Steel Boats and Welding

[haidan]

Originally Posted by nitpik

SaltMonkey:
I have been sailing a slightly modified Tom Colvin "Doxy", mostly single-handed, since 1988. She is 41'LOD, and 50'LOA. Gaff-rigged schooner. 17.3 tons reg.
Be glad to share my experience/opinions regarding steel hulls in general, or this particular design of Tom's.
~ David

Those are nice little boats (well not so little really) My friend just put her doxy into the Caribbean this winter, her's is junk rigged though, looks as though you have the gaff version. Not too many of those designs built, for some reason colvin stopped selling the plans, they're kinda like gazelles but heavy, like they should be. I know another guy up in alaska who has an aluminium one, gaff rigged I believe.

[SaltyMonkey]

Haiden, lets just add this up a bit as an exercise:

10k for base steel
4k for stainless trim (extra 1k)
5k for paint and sprayfoam
10k for engine
5k for interior (less labour?)
24k rigging etc

58k - gross cost for boat
69k - add in 20% buffer

Then labour, which is a question mark

Sails etc don't count since most used boats would have to be outfitted the same way.

Almost doable...

[SaltyMonkey]

haiden. Pardon my ignorance, but when you speak of stick, I thought MIG was stick - eg three types of welding TIG, MIG, and Oxy.? What am I missing?

[Stillraining]

Originally Posted by SaltyMonkey

What am I missing?

Stick.....

[SaltyMonkey]

ok I get it. So stick actually goes by the used to be more common name of ARC. And MIG had me confused with "stick" because "wire-feed" is sort of related. And I understand ARC welding is still rather difficult to master at first, and can only be used to 18 guage.

Would ARC welding cover building everything in one of these boats, or does someone also have to know MIG or TIG? Can ARC also be used on stainless steel e.g. if say I wanted to repair or make a Radar Arch?

[SaltyMonkey]

I just applied to my first welding course - starting with MIG. Hope I get in.

SaltyMonkey has to start somewhere. Someday SaltyMonkey will be at some small level close to all of you in welding, machine shop skills, fiberglass, wood and engine skills as you all. Until then, I am wimpy SaltyMonkey.

[haidan]

Molten metal needs to be shielded from oxygen to crystalize (read harden) properly there are different ways to do this.

MIG Metal Inert Gas welding is wire feed welding the machine has a spool of wire and it just feeds it out into the puddle of molten metal, there's a current that is run through the wire that melts the metal. You can either use an inert gas which is usually Argon mixed with.... CO2 or Nitrogen can't remember, you can also use wire that has a flux core and so needs no gas, and yes technically it not MIG but uses the same machine so really no difference. You can't weld with wind blowing away the gas, so outside is a no go - unless you use the flux core stuff which is a little more expensive. As far as I know there is no flux core stainless wire so if you are to MIG stainless you have to be inside, I found stainless MIG to splatter a whole hell of a lot and so when you're paying 20 bucks a pound for wire and 1/3 ends up in little balls all over where you don't want it, well..... When welding aluminium it's best done with MIG if the job is big, usually people use a pound gun which is just a small spool near the nozzle so that the run for the aluminium wire is kept short, it's soft and it jams easily in longer runs.

TIG Tungsten Inert Gas Welding is kinda the same as MIG except you feed the wire in by hand. The "torch" uses a tungsten electrode to created the arc to melt the metal and uses compressed argon as a shielding gas. TIGing is very much like welding with an oxy-acetylene torch, but has a much finner control of the heat and focuses the heat better so you can weld very thin stuff without melting holes through it. It's a little slow but produces very nice looking welds and if you know what you're doing your welds will be as strong as any but it's slow and MIG is very fickle about cleanliness especially if working with stainless or aluminium any contamination with oil or rust or different metals will produce a flaw in the weld somewhere. I think playing around with a TIG torch is a great way to learn how to manipulate the puddle, TIG is lots of fun but slow.

Then theres stick welding also called arc welding though really any electrical welding is arc welding. You have these rods that are usually about a foot long, they have a coating on them called flux, it's made of a bunch of different metals and it melts and floats to the top of the puddle covering it and shielding it from the air. When it hardens you chip it off with a hammer to reveal your nice new shiny weld. As I said it's not so picky about rust, burrs, paint, grease. There's a variety of welds some are more suited for different applications and stresses.

