Conchfish AL 17.6T build

[m32825]

Kevin,

I like the little keel things, just don't know if I can weld them yet. The tunnel takes out the last couple feet of the keel bar and there's not a lot of skeg in the water, so a little help with directional control towards the back is a good thing for high speed turns. That said, I could trim them off and convert that joint into something a lot closer to an outside corner.

I reduced the short leg length to 1/4" for my practice session this morning, same height as the real deal. I kept melting the top edge though. I experimented with pulse settings and that seems promising. The section around the 2" mark looks pretty good, but the edges aren't as blended.

-- Carl
​​​

IMG_20240610_073804273_copy_1600x900.jpg (59.59 KiB) Viewed 6475 times

 
 

[m32825]

More fillet practice with a 1/4" short leg. Last week the first half was too cold and the second half was too hot, so I focused on that. I like most of the second half of this one, the first half is improved but still on the cold side. Most of the "bites" out of the upper edge were from my initial tacks.

IMG_20240615_092827825_copy_1600x900.jpg (59.69 KiB) Viewed 6419 times

Tried a fillet around pipe for variety. Took about eight segments to get all the way around. Looks like it could use more heat. Kind of surprised that I managed not to dip!

IMG_20240615_093318256_copy_1600x900.jpg (49.02 KiB) Viewed 6419 times

 
 
 
 
 

[m32825]

Kevin,

Thanks for posting the aluminum finishing thread in Helpful Hints. Very educational. I want to etch mine and leave the hull unpainted. The area I fish often has clear water, but when there's a lot of rain there are more tannins in it. I think I'll need some kind of surface treatment to preserve a uniform appearance. I'd be fine with dull gray too, as long as it's uniform.

The deck and cockpit areas need something for traction, reflection control, and heat on bare feet. I'm looking for functional, not a beauty queen finish. I've seen spray on bed liner suggested. If it's a good fit for a truck bed it should be durable. Would have to experiment to see how well it adheres.

-- Carl

[kmorin]

Carl, the latest fillet weld looks good. Not sure the first half (right on screen) is too cold. I think its just a slightly wider arc cone wetting a bit more metal.  If it were actually cold I'd expect to see some curl at the toe or top and I don't - the fusion shape is good. I will agree the 2nd half if more uniform and maybe the arc (tungsten to work distance) was shorter so the bead is just slightly narrower and the movement/dip seems more uniform. 

Nice weld, I'd take it on my boat.  Getting the pure machine-like 'stack of dimes' is accomplished by both repeating the work and having muscle memory that will deliver uniform movements.  A non-trivial exercise! 

I used the online post of about painting to reply to several people's conversations, including some here in my shop.  Truck bed liner will coat aluminum fairly well, but the remarks about adhesion still prevail in regard preparation and durability. 

One step we've used here is to paint fully to a top coat. Then tape off the areas for "traction-ization" and mix the same topcoat paint both color and mix, and add white filter (silica sand) sand to mix. This allows the top coat to encapsulate the sand particles which are then trapped in an epoxy layer but still provide a good traction when walked over.

I'm not sure what your decks will be (?) but 3M(TM) Traction Tape has worked well for us in the bottom of beach net skiffs. This material can be put down on buffed/anchor patterned/abraded aluminum and will stick pretty well for many years.  I heat the sanded plate and use a linoleum roller to press the tape down to the warmed sheet/plate.  It won't do anything for temperature and is often only available in black... so it may not be very conducive to hot climates?

Also aircraft 'wing walk' can be troweled on to taped off areas and will adhere well and provides an area-wide uniform traction coating. However, its only black in my experience so not sure the temperature issues will be resolved - but the walking safety is pretty good.

Plywood decks may be the fast, low cost temperature tolerant decking solution?  Plywood can be encapsulated in soaking epoxy, the top coated with thicker types, and finally sand and color can be added to create a very long lasting decking that could be thin, light but still have a "traction-ized" surface. 

