alu sailboat buliding

[zeyang]

Hi list.
Im building an aluminium (7 and 8 mm plates ) double ender sailboat. 40 feet long, The boat is built upside down.
First i was thinking tig welding this together, but since i built in 20 cm wide lapstrakes it will be a lot of welding, so probably i will switch to MIG to weld the laps (welding laps on both side it means at least 1000 meter of welding, so its some hours welding job to do)

for tig im using a lincoln squarewave 255. for mig i have a smaller lincoln powertec 250 but probably need something bigger and better. (hopefully with wirefeeder)

zeyang

[Easygo]

O.K. That sounds really impressive. I for one would love to see some images of that boat or whatever stage of the building you are in. I can offer no advice on the welding though. My knowledge is quickly challenged even when I build things for my small tractor. Did you buy plans or designed the boat yourself? Just wanted to express my interest and appreciation.

[Joker11]

Might I suggest you look at the Lincoln PowerMig 350MP!!! That is the machine just made for MIG welding aluminum. It has pulse on pulse and is programmable. Check it out.

[WHughes]

I have built aluminum jet boats for many years. Mig the inside corners and structural stuff, and tig weld outside corners and parts that people will see. Tig creates alot of heat and then warpage, mig will reduce the heat put into your hull.

Bill

[Joker11]

If you use the Lincoln PowerMig 350MP you can use Pulse-on-Pulse to MIG those inside corners!!!

I just want more people to buy that machine so I can start a new club. heheheheh

[fishon91]

wow, that is very impressive. please post pics of as many stages as possible. i just wanna see how it's done. 1,000 m of welding, thats when you say thank god for duty-cycle!

[rhapsody]

Also check out the new Lincoln Power wave C300, it is an inverter base welder.

[cadmus]

Dear Zeyang,
At any time in the next few years you can tell me to stop bothering you... But i have a feeling i will have many questions. I hope to build an AL sailboat in the next 3 to 10 years. 35 to 40'. I spend all night designing in autocad, reading up on hull and sail design, figuring out the best combination of specs. As most sailors are i am obsessed. Are you using molten or solid balist? lead i assume? can you send me you specs (draft, beam, LOA, LatWater, Displacement, rigging type, etc)? Are you using an existing design or your own? what do you know about these "Self-jigging" flat pack hulls kits? ...I will flood you inbox shortly. - pete


Everyone else,
I know little of welding, I hope to demonstrate that by asking a lot of dumb questions when you are all done answering Zeyan. I spend alot of time surfing welding and boat building sites. I was SUPER exited to to see this post.

I have been wrestling with the same question. I am looking for a used TIG welder to practice with for now. But I know it is slow moving when welding a those LONG chines.


-Does a solid AL wire feed with inert gas make as clean/strong of a weld as TIG?

-My friends claim a AL with flux core (so you don't need a shielding gas) wire is out there, BUT IS THE WELD AS STRONG as TIG and MIG?

-Most folks have told me wire feed AL one should use a system with the wire spool in the gun instead of the wire being fed through a long hose like on most steel wire welders. Is this always true or just when using AL with flux core.

Please answer zeyang's questions first but since he got you attention I am going to piggy back on him.

[WHughes]

For aluminum mig, you should have a push pull system for boat building. You can do AL without a push pull system if its shorter than about 15 feet and in a straight line. You can use Argon, but I am noticing more and more people using argon/helium mix for welding on the under side. From my boat building experience, you weld the under side during a repair.
About the chines, you can use a cap chine or a extruded slide on chine. The benefit to a cap chine is that it makes hull repair a little easier should you bang your boat up. It is welded on the exterior.
An extruded, slip on chine is easier during the build but very hard to repair a damaged boat. My guess is that you wont be bouncing your sailboat off the rocks in Death Valley Idaho, so I would use the extruded slip on chine.
I have never used a flux core aluminum wire so I cant help in that department. If you have argon around to tig, you can have it around to mig, in my opinion.

Bill

[rhapsody]

Hi Zeyang & Cadmus

I am in the same boat. What is the design of your boat?

Go with MIG, TIG is too slow for such a big job and stick welding Aluminum is very difficult. FCAW (Flux core) welding in general is more difficult than MIG and the process create spatter and slag. I've never done aluminum flux cord welding before.

A 200 to 250 amp (60% duty cycle) welder with a spool gun is probably the minimum needed for welding 3/16(7mm) aluminum plate.The push pull feeder gun system as suggested by Bill is ideal. The latest innovation in welding aluminum is the Pulse MIG welding process, that is if you can afford it.Use properly, PULSE MIG causes less heat related problem and is easier to get a good weld. The best one like Fronius TPS 2700 costs upward of $10,000, Miller and Lincoln both have welder that can PULSE MIG for a lot less. All 3 brands have machines that can be set up specifically for welding aluminum. I learn welding at a night class at the local community college and I highly recommend it for those who do not have the skill.

