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Help me pick a process

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Help me pick a process

Postby mworthan » Thu Dec 28, 2017 6:15 pm

Hello gentlemen! I need advice and I'll be really specific about what my intentions are.
My experience: DIY and small welding projects using a small Lincoln welder as a young man making extra cash on the side as part of paid construction projects AND as a certified farrier as an adjunct to forge work (mostly experience blacksmithing).
My current need: Been building a boat for a few years and will build a full size canopy. This is a change in direction on the boat since I've been moved by my job to the Georgia Coast. My blog covers it better than here: redwing23.blogspot.com
The canopy frame material is up for debate but it would be between stainless or aluminum. Either would be painted so I'm leaning toward aluminum.
So here's the question... What process? TIG or MIG with spoolgun? This will be done outside. I have a large canopy but would pull the boat up next to the garage to work then return back to the carport. Schedule 40 6061 Aluminum Pipe 1-1/2". I would notch the pipe for the lower rails or may use aluminum sphere's and hole saw to emulate the old ball jointed handrail. I have looked at the AHP 200 as a TIG unit. Maybe Hobart 210 and spoolgun as the MIG option. Don't know the next project but it would open up possibilities. I know the TIG is more versatile, just worried that I'm wasting my time trying to use it anywhere but in an enclosed building or on a bench.
Thanks,
Mike
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Re: Help me pick a process

Postby cj737 » Fri Dec 29, 2017 10:30 am

Both processes are susceptible to draft, so it’s a toss up. MIG will be faster, TIG would be “better” from a control perspective. Painting aluminum wants a specific primer, and painting stainless is pointless since it’s already corrosion resistant (316grade is marine preferred). You’ll really need to watch the distortion on both materials. Also, where the saddles intersect, drill a small hole in the mating tube to vent the pressures. 5356 aluminum wire is best choice if you go the ally route.
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Re: Help me pick a process

Postby mworthan » Fri Dec 29, 2017 2:04 pm

I appreciate the feedback! I guess what you mean by "both are susceptible" is that neither is more forgiving than the other if there is draft, precautions for either process would have to be made equally. I can understand that.
I have actually considered mild steel since I will definitely be looking at a marine coating (want this a color). There are some aluminized marine paint systems like Pettit Rustlock Primer that have a successful record in sealing mild steel in marine environments and can be topside coated with a LPU. If I go mild steel tubing, MIG would be the way I head and a complete capping of all tubing. This I suppose leads into a discussion regarding mild steel interior corrosion once sealed.
I agree concerning SS and AL. Both require a special oxide removal system and process and the stainless still has trouble. I am not interested in the stainless look (just an aesthetic thing for this boat in particular).
Thanks again for the imput.
-Mike
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Re: Help me pick a process

Postby noddybrian » Fri Dec 29, 2017 4:04 pm

Stainless of any grade will corrode with sea water unless treated - polished less so as the salt has more trouble adhering to the surface so takes longer - i would think as it's a canopy your adding weight up high so use aluminum - to reduce change in C of G - as to the process I would say that mig is less affected by drafts outside than tig & has the advantage you only need one hand so you can use the other cupped around the area as a wind break plus the faster the weld the less chance of gusts causing issues - as your going to paint anyway & could grind defects out the appearance advantage of tig is less important - as to coatings have a look for " Brantho Corrux " - I've been using it on marine applications & outside steel work recently & am impressed - had never heard of it till it was spec'd on a government job a mate was doing - worth a look - we got an agent for it quite local but I believe they will ship anywhere.
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Re: Help me pick a process

Postby mworthan » Fri Dec 29, 2017 7:47 pm

Great advise! I was looking for a "leaning" toward one or the other and your points make solid sense. As far as the Brantho coating, I am really interested as it seems too good to be true. I wouldn't believe the claims if you hadn't testified as an actual user. As far as a distributor in the US, I didn't see any. In regards to a ready outlet, EBAY had 5 liter containers 1
$150 US + $50 shipping.
What are the thoughts out there on mild steel aboard boats if I used a light tubing (16GA) and a high performance coating such as the Branco? 1.5" x .065 welded steel tubing looks comparable to sch 40 6061-T6 1.5" in weight. Tensile strength would make me think it comparable using a tube calculator.
I guess here's a question... If I used a welded steel tube for the canopy frame, 1-1/2", what would be the lightest you would use?
I guess it also comes down to, "Can I protect it from the marine environment?" Probably so but it would take vigilance in watching for a breech in the coating.
Thanks,
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Re: Help me pick a process

Postby mworthan » Fri Dec 29, 2017 8:08 pm

Amazon UK states this about Brantho: "No sellers are currently delivering this item to the United States" So...
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Re: Help me pick a process

Postby cj737 » Sat Dec 30, 2017 8:37 am

If you use steel, use DOM for certain. If you "cap" all the ends, then you need a vent hole somewhere. Have access to a tubing bender? A 4.5" CLR die with 1.5 tubing can make a pretty decent bend without distortion. Make "hoops" running across the beam, then straight notched sections bow-to-stern for ease. Notched joints, MIG welded up (0.024), then "wash" over it with a TIG torch for aesthetics. Bob's yer Uncle!

