Glen-L.com

Hey.

I am thinking about undertaking a small aluminum boat project to test out my ability to eventually build a trawler or motor yacht. I looking at various kits for a smaller boat, I have seen that I will need to tack weld pieces in place, before making the full seam and other structural welds.

I have zero experience in welding. I was wondering about the feasibility of using one of the brazing bar products to tack weld everything in place, and then letting a pro come in and do the seams and "real" welding.

Does this sound like a fool's errand. Do I have to bit the bullet and buy a mig, and then learn how to use it?

Doug Hilton
Madison, VA
No boat picked, yet.

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Doug Hilton
Madison County, VA

Not building now, dreaming of crusing the Loop in my trawler yacht.

Doug:

Just a thought... Check your local community college for basic welding classes. I know the one in Lynchburg offers them, but can't vouch for them. My experience is limited to stick welding farm equipment. Not that difficult... just takes patience and practice... my work was nothing to brag about, but it held the bush-hog together.

welding aluminum is a different critter than regular welding If i was serious about doing a boat out of that material I would take some classes for sure and practice allot

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Don't be afraid to attempt anything. You might surprise your self in the attempt.
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Modified Jubilee-"Wild Flower" 40' house boat
14' Mr John-Wild Flower 2
32' Supper Huck- Wild flower 3

Rod H

Hey Doug , look up alumalloy on the net , they did an infomercial on this product , made welding aluminum look very easy , but you know it always looks easy with a ton of practice.

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Rick

I had a conversation with an expert welder over a repair to a small engine using a product similar to Alumalloy. Basically, it can be used to fill a hole or build up a small area of no stress, but it has very little strength, and worse for your purpose it will cause contamination of the weld when they go to finish weld it. I wouldn't advise it. If you are going to tack it and get somebody to wled it properly, use a mig to do the tacking as the welder can then just weld over teh top or clean out your tack if needs be and finish it off.

I kinda like welding, and have done a fair bit over the years, but I am still wary of aluminium welding as it can look great, but be just sitting on the surface with little or no penetration (of course that may just be my stubborn old school attitude). If you want to weld it yourself, get at least basic tuition and practice, and get an expert to check over your first few welds to help you get the technique right. Do buy a MIG if you can, a Bloke can never have too many tools. Steel welding is a breeze with them and fun. You use the same welder with different gas for ally. Mine doesd TIG as well, which I haven't tried yet.

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By the time I have built a boat, I'll be ready to build a boat....

Thanks guys.

This is about as I figured. If you are going to undertake a project like a boat, don't do things half way. I was worried about the possible contamination of genuine welds later on.

This is all way in the future for me at this point. If I ever do take the plunge, looks like I might be going with plywood/epoxy as my method of choice. I think it may be a drop off in the end strength of materials, but I am far more confident in my workmanship not being the problem with my boat later.

Thanks again.

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Doug Hilton
Madison County, VA

Not building now, dreaming of crusing the Loop in my trawler yacht.

Doug, building a full sized power boat in welded aluminum will require literally hundreds of hours of MIG and plenty of TIG or you will waste the money spent on the metal. It would be much more reasonable treatment of your trawler's metal value to be sure you can weld before you take on a big project.

I have beat this dead horse here at Glen-L before.... but will take another swat at the carcass in reply. The smallest boat you should begin to built is about 16-18' LOA made of 1/8" or thicker material otherwise you will run into problems welding. Even experienced aluminum welders have more problems and find it harder to weld if the material is less than 0.100" or 0.080" thick- so I'd recommend you stay with 0.125" and heavier as this material is much easier to weld with standard MIG equipment. The idea of building a 'small' boat for practice in welded aluminum doesn't take into account the materials' difficulty if you go below the minimums shown here.

Discussing a skiff as practice; there is no* other method besides tacking with MIG, then cleaning up the tacks and finally, welding out; in sequence. The work can be done in TIG but that is not as easy as MIG. [* 'no' is used here to indicate not widely used by more than 1% of builders].

