First-time build Questions and thoughts

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FullMetalJacket0317
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First-time build Questions and thoughts

#1

Post by FullMetalJacket0317 »

Hello everyone,

I am new to the forum but really like the content I’ve seen so far. I have had an AAB for about 6 years now and love it, but know someday I’d like to upsize to a center console. I have read quite a bit about building and the more I think about it, the more I think I’d like to tackle one myself. Has anyone had any experience with the prefab kits/cut files online?

I am also interested in anyone’s opinion on their first build/if they have done one and why they would or wouldn’t again. I have done some basic fabrication work and feel comfortable tackling new technical projects, but I feel this would be a big step. I also thought about possibly building a small skiff first to gage if I really can/want to build a larger boat in the future. Any insight is appreciated. Thanks for looking!
alumioforte
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Re: First-time build Questions and thoughts

#2

Post by alumioforte »

If you are in Seattle, stop by our shop and try out a pulse MIG gun on some scraps if you arent already familiar with those, as you will need one. A miller 350p is a good starter grade unit. If you feel comfortable with inside and outside welds etc, then get yourself a welder and go for gold! the rest is common fab sense and following instructions. Just my 2 cents.
kmorin
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Re: First-time build Questions and thoughts

#3

Post by kmorin »

fullmetal,
my remarks are focused on the idea of building "small" as a warm up to building "larger".

I will say skiff sizes are as follows; 10-14' long (?) being small, mid-size being 14' to 18', and larger skiffs being longer than 18'- maybe beginning at 20' and larger? I'm trying to make some definitions so I can avoid sm, med, & lrg designations which are lots of times too vague.

The primary point I'd like to make is:
A) most designs feature proportional scantlings in the design.
B) A small skiff's materials (scantlings can be used as both a decription of a table of material specs AND to describe some of the framing elements in skiffs) are usually thinner than their larger sized cousins.
C) Welding thinner aluminum is much more level of effort- requires significantly higher skills (usually translated as experience) than welding thicker aluminum.
D) Therefore; a 10' skiff with proportionally thin bottom and topsides, say 0.060" or 0.080" will be much greater challenge to weld proficiently than a 18' skiff with 1/8" sides and a 5/32" bottom- for example.

Just noting the welding aspect of thinner material- it will be easier to handle, cut, fair, and cold form to a frame, a jig or to 'pull-up for tacks' the hull's panels and framing. However, tacking thin material is equally more challenging to do compared to the thicker/heavier scantlings/stiffer materials found in larger size skiffs.

So, I'd would say the better course is to build something of a very simple SHAPE in the 18'-20' range using the 1/8" min. thickness target in the design, and not to attempt a 10' dingy of 0.060" (or so). I suggest the best beginning boat project to be a flat bottom skiff of hollow sheer targeting a 20-30hp outboard mounted onto the transom cut down to the shaft length, and featuring box like seats or thwarts as compared to a V-bottom with reverse chines and more overall sophisticated lines.

A couple of the online kits I looked at, from Canada I think? were smaller in size but incorporated exclusively 1/8" plate- resulting in a very out of proportionally heavy, but still very short skiff. This is another aspect for your consideration- build the smaller sized skiff from dis-proportionally large scantlings? Would at least make welding more in reach for the low hour newbie.

I caution that the idea of starting small in welded aluminum boats may not be a logical as it may appear where building a garden shed as prelude to your new shop would be logical.

cheers,
Kevin Morin
Kenai, AK
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gandrfab
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Re: First-time build Questions and thoughts

#4

Post by gandrfab »

From the hands on welder side, a pulse machine makes welding easier but does not make a non welder a welder.
Many boats have been built without pulse and it would take more then a skiff build or 3 for me to upgrade the millermatic 251 W/spoolgun I have. But if you are shopping and building a nice boat the welding machine is far from the most expensive part.

Not that kmorin needs any affirmation, I'll also say plan on 1/8" or thicker for a 1st project.
FullMetalJacket0317
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Re: First-time build Questions and thoughts

#5

Post by FullMetalJacket0317 »

Alimioforte, I’d love to be able to do so but unfortunately am located in the northeast.

