GV10 Stop and Start Project

[Netpackrat]

I have never welded. Is the distortion because the aluminum is not thick enough?

That's part of it. Another big factor is the method he is using (TIG) is great for some things, but large weld areas in large, flat, thin panels is not one of them. It is a slower method than mig (wire feed) and so you are heating the panels for longer while moving more slowly, which increases distortion. I understand that he has to use the equipment that he has, but a MIG welder with a spool gun would work a lot better for most of this. Another factor may be joint design in a boat that was intended to be built with plywood, available materials (need to splice panels to get the needed length, etc).

[MikeyGnz]

I have never welded. Is the distortion because the aluminum is not thick enough?

That's part of it. Another big factor is the method he is using (TIG) is great for some things, but large weld areas in large, flat, thin panels is not one of them. It is a slower method than mig (wire feed) and so you are heating the panels for longer while moving more slowly, which increases distortion. I understand that he has to use the equipment that he has, but a MIG welder with a spool gun would work a lot better for most of this. Another factor may be joint design in a boat that was intended to be built with plywood, available materials (need to splice panels to get the needed length, etc).

It is possible to TIG thin sheets, I have seen people cut coke/beer cans to get thin sheet and weld that with no problems. MIG is the better option if available though.

I am completely self taught when it comes to welding alloy and this build is a practice project to gain skill. The distortion in these particular sheets was a mixture of insufficient separation between the 2 pieces, too much current and not enough technique.

I'm finding I am getting reasonably distortion free welds on lap and outside corners and am getting much better at butt welds but struggle with fillets/inside corners which is why I have so much distortion in the bottom from welding in the frames and stringers.

I have started using the pulse function on my welder so I only get high current for the short time period when I dip the filler rod in and that is helping a lot.

There is a reason they say that if you can weld aluminium you can weld anything. Aluminium has a very high ratio of heat expansion but does not shrink back fully once cool. Being such a good conductor aluminium needs to have a lot of heat put in to start the weld as the surrounding cold area sucks the heat away, but when the surrounding area is hot as well aluminium needs less heat than the same thickness steel so you need to constantly adjust settings as the weld progresses. Also alloy doesn't change colour before melting so if you are not paying attention it is easy to go from a solid part to a puddle on the floor.

[Netpackrat]

Yeah, there's definitely the fact that welding aluminum is not easy in general.

I took a metalworking class once, and one of the things we got to try was welding thin aluminum with oxy-acetylene, which was pretty cool and also pretty difficult.

[MikeyGnz]

Been busy with work so another break in the build but back at it this weekend.

Bad welds and pinholes all fixed. Watertight compartments theoretically sealed. Second leak test to happen tonight or tomorrow depending on when I get home from work.

Doesn't look much different from when I last posted so no pics today.


I tried beating some of the distortion out with a panel-beating dolly and a hammed attachment for an air chisel. Not enough power to do anything so I tried swinging the sledge. Thais only added hammerhead sizes dents so I'm going to leave it all as is. I will try and pull the rub-rail seat straight with clamps but the rest of the boat is as fair as it is going to get.

[MikeyGnz]

Did a quick leak test of the watertight compartments and hull last night. Hull now appears watertight. 1 Pinhole in the front watertight compartment that I can easily weld. The rear watertight compartments have quite a few places where water is seeping through the welds, mainly in places where due to access I have only welded one side of the joint. Now that I have glued the drain bungs in with 5200 I don't want to put too much heat in there and in the interests of saving argon and getting in the water sooner I think I will just put a bead of 5200 along the unwelded side of each joint.

Only 7 more pieces to weld in and all metalwork will be done.

[Fuzz]

Watching your build with great interest but I do not know enough about welding to be much help.

[MikeyGnz]

Did a quick leak test of the watertight compartments and hull last night. Hull now appears watertight. 1 Pinhole in the front watertight compartment that I can easily weld. The rear watertight compartments have quite a few places where water is seeping through the welds, mainly in places where due to access I have only welded one side of the joint. Now that I have glued the drain bungs in with 5200 I don't want to put too much heat in there and in the interests of saving argon and getting in the water sooner I think I will just put a bead of 5200 along the unwelded side of each joint.

Only 7 more pieces to weld in and all metalwork will be done.

Ran out of argon so didn't get all the welding completed last weekend. Now refilled and ready to finish ASAP.

In other news, since my build has been so start/stop I'm thinking of Hop-a-long as a name.

[Fuzz]

[MikeyGnz]

Been another slow few weeks on the build. The weekend before last I got the seats/buoyancy compartments finished but not much visible progress so no photos. Last weekend I had a day up the river in the jet boat and spent the other day trying to pull some of the welding distortion out of the gunwales.

The welds where I joined the two parts of the side and bottom panels were dodgy and had some seepage when I did the leak test. I fixed this by running reinforcement over both sides but this gave me some significant distortion in an area I want straight to fix the rub rail.


I used some G clamps and steel plate to try and pull this fair. It worked a little bit

but once I got to that point the clamp got harder and harder to tighten. Applying some leverage (16" adjustable wrench) got me more turns of the handle; however, after looking to see why the gunwale wasn't getting any straighter I saw all I was managing to do was bend the shaft on the clamp. Below is after straightening it, it was so bad that it couldn't be loosened or tightened at all.


This week the jet boat trailer failed its inspection. Eyes in the springs and holes in the spring hangers too slogged out after 40 odd years of use so needs new springs and hangers. Lost all boat build time this weekend to boat trailer fixing. Dropped the boat off the trailer onto some old tyres and wooden props. Ground off the old hangers and slippers and welded on new ones. Need to buy some new U bolts but almost ready to reassemble.










While I had the welder out I decided to make a clamp that would manage to pull out the distortion. Using some 6mm 1/4" steel plate and a 20mm bolt. Lets see it bend this one.

[Fuzz]

Seems like you are getting all the joys of metal boat building You will get there but it is tough, hang in there.