Re: [bolger] Digest Number 2357
For working with aluminum, I used (and STRONGLY recommend) two reference books:
BOATBUILDING WITH ALUMINUM by Stephen F. Pollard
http://www.glen-l.com/books/bb-alum.html
The Elements of Boat Strength by Dave Gerr -
http://www.gerrmarine.com/books.html
The most important question is what alloy. I used the "recommended" product (series 6000 - or was it 5000?) and after 3 years, in salt/brackish water, never under cover, no paint, cleaning or other maintenance, the aluminum is developing its nice gray patina. But it sure is bright - visible for miles - when the sun catches it, turned upside down on the bank.
It comes in sheets 6x20, other sizes by special order. I lucked into a "scrap" 6x14, which resulted in my "stretching" Teal a bit, to assemble of 3 panels, with scraps for bulkheads, decks, pivoting leeboard...
Your weight numbers sound about right - for comparison, a 4x8 sheet would weigh 56 lbs - heavy, but as noted earlier, maybe comparable to 1/2 ply plus glass and paint.
- when cutting the aluminum sheets with your (cordless) circular saw, wear earplugs and socks! (the hot metal sawdust is nasty in your shoes).
- clean up shop space after cutting - and if you do it in the backyard, use a dropcloth - I'm still finding sharp shiny shavings in the grass, 3 years later.
- make sure you attach flotation to your aluminum rudder, or secure with a lanyard before you head for deep rough water!
I have some thoughts on replacing my Diablo with a stretched metal version (remember those 20' panels!) or, better yet, an Atkins "Rescue Minor".
Curtis
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BOATBUILDING WITH ALUMINUM by Stephen F. Pollard
http://www.glen-l.com/books/bb-alum.html
The Elements of Boat Strength by Dave Gerr -
http://www.gerrmarine.com/books.html
> My metal books rate 0.125 thickness aluminum at about 1.75 lbs/sq.ft.125 plate, or 1/8". My reading suggested that this was the thinnest that could be welded up by most shops. Even with this thickness, there's visible distortion (bending) at welds, especially bulkheads. I suspect it would be hard to get a fair hull - not that I care about such things.
> and 0.10 at around 1.4 lbs/sq.ft.
>
> Questions:
> - what thickness did you use?
The most important question is what alloy. I used the "recommended" product (series 6000 - or was it 5000?) and after 3 years, in salt/brackish water, never under cover, no paint, cleaning or other maintenance, the aluminum is developing its nice gray patina. But it sure is bright - visible for miles - when the sun catches it, turned upside down on the bank.
It comes in sheets 6x20, other sizes by special order. I lucked into a "scrap" 6x14, which resulted in my "stretching" Teal a bit, to assemble of 3 panels, with scraps for bulkheads, decks, pivoting leeboard...
Your weight numbers sound about right - for comparison, a 4x8 sheet would weigh 56 lbs - heavy, but as noted earlier, maybe comparable to 1/2 ply plus glass and paint.
> - assuming it was a long hull, were you able to eliminate anyNot really - I did leave a bit of framing out, and there's some oilcanning of the bottom. Gerr's book has good info on how to "do it right" - stiffening stringers 8" o.c, for example, but this is for serious big boats. I wish I had added a bit of a keel to stiffen things up, and pipe on the gunwales (I tried gluing wood rails on with 5200 - it didn't stick - epoxy works better!)
> bulkheads, knees or bracing?
> - what would you do different?Lots of things, it's different from working with wood...
- when cutting the aluminum sheets with your (cordless) circular saw, wear earplugs and socks! (the hot metal sawdust is nasty in your shoes).
- clean up shop space after cutting - and if you do it in the backyard, use a dropcloth - I'm still finding sharp shiny shavings in the grass, 3 years later.
- make sure you attach flotation to your aluminum rudder, or secure with a lanyard before you head for deep rough water!
I have some thoughts on replacing my Diablo with a stretched metal version (remember those 20' panels!) or, better yet, an Atkins "Rescue Minor".
> Couldn't get the links to work but would love to seeThe pics referenced are in the Bolger2 Yahoo group - you have to register... I will try too dredge them up and send.
> images. Can you email pix?
Curtis
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