I think a new builder should build the Glen-L 20' (18-22') dory - Hunky for example- as your first welded aluminum boat. This boat builds well in aluminum, results in a great work boat hull that will move well with some outboard (bolt on) power and likely sell to recover it's costs to build if you build her well? I'd suggest trying several of these class boats before taking on a larger boat, after the Hunky, I'd suggest you move to the Chinook and put in a welded deck instead of the ply option shown on some plans. Then I'd suggest you consider a power boat of the 20-24' class - maybe one of the tugs with an inboard- say Titan as Carlos is building now? There are several other metal plans sets here that would provide you a good sequence of boats leading upward in size and complexity.

My reasoning is that the steps from skiff to trawler are not linear they're exponential or greater. In order to be successful in the larger project I'd recommend you take smaller steps and build more and more complex boats - beginning with and simple open shape with outboard and moving to a more complex hull shape -then adding inboard power and mechanical systems and finally I'd say you'd be ready to spend the 'big bucks' to buy a trawler's BOM.

As the man hours and costs of a boat go up in proportion to displacement, not length, the difference between a 20' skiff and a 40' power boat is not double the work or cost. The skiff displaces a few hundred pounds- maybe 350lb. ? That 40'er will displace hundreds of times that wt. and that is how much more is involved in building the larger boat; hundreds of times the costs and hours.

I do think anyone can do what you've mentioned in your post if they have sufficient drive and interest; but it wouldn't be realistic to expect to make a single step from too small a skiff, with the wrong welding ideas, and expect to be prepared to build a full sized power boat.

Cheers,

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Kevin Morin

Thanks Kevin,

I real life, I am a lawyer. In that profession I run into many people who think that something should be easy, when I know its a genuinely complicated problem.

So, I have a sense for what's going on when experts here tell me I don't understand the scope of my "problem".

I am convinced. I have to either invest the time to learn how to weld a big boat right, pay someone else to do it for me, or stick to skills I have a better mastery of.

From elsewhere on this forum I know there are dangers in assuming that my carpentry skills as a DIY homeowner will allow me to build a wooden boat either, but it seems like a better bet to work my way in that direction rather than undertake a new (uncompensated) career in welding.

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Doug Hilton
Madison County, VA

Not building now, dreaming of crusing the Loop in my trawler yacht.

Hi doug
I am building the Monte Carlo and started with no work working experience so dont let that keep you from building. The nice thing about wood is if you screw up a piece just glue another one on and keep going.

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John Amundsen
Monte Carlo
Winter Haven, FL

Maybe it will be done by G6 and maybe not.

I wouldn't say that about Home DIY skills not helping.

Depending what you have done,you already know how to handle wood,saws,hammers,sanders,brushes,rollers,screws,etc.

You just need to fine tune your skills to pull it all together in a shape of a boat,and pay more attention when picking out the materials

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Boat building can best be defined as an endless series of
tragedies obscured by the occasional miracle, followed by a good bottle of beer.

Don't Dream Your Life, Live Your Dream

Whoops

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Steve Schefer
Santa Rosa, Ca.

New Years Resoluiton - Never leave something for someone else to do when I should be doing it myself.

Since the topic has wandered a bit, and DougHilton, is able to take time to plan the project I'll make some remarks about the value of money spent on welding machines, and to some degree this will apply to other critical path tools. My net point will be: don't buy hobby scale power supplies, buy the real thing.

Welding (fusing molten metal at human movement speeds) is essentially an art because some folks learn to do it better and faster with less effort in the learning; than others. And with sufficient refinement of skills welding becomes not only a functional fusion of metal(s) but is also esthetically pleasing aspect of metal fabrication. However, weld quality is dependent on the purity of the weld deposited and that can be effected by two primary means; skill or/and arc controls built into the welding power supply.

(since) Welding is the key or critical path to welded metal boats so combined with its variable rate of learning, money spent on 'the best' welding power supplies is returned by reducing the skills required to (learn to) weld and reduce the time to develop those skills by employing digitally controlled circuits to enhance the new welders' "hands". Much as a word processor in this dialog box underlines the words I've misssspellled so I can correct them, newer digitally controlled power supplies provide arc controls that are worth the costs.

