Butt Joints For Hull Plating

Hey Ad Hoc
I never did say or imply that I was a pro at aluminum welding nor did I say I was a NA or an engineer. I am an amature boat builder and I do it for a hobby and have fun doing it. Insulting me because of those facts realy makes me wonder what kind of person are you.
Sean as how you think my work welds and myself are crap and there based on nothing, I'll give you something to base them on.
Here is a couple pics of one I did last summer, grandaughter even helped and it was a lot of fun to do. I learned a heck of a lot about aluminum welding on this one. started out with just a cv welder and about half done I bought a pulse welder and that sure made things easier working with
.100" material. I guess in your eye's it's a total peice of crap because I didn't hire a NA, I'm not certified in aluminum nor did I send weld samples out to be tested.
Now you have somthing to base your asumptions on, Have at it
Tom

 

Tom - nice looking boat - well done.

All people who build boats are boat builders - amateurs have the advantage of being able to build the way they want to because they don't have to sell their products. Lots of amateurs build better boats than professionals because they don't have to account for every minute and they often just take more care. As a professional marine surveyor I see this.

I have done courses in alloy welding but I still learn a lot at these forums. That is what they are supposed to be about - the free exchange of ideas.

I have not got a pulse arc machine - just a 260 amp mig and an AC/DC Tig. I know that a pulse arc will weld thinner metal and give better control of the weld pool but how does welding with the pulse arc machine compare with a conventional TIG? What is different about how you use it?

I don't normally use plate thinner than 4 or 5mm for the hull structure but I do use 3mm for some inside "joinery" such as consoles. The conventional mig will handle that with care but it is abit clumsy.

Cheers

Alan

 

In response to the original question, on large commercial boats the yards here join the plates on the floor, add the stiffeners and the fit the panel to the boat. There is usually a lot of buckling between stiffeners. Its done this way to keep cost down.

On small boats where buckling is not wanted, they frame up the boat, fit the plates and weld the seams on the boat. If the seams are within 50mm of a frame or stiffener they just weld it, if it is further away they will brace it at 90 deg as others have already described. Large flat panels are also braced.

Saw horses are never used, its either on the boat or on the floor.

Typical weld lengths are around 250mm - determined by how far the operator can move the torch before needing to reposition.

 

Hi Tom,

Nice boat. Kevin has got some competition

Cheers,
Mark

 

Thanks Alan
I never did take the time to try to master tig, played with it some and when I tried welding on the hull in awkward positions my hands would get shakey so I just stick to mig. On this hull I finished it up using .023" 5356 wire in pulse mode and it did weld pretty easy but I could never get the apearance I wanted. I have just got around to playing with the pulse on pulse mode with .035" 5356. With that sofar I found I can dial it down some and make a real pretty stack of dimes bead, no strength but dang it looks good. When it is dialed in it still makes a nice looking bead with a little less heat input. I am going to build another 8' dinghy so I will see how the pulse on pulse mode works.
Tom

 

Thanks Mark

Give me several more boats and years I might get close LOL
Tom

 

Thanks Tom - interesting - I have never used anything thinner than 1.2mm wire (0.047") - (in 5356) but I am not using a pull feed gun so I am limited to a 10 foot cable to the gun and 0.9mm / .035" wire won't push feed very well. This has not been a problem so far as I work on a concrete floor and I normally hang the wire feed unit of a gantry but if I ever build a much bigger boat it might be a pain.

We have a lot of NZ built alloy boats for sale here in Oz (Surtees and Barcrusher), which are pulse migged and the welds are a thing of beauty. They are all butter smooth and evenly rippled - makes me feel inadequate!

Cheers

Alan