How to Make a Modern Metal & Wood Sectional Sofa

This whole project was born because our lovely dog, Rain, has some anxiety issues. Most the time she’s fine, but sometimes you come home and your brand new sectional has been destroyed. Yes, she is crate trained, but since 99% of the time she’s fine, we don’t usually leave her in the crate when we go to work.

At first, we tried to find a dog-proof couch on the market. Something that had removable cushions, durable materials, and was safe for the dog in its disassembled state (so no straps they can get their paws caught in). We couldn’t find a single thing that met our needs, so I proposed to my fiancé, Mat, that we design and make a couch that fits those requirements.

To save money, we wanted to repair and repurpose the leather cushions from the existing sectional. That would mean basing them measurements of our new design on the measurements of the old couch.

Our requirements:

Metal frame
Wood embedded within the metal (so even if our dog wanted to, it’s not possible to chew on the wood)
Repurpose and repair the existing cushions
The ability to adjust sides of the couch separately. We have an old house with unlevel floors. Industrial design
Removable cushions
The couch should still be usable without the cushions

Tools / Tool Recommendations

Flux-core MIG welder
Slider Mitre Saw
Palm Sander
Belt Sander
Angle grinder
Impact drill
Square magnetic welding clamps C-Clamps Bar Clamps

Safety: Welding helmet, Safety Glasses, Gloves

Materials

4x8’ plywood
1x1” square tubing 3/32” wall
½” x 1/8” angle iron
Cappuccino brown spray paint
Wood stain
½”- 13 bolts and nuts
Wood screws

We purchased our metal from a metal distributor. It was a lot less expensive to do it this way than to go to the big box stores. The only caveat being they didn’t have a lot of variety, so we choose the metal they had the most of that was also the least expensive.

Step 1: Designing a Metal Sectional

Metal Sectional Design Inspiration:

Our Design

All of the above designers do such an amazing job blending the coolness of metal with the warmth of natural materials. We also both really love industrial design, so this was our opportunity to incorporate that into our home.
We measured the old couch and created some 2D diagrams. Since we were working as a team, we both needed to fully understand what we were building. We decided to try mocking it up in a program called Sketchup , free 3D modeling software.

As you can tell by the video, we’re definitely not experts in the software. That being said, it really helped us visualize what we were building ahead of time, and the software comes with a bunch of useful tutorials to help you get started.

You can also use Sketchup to get your measurements. So while you may invest hours (in my case) mocking up your concept, you save time and money down the road solving problems before they pop-up.

I’m sure you’ve noticed that we changed the arm design last minute. At first, we were going to have cushions going up on an angle similar to the District Millhouse’s Hourglass Couch but eventually decided that squaring off the arms would be more comfortable.

Step 2: Cutting Material for Your Sectional

I can’t emphasize this enough, create a cut plan. I won’t lie, if Mat wasn’t around I’d probably just start cutting instantly with no plan in place resulting in wasted time and material.

Based on the 3D rendering, he diligently mapped out each section’s pieces and figured out a way to get the most out of the metal. As well as this acting as our roadmap, it also acted as our checklist. When we cut off a piece, we checked off that it was complete and wrote on the metal with a permanent black marker where it was going.

We used our miter saw to cut the metal. I should note ours is fine to cut up to ¼” metal but not all miter saws can do this. Make sure you read your saws capabilities before you start cutting. Also, make sure your saw blade is for metal.

We went through 3 saw blades during this process. The best by far was the LENOX 10-in 52-Tooth Steel-Cutting Circular Saw Blade. We probably got 80% of our cuts with this blade.

Tip: Be conscious of corners. You don’t want any butt joints because the metal is hollow and it would look terrible. For the corners, you should be doing miter cuts so it looks solid.

Step 3: Welding the Sectional Frame

As you can tell by the photos, we do not have a proper shop setup. The ground isn’t 100% level, and we don’t have professional tools. We did our best with what we had to keep the frame square with magnetic welding clamps.

First, we held the couch together with tack welds. That way, if a measurement was inaccurate or we tacked it in the wrong spot, we could easily break the weld, fix it, and tack it again.

