Aluminum Boat Fishing Rod Mounting Plates (jakeru's #8)

[jakeru]

I welded some aluminum plate onto the gunwales ("side walls") of an aluminum boat last week. These 3/8" thick plates will be subsequently drilled and tapped by the customer for mounting a heavy downrigger style fishing rod setup, used for salmon fishing.

The gunwales of the boat were approximately 1/8" thick aluminum. Just below the aluminum, there were air tight cavities filled with foam (for buoyancy.) The gunwales were drilled for a previous fishing rod holder, which I would be covering over and reinforcing with the plate.

I prepped the surfaces by removing all paint and aluminum oxides with a flap disc (taking it down to "bare aluminum"), followed by a solvent wash.
Surfaces prepared for welding:




I also beveled two edges of the 3/8" aluminum plate to ease the sharpness a bit, and also make them easier to weld along those edges. I performed the beveling on my horizontal metal cutting bandsaw. Below you can see one plate ready for tack welding. Some weight is provided by the "third hand" to hold the plate firmly in position:


Due to existing holes drilled in the gunwales for a fishing rod holder, the cavity below being quite wet with water, there were special challenges for covering/sealing over the top. The heat of the welding would tend to boil the water in the cavity below, and the expanding steam would need to escape somewhere. If the expanding steam escaped through the weld puddle, it would cause an oxidized mess and a "blowhole". When the blowhole would form, the arc would veer off dramatically to the side (I think indicating the conductive (plasma) inert gas was being pushed away by the escaping gas/steam out of the "blowhole".) The badly oxidized blowhole area would then need to be ground away and be patched shut with a special technique.

The solution to prevent the blowholes from happening was to drill a relief hole through the plates to provide an escape path for the steam.

You can see the relief hole below in the picture of the completed weld:


Settings used:
* 200 amps peak current, 1-1.5 second downslope (regulated current by pressing/releasing torch switch.)
* blunted 3/32" lanthanated tungsten
* minimum (20% EP) cleaning / AC Balance
* #6 gas lens w/ 15 cfh argon (provided acceptable shielding even in an outside moderately windy environment)

Note: I was a little surprised that the 200 amps, 20% EP setting gave me an "instant puddle" on the 3/8" aluminum. I was expecting i'd have to wait a little bit for the puddle to form and progress, but I actually found myself throttling the current back quite a bit with the torch switch. I used the torch switch to provide "manual pulsing", and vary the pulse duty cycle (using the switch) to regulate the power. It actually works quite well for out of position welding!

[jdt1986]

did you use 5356 filler? and also what type of aluminum is the plate made of? looks good your pretty steady with that torch switch.that thing is pretty handy.
keep it coming thanx for posting

[jakeru]

I did use 5356 filler, I think I used mostly 3/32" thick (but possibly some 1/8" thick here and there.) 4043 would probably have worked just as well.

The 3/8" thick material was some kind of extruded flat bar, some 4" or so wide. Based on that I would guesstimate it may be 6061 material, but I don't know what alloy it was for sure (it was material supplied by the customer and he didn't know what it was, and it had no markings. Pretty dirty stuff too, when I received it.)

On a joint like this you can rest the cup (or if that does not work, then at least the butt or side of your torch holding hand) against a surface and just slide it along as you go; it can really help keep the torch steadied and under control.

I do also have a flex neck torch, which helps quite often with getting at the same time the proper/necessary torch angle and also a comfortable/controllable torch hand position. The torch switch is something I added/swapped onto my aftermarket torch, that was originally on my factory WP-17 torch. It has a nice, big, easy to reach switch and the way it is ziptied to the handle, I can even rotate it off to the side if needed, although I find I usually don't need to do that.
Attachment 2571

One thing I had to be careful about was not to angle (or to "aim") the torch pointing down too far towards the thin material surface, to avoid over-penetrating all the way through it (and causing one of those nasty "blowholes" I was talking about earlier.)

[jdt1986]

Whats that connection all the way on the left side of your machine?it looks like the ground is on the right and it looks like you upgraded your ground how, how much of a diifference did the ground make. How has your machine held up?

[jakeru]

The Everlast Super200P has proven itself to be quite reliable. (I think it's just about four years old at this point.)

The ground clamp is the harbor freight "400 amp" brass ground clamp. It's been nice, although the spring got a little weak since since I did some welding after forgetting to hook the clamp up - and just had it laying on a metal table. (The welding current arc'ed across the rubber spring bushing and out of the spring, setting the rubber bushing on fire, and the spring has been a little "soft" ever since!) I was not fond of the original (flimsy, stamped steel) ground clamp though.

The left most connector is a Dinse connector, which is electrically connected to the adjacent "inert arc" fitting. You see the TIG torch hooked up to the inert arc itting in the picture. The inert arc fitting provides both welding torch current as well as inert shielding gas. The plasma cutting seting is similar to TIG - cutting torch current and compressed air are both provided by the inert arc connector.

The stick welding electrode holder (when stick welding) uses the second Dinse connector. Typically for DC stick mode, the electrode will get hooked up to the Dinse at the right (positive) and the ground/work clamp will get swapped over to the left (negative) Dinse connector. I rarely do any stick welding however.

[jdt1986]

Is it a plasma cutter too?

[jakeru]

Yes the "Super200P" is a multi-function machine, with a plasma cutter function in it too. The plasma does not have pilot arc like the newer Everlast models. I use the machine primarily for TIG welding.