I found the book "Boatbuilding with Aluminum" by Stephen F. Pollard very helpful. It answer most of my questions on tools, materials and the process of building Aluminum hull.

[WHughes]

I dont know where you would get plans for the bottom. The company I worked for pretty much winged it, found a pattern that worked and made small adjustments from there. I know there are people selling sailboat plans because I knew a guy that had them at one time.

Have fun.

[cadmus]

Thanks for help you 2.

I have the Pollard book on my ebay/amazon hit lists. Glad you mentioned it 'cause It looked a little too heavy on the motor boats. Do you know anything about "Elements Boat Strength" by Dave Gerr? Does it cover the common alloys of AL?

Yeah lots of folks out there with plans. Always safer to go that route, but since it is only a dream for me right now it is an excuse to get nerdy and read up on aeronautics and start from scratch.

WH, Correct on not hoping to hit boulders in ID... but that being said fetching up on coral or hitting rogue cargo containers IS why i am looking at a metal boat, otherwise composites are the way to go.

-I know AC is desirable for AL. So as the boat switches from being the anode to cathode there is removal of built up oxidation. Is this possible in a MIG system? What is this called? How new of a technology is this (as I will have to buy used for now).

-I am reading that some of the high end Lincolns and Millers let you use an uneven AC so that you get just enough of a current flow direction to remove oxidation but a longer time heating the boat. Is that what Lincoln calls "AC wave balance" or is that something different? How necessary is this uneven AC technology and how long has it been around?

-What is "Pulse" .

thanks, pete

[cadmus]

Also, i assume you all have found these Forums? lots of boat construction talk on these forums. But far less about welding.
http://www.boatdesign.net/forums/
http://forums.sailinganarchy.com/

[WHughes]

Dont worry about pulse technology if you dont have the knowledge or means. Those building aluminum boats are not using it and frankly, once you understand the principles and procedures of the welding process you would likely prefer not to have it.

Your post did remind me that aluminum gets a lot of corrosion in salt water so I assume you will need a sealer of some sort. Not really my expertise there.

[cadmus]

It's still good to know what Pulse is... if anyone wants to explain it.

I have only seen a few aluminum boats at sea that didn't have the usual marine paint job. Even those had anti-fouling paint below water line (high in Cu and other heavy metals to keep the algae and barnacles off, real nice sealant and water barrier, hard to chip off, leaches toxic metals into the environment). Some racer folks will use a filler to smooth out the chines or TINs and make it more of a soft/round chine and bilge. I do not know what this filler material is, do you? I know polyester fiberglass epoxy doesn't stick well to metal.
I have seen pics of stainless steel boats that are left bare and brushed, pretty sexy looking, like an old airplane, sadly i don't feel safe doing it with aluminum.

[zeyang]

hi list,
heck, what an interest. i always think im the only crazy guy out here welding my life away on a boatproject.
here is a link: blog.sina.com.cn/gosailing. run it through translate.google.com.
mind you, you will not find any welding pictures yet, since im just starting this step. It seems welding is the smallest part at this stage. making templates for laps and boatframes has taken most of my time. since its wineglass hull, double ender, i only had two option. Use a lot of bending force to make it a double curvature or make a boat in lapstrake, so i choose the latter.
I will do tig welding until i can find a good second hand mig machine. actually i found a powerwave 450 but unfortunately i dont have the wire feed part so if anyone have a wirefeeder for a powerwave 450 i would be very happy.

For those interested in original double-enders rescue boat i will try to save all this templates in cadfile to make it easier to dublicate this boat at later stage. Then I think it will be possible to save up to 50% of building time. Just put up 4-5 inverted wooden frames as template and go for cutting out the lapstrakes from the cad and start welding pieces together. (no need to spend a lot of time for fitting out, which i have done now)
lead will be made in ingots and put inside the boat. (15-20 kg each)
There is one rule i follow strictly: KISS (keep it simple stupid) No fancy stuff, no gadgets and a plain simple sailrig you can build out of an old telegraph pole (junk or gaff rigged) This is purely an escape machine, fitted to go around the world.

For those dreamers out there, i just found out: building boats is really time consuming hobby. spending 5000 hours in the boatshed is no problem. (that is for a 12 meter long x 4.20 meter wide boat)

zeyang

[cadmus]

lapstrake. like where skinny planks overlap each other...? you WILL have a lot of welding. But that will be gorgeous. How wide will the planks be?

