Aluminium boat building - 25ft fisherman

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lucastefanel
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Re: Aluminium boat building - 25ft fisherman

Post by lucastefanel »

Matt Gent wrote: Wed Mar 24, 2021 12:29 pm Super cool project!

A friend and I want to learn to weld. We are tinkering with adapting a small S&G skiff (Lillistone's Fleet) to Aluminum as a "senior design project"' once we have the hang of it. CS25 is on a whole other scale!

Aluminum boat building seems to be very regional. The petroleum industry in the gulf supports a bunch of Louisana builders, plus the PNW. I'd think it makes sense for low production / semi-custom boats elsewhere but tradition seems to reign.
Hi Matt, you are right, is very regional and tradition reigns, i think because aluminium has been always associated to professional boats for very strong use!
Now even in italy we are starting to see the first aluminium made boats, in my opinion aluminium boat building will increase as soon all the fiberglass boats at the end of their life are starting to be scrapped, i know there are huge costs for demolition

lucastefanel
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Re: Aluminium boat building - 25ft fisherman

Post by lucastefanel »

Dan_Smullen wrote: Wed Mar 24, 2021 1:41 pm This will be a great project to watch!
Thanks Dan, i will keep posted my progress

lucastefanel
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Re: Aluminium boat building - 25ft fisherman

Post by lucastefanel »

Cowbro wrote: Wed Mar 24, 2021 2:43 pm
Matt Gent wrote: Wed Mar 24, 2021 12:29 pm Aluminum boat building seems to be very regional. The petroleum industry in the gulf supports a bunch of Louisana builders, plus the PNW. I'd think it makes sense for low production / semi-custom boats elsewhere but tradition seems to reign.
I have looked into it for a bit, there are plenty of options out there to order a CNC cut aluminum boat kit for anything from a 10' dinghy to a 40' trawler, the problem lies mostly in the construction technique. There isn't as much information out there like there is for S&G boats. If your welder settings aren't dialed or you weld something out of sequence you risk turning the whole thing into a giant curvy noodle. It also requires some much tighter tolerances for fit-up. You can't just pile in thickened epoxy to fill a 1/2" gap.

Luca, I am watching this with much interest, it seems like you are off to a great start and seem to be more than capable. 8)
what you say is totally correct, aluminium is subject to overheat deformation especially for small thikness plates, actually i'm using 6mm for hull, 8 for structure, 15 at transom and 4 for deck, this problem is quite limited as already considered as big thikness so the overheating problem is quite limited.
Of course without proper welding machine settings you can easily make holes on plates or damage the material.
There is also a big preparation for welding area, oxide removing, compressed air cleaning, axetone cleaning in order to remove all the workshop oils/paints etc and then finally you can weld.
I work for a maritime building company and we recently delivered 2 vessel funnels over 75 tons of aluminium so i had the opportunity to see how to properly work aluminium.
For sure i still have lot to learn. 8)

lucastefanel
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Re: Aluminium boat building - 25ft fisherman

Post by lucastefanel »

MikeyGnz wrote: Wed Mar 24, 2021 4:15 pm Hi Luca

I've been building a GV10 in alloy as a practice project before I build a kit-set boat. See My Build for more details. Just looking at what you have done so far you seem to be a better alloy welder than me and are using heavier plate/sheet so you shouldn't have as many distortion problems as I had. Looking back on my experience the two main things I learned were:
  • Do a lot of practice on off-cuts to get the welder settings and technique dialled-in. Once confident everything is correct, do more practice.
  • Short welds then let cool to reduce heat build-up.
Looking at your welds and gear you probably know all this already though.

Good luck with the build, I'm looking forward to see how it all goes.

Mike
Hi Mike, thanks for suggestions!
i gave a look into your build, great job!
you faced overheating issues caused by low thikness of plates, actually i'm working with 6-8-15mm plates and MIG-pulsed machine.
The difference with a traditional MIG machine is that the first shot of electricity is burning the oxide on plate and it allows me to use low amperes on weldings and of course less heating.
At least this is teoretically :wink:

lucastefanel
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Re: Aluminium boat building - 25ft fisherman

Post by lucastefanel »

TomW1 wrote: Wed Mar 24, 2021 11:58 pm Luca I look forward to following your build until you launch it. I know you will need to prime it with zinc chromate before painting for corrosion protection. What aluminum alloy are you using 5053. I worked for a major aluminum company. :D

Regards, Tom
Hi Tom, correct, i'm using 5083.
Actually this grade alumium should be able to sail row without any paint without problems.
At work for maritime construction we used International paint with very good results so i think i will copy paste.
In details first coat of epoxy primer, second coat of aluminium specific paint and then at the end the final RAL paint, very long progress!

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Re: Aluminium boat building - 25ft fisherman

Post by bklake »

That is one sure way to solve the Slow-Medium-Fast hardener question.

Good luck with your build.

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Re: Aluminium boat building - 25ft fisherman

Post by TomW1 »

lucastefanel wrote: Thu Mar 25, 2021 3:05 am
TomW1 wrote: Wed Mar 24, 2021 11:58 pm Luca I look forward to following your build until you launch it. I know you will need to prime it with zinc chromate before painting for corrosion protection. What aluminum alloy are you using 5053. I worked for a major aluminum company. :D

Regards, Tom
Hi Tom, correct, i'm using 5083.
Actually this grade alumium should be able to sail row without any paint without problems.
At work for maritime construction we used International paint with very good results so i think i will copy paste.
In details first coat of epoxy primer, second coat of aluminium specific paint and then at the end the final RAL paint, very long progress!
Sounds like a plan, keep posting pictures sure want to see the finished boat. :D

Tom
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

lucastefanel
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Re: Aluminium boat building - 25ft fisherman

Post by lucastefanel »

Hello and thanks for your support!!
Here some progress made last week.
Actually structure is done and tack welded and now is serving as jig exactly as per wooden building, the only difference is that i will tack weld bottom plates on frames as soon i reach the perfect shape.
When i prepared the files for cutting i decided to add 60mm of green material in order to be able later on to adjust any mistake, in order to find position for transom and starting reference point i had to mark on aft bottom plates the green material.
Now....the job became harder, 2 plates 6 meters long to move and handle, with a bigger truck i have been able to transport from warehouse to home and i directly putted on structure in order to prevent any unvoluntary shaping, this operation had been done by 3 persons without any big problem.
I used a building trick learned during last project, by using a rope from first and last bulkhead i have been able to alway have center line clear and mark, this is avoiding any mistake on bottom plates positioning.

You can also see these progress on this youtube video:
[youtube]https://www.youtube.com/watch?v=8lw-5Adjfuw&t=20s[/youtube]

Cheers!!
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Re: Aluminium boat building - 25ft fisherman

Post by BarraMan »

An interesting build to watch, Luca. Thanks for posting!
Way above my pay grade!
I am proof that it doesn't take a lot of skill to build a S&G boat - and you can learn as you go!

TomW1
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Re: Aluminium boat building - 25ft fisherman

Post by TomW1 »

Very nice Luca. Keep the pictures coming, You have a very interesting project that a lot of us are following. :D

Tom
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978

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