Kevin and gandrfab, you both highlight a very good point in that a novice like myself will struggle with thin material in a small boat to warm up building a larger one. do you both recommend strictly a pulse setup versus regular mig?
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Re: First-time build Questions and thoughts

#6

Post by kmorin »

Fullmetal,
no I dont' think the HAVE to has pulsed MIG to be able to build a skiff. But, once learned the pulsed MIG process allows for a finer tuning of the arc.

Let me try to use text to give an example of what I'm referring to. Normal MIG is Constant Voltage or CV; so the voltage is the primary variable of the control circuit. Therefore if you're welding and move the contact tip/gas cup up- away from the work- by even a fraction of an inch (too slight to really measure without some pretty serious test rigging) the voltage will surge a bit too. Why?

V=I/R or voltage equals current divided by resistance- so if the R (gap/distance to work) goes UP- & the current is going to change to keep the V constant. Our hand motions, while welding shift R and the power supply shifts I; in other words by moving our hands outside a very tight parallel track to the weld - the power supply automatically shifts the current !

Same if you get closer and reduce the resistance of the arc gap- this is how the wire is "burned" evenly- the power supply compensates for the variable R and I to keep V as constant as it can. A change in any of the values- V, I, or R will make the others adjust- while you weld. If you're welding 1/4" - the variations are not as noticeable since the bead is more stable- being a lesser percentage of the overall combined thickness of the parent metal parts.

But... if you're welding 0.080 or even 0.060" with MIG- those variations in your hands' movement in a normal weld bead can translate to proportionally huge!!! (big, large, gigantic) surges of wattage (V x I) and make the parent metal blow out with large voids!!!

Now, the pulse adjusts the V, I & R up and down with a program/routine/pattern and the independent variables are still interactive BUTTTTT; the welding power supply is not reacting (primarily) to the R of the gap with the same priority in circuit control. The pre-programmed pulse takes precedent- therefore tiny movements of your hands aren't as critical to the weld bead wattage.

By imposing a voltage/current 'pulse' of power increase and decrease- the pulsed MIG stabilizes the arc in a manner not used in the older/previous control algorithm of purely V=I/R. Now the pulse is going up and down so many times a second- regardless of your gap/R/hand movement.

In thinner metals this control allows more hand inconsistency, inexperience, lack of uniformity by comparison to the older 'straight MIG' modes of arc control. Therefore; pulse will allow anyone's skill level to be MORE APPLICABLE, to thinner material with more control than an older control scheme.

But being able to lay down a uniform MIG be in aluminum is still a requirement - a prerequisite to welding with pulsed MIG.

Would I recommend pulsed MIG over straight MIG? yes for thinner material- especially anything under 1/8"! However, for a first skiff project I'd focus on a mid-sized, flat bottom, traditionally shaped skiff of 1/8" or heavier scantlings using 0.035" 5356 wire. IF can afford pulse? well it will be there to add to your project once you learn to use it.

I'd recommend at least 100 hours of welding time on scrap and off-cuts before bothering to build a skiff.

Cheers,
Kevin Morin
Kenai, AK
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alumioforte
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Re: First-time build Questions and thoughts

#7

Post by alumioforte »

another thing- pulsed machines put a lot less heat in to the metal. So you get less wavy potato chip effect on a hull side.
In reality, a pulse machine is not that expensive. You can get a 350P with a push pull gun on craigslist for less than 5K.
Would I instead spend 1K on a Miller 252 with a spool gun to build a skiff? No way. Because both machines could be sold again after the project is done for about what you paid for it.
As you notice, on this forum there are a range of very different and assertive opinions and all of the above are by very experienced people, so the long story short, is they are all right. The deciding factor is what is your objective, to have a good time and build your own quality boat, or be the maserati of aluminum boats and be uber epic.
kmorin
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Re: First-time build Questions and thoughts

#8

Post by kmorin »

alumio, Fullmetal,
alumio's point in regard net heat or total wattage imparted by welding with Pulsed Vs Straight MIG is very important and I should have mentioned that fact.

The wave of up and down power/wattage surges allows the MIG bead to melt the parent metal and wire on the upsurge and "cool" by reducing the power on the down swing of the wave form- so like any sine-type wave- the NET or average power is lower than the flat line "straight" MIG which would be a constant amount of power- at least enough to melt/fuse/weld the parent metal AND wire.

