Building a bunk bed for our Airstream Sport 22FB: Part III (learning to weld)

I’ve always wanted to learn to weld, but it’s always seemed a bit overwhelming to get started. Building a bunk bed for our Airstream has provided me with the perfect excuse! My original plan was to just use my friend’s welder, but pretty quickly I found myself at our local welding supply shop buying myself a whole welding setup.

A welding sleep-over

We had plans to camp out with Wobbles in our friends’ driveway in SE Portland for 3 nights so that we could hang out and let our kids play. That was also the perfect excuse for some welding practice.

I asked my friend Josh what kind of welder he had, and I stopped at the welding shop the day before we went over and picked up a spool of aluminum filler wire that the shop said would fit his welder.

I probably should have done more research up-front on what kind of welding equipment was needed to weld thin 1/16″ thick aluminum pieces… but I was really just excited that I knew someone that had welding equipment and experience.

We fired up his MIG welder and I started practicing on some small extra pieces of aluminum I had purchased. Things were off to a bad start. I was melting holes right through the thin aluminum… and even when I didn’t, the welds (if you could call them that) looked charred and contaminated, not like the clean “stack of dimes” look that expert welders produce.

We only had about an hour to play around before it was time for me to stop and help put our girls to sleep. That night, I did a lot of reading and You-tubing to learn about why I wasn’t getting the results I had hoped for. Here’s what I learned:

1. MIG welding is really difficult with thin aluminum– it’s typically used for 1/8″ or thicker aluminum only.
2. Aluminum should NOT be welded using a shielding gas mixture that contains CO2. Typically, it’s welded with pure argon gas. We were using 75% Argon / 25% CO2. The CO2 contaminates the weld with too much carbon– hence the charred look.
3. Aluminum contains an oxide layer that protects it. This oxide layer has a very high melting point of 3600 degrees Fahrenheit, where as aluminum has a comparably lower melting point of 1200 degrees. By the time things get hot enough to melt through the oxide layer, the aluminum underneath has turned to soup, which is why I was punching holes through it. Using an AC (alternating current) welder fixes this problem, as the alternating current blasts away the oxide layer, exposing clean easily meltable aluminum (don’t ask me how, it just does).

From my research I had learned that the proper equipment for thin aluminum was an AC TIG welder with pure argon shielding gas. The next day I called the welding shop and found out that they rented TIG welders, so I drove right over. I should have asked on the phone if they had one AVAILABLE, as when I got there I found that they didn’t.

I also found that the price they had quoted me on the rental was incorrect, and the real rental cost was quite a bit more expensive than they had thought (I believe it was $275/week). The guy I talked to at the store was very knowledgeable about welding, and he told me that the Lincoln Electric Square Wave TIG 200 welder that they carried for sale would be perfect for what I was doing. However, I wasn’t ready to drop $1,600 just yet on a welder when I didn’t even know how to use the thing.

I sat out in the car in their parking lot for at-least 30 minutes researching the Lincoln Electric welder that the employee had recommended. I also looked on Craigslist for TIG welders for sale, and saw that used welders were selling for pretty close to what they cost new. That made me think that perhaps buying a welder wasn’t such a bad idea. I could buy it and, even if it didn’t work out, I could likely sell it and lose less money than I would from renting a machine for a few weeks.

I went back in the store and put together a welding package– the welder, a welding mask, a tank of gas, gloves, filler rods, clamps, and a wire brush. All-in-all, the whole package cost about $2k.

After getting the machine hooked up I immediately noticed a huge difference in results. I still did melt a few pieces of my aluminum at the beginning, but once I got the hang of it I started making welds that at-least resembled what I imagined a clean aluminum weld should look like.

Setting up shop at home

After we got home from our sleep-over I needed to set up a welding shop at home. Unlike my friend’s house, we don’t have a big garage workshop or driveway space (Wobbles takes up our whole driveway). Instead, we have a small bike garage that is mostly full of bikes, and has a small workbench in the corner.

We were worried about the girls running into the garage while I was welding in there, so Sarah made me a nice sign to warn the girls to keep out.

A practice project

I really didn’t want to waste any more aluminum just for the sake of practicing.. but I didn’t feel like I was consistently producing strong welds just yet, and I was sometimes still melting through the aluminum and ruining it. I didn’t want to start working on the large aluminum pieces for the bunk bed only to ruin them. I needed a smaller practice project where I would produce something real.

The A-frame on the front of our Airstream has a spot where the battery used to be. I removed the battery when I installed lithium batteries inside the trailer. Given how tight we are on space, I’ve felt this spot should be used for something. I thought perhaps if I made a tray that fit in there, that we could use it to carry firewood (which we had been carrying inside the van, but would rather keep outside).

I measured the A-frame and made a basic model in Sketchup, and then designed a tray to fit.

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I set up a cutting station (we hadn’t put Wobbles in the driveway yet, so I was able to work there– although later when we put Wobbles back I had to move to the sidewalk.)

I also got a few things from Harbor Freight, including a corner clamp which was super helpful to get my corners square.

Progress was slow at first. The first couple days it took me about an hour to weld each joint. After a few days my pace started picking up and I was going at a rate of about 4 joints per hour. Still not blazing fast, but workable– and I hadn’t ruined any of my material!

Progress slowed due to me starting my summer job .. but after almost 3 months of poking at it now and then it’s finally finished!

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Now on-to the welding the bunk bed!

You can read part I, II and IV of this series of posts here:

• Building a bunk bed for our Airstream Sport 22FB: Part I (removing the dinette)
• Building a bunk bed for our Airstream Sport 22FB: Part II (the design)
• Building A Bunk Bed For Our Airstream Sport 22FB: Part IV (The Completed Results)