Yes, truck bed liner products will adhere to aluminum pretty well if the metal is prepped. I'd want to be sure I understood the mfg's recommendations for aluminum application and even test patch it a bit.  Spraying bed liner is one option, paint roller application is another I've seen and that way you could reduce the taping to avoid over spray - or taping and completely draping to prevent getting bed liner applied inside a skiff on topsides, seats, and any area you want to leave clear.

Cheers,
Kevin Morin
Kenai, AK


 
 
 

[gandrfab]

Talk with the line X guys. It's not a DIY project but seems like a very good product.

[m32825]

My deck is 1/8" aluminum. Some guys are using SeaDek, which certainly addresses heat and reflections, but I want something more durable.

Did some research on Line-X, seems to check a lot of boxes. Looks like the guys down in Sarasota have experience with marine applications over aluminum.

I'm up for etching scale because I can see how to do that. Hydrochloric acid will dilute and break down pretty readily. Going beyond that seems like a job for the pros because of all the chemicals that have to be properly handled so as not to create an EPA superfund site.

-- Carl

[m32825]

Worked on fillet welds more this week. I had been using 3/32 filler but switched to 1/8. I seem to do better on a normal fillet with larger filler. I haven't been able to do the short leg fillet with 1/8, but maybe that will come with time? Maybe that's impossible?

I got a better start on this sample, decent restart at the 2.5" mark, and controlled the heat at the end. Lots of things to like. Now if I can just do all that and be more consistent.

IMG_20240622_095859174_copy_1600x900.jpg (64.53 KiB) Viewed 6269 times

 
Let's see if this works, video of the above weld from the restart to the end. It's a little awkward welding around the camera, so I'm going to blame that for my lack of steadiness.

weld video
 

[gandrfab]

Start out hotter and once up to temp back off the heat, then still use more heat then you are in the video, higher travel speed.
Practice, it will get smoother.
Maybe a better smoother hand rest. Practice the weld stroke you will use without any arc. Nice and smooth cold, once comfortable run with the heat on.

Don't want to ease into the start, it heats up the surrounding metal more than it needs to be and will help create more warping.

[kmorin]

Carl,

I agree w/ G&R, I'd add more heat/amperage to begin and get a full width puddle sooner- in less time than shown.  I realize that caution still plays a big part in your reflexes but adding more heat and getting a fully wetted puddle sooner will help you to keep overall heat slightly down- G&R mentions that too. 

One thing you might try is to do a 'pull up' just after the arc forms and stabilizes. This will widen the cone of the arc instantly so when you drop back in closer the parent metal has been heated in a slightly wider area. This can help form a fully wetted puddle a bit sooner.  In your video you went back and forth, a puddle width or two, to get parent metal wetting by building heat from longer duration instead of increased amperage. 

You can build heat by adding pedal/slider/amperage or by lifting the arc or by making the torch more 90 deg to the direction of travel even when the angle between the two plates is 45 deg as in the fillet shown.  In coupon welds, this can lead to overheating due to limited mass of the pieces so you'll end up dialing WAY back on heat to end the weld.  Not such a problem in the hull with the much larger mass to soak up heat.

Next, IMO the arc was directed too high; it seemed mostly above the center-line of the puddle. While the lower edge (toe of the puddle) does fuse, it doesn't do so continuously and I prefer to keep the arc lower in the puddle so both toe and top are wetted pretty much all the time.  The center leading edge of the puddle shows a little bit of concavity- not convexity - (to me) hollow outline there indicates a bit more pedal/slider/amperage would help.

The ripples are just a little 'lumpy' for my weld bead.  By this I mean that the inter weld ripples (edges of the "dimes" overlaid) are a bit too high compared to the face or the adjoining puddle.  IMV this comes from the puddle chilling too fast and that means too much rod volume added, slightly too low amperage, slightly too high travel speed for the other two variables;  I'd use very slightly less volume/length of rod, a smaller diameter filler OR just that tiny amount of extra amperage to 'flatten' the puddles' faces just a bit more.  