There is also welding with an oxy-acetylene torch, the two gases are burned and it melts the metal together and you may add some as well just like TIG but it's slow slow and the gas expensive and doesn't make very nice welds due to it's lack of shielding gas. It's a cheap easy way to cut mild steel though, doesn't cut stainless you need a plasma cutter for that, but zip blades work just fine for what you would need to do. I know some people have rented plasma cutters for the weekend and done as much cutting as possible with it.

Originally Posted by SaltyMonkey

Haiden, lets just add this up a bit as an exercise:

10k for base steel
4k for stainless trim (extra 1k)
5k for paint and sprayfoam
10k for engine
5k for interior (less labour?)
24k rigging etc

58k - gross cost for boat
69k - add in 20% buffer

Then labour, which is a question mark

Sails etc don't count since most used boats would have to be outfitted the same way.

Almost doable...

well the 24k was for a totally professional finished mast if you're going to pay someone to build you a mast you may as well just pay a welder to scarf together a few pieces of 6" sch 40 aluminium pipe and make your mast that way, that's what I would have done if I hadn't happened along the aluminium extrusion that I got, a mast like that I way stronger than your typical production mast and shouldn't run you more than 3 - 4k materials and labour. That's what those folks put on MOM, there's a few of them around. And also not all that has to be spent all at once either I took two years to spend all that.

[GordMay]

Originally Posted by SaltyMonkey

ok I get it. So stick actually goes by the used to be more common name of ARC...

Yes, or Shielded Metal Arc Welding (SMAW) also referred to as Covered Electrode, or STICK welding.

[haidan]

Originally Posted by SaltyMonkey

ok I get it. So stick actually goes by the used to be more common name of ARC. And MIG had me confused with "stick" because "wire-feed" is sort of related. And I understand ARC welding is still rather difficult to master at first, and can only be used to 18 guage.

Would ARC welding cover building everything in one of these boats, or does someone also have to know MIG or TIG? Can ARC also be used on stainless steel e.g. if say I wanted to repair or make a Radar Arch?

My boat was built nearly entirely with a AC buzzbox that someone gave me, they had it lying around in their garage.
For stainless stick is the best IMHO, stainless rods are the easiest to learn to weld with, unfortunately they're expensive.
Arc welding is what they use to for welding up pipe lines which have a wall thickness of several inches, so no you are not restricted to thickness. 18 gauge is about 3/32" or less
Although there are aluminum sticks I've never used one they're rather expensive and I've heard make pretty ugly welds. So if your radar arch is stainless no problem with stick but with aluminium you're better off with something else.
The hardest thing to learn when first starting with stick welding is how to start the arc without the rod sticking to the work, last person I taugh how to weld took 2 hours getting that down then was laying down nice looking welds over the next hour, it's really not that hard, a friend of mine said once, if you know how to use a hot glue gun you can weld you just have to learn how to strike the arc.
And really the best, and in the long run cheapest after buying the equipment is if you're doing a few aluminium projects like an arch, hatches and a mast the best thing to do is do all the cutting and fitting your self then, maybe wire it or pop rivet it together then take it to a shop and have them weld it for you. If all they have to do is run over it with the welder it'll be done very very fast and you'll only owe them for half a shop hour or so.

[SaltyMonkey]

Heres a link. Don't know how truthful this is. Seems to conflict:

Welding 101 | Extreme How To, DIY - Do it Yourself, Home Improvement, Home Decorating

OK, let's revise costs a bit:

10k for base steel
4k for stainless trim (extra 1k)
5k for paint and sprayfoam
10k for engine
5k for interior (less labour?)
10k cheapo mast, rigging etc

44k - gross cost for boat
53k - add in 20% buffer

plus additional labour.

How's that?

[Brent Swain]

Originally Posted by SaltyMonkey

Heres a link. Don't know how truthful this is. Seems to conflict:

Welding 101 | Extreme How To, DIY - Do it Yourself, Home Improvement, Home Decorating

OK, let's revise costs a bit:

10k for base steel
4k for stainless trim (extra 1k)
5k for paint and sprayfoam
10k for engine
5k for interior (less labour?)
10k cheapo mast, rigging etc

44k - gross cost for boat
53k - add in 20% buffer

plus additional labour.

How's that?

