Tape and tack 16 gauge steel RowMe?

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DeltaDawg
Posts: 413
Joined: Wed Jun 20, 2007 5:55 am
Location: Bethel Island, CA

Tape and tack 16 gauge steel RowMe?

Post by DeltaDawg »

I have been looking for a project to develop my welding skills with my Lincoln Electric 140HD (Home Depot) welder. When it arrives from the East Coast by Yak caravan book rate postage I will read Stephan Pollard's "Boat Building with Aluminum" recommended on this site. My welder supports a spool gun but after reading the thread on this board I do not want one, looks like a lot of trouble. I also do not want to weld in my garage I do not like the fire hazard. Welding outdoors the Argon shielding gas would blow away so I am kicking the aluminum can down the road if I do it at all.

A Harbor Freight birthday coupon was burning a hole in my pocket so I bought the pneumatic nibbler and the flange-punch tools.

I was intrigued to find this thread https://www.boatdesign.net/threads/my-o ... EWuPJ7cJmM and I am just finishing up my Glen-L stitch and glue plywood RowMe so I think my pandemic fall winter project with be a tape and tack 16 gauge steel RowMe using inner shield flux core wire in my Lincoln Electric 140. Attached are some pictures of some recent welding projects the largest and most accurate to date being my router sled for live edge table tops.

I welcome your steel boat building, welding knowledge, advice and experience. Thank you, Leland
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DeltaDawg
Posts: 413
Joined: Wed Jun 20, 2007 5:55 am
Location: Bethel Island, CA

Re: Tape and tack 16 gauge steel RowMe?

Post by DeltaDawg »

My Boatbuilding with Aluminum book has not arrived still traveling book rate via Yak caravan from the East coast. Moose Metal my local steel supplier sells 16 gauge hot rolled mill finish steel for $88 per 4'x10' sheet; 316 stainless steel for $385. West Coast Protective Coatings has a big enough oven to powder coat she says they charge $1,200 for a car body so a boat might be in the same church.

I learned FreeShip can "Develop Plates" for the flat patterns; downloaded the software runs okay on Windows 10; printed and read the 57 page manual; well written and a really nice app.

I got Glen-L's RowMe line drawing loaded as a background and am ready to start moving around points to make a model. This is fun, station, buttock line and water line coordinate system just like old times at Boeing.

I don't know if I will powder coat or not auto bodies were sheet metal for years just primed and enamel painted. I have a name for the sheet metal boat "Magneto". When I worked at Boeing one of the guys told me old timers in the south use to telephone for catfish with a crank telephone generator, one lead to the aluminum boat hull, one lead cast off in the water and got gunny sacks of catfish until Fish and Game took their generator. Years later I saw a YouTube of some fool wiring his outboard's magneto to the aluminum hull, shocked himself and landed in the water, made for a funny video. :shock: Anyway I think this boat will be called "Magneto". Leland
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DeltaDawg
Posts: 413
Joined: Wed Jun 20, 2007 5:55 am
Location: Bethel Island, CA

Re: Tape and tack 16 gauge steel RowMe?

Post by DeltaDawg »

"Boatbuilding with Aluminum" by Stephen Pollard arrived and I paged through it. The book might be more useful to someone thinking of setting up a small aluminum boatbuilding shop than it is to me building a 1 of boat for personal use. The author writes about $1,800 investment in welding equipment, using special alloys for construction, cleaning well before welding and welding both sides because when you apply heat to 1 side the other side oxidizes. He also writes about using special aluminum extrusions for the chine and gunnel and calls out the die # used for the the extrusion probably cost prohibitive to have 20 feet of extrusion for 1 boat from a mill.

I do not think it would be possible to weld an aluminum boat with my Lincoln Electric 140 HD even if I bought the $250 spool gun.

I did find a Harbor Freight store with a piercing and flange tool and picked up a pop rivet gun. I read a lot about rivets including about old Grumman rivet canoes and I remember those from when I was at Boy Scout camp 50 years ago. To do a nice job with rivets would take a lot more tooling and practice.

I want to finish learning in FreeShip developing plates to make flat patterns out of the 3D model and maybe making some of my own boat designs

While Stephen Pollard writes about building with aluminum is easier than wood I just don't agree with that so for now I plan to finish my plywood build and enjoy fishing. Leland
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Yofish
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Re: Tape and tack 16 gauge steel RowMe?