I'm splitting hairs in these remarks, but if you hold the sight picture of a good weld as you practice you'll improve more than if you accept slight differences as 'normal'.

Carl, I think your skills are building very nicely and this is exactly the type of practice hours that build reflexes you'll need when you get on your hull's seams.

Cheers,
Kevin Morin
Kenai, AK
 

[m32825]

Haha, I knew if could get video it would result in good feedback and you guys did not disappoint. I will work on "hotter and faster" this week. I added 15 amps and did the other side of that tee joint with smaller steps/dabs. The first half looks pretty good, second half after the restart got too hot and is a bit concave.

IMG_20240623_053908435_HDR_copy_1600x900.jpg (57.73 KiB) Viewed 6199 times

 
 

[kmorin]

Carl,

I haven't welded for a while (old joints ache a bit) but decided to try to run a few inches to show an example of a 'flatter bead' where the puddles' ripples are (more) uniform; not too 'lumpy'.  This example was done with a very small filler, fed by a cold wire feed TIG gun, but is provided to try to illustrate a proportion between the filler volume and the weld profile. 

Lots of filler will often give a greater surface irregularity- more ridge between the separate puddles.  In many years of bend-break testing my welds I find the flatter more uniform weld face is actually stronger than one with more ridge or rise between puddles.



1/8" plate, 5086; 3/32" pure tungsten bulbed/domed not balled outside the electrode profile, filler is 5356 ; 0.030" wire. Miller Dynasty 300DX w
72% cleaning, 160 Hi-Freq.  165 Amp max. (can't see amperage while under hood) using remote control pot for amperage. About 30 CFH 70/30 (Argon/Helium).


Ruler for scale, narrow bead is about 3/16" to 1/4" wide on face on 1/8" mtl' inside fillet.


Closer view of 1st half of the weld (right to left) showing ridges/ripples between puddles to be relatively low profile.



End view trying to show the ripples/weld face relief to be low. Toe and top legs of each 'C' or 'e' flows into parent metal and there is no curl of the bead lines under the bead - all flow lines are into the parent metal.


 Dime for scale. 

Carl, the purpose here is to illustrate what I've remarked about in my posts above.  Trying to get a TIG bead that flows into the parent metal at both top and toe of each puddle along the bead is important and keeping the face of the bead relatively flat, not too bumpy/lumpy reduces stress raisers and also keeps from having a saw tooth edge to the weld which might increase failure along the HAZ.

Also, working to establish a uniform movement (travel per dip) will help you establish more uniform puddle width.  BY metering the amount of filler added to any given puddle you'll more closely match wetted area and depth of penetration with the added filler volume and this will help keep the weld face more uniform which, in turn, helps keep the HAZ and weld edge more uniform and less saw toothed.

Please remember that I use wire feed TIG gun to weld, so I have "both hands on the handle" and I'm not trying to weld using "two hand dip".  Old carcasses don't move as well as they once did so; I can use all the help I can get!

images for sight picture as you practice your bead.

Cheers,
Kevin Morin
Kenai, AK

 
 
 
 
 
 

[m32825]

Kevin thanks for the pictures and explanation, gives me specifics to focus on.

My skills have developed to the point where I can imagine having an inch or so of weld bead that I'm happy with here and there on my boat. Which is to say: big progress!

This attempt came out better from a step size and uniformity point of view.

IMG_20240624_201004003_copy_1600x900.jpg (47.77 KiB) Viewed 6171 times

 

IMG_20240624_201517322_copy_1600x900.jpg (50.11 KiB) Viewed 6171 times

 
 
 

[kmorin]

Carl, I think you're ready to weld out your boat; surely in terms of TIG welds, at least.

The images show a clear progression from 'getting started' to a very nicely uniform bead with great cross section and fusion lines.

I'd suggest you stay with the TIG practice and add some MIG beads?  Reason being that 90-95% of most hulls are MIG, even if the TIG percent can be critically important to the quality of the complete build.