When you consider the million dollar value associated with a large welded aluminum trawler yacht, once it was complete, the cost of a few thousand more for a power supply or two is not worth saving.

Buy the Miller Dynasty 300 or 350 DX (or larger) TIG power supply and learn to TIG weld with that power supply. I use the OTC TIG Gun (no longer manufactured) on this power supply and find it worth the cost of the both pieces of hardware. They cost approximately 10K $US for the pair, but may be found used for less. ANY TIG torch you consider should be 300A rated and water cooled and be capable of at least 5/32" tungsten or it will not be near large enough for a full sized yacht.

Lincoln's Power MIG series power supplies, MP350 for example, with a push pull feeder like the Python or Cobramatic from MK are the best choice for a MIG set up and will allow the work implied by a large power boat. Miller makes a similar power supply but the difference in the two companies is that Miller's TIG controls are 'better' and Lincolns MIG controls are 'better'- IMO.

In each case, both companys' professional quality welding equipment will work fine, TIG or MIG from either company will do the work well. My opinion comes from owning many power supplies from both companies and from thousands of hours of looking at an arc while welding aluminum, I prefer the Miller TIG controls but I still have a Lincoln 300/300 TIG power supply but have sold all the Miller MIG power supplies with spool guns I've had; to retain the Pythons, and Cobramatics on a Lincoln MIG power supply. And, yes, I agree that if you welded those thousands of hours you might come to completely different conclusions, so I'm not saying these choices are definitive; just reporting an opinion.

I'm not building full time and the tools we have are like any other overhead in a business equation, but I can't see any "savings" to the boat builder buying minimally capable power supplies when the scale of the project is as large as you've outlined. One or two skiffs might only justify lower amperage power supplies and a spool gun for MIG instead of the push-pull I've advocated, but when you build a hull over 24-26' the spool gun is not in scale to the work. I'd also suggest you learn with a TIG pencil (wire feed) from as early as you can so that TIG can be higher quality earlier in the project, regardless if its a skiff or larger power boat.

Cheers,

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Kevin Morin

For example, newer MIG power supplies have arc controls that simplify welding in different conditions. In the past using different welding wire diameters was only compensated for by increasing the voltage/welding power so that more voltage would melt/vaporize a larger cross section wire and therefore create a larger molten puddle which melted thicker parent metal.

Now, may power supplies have 'wire ranges' that is built in voltage and amperage combinations for specific wire diameters and filler metal alloy. Formerly a welder's skill was required to weld a good bead with either 0.035" 5356 wire OR 0.035" E70-6 hard steel wire; now these power supplies have settings for each. Inside the setting ranges are fine adjustments but the power supply will (almost) automatically default to a range that will weld a decent weld- right out of the box.

Aluminum is more heat conductive than steel (7-10X more ) so the heat of fusion happens for less time, thank heavens or the puddle would drop on the floor in a wet splash, and that used to mean weld speeds had to MOVE right along. Now, digital controls surge the voltage and amperage up and down so there is created a hot flash of weld heat which allow deep fusion only to instantly cool that same flash before the weld metal overheats. This Pulsed MIG is very handy and is so controllable that by using default settings most new welders can achieve a decent bead in aluminum MIG in a few minutes practice. In fact, there is a Pulse WITH Pulse which even more exotically heats and cools the weld puddle achieving even more penetration with less net heat conveyed to the parent metal and appearance is enhanced as well.

Formerly, 60Hz transformer based power supplies, didn't have digital circuitry controlling the various arc effecting circuits and therefore these new arc controls were wholly impossible to achieve. As a result welders spent many hours learning to make uniform precise and repetitive movements of their MIG bead in order to get the best appearance while achieving the best penetration and joint strength. Whipping a 0.045" wire bead on heavier (>1/4") plate in order to have the power supply's voltage up high enough to get single pass fusion was something to learn. Voltage was kept artificially high and that lead to a spray mode transfer, which was then converted to short arc for appearance and closure by changing the length of the contract tip to the work (resistance change/reduction would make the power supply reduce amperage to keep voltage equal) in a series of syncopated movements tracing an endless line of lower case 'e' s with the torch. This method allowed a row of dimes look, hot spray mode molten fusion and then a short arc cover and cool down instant that was considered the best bead.