Post by Yofish »

I see that the person in your link did make a boat, rather surprisingly. You will be challenged using 16 ga. material. The only thing I can ad is keep gaps as small as possible.

Kevin Morin
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Joined: Thu Jan 24, 2008 11:36 am
Location: Kenai, Alaska

Re: Tape and tack 16 gauge steel RowMe?

Post by Kevin Morin »

D'Dog,
I've made boats similar to the one you're showing in different images and vaguely similar to the link of the small rowing skiff (semi-dory?) and so I have some remarks based on experience. I have also built in welded aluminum for many years and have done boats from 42' to 30" with a pretty wide variety of scantlings; from 0.040" up to 1/4", 3/8" and 1/2" plate.

Image

Image

17'-2" LOA, Chamberlain gunning dory (copy from J.Gardner's Dory Book) of 0.080", 0.100" and thicker extrusion at the gunwale, 5052, 5086 and 6061 extrusions. Double bottom and air chambers in the ends and gunwales- all welds air tested to 2.4 psig. ready to row, still weighs 168 lbs ! so even making a boat of thin material- welded aluminum can add up pretty quickly. This was not my first welded boat it was #'ed somewhere over 100. Level of difficulty was pretty high and would not recommend a new builder try this material thicknesses for a first project.

Here, are a couple of rules of thumb that I think are relevant to your learning as regards welded aluminum boats.

First, welding 5000 and 6000 series (considered "marine" aluminum) thinner than 1/8" becomes more (and more) difficult to do successfully (clean, uniform welds, with minimal hull distortion) for every 0.025" thickness you reduce the materials.

This translates to 0.125" (1/8") being 'simple' to learn to weld - still requires hours of practice and a hull design where joints are mostly 75 to 90 degrees not 5-15 degrees between hull panels along the main lengthwise seams. However: at 0.100" or 0.080" the skills required go up by 2x for each thinner section parent metal.

Next Rule of Thumb: Smaller boats, rowing boats, prams, punts and other light wt. less than 15' LOA usually have a wt limit to be practical. That implies hull and framing materials that are proportional to the overall finished boat. This again implies the materials generally be less than 1/8" thickness.

For example a 15' row boat built of 1/8" 5086 material would probably weigh 120lb for hull sheeting alone? add some framing and gunwale extrusion and I'd estimate we'd be looking at nearly 200lb for this size and hull type. (complete approximations only!)

In thin plywood, the boat would weigh a fraction of that for this size class. However once you begin to thin the scantlings down to reduce weight, the welding becomes many times more critical and complex. Not saying it can't be done... but I'm implying the level of difficulty has gone up quite a bit.

Last Rule of Thumb for consideration: welding two thin sheets of aluminum (even 0.040" thickness) at 90 degrees to one another is 5 to 20 times easier than welding the same two pc with a 25 degree angle between the two pieces.

This goes to hull design or boat shape, and looks at the Body Section to help guide the designer/builder/welder by examining the Stations' hull panel angles to one another. You show as round bilge hull form (like the default in D'Ship) that you perhaps added hard chines too? Then a similar rowing shape was shown in the link- laid out and tacked up? in Body Section, the chines or 'creases' between hull panels are the edges of developed plates and will be the hull's weld seams.

If these seams are left as shown in the screen dumps and the linked images; there is little way to MIG weld these seems without having many 100's of hours of weld time. Further, even then, the seams as shown very likely didn't come off with a smooth hull. And further yet; the quality of those seams, fitted as shown and welded with wire larger than 0.23" dia. is almost assured to turn that tacked up boat into a "pretzel".

If you're going to give a welded boat a try? which I'd encourage you to do, as they are nice when the work is done. I'd encourage you to build in the 18' to 20' range our of materials that are 1/8" and thicker as the odds for success are greater due to the issues of MIG welding "scale" or proportionality.

And last, I'd suggest you consider a 'hard chined' power boat, even if it's low powered so the hull welds are mostly 70-90 degrees. There are several nice looking boats in the Glen-L catalog in this class- Chinook is a good beginner boat, for example. Some of the smaller and flat bottom designs in wood could be converted to welded aluminum but then you may be designing your own boat too?