If you could treat the interior of the tubes with a Zinc primer after welding, that would be very effective. Tricky to insure, but if the sections are fully welded, no air infiltration, I don't see how you'd get too much rust in there anyway?
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Re: Help me pick a process

Postby mworthan » Sat Dec 30, 2017 9:29 am

Great advise. I appreciate it. I looked up the DOM description and appearance would be improved as well as dimensional tolerance (aid in fit up). Small wire and maybe I should be looking into a MP setup for a hobbyist with DC TIG capability or I go with a small MIG and go ahead and opt for a nicer AC/DC TIG for the future flexibility. So, on a budget, I'm thinking a small Handler 140 or Everlast 140 for the MIG and maybe the AHP 200 TIG unit for a TIG with AC capability. I'll need a notcher and bender or maybe roll bend a continuous arc for an athwart ship awning truss between uprights saddle notched to give me a 2 to 3 inch crown on the canopy top. One other option I have seen on these picnic launches are mahogany awning frame and trusses bolting to the steel uprights. That means either sawn, steam-bent or laminated girts and trusses. That's not a welding topic and one for woodenboat I guess. I actually lean toward all metal and with that much tubing up high I am starting to wonder if my best bet wouldn't be aluminum pipe.
Question? If you use MIG for aluminum would you still TIG wash the weld for appearance or is that a bad idea with aluminum?
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Re: Help me pick a process

Postby noddybrian » Sat Dec 30, 2017 3:22 pm

This is an odd topic as there is no " right " answer - only opinion's - I do a few hand rails & such like for sea boats & they are always stainless but with the amount of tubing your build appears to need I would stick with aluminum just on weight - I would not entertain steel - no matter how much you try the rust will get to it in very short time - a tug I regularly work on has railings made of 3" sch40 & they rot away quite quickly so going thin wall makes no sense - the Brantho coating I bought in the summer came out at £77 plus tax for 5 liters - it's easy to buy here as it's made in Germany so not far to ship & we have an agent in the UK - if you look up the Brantho website I believe they ship worldwide but don't know cost to you - our local hrbourboard has switched over to it & Trinity house the people responsible for coastal marker buoys & light ships now use it so I think it's a proven product - they used to use 2part epoxy primer & color requiring sand blasting followed by 5 coats total now they steam clean the loose off & do 3 coats of Brantho so it's quite a cost saving - I applied quite a bit this summer but have not revisited any of the projects to say how they are weathering - I do know a local firm that sells shipping containers & if you want a good one they paint them with it & offer an impressive warranty against corrosion so I think works - only thing I found was if the weather is too hot it's difficult to paint fast enough to keep a wet edge - with regards to your original choosing a process I'm still in favor of mig I think but what model is down to how you budget for this job & how much further use you'd have for one - I think a synergic model would be good but maybe too pricey such as the HTP pro pulse 200 - quite a few people that do out door aluminum builds / repairs love them - Peter Zila has some videos of his working - also Everlast & Esab have a multi process that does mig / tig / stick including AC - sure others will follow - interesting to see which way you end up doing this - one other option I've seen quite often where welding is not an easy option is to thread all the pipes & use threaded elbows / tees etc to build the shape.
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Re: Help me pick a process

Postby mworthan » Sat Dec 30, 2017 4:41 pm

Excellent food for thought. Thanks! I have considered the assembled version of this and its not cheap either. To look decent it would need to be internal fittings in Aluminum Pipe. At least how I want it to look. I think I will go Al. I don't think that I need the headache of steel. Not at what little difference there is in cost. The only luxury here is that I am painting so I can grind or sand ugliness as my skills develop with the last weld being my best I'm sure. I will update you guys along the way and hide nothing. I am still up in the air concerning a MIG outfit. I think 180A minimum. I don't see myself using it more than occasionally. If others can chime in concerning recommended machines or spoolgun combos, please do. I would like to stay in the $1000 - $1200 range and capable of 1.5" SCH 40 AL pipe.
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