Now a welder can 'dial' in a weld that is constantly converting from spray to short arc droplets by using the digital controls. This reduces the learning curve by at least a few hundred hours of welding.


Cheers,

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Kevin Morin

I mentioned that aluminum transfer's heat faster than steel which results in a faster 'freeze' time in the weld puddle and this is a very large factor in learning to TIG weld aluminum as well. One very effective way of controlling weld beads, as mentioned above, is to add 'too much heat' and then 'too little'- in a rhythm that allows the aluminum to melt deep into the parent metal and then cool down somewhat so that the puddle is strong enough to 'stay put' and not drop out.

This is true of TIG welding as well where the welder usually uses a remote amperage control (Constant Current instead of MIG's Constant Voltage) to increase and decrease the 'heat' which controls the size and depth of the weld puddle. In the past, many welders had learned to add heat and filler rod then cool the puddle and repeat that process so they were able to weld large puddles that reached deeper into the metal but not have the entire weld so hot the seam just sagged like a overly hot candle. You may have heard the term 'row of dimes' used to describe those welds, and that is not as easy to learn to do with older power supplies.

Pulsed TIG in its simplest form could be done with the pedal or torch mounted controls but that requires the welder to constantly and uniformly push and release the pedal or roller pot or slider up-and-back to add and subtract 'heat' in the puddle. Now with digital controls this control is built in, where you can configure ("program" as they say) the weld output to surge to an amperage for a time, then revert to a lower amperage for a time and repeat. This is rough description of pulsed TIG and it means the new welder can achieve penetration, full fusion and great appearance in a very short time compared to the same weld being accomplished by a new welder using the older transformer machines. [Of course, if anyone had the great enjoyment of welding with the Hobart CyberTIG series they asked to excuse my generalization about 'older' power supplies! I truly enjoyed my first CyberTIG300 with the 120 drawer.]

There are several other aspects of newer digitally controlled power supplies that enhance the welds they deliver without requiring near the skill, implying less learning time, that was formerly required for that same quality using transformer based and analog electronic sensing and control circuit based welding power supplies.

The value of the increased cost of these new power supplies is proportional to the increased costs in increased weld quality; achieved at lower hour stages of learning. Further, there are welds which cannot be done to the same level at all, regardless of welders' skill level, without these newer digitally controlled power supplies and therefore the final welded boat can be of a quality not formerly possible, even in shipyards. As an example to illustrate this last point, (or exaggeration as some may view it?) even the most capable photographer can't equal what the weekend tourist captures as long as the tourist can import their pictures into Photoshop or some other digital environment to edit the image. The most talented draftsman couldn't draw a 3D view of a large structure in a week's time but a Jr High student can do a hundred views in twenty minutes with a digital processor and a 3D CAD application.

Cheers,

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Kevin Morin

Fully agree Kevin, in my first post I was thinking the OP wanted to build a small boat project and, if he completed it successfully then move on to a bigger project. In either case he was talking about tacking for the most part and I couldn't see him spending 8000.00 on something like a Miller Dynasty 350 TIG runner for a bunch of little tacks. I thought I understood that he was going to have a pro welder come in after that and do all the finish welding.

My assumption was that he would also do that with the larger boats he had in his minds eye since the construction of the larger boat is quite a difficult project. So, if after completing the first project he decided the bigger projects were too far beyond his skill level, he could easily sell the welders since they are in high demand by home hobbyist.

My personal outake is to size the welder to the project since most of us only have enough spare time to build one or two boats in our lifetimes. In my case (Canyon Cruiser) I bought welders that would be adequate for the project. I had enough experience with MIG but none with TIG. I bought a transformer TIG machine but it has some of the basic new functionality (pulser, A/C balance control, post flow) and that's given me enough to produce some quality welds with practice.

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Steve Schefer
Santa Rosa, Ca.

New Years Resoluiton - Never leave something for someone else to do when I should be doing it myself.