on some odd
positioning of thicker plate. Back chipping and back welding some of the
thinner stuff commonly used in small boats just isn't practical. I think it
would do more damage than good.