One MIG preparation exercise that may be of value to your build(?) is to learn to groove/cut weld allowances/weld zone prep in butt-fitted longs and x-verse framing.  Since most designers don't build, and fewer still weld; weld-prep isn't really understood or taken much into account in welded metal boats' plans- regardless of size.

Where a pair of components are butted (classic T-fillet) together say, a bulkhead or transverse frame meets the hull panels' inner surface; most designers expect the builder to add fillet welds with little or no joint prep.  I have found this results in maximizing hull warping, distortion and 'hungry rigs' sided boats. And, if the welds aren't kept in proportion to the parent metal scantlings, which is way too frequent even in name brand builders' hulls, then the warping is increased. 

When two elements meet in a flatbar-to-sheet butt joint which will be fillet welded (?) I prefer to bevel the T-forming element to allow the fillet weld to be 'under' the edge of the right angle hull framing.  So, if a bulkhead will be welded continuously from shear-to-shear (?) or a below decks bulkhead will be fillet welded from chine-to-chine, for example, that transverse hull frame component should be beveled to accept the weld.

Weld contraction happens both along the length of the weld AND.... across the face of the weld too.  It is the face contraction (from toe to top) of the fillet weld face that most often causes transverse interior frame 'stitch' or chain welds to pull 'cupping' along the hull's outside surfaces.

Longitudinal bars, T's and angles' welds aren't quite as much a contribution to hungry sides as x-verse welds.  It's good practice to bevel those if possible, but not as critical to avoid unprepared fillets that are at 90deg to the keel plane.

I'd say it was worth the effort to plan the welds, and to plan their prep- so if a chain weld pattern will be used to join longs or transverse frames- their outer edges should be beveled before the topsides/hull plates are tack on.... the interior bevels are where the planned stitch/chain welds will be placed, most often with MIG.

I realize you've tacked-up the hull but encourage you to plan some weld scale exercises to keep bead size small, and to plan to add 'pockets'/bevels/joint recess to the weld areas if possible. Interior frame elements can be beveled after tack up by using a die grinder (air or electric) and carbide burrs; especially if the tool has a 'foot' or guide plate added.

Narrow faced fillets, put in planned locations with as much prep as possible, and judicious selection between MIG & TIG, as needed, will result in as smooth a hull as possible.

Congratulations Carl, your progress is very unusually fast in becoming uniform and consistent in TIG. I believe your hull's beauty will be vastly improved over others' who haven't taken time to weld, off their hulls, before final hull welding.

Cheers,
Kevin Morin
Kenai, AK
 

[gandrfab]

In few words.
You are going to want to mig as much as possible on the hull to lessen heat distortion.

[m32825]

I really appreciate the feedback and encouragement.

A big chunk of credit for my progress has to go to Dusty's course over at Pacific Arc TIG Welding. Those lessons helped me climb the learning curve and put the fundamentals in a sequence that builds on previous steps.

The gang here on the forum has been great support, especially with how welding applies to our problem domain. I didn't set out to spend this much time practicing welding but I wanted a project and see this as a key part of the journey. When the puddle is moving right and I manage a string of good dabs it is so satisfying, I hope that never goes away.

    -- Carl
 

[gandrfab]

moment.PNG (177.57 KiB) Viewed 6105 times

 
 

[m32825]

Yes, absolutely. Mihaly Csikszentmihalyi is a psychologist who pioneered study of flow state, I think TIG welding is an activity conducive to achieving flow.

.
 

[gandrfab]

!0.png (87.52 KiB) Viewed 6100 times

                                                 One can hit all levels on a single project. 

0flow.png (448.58 KiB) Viewed 6100 times

 

 
 
 
 
 

[m32825]

There's another aspect in which this is a journey, you guys have to suffer through a slide show of all the places I've been. "Oh no, not another cold start picture... for crying out loud, add some heat!"

Okay, here's one with more heat...

weld video
 

[m32825]

Testing joint in the above video. Should I be aiming to get penetration into the base of the T? Cause I'm not seeing much. Parent metal gave up and the weld still looks fine so, good enough? This is 5052, how would 5086 be different?