By using the up and down wave for power there is less net wattage/power/heat added to get the weld done. Less heat on a weld- still with the adequate penetration- means the aluminum sheet expands less along its edges when being welded. Therefore- the metal has less contraction to do when the puddle freezes and the overall area cools back to room temp.

The wave can have a higher high peak - where the weld has a short period of time at much higher wattage than a standard weld setting (ie one so high you'd burn through if the setting were constant) and then drop to a much lower setting where the weld might not even 'sustain' or keep welding. However since neither of these conditions is kept for more than a part of a second; the result is penetration and puddle edge "wetting" from a very high setting; coupled with a chilling effect at the lower or background settings- allowing the weld to stabilize and not sag or droop in the other part of the wave's cycle. These two features add up to an improved MIG weld.

This (reduction in overall heat/wattage) results in less wrinkling of the hull plates- especially in the more difficult 'field' welds where you add longitudinals inside and outside the hull- or where transverse frames or bulkheads are welded to the bottom and topsides. The keel, chine, and sheer welds (edge to edge and lengthwise at the outside of hull panels) are easier to keep fair- without wrinkles- because the tension along a hull panel's edges translates to a overall convex shape, but not necessarily wrinkles. Where welds half way from the keel to chine, or chine to sheer do result- more often- in contraction wrinkles or waves - and these are areas where Pulsed MIG REALLY pays its way.

What this translates too in practice is; a lower hour welder can use pulsed MIG to produce reliably proportional beads on thinner metals ONCE the correct adjustments are made to the power supply for the weld section, material scantlings, wire and skill level (usually steady rate of travel at a given speed of movement)

wanted to post total agreement with alumino's points about pulse. It is, I THINK, however, plenty-rific mo' dough! (and I have one!)

Cheers,
Kevin Morin
Kenai, AK
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FullMetalJacket0317
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Re: First-time build Questions and thoughts

#9

Post by FullMetalJacket0317 »

Kmorin,

I appreciate your in-depth explanation of pulse mig. It definitely seems like it’s the way to go when building Aluminium.

Do you think it would be worthwhile to buy a regular mig setup initially, practice running beads and then if I feel comfortable to attempting to build a small skiff as you described, graduating to a pulse mig? I have very little welding experience and would like to get some practice and feel like I have have a reasonable amount of experience before tackling any project.

Regards, Brian

Regards, Brian
kmorin
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Re: First-time build Questions and thoughts

#10

Post by kmorin »

Yes, Brian, I think buying a simpler, less expensive MIG rig is the way to go for a first skiff. AND I'd recommend finding a local welding shop that can do some TIG work for you too.

Seams, longs, ribs, bulkheads and all the other longer welds of the hull can be done well in MIG... but the ends of rails, intersections of chines and bulkheads, and countless other small "Corner Joints" look MUCH, MUCH, MUCH better if you can do them with a TIG weld.

Remember that MIG uses the wire to create the arc- no wire=no arc. Also; no arc=no heat or fusion of the metal so you have to make a deposit of wire to heat up the metal and fuse it in welds- MIG is great for longer seams.

BUT... TIG (tungsten gas welding with a torch and electrode that does not enter the weld puddle) allows a welder to add wire/filler OR noT to add. So the arc can be kept "lit" even when there is not filler being added.

Why is this a nice touch with skiff building? At the end of a long seam between two hull panels- like the keel or chines, another or third pieces appears- as the chine or sheer reach the transom Or the bow stem- for example.

So, unless you're experienced with MIG/wire welding you'll find the settings to be bit cold- that is not set to weld the thicker parent metal intersection. The previous MIG settings will be for the two edges of the longer hull seam- add more parent metal (?) and the weld can be "cold lapped" as it is called. Very common circumstance.

So, if you'd like to do a nice job of a skiff? I'd suggest you spend some time organizing to TIG weld the corners, ends and even to 'float' MIG welds on tanks if there are leaks?

If you're just getting started with MIG welding- then TIG welding will be an added burden and slow your learning progress (unless you can work full time on the project?) so... my suggestion to locate someone in your area who can to a bunch of 2"-3" welds in the corners, ends and overlaps of various parts and pieces of a typical skiff build.

