[NF6X]

HI! I'm a real beginner at welding, and I hope that y'all won't mind my very noobish question. I don't have any formal training, and so far I have only done oxy-acetylene torch welding on steel.

I'd like to mount a carport cover between two shipping containers to make a covered area between them. Rather than bolting or welding directly to the containers, I think that I would like to mount the cover to rails attached to the containers with upside-down standard shipping container twistlocks.

I've found a few sources for this style of deck-mounted twistlock:

http://seabox.com/products/detail/SB147 ... -twistlock

They're said to be weldable, though I have also found pictures online of them slipped into dovetail mounts, presumably to make them easier to replace. Here's a picture of a dovetail mount that I found in an Alibaba listing:

Dovetail mount picture from Alibaba

Container-dovetail-twistlock.jpg_220x220.jpg (27.12 KiB) Viewed 2767 times

I think that using dovetail mounts would be overkill for my application, unless they're really needed for weldability.

The spec sheet for the twistlock I linked to above states that the body is ductile iron. So, that leads me to my total noob question: What do I need to know in order to successfully weld mild steel stock to these things, or alternately, should I approach this a different way?

Those twistlocks also appear to be available already welded to bolt-down mounting plates, but I don't know how much those cost, and I presume that they would cost a lot more than random surplus twistlocks.

Thanks in advance for any suggestions and advice.

[ldbtx]

Hi Mark,

Welcome to our little asylum here. Welding cast iron is not my area of expertise, so I'll leave the answer to your query to others more informed. I just wanted to say "Howdy" to another ham, and one who lives in a town I used to live in, at that. Many moons ago, late 70s/early 80s, I lived in Riverside and out in the Gavilan Hills. I managed the old J&T Surplus on Jurupa. It changed hands after I left and I don't know if it's even still a surplus store now. I haven't been in CA in nigh on 25 years.

Anyway, welcome aboard, and I'll guarantee that with all the talent here you'll get an answer to your question.

73,
Larry
K5WLF

[NF6X]

Hi, Larry! I'm over on the other side of Lake Mathews from where you used to live, off of El Sobrante. 73 de NF6X

[Olivero]

Well....

I would never recommend welding something in transport application if the person is not professional or has at least successfully welded this type of thing before BUT

I Will still tell you what I would do, Cast iron and the Cast types of ferrous alloys out there in my opinion seems to weld the best with stainless filler, I personally use 308L and have great success with it.

Since I am not sure what you plan to do with it or its role in your life then I would say its up to you, depends on what its doing really.

Bolting things tend to work good in most cases, it just sucks to mount them and welding it on is much more fun.

[NF6X]

Well....

I would never recommend welding something in transport application if the person is not professional or has at least successfully welded this type of thing before BUT

Understood! This application would be stationary. It would just be mounting some sort of carport cover, kind of like this (random internet picture; there are lots of pictures of similar installations out there):



I think the main structural load would be holding down the carport when the winds are strong. If the welds are stronger than the thin wall sheet metal tubing structure of the carport, then they should be fine.

I Will still tell you what I would do, Cast iron and the Cast types of ferrous alloys out there in my opinion seems to weld the best with stainless filler, I personally use 308L and have great success with it.

Interesting. Can I do that with my torch? I'm sure I'll learn other processes eventually, but I already have the oxy-acetylene gear.

Another option has presented itself. Instead of welding rails to upside down deck-mount twistlocks, maybe I could get (or make) aperture plates like these:


https://www.tandemloc.com/securing-aper ... 1A-100.asp

Then weld my rails to those, and connect them to the containers with ordinary container stacking twist-locks. I think that most folks just bolt or weld things right to the containers, but I like the idea of using the corner castings. Kind of like Lego bricks for big boys!

[Poland308]

On the web page you posted there is an associated link to a similar mount with a mounting plate. It says that model is forged steel and will probably weld better.

[NF6X]

On the web page you posted there is an associated link to a similar mount with a mounting plate. It says that model is forged steel and will probably weld better.

The twistlocks pre-welded to plates with mounting holes look like they might be good for things like fastening the containers to a concrete pier foundation. I don't know how much they cost yet, though. I was kind of interested in finding ways to use random, inexpensive, surplus twistlocks like these ones:

http://www.m2distributing.com/intermoda ... s/65MLTLBL

[Poland308]

You will fight the galvanized coating but the ductile iron should be weldable. I would consider welding them to a heavy piece of plate steel then adapting or welding onto that. This would allow you to put a good fillet weld from the base of your lock to the plate.

[NF6X]

You will fight the galvanized coating but the ductile iron should be weldable.

I want to fight it with an angle grinder and a respirator, right?

[Poland308]

Those are probably hot dipped so grinding will help, but it gets into the pores of the metal. If you tig them be prepared to grind a lot of tungsten.

[NF6X]

Ah, I see. What effect will the non-grindable zinc residue have on torch or stick welding? I think that TIG is in my distant future.