Hope this attempt at explaining my experience with welded aluminum boats is helpful in your exploration of the subject. I've read Mr. P's book and would refer to it as an overview of the subject and his remarks would have to be taken in the context of the boats he's describing- not a thin skinned row boat!! And especially appreciate that he takes welding for granted!

There are a series of posts here in the Metal category that review lots more 'hands on' methodology about building in aluminum that may be of interest in your research?

Cheers,
Kevin Morin
Kenai, AK
Kevin Morin

DeltaDawg
Posts: 413
Joined: Wed Jun 20, 2007 5:55 am
Location: Bethel Island, CA

Re: Tape and tack 16 gauge steel RowMe?

Post by DeltaDawg »

Yofish, thank you for your guidance I have been thinking about how I could fold along the chine and make a lap weld the length of the keel but not sure how a backyard builder could make that bend on the chine.

Kevin, thank you for your well thought out reply and guidance. The Chinook looks a little big for what I want to build and I think welding aluminum is difficult and has to be done indoors so I may build a little steel row boat out of 16 gauge. More planning, reading and studying ahead for me and maybe some researching on Dutch steel prams and work boats. I may get some 16 gauge mill finish steel and make some buckets and see if they will hold water with a flange and lap weld for the bottom. By the way the flat pattern picture above is from the FreeShip manual not from my RowMe model I am still working with the model to figure out how I can make 1/2 the bottom and 1 side as 1 piece with a bend lengthwise along the chines so I can lap weld along the keel. After I figure that out I will add a transom face and move the faces to layers and develop the plates. Leland

Yofish
Posts: 101
Joined: Wed Jul 04, 2018 9:40 pm

Re: Tape and tack 16 gauge steel RowMe?

Post by Yofish »

Oh! One other thing! Get rid of mill scale! Very important on thin stuff, more so than on thicker...

Three cheers to Morin! I'm certain he'll chime in, he's is the mill scale jihadist. And, I agree with him.

Kevin Morin
Posts: 756
Joined: Thu Jan 24, 2008 11:36 am
Location: Kenai, Alaska

Re: Tape and tack 16 gauge steel RowMe?

Post by Kevin Morin »

Leland, as Yofish notes, I'm always recommending (some say ranting?) about cleaning metal, both steel and aluminum, of the mill scale before trying to weld it. On steel the results of trying to weld through mill scale are pretty dramatic- porosity, worm holes etc. On aluminum the puddle (in MIG) freezes or solidifies so fast that most porosity is trapped below the surface- so the welds may look 'OK' but aren't fused too well and they are weaker than they should (or could) be.

While doing some boring shop work yesterday, feeding sanders to dress some wood stock, I recalled a discussion that I had with a builder from Oregon quite a while ago. We discussed ways to make "MIG-able" seams in very thin sheet material. And while I wasn't in a position to test these joint types, he did to some extent.
Davis Joint_1a.jpg
this image shows a small diameter rod - say 3/8" which has been run over a router bit to shape a cup in the rod, and the two pieces of sheet are clamped to the rod (held in shape by temporary station formers like a wood boat build) with dry wall screws holding sections of EMT that was cut to a C about 1" long or so.

by pre-drilling the rods, with holes for the dry wall screws to hold the EMT/conduit 'clamps' while the entire hull was fitted and tacked up... the idea was to go back and remove the 'clamps' and then have a fair and unwrinkled, tacked up hull, ready to weld.

This joint (or some variation of it) could allow the heat of MIG bead to be mainly absorbed by the hollowed out rod while still fusing the hull sheets. Welding this in aluminum (say 0.080" sheeting and a 3/8" or 1/2" dia. rod would still require pretty good welding skill but would be much more 'doable' than the two sheets just touching together as is commonly done in 1/8" and heavier materials.

I don't think any boats were built this way? but I do recall some successful 2' and 3' curved seam simulations so I thought I'd attempt to describe them. Mainly food for thought about welding super thin sheet metal using MIG while maintaining a smooth finished weld seam and adjacent hull panels.