[Craig in Denver]

If you guys would like, you can go up to the left side of the page, to User CP, and fill in your location. It will show up in all of your posts, where mine says Colorado. It's interesting to know what parts of the World everyone lives.

[zeyang]

lapstrake. like where skinny planks overlap each other...? you WILL have a lot of welding. But that will be gorgeous. How wide will the planks be?

I think around 8-10 inch would be close to the original on these kind of boats. (overlap approx 0.5-1 inch)

zeyang

[zeyang]

Hi Zeyang & Cadmus

I am in the same boat. What is the design of your boat?

Go with MIG, TIG is too slow for such a big job and stick welding Aluminum is very difficult. FCAW (Flux core) welding in general is more difficult than MIG and the process create spatter and slag. I've never done aluminum flux cord welding before.

A 200 to 250 amp (60% duty cycle) welder with a spool gun is probably the minimum needed for welding 3/16(7mm) aluminum plate.The push pull feeder gun system as suggested by Bill is ideal. The latest innovation in welding aluminum is the Pulse MIG welding process, that is if you can afford it.Use properly, PULSE MIG causes less heat related problem and is easier to get a good weld. The best one like Fronius TPS 2700 costs upward of $10,000, Miller and Lincoln both have welder that can PULSE MIG for a lot less. All 3 brands have machines that can be set up specifically for welding aluminum. I learn welding at a night class at the local community college and I highly recommend it for those who do not have the skill.

I found the book "Boatbuilding with Aluminum" by Stephen F. Pollard very helpful. It answer most of my questions on tools, materials and the process of building Aluminum hull.

Design is original double ender rescue boat. You can get the original drawing for 50 bucks at the norwegian maritime museum.
(http://www.norsk-sjofartsmuseum.no/images/liste.pdf)

[rhapsody]

Sorry for the late reply

"Elements Boat Strength" by Dave Gerr is a very good book on boat scantlings. It has a section on Aluminum and Steel. The book have lots of formula, charts and engineering info on scantlings.

You need AC to TIG and Stick weld Al. I would still clean the surface prior to welding. Any inclusion may cause the weld to corrode and water may leak thru over time.

Lincoln Electric has a very good explanation on Pulse MIG, search for "Next Weld" in Lincoln's site

Pulse Mig is a different way of transferring metal to the weld. In short, The pulse MIG machine uses a build in computer to control the electric current and sent it to the MIG gun in pulses instead of a constant stream. The computer regulates the frequency and the wave form of each pulse and thus control the strength, length and shape etc of the arc. By setting the type of metal, its thickness and the welding speed, you can achieve the optimal arc pre-program either by the manufacturer or the user. Since the current is sent in pulses, there are less heat generated during the weld and therefore any heat related problems are reduced The learning curve is much shorter for a OK welder to lay down his first decent Al weld. If you are good with the newer pulse welding machine mentioned in earlier in this thread or miller equivalents, you can weld thin gauge Al previously consider too thin for MIG welding.

[cadmus]

is the URL to your blog:
http://blog.sina.com.cn/gosailingba
or
http://blog.sina.com.cn/gosailing

The URL you sent in your recent email seems to be more sailing related than the one you listed above.

[cadmus]

The self jigging flat packs I spoke of above are advertised hereon the Corus websites.
You may have to play with the background colors on your PDF reader, the font is white on white background?
http://www.staaltagmester.dk/file_so..._DATASHEET.pdf
or also found here
http://www.corusservicecentres.com/f...aflet2page.pdf
I have ideas as to how i would do this... but if someone knows how the pros are doing it i would love to hear about it.

[zeyang]

The self jigging flat packs I spoke of above are advertised hereon the Corus websites.
You may have to play with the background colors on your PDF reader, the font is white on white background?
http://www.staaltagmester.dk/file_so..._DATASHEET.pdf
or also found here
http://www.corusservicecentres.com/f...aflet2page.pdf
I have ideas as to how i would do this... but if someone knows how the pros are doing it i would love to hear about it.

look expensive...

For homebuilders i think its better to stick with simple alu plates at 30 rmb/kg (4 USD /kg) the big advantages of alu is: you can cut it with ordinary wood tools and its fairly easy to move around alone if the pieces is not to big.
building boat is an expensive hobby, the only cheap part is your own labour, so everything which can be pushed in that direction is money saved. You just need to find an good excuse for more workhours when you gf/wife try to trag you out of the boatshed :-)

zeyang

[oxy moron]

If you guys would like, you can go up to the left side of the page, to User CP, and fill in your location. It will show up in all of your posts, where mine says Colorado. It's interesting to know what parts of the World everyone lives.

(the OP) He's located in Beijing, China. unfortunately, the location is listed in chinese, so, that leaves the other 75% of the world unable to read it