[Rudy Ray]

They are made of ductile iron? Just like pipe fittings, yes very weldable. If galvanized, take the zinc layer off with a 40 grit jumbo flap disc. For what you are building a good brazing job will be more than adequate if you have and are good with a torch.

That is one old school method I'd like to learn.

[NF6X]

I hadn't considered brazing them. Thanks for suggesting that! Yeah, I think that could be a good option for this project. I only have a torch right now, and I've done a little bit of welding and brazing with it. I recently bought my dad a MIG welder for his birthday, but neither of us has tried it yet. I think I will buy myself a stick welder at some point, but I'd like to put that off for a while if I can because I'm just now draining my wallet buying a new tractor. TIG is in the more distant future.

I'd still like to learn how to weld to these iron twistlocks. I expect to set the containers onto concrete piers at the corners. This is earthquake country, so I want the containers properly secured so they won't slide off the piers. I was thinking that one way to do that could be to set twistlocks on top of the piers, and weld them to protruding rebar to secure everything against sliding or lifting in an earthquake. But I'm a lot less sure about how to design that than I am about securing a carport cover on top of the containers. Of course, I could find a much simpler way to secure the containers to their foundation, but where's the fun in that?

[Olivero]

Mig with stainless wire and 100% argon I think you'll be good to go. I only ever TIG welded cast but hey, give it a shot. Worst case, weld it to a steel plate and then bolt it on.

The weld strength will only ever be as strong as what its mounted to, if part of the container that this thing was welded to rips out of the container and leaves a hole for some reason, don't matter if your weld broke or not, piece still came off, you know what I mean?

Man, a lot easier to think than to write this.

You can weld it to the container and do some serious welding and make it stronger than it would ever need, but if the welds don't break and you just rip a hole in the container, your in the same boat regardless of the weld breaking or not. I have seen some crappy welds hold a lot of weight, working in the kitchen industry you see tons of this shit.

[NF6X]

The weld strength will only ever be as strong as what its mounted to, if the piece rips out of the container for some reason, don't matter if your weld broke or not, piece still came off, you know what I mean?

Exactly. In the case of this carport mount, the weld is competing with a structure made of thin-walled sheet metal tubes on 5' centers. Even in the likely case that I make poor-quality welds, they probably won't be the weak link. I'm more concerned about the foundation stuff on the bottom, which needs to keep the containers from taking a walk in an earthquake. For the foundation, I may be better off paying more for twistlocks that are professionally welded to plates that I can bolt to a foundation.

[Otto Nobedder]

Please don't MIG steel with 100% argon, unless you have a power source that can do spray-arc, and even then you should be using a mix gas for best results.

Steve S

[Olivero]

Please don't MIG steel with 100% argon, unless you have a power source that can do spray-arc, and even then you should be using a mix gas for best results.

Steve S

even on sheet metal?

I don't know a whole lot about MIG as I only TIG and Stick. If he uses stainless wire doesen't it have to be 100% argon?

[LtBadd]

Please don't MIG steel with 100% argon, unless you have a power source that can do spray-arc, and even then you should be using a mix gas for best results.

Steve S

even on sheet metal?

I don't know a whole lot about MIG as I only TIG and Stick. If he uses stainless wire doesen't it have to be 100% argon?

Pretty sure stainless MIG uses a tri-mix

[Otto Nobedder]

Please don't MIG steel with 100% argon, unless you have a power source that can do spray-arc, and even then you should be using a mix gas for best results.

Steve S

even on sheet metal?

I don't know a whole lot about MIG as I only TIG and Stick. If he uses stainless wire doesen't it have to be 100% argon?

There are a few mixes that can be used with stainless. Even 75/25 will do it, but it's ugly. I use tri-mix at work (90% He, 7.5% Ar, 2.5% CO2). There's also 95% Ar/5% CO2 (if I remember right) and 98% Ar/2% O2. I'm sure there are other specialty mixes.

I did have a helper accidently hook me up to pure argon while MIGging stainless. It was 11ga. duct. It would barely weld in flat position, no penetration, ugly bead, and was not useable at all in other positions. This was in the morning, and I didn't know the bottle had been changed, so I was scratching my head as to what the hell was wrong with my machine. It was a suitcase, and I didn't figure it out 'til I went to check the power source and flow meter.

Steve S

[Olivero]

Well, I stand corrected then, Don't MIG it with 100% argon.

Are you able to MIG stainless? You got bottles? I am thinking if you don't already have the gear to weld stainless, its gonna cost you more to get it then to buy the bolt-on ones.

[NF6X]

Are you able to MIG stainless? You got bottles? I am thinking if you don't already have the gear to weld stainless, its gonna cost you more to get it then to buy the bolt-on ones.

You're probably right. All I have right now is an oxy-acetylene torch and the ability to borrow a MIG welder.