A note about Freeship; based on my use of DelftShip for quite a while, I'd say that a "layer" is a "single surface" component in regard developed shapes. So if you leave the bottom and topsides panel attached at a common edge, and assign that single surface to the same layer- I think the software will attempt to develop them both as one surface.

However, since the hull panels shown all taper fore and aft; the only place a bottom panel and topsides of this hull shape would meet will be amidships for a very short length. There, a chine could be a bend in the single surface, or common line between the two shapes I'd say that would look roughly like two back to back "crescent moons" touching at the point of greatest outside curvature?

If the two panels do meet for their entire length prior to 'unfolding' onto a flat sheet then the hull shape will have to be a box!

IF you want to attempt a lap joint then the best method is to draw the hull form with two separate surfaces, and when they're fully developed simply import the outline shape contour into a CAD application and use the OffSet tool to add the flanges on all sides of a panel. If you won't want flanges on all sides then erase the sides not wanted. Sketchup, for example, has a tool that will 'expand' a shape/surface by some assigned distance and this would make your overlap for the side-to-bottom chine seam.

Bending a flange will require a beading tool for sheet metal- there are both fixed base and hand held tools to crease/bend along curves- utube shows both. Then the welds would be lap joints similar to the one shown, and much easier to accomplish due to the double thicknesses and to the flange's contribution to reducing extortion. Just more to consider, good luck with your building planning, and design.

Cheers,
Kevin Morin
Kenai, AK
Kevin Morin

Yofish
Posts: 101
Joined: Wed Jul 04, 2018 9:40 pm

Re: Tape and tack 16 gauge steel RowMe?

Post by Yofish »

Delta, please don't take this as rain, but I just HAVE TO bring up the fact that 16ga. material does not leave you much 'down time' in terms of maintenance if your ride is to be used in salt. Sandblasted and coated with 235 would be a recommend. Otherwise mere debriding and enamel paint of even the best quality is time certain, only. If you let her go, she will be gone and the worst part can be under paint; little bubbles that fester under what appears to be an intact surface but disguised by paint.

Combo post to allude Morin: A cat who will ALWAYS have a take that makes me go - OH!?

DeltaDawg
Posts: 413
Joined: Wed Jun 20, 2007 5:55 am
Location: Bethel Island, CA

Re: Tape and tack 16 gauge steel RowMe?

Post by DeltaDawg »

Yofish, Please refer to my 16 gauge steel 12 foot rowboat as "Magneto" going forward so named after the X-Men villain. Magneto is a he but since vessels are she maybe we can refer to her as Ms. Magneto. Aluminum is not magnetic so Ms. Magneto cannot be made of aluminum. :D Now I think I want 16 gauge steel because 12 foot is not very long and the thicker the gauge the harder it is to bend to shape Ms. Magneto's shapely curved hull. Ms. Magneto is a training exercise to really put my Lincoln Electric 140 HD flux core welder on a good size job. This is 120 volt so Lincoln only has a 25% duty cycle to lay down the seams on Ms. Magneto. If she turns out nice and tight (water tight that is) West Coast Powder coating is less than a mile from my house https://westcoastspecialtycoatings.com/ and they have a big big oven Ms I like Miss better Miss Magneto can go into. I could give her a nice bright color powder coat finish or if you or Kevin who know a lot more about steel than I do give me some guidance on what they refer to as thermal spray metalizing maybe she will get that as a coating. I stopped by and talked to them when I was at nearby Moose metal inquiring about 4x8 16 gauge steel sheet and the lady told me they powder coat car frames for about $1,200. I she doesn't turn out that nice I may just spray primer and acrylic enamel for Miss Magneto's finish. The only salt water I may take Miss Magneto to is the Dungi crab opener in what the heavy duty salt guys call the kiddie pool at Bodega Bay seen in this video https://youtu.be/jrfMBq-XNDk Leland

Kevin, thank you thank you thank you for the tips on daisy chaining Miss Magneto's 3D model developed plates from FreeShip to SketchUp for the flange offsets. And thank you for the fabrication tips on making the flanges, I bought the Harbor Freight pneumatic piercing and flange tool and look forward to using it. And thank you for your guidance on modeling and fabricating the forward section of Miss Magneto's curvy hull. You are metal working genius and I will clean mill scale before welding. :D Leland

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