IMG_20240628_071349045_copy_1200x2132.jpg (21.89 KiB) Viewed 6066 times

 

IMG_20240628_071439210_copy_1200x2132.jpg (25.11 KiB) Viewed 6066 times

 

IMG_20240628_071744158_copy_1200x2132.jpg (22.11 KiB) Viewed 6066 times

 
 

[kmorin]

Carl,

First a remark about the 'flow' mental state of TIG.  Yes, I agree, when you weld for a while and get 'your hand in' as it used to be described; there's a relaxing state of mind and unless the weld position is gymnastic (! inside hull, below your knees, while crouching) welding with the TIG process is very enjoyable.  And by extension, running your skiff on the water for the first few trips, also provides a very rewarding state of mind- one only experienced by those who build their own boats.

Along with this reward for the various processes of building for yourself is the enjoyment to had when you are able to end your build with a clean, smooth finished, nicely shaped skiff that is pleasant to see on the trailer and in the water.

re; latest video.
I see you very quickly got the idea of adding more heat to initiate your weld as shown in the latest video sequence.  I've read that most experienced TIG welders (read because I only do this in some instances) set the power supply to FULL range and then use the pedal/button/slider to add the needed amperage to 'wet out' fast and allows them to get moving along the weld in less time from arc initiation.  Also this will give you a beginning puddle width w/o a cold start and some puddle width to follow as you continue the bead.

However, I prefer to have a very clear puddle size/width in my mind's eye before I light up- then I don't 'overweld' as is my opinion of about 70-80% of the online welds I see.  Those practices, too wide a puddle and weld cross section, are what G&R is responding too in his comments about using more MIG and less TIG on a  hull weld.  I've done entire hulls with TIG before and not warped anymore than MIG distorts some hull shapes.  But bead width IMO should always be proportional to the parent metal.  Once you 'have' your TIG up to uniform, and well fused the next battle is to acquire the habit of proportioning the welds to the parent metal's scantling.

re; bend & break/bend.

One problem with many unskilled workers or even skilled workers who're not well vested in their work as welders is lack of fusion.  I have seen many well known brand boats (not all certainly) where the welders are not very concerned with quality. One name brand builder's keel seam was driven onto a rock by that boat's Skipper.  The hull seam, being cold lapped and not well fused, actually bent upward and pulled apart. The boat sank as a result of the size of the hole left by the keel weld coming apart due to lack of fusion.  This particular instance was a MIG welded sheet edge to sheet edge weld along the keel seam about amidships.

When I was called to look at the boat (salvaged locally) to offer my view- I could see that seam's weld wasn't torn; it simply let go due to being cold fused or cold lapped and that poor quality simply couldn't hold the boat's weight when it hit the rock at high speed.  While I admit this isn't typical, and don't condemn all production (mfg'd) boats, care to each weld requires a state of mind and application of both skill and attention to the job that isn't always present even with experienced welders.

Using a bend or bend break test reveals if the weld will "beat the metal".  Or is the weld a weak spot in the joint.  If you bend a weld and it breaks loose from the parent metal, or the parent metal breaks before the weld turns loose or cracks; the weld will hold as much as possible in a catastrophic collision event.  Crashing, collision, impact is one of the two forms of failure most often seen by welded boats' hulls.

The other weld strength issue is fatigue due to vibration or flexure of the joint. Where vibration is really just high speed flexure, they both test a joint for duration to equal the metal which is joined.  We usually don't try to test for vibration due to the equipment implied so we rely on bend break tests to more or less approximate vibration "flex to failure". By bending back and forth, as many times as needed to have some part of the joint come apart: we consider that a test for the joint's strength overall.

Its not very common that a boat will crash on the rocks or explode (!)- but that is what we're testing our welds to overcome.  You show the parent metal failing at the HAZ edge of the weld.  What more can the original metal offer?

To decide if you need to get more penetration?  Bevel the T component of your joint enough to allow your weld to fully reach the face of the bevel. Weld the joint and redo to the bend/break and see if the joint withstands more flexure?