Once we got the pieces in the places we welded it solid. We alternated which corners we welded so we could minimize any warping in the metal caused by the heat.

Safety tip: Along with your welding helmet and gloves, wear long sleeves and long pants. You can get a sunburn from welding.

Step 4: Grinding

I have never done so much grinding in my entire life. Every weld needed grinding. And although convenient, flux-core welding is messy.

If possible, let the weight of your grinder do the work. No need to push down, just hold on.

You want to spend the time getting this stage right. For the style we were striving for, we wanted our welds to be flat.

Safety tip: Always wear earplugs and safety glasses. Take breaks, drink water.

Step 5: Attaching the Angle Iron & Bolts

The Angle Iron

We decided to use angle iron to hold the embedded plywood. We built a little jig to assist with alignment. It was literally just two small pieces of the same plywood we used screwed together. The top of the jig would rest on the frame, the bottom piece would give us the depth of the wood. We got the positioning using the jig, held the angle iron in that place, and tack weld it.

For the back of the couch we did one long stop of angle iron along the top and two small pieces on the bottom.

After we tack welded all the angle iron we did our full welds. And of course, more grinding.

We drilled two holes into each angle iron that would be required to hold or secure the plywood. We didn’t bother drilling into every angle iron if the wood was just resting there.

The Nuts and Bolts

As I mentioned before, we live in an old house with unlevel floors. That, combined with the fact that we don’t have a completely level workspace caused us to use a little more ingenuity. On the corners of the couch we welded a nut inside the metal frame. This way, we could screw a bolt inside and use the bolts to level out the couch. If one area of our floor is unlevel, we just make that bolt a little longer.

We had to grind the edges down a little bit so the ½” bolt would fit snuggly inside. After, we just placed them in and welded them in place.

Step 6: Plywood Prep for the Frame

Similar to our cut plan for the metal, we mapped out our pieces to get the most out of the plywood. We went to our local hardware store to buy the plywood, and they were kind enough to rough cut our pieces.

Dry Fit

Of course, nothing is perfect. We still had to get out the old hand saw and belt sander to dry fit everything perfectly. It was pretty satisfying being able to sit on the couch for the first time, even if it was looking a little rough still.

Sand Plywood

Each piece of plywood needed to be sanded down so it was soft and the corners needed to be rounded. A rounded corner is visually more forgiving than an angled one.

Stain

The best advice I can give here is to read the label of your stain and follow those instructions. We chose a dark stain.

Varnish

We actually used a spray varnish. Much faster than painting, and I was pretty pleased with the results.

I'm always amazed at how beautiful plywood looks when it's finished.

Step 7: Painting the Sectional Frame

We sanded all the metal down, just to remove any rust spots. After, we wiped it down with paint thinner just to give it a good clean.

At first, our plan was to paint it black. But when we saw the frame painted black it just reminded me of one of those futon couches from my college days. Not the look we were striving for. We switched gears and found this dark brown cappuccino coloured paint.

We went through 4 cans of paint. Again, following the instructions on the label we did light coats flipping the couch over.

Step 8: Assemble the Sectional

Assembly was easy. We just secured the plywood to the metal frame with wood screws thru the holes we drilled into the angle iron. Originally, we thought we would need to bolt each section of the sectional together, but with the weight of the metal, it wasn’t necessary.

The most satisfying part was adding the repaired old cushions to the couch and sitting down. If I’m honest, I think our new couch is better looking than the old one. But maybe I’m just biased.

Step 9: Mistakes & What We Learned

I did not think this project would take as long as it did, nor did I think it was going to be as physically grueling as it was. From start to finish, this project took us a year to complete. We picked away at it slowly. We finally finished it 2 weeks ago when we used our vacation time to complete this project.

We struggled a lot, in the beginning, using the wrong tools. As crazy as it sounds, our original plan was to make this couch with a hacksaw and an OxyAcetylene welding torch. With the right tools, half of the job is already done.

The best piece of advice I would give someone is to take your time with the design and planning stages. Work out your bugs in the beginning because it will save you so much time in the long run.