I have put steel masts for the 36 together for $1k, including labour. The rigging wire has cost as little as $24. Turnbuckles are $22, less that when I bought mine in 84. Used cars with good diesels can be found for under 1K. Add 1.5K for a tranny. The interior for my 31 cost me around $50, using a lot of scrounged materials. Surplus paint is often free from recycling depots.
Stainless can be found in scrapyards for under $2 a pound.
I don't think you'd use any where near 2,000 lbs of stainless for trim.
We are awash in used sails and gear in excellent condition for a fraction the cost of materials.
Blocks cost under $2 to make, and it takes les than 20 minutes to make one.
I have never felt the need for anything but a cheap buzzbox to built a steel boat.

[SaltyMonkey]

Ok, hmmmm...let me revise

10k for base steel
2k for stainless trim (cut 50%)
2.5k for paint and sprayfoam (cut 50%)
1.5k for engine (used)
100 for interior (less labour? stove?, pipeberths?)
2k cheapo mast, rigging etc

18,100 - gross cost for boat
21,720- add in 20% buffer

plus labour....ok how reasonable is that?

I have a sudden urge to weld something...

(ps: haidan thanks for the welding details. its a good record on this site for others)

[haidan]

well no that's pretty accurate, it doesn't really conflict, but keep in mind that building a boat (as quickly and cheaply as you can) and doing a little body work here and there are two very different things. MIG is easy you push the button it welds, and CAN produce totally nice welds that are as strong as any, however the one thing that you can do with MIG is just cover the joint with weld metal without actually getting into and melting the joint together (due to not enough heat) and it takes trained eyes to see this, the weld will look just fine but if you cut it you'll see it didn't go all the way through, if the current is too low with stick you won't be able to strike the arc and all you have to do is make sure you're using a rod which is about the same thickness as the work you're going to be welding.
The other thing about MIG is all the parts, there's a few different parts near the nozzle that wear out, and the housing for the wire will wear out a few times in a boat build and the wheels that push the wire through will wear out eventually, it all adds ups and costs a bit and it slows you down when you just used up your last tip a 4pm on a sunday. The good machines that are built for a heavy job like building a boat will do much better but then your talking a few 1000 for the machine versus less than 500 for an arc welder. Acr welding is kinda the KISS principle of welding which is why I like it so much plus it can do stainless really nicely.

Originally Posted by SaltyMonkey

Heres a link. Don't know how truthful this is. Seems to conflict:

Welding 101 | Extreme How To, DIY - Do it Yourself, Home Improvement, Home Decorating

OK, let's revise costs a bit:

10k for base steel
4k for stainless trim (extra 1k)
5k for paint and sprayfoam
10k for engine
5k for interior (less labour?)
10k cheapo mast, rigging etc

44k - gross cost for boat
53k - add in 20% buffer

plus additional labour.

How's that?

Yeah I figure I have about 30-40k in my boat, I got a great deal on the mast and engine though. These boats are keel cooled, so with that and dry exhaust some people have used converted VW diesel engines, which used can be found quite cheap say from a written off accident car. All that needs to be done with them is the mating to the marine transmission.

[Brent Swain]

Originally Posted by SaltyMonkey

haiden: I looked at every picture on the MOM site. I'm totally transfixed by the process. It did take quite a bit of time though. The labour $ look big. Lots of small things need to be "glued" on and cut. 500 tabs alone! So, its not just the hull itself, it's all the dre$$ing.

I have no idea how much a boat like that would foot $. But I love the designs and construction method.

* * *
Learning to weld. For the record, community college my way are either too far away or have temporarily suspended welding programs. Another option to learn is to take lessons from artistic organizations or artists that offer lessons privately. I'm looking into taking a few weekend intensives in TIG, MIG, and torch. I think that would be enough to get a decent exposure.

I use about 34 tabs to put my interior in. Evan, the guy hired to build Mom, milked the job for the maximum number of hours pay. He took years to do what I do in a few weeks. I have taken as little as ten days to put a 36 foot hull , decks, cabin, cockpit, wheelhouse, keel, and skeg together ,a huge savings in labour over more traditional methods.
Welding courses consist mainly of practice. You can do that at home with a buzzbox, a pile of scrap and a box of rods. The technical stuff, you can get out of a library. While you are practicing, you may as well be making useful stuff like anchors and detail bits and pieces. In a course, you can shanghai your fellow students to weld your stuff up.

[Stillraining]

Originally Posted by SaltyMonkey

Heres a link. Don't know how truthful this is. Seems to conflict:

Welding 101 | Extreme How To, DIY - Do it Yourself, Home Improvement, Home Decorating

Info is Right on AFAIC

Except I find tig to be the best and the easiest for SS or Aluminum...Your 500.00 mig machines will not do it...more like a 6K machine needed.