You can use MIG to do these welds' "ends" and transitions, but it is very typical to need a much higher torch motion- not really an out of proportion travel speed motion.... but, an out of proportion motion of the MIG torch body to get the arc/weld angle in these joints.

For example- lots of skiffs have pipe or other rounded shapes at the sheer line- along the top of the topsides. These may be ended with miter cuts or with various other shapes and joints- but.... they all have one thing in common- MIG welding a 2" or 1-1/2" pipe miter is going to require some pretty athletic movement of the torch to keep the wire fed at a correct angle to weld.

Consider for example a hull seam? there you can set your hands to hold a torch angle that is good for the gas coverage, lead and arc angle .... and simple move along the seam with that approximate angle - regardless of weld travel speed torch motion is sort of parallel to the work seam.

Not so with an extrusion shape, pipe end or other trim piece ending weld! There you have to go at MIG speeds around the pipe or bar or pad- and that is what I meant about high torch movement (not referring to the gas cup) and that is a bear cat. To keep the arc angle correct in this case- you have to swing the entire torch around the joint- while keeping the gas cup and contact tip aimed at the weld joint....!!! Much easier to weld those joints with TIG..... But TIG is an added equipment and learning burden, I admit.

Another solution, not one that is too attractive, is to sand off lumpy MIG welds that were done at the ends of longs, rails, seams in order to be able to stay with MIG but still have an attractive result!

Cheers,
Kevin Morin
Kenai, AK
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Re: First-time build Questions and thoughts

#11

Post by gandrfab »

And welding is easy, the metal does not fight you. Just a misunderstanding or miscommunication.
FullMetalJacket0317
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Re: First-time build Questions and thoughts

#12

Post by FullMetalJacket0317 »

I think now I have a rough plan of purchasing an entry level MIG welder, do you have any recommendations on what machines would be a good option? I’d like to get something to first practice with and work my way up to being ready to build a small skiff.

My other question is, does anyone have any suggestions on preparing for a first time build? I of course want to practice welding, but I am also interested in any books, video, or anything anyone suggests as a means of learning to better prepare for his project. I have read quite a bit of content on this forum, but looking to absorb as much specific information as possible.

Thanks, Brian
kmorin
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Re: First-time build Questions and thoughts

#13

Post by kmorin »

Brian, is there a community college or trade school near you your location? Many time these programs offer welding courses for a very reasonable fee? This would work to give you some welding time, close by instruction and allow you get to your 'feet wet' without having to buy equipment?

Steve Pollard has a book on welded aluminum boats, and here's an older book by Gilbert Klingel (low cost copy from Alibris : https://www.alibris.com/Boat-Building-w ... ?matches=8

https://www.alibris.com/booksearch?keyw ... x=0&hs.y=0 some others by various authors.

I have a set of posts located at Glen-L Forum in the Metal section, and some of these posts might be helpful? I try to use illustrated posts for the novice to become more skilled in those posts- so they can help in the overall picture of learning to work with aluminum.

As to a power supply and torch- I'd say the highest resale value (you'd mentioned working your way 'up' so I'll presume this power supply will be for sale as you improve your welding skills?) will be with the Miller and Lincoln brands... but the initial costs will be lower with the imported brands from the orient. There is a site focused on welding " weldingweb.com " which is quite large in membership. They have an archive that you could read for months about different opinions on new or used welding power supplies or torches for different applications.

Jodie Collier (last name sp??) has a web site called <weldingtipsandtricks.com> and he shows all kinds of welding in videos and gives a great commentary on his circumstances, work procedures and other details that is a treasure trove of information.

Hope this helps you to become more informed about your search for information on building your own welded aluminum boat?

Cheers,
Kevin Morin
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Re: First-time build Questions and thoughts

#14

Post by gandrfab »

The line between saving a buck and ending up with junk is hard to find.

Like a electric guitar,
You can get a very expensive one with all sorts of controls and options and still not be able to play the guitar. I have a thread on that subject here. kmorin saved the day for that machine and myself.

Or you can get a guitar that has everything necessary, body, neck, strings, frets, head stock, tuning pegs.....that can never hold a tune. Leaving you forever chasing the notes.
I'm a Miller fan, Lincoln 2nd and I have seen Hobart run hard by idiots.
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