Generally 5052 is softer and more flexible/malleable/'bendable' than 5086.  SO, weld joints will often perform slightly differently in the two alloys used as coupons when weld testing.  Larger hulls gain from using 5086 since the stronger alloy allows fewer structural elements in design and thinner scantlings of materials in the build.  For a tiny skiff like you're building; '52 is more than adequate, especially as thick as it has been designed.

Cheers,
Kevin Morin
Kenai, AK
 
 

[m32825]

Good info Kevin, thank you!

I did a few bend/break tests with that short leg fillet. I can get a consistent bead now without melting the short leg, but the weld breaks without much bending of the parent metal. The bead is a little on the starved side. If I fill the bead more the short leg starts to melt. I'm starting to lean towards trimming that "keel-let" down and turning that portion of the seam into an open corner.

-- Carl

[kmorin]

Carl,
Before taking off the topsides' overhangs at the chines, I'd suggest you consider that joint back welded?  If you run the TIG test on a short legged fillet, then back weld inside with MIG, as would be more realistic test of this joint in the hull's final as-welded form.... what does the joint do in a bend/break?

Next, most of the chine seams would be best welded in MIG, so just the after most and forward most 6-10" would be TIG welded (IMO).  Were you planning to TIG the entire chine seam(s)?

I can see what you're saying- the short legged T-fillet needs a proportionally smaller weld bead so you avoid collapsing the short overhanging topsides leg (short leg of T-fillet) but when bent that fails more easily due to the smaller bead.

I have never built any hull with this type of overhanging topsides/short legged T-fillet type of joint.  I always used and outside, open joint, fit inside-edge-to-inside-edge and welded both sides to fully penetrate the parent metal- not to end up as a T-fillet which is what you've shown in your design and tack-up.

My tendency is to make all joints the inside edge to edge type, but before you go to  the trouble to trim your seams from the overhanging topsides to chine flat joint.... I'd test the double sided welds of those joints first.  I think they'll end up fine and you'd avoid the work of trimming and re-tacking.... 

If you do decide to trim these joints? I'd suggest you do so with specific tooling and do the work of cutting/trimming and re-tacking as you go along the seam trimming.  IF the joints aren't tacked inside yet (?) you don't want to turn loose the entire joints' run that are now tight and try to re-tack; instead you'd want to trim 6" then re-tack, and move along the seams in that pattern.

Specific tooling would be a carbide cutter or carbide saw.  I'd avoid grinders or sanders as they're less exact. Making a guide to ride on the chine flat's horizontal surface that holds your blade/burr/bit at the correct ht. to trim to the upper surface of the chine flat would be best.  Then you could guide along the chine flat and cut the topsides' overhanging strip for a few inches, re-tack and continue along leaving a replacement seam that was clean, uniform and ready for an outside corner weld.

Of course before welding the outside seam it would be best practice to dress the tacks to a hollow shape so the final bead has the absolute minimum increase in volume as the weld passes over the tacks.

Don't mean to be vague, my preferences for one seam type don't mean those you have tacked into your hull are not usable.  A back-welded bend test might help your decision process? If you decide to trim, taking time to make a guide for whatever tooling you select is worth the preserved joint quality over a hand-held cutting tool where variations in the joint width will show in the final weld and hull shape.

Cheers,
Kevin Morin
Kenai, AK

[m32825]

Good point about back welding. After seeing your message I went back and tried one with more filler, if I fill enough the parent metal breaks in the HAZ. The challenge is doing it without melting the short leg, but I bet I can do that for six inches or so, and I'm sure it will be fine once welded on the back side.

This weekend I'm going to insulate my other garage door, so not as much time for welding practice. I think I will do a little more tig fillet this weekend then switch to mig next weekend. I've got a new filter to try for video, too.

-- Carl

[m32825]

Check this video out: Neutral density filter 

IMG_20240704_080439627_copy_1600x1200.jpg (69.78 KiB) Viewed 5910 times