I had a perfectly good metal heater housing left over from a previous project (https://www.instructables.com/id/Old-rusty-heater-resurrected/), so naturally I had to make something out of it. The more I looked at it, the more I envisioned a new computer. I just happened to have all the parts needed, including a mini-itx board, and this little heater housing was a perfect size for building a small desktop pc.

Step 1: Materials Required

Since I had all the parts I needed, I really had to buy nothing. The parts used were:

- empty metal heater housing
- mini-itx motherboard
- 160 gb hard drive
- 300w power supply
- DVD combo writer
- wireless PCI card
- momentary switch
- two LEDs for the front panel
- two IDE cables
- internal speaker
- 1gb PC2700 memory (maximum for this motherboard)
- software (operating system, hardware drivers, application software)
- miscellaneous nuts, bolts, and washers

The tools used were:

- drill & bits
- jig saw with a metal cutting blade
- files
- screwdrivers

Step 2: Determine Layout

I began with taking all the major components and figuring out the best place to mount them. I finally decided on mounting the power supply on the bottom right, the motherboard on the top right, and the optical drive at the bottom left. This would give good access to the optical drive, the motherboard back panel ports, and the optical drive. I mounted the hard drive behind the motherboard.

Since the heater housing came apart in two separate pieces (front and back half), I had plenty of room to work, even though when assembled very little space was wasted.

Please note that the parts shown in the photo are for reference only, and not the actual parts I used (a mini-itx board is significantly smaller than the ATX board shown).

Step 3: Install the Power Supply

The power supply, motherboard, and optical unit all needed to be mounted in cut-outs on the heater housing. I began with the power supply.

I first covered the side of the housing where the power supply was to be mounted with tape to prevent the shoe of my jig saw from scratching the paint, then I marked the exact dimensions of the required cut-out onto the tape using a fine line marker (1st photo).

Because the corner of the heater housing was curved, I had to make a wooden spacer to go between the power supply and the opening. I made a paper template and drew the spacer onto a piece of 3/8ths inch plywood (photos 3 & 4). I cut out the spacer and sanded the lower corner to match the curve of the heater housing. Next, I tested the fit and kept modifying the curve until everything fit snugly (photo 4).

Then I painted the spacer black and set it aside to dry.

Step 4: Install the Motherboard & Memory

While the spacer was drying, I made a similar cut-out for the motherboard (photo 1). I made all the cut-outs as exact as possible, since I didn't want to have to fabricate any trim around them. In sawing them out with the jig saw, I sawed them out a bit small, then used a file to enlarge them until the fit was perfect.

I mounted the motherboard on some wood shims that I carefully sanded until the fit was perfect, then I attached the wood shims to the housing with screws, and then attached the motherboard to the shims using the board's mounting holes (photo 2).

By now the spacer for the power supply was dry, so I also mounted it (photo 3).

Step 5: Install the Optical Drive

Next I mounted the optical drive on the other half of the housing using the same technique used in the previous components. Because the optical drive was not as thick as the power supply, I didn't have to worry about making a spacer.

Step 6: Install the Hard Drive

I installed the hard drive in the space above the optical drive (which would place it opposite the motherboard when the two halves were reassembled). I mounted it using screws inserted through the front of the housing, and used rubber grommets between the hard drive and the housing to dampen any vibration. The rails on the side of the hard drive were parts that I had salvaged from an old computer.

Step 7: Install the Wireless Card

I cut a slot out of the housing at the top of the motherboard to allow for an external antenna for the wireless PCI card.

Step 8: Connect Everything

I drilled holes in the top of the housing for a momentary switch and wired the switch to the motherboard (photo 1).

Next I attached an internal speaker (photo 2) and wired it to the motherboard. I also installed a case fan (photo 2).

The final step was to connect all the other cables (IDE cables for the hard drive and optical drive, and power cables).

Step 9: Put the Halves Back Together

The final assembly involved putting the halves back together and attaching the front guards and the handle.

Step 10: Load the Operating System, Updates, and Software

The final step was to load the operating system, device drivers, and all critical operating system updates. Then I began loading application software.

This turned out to be a pretty slick little computer. It is quiet and takes up very little space. It's motherboard uses a fairly low-powered processor so it certainly isn't a gaming machine, but it works very well for email, surfing the web, word processing, and submitting Instructables!

This is the third computer I've built where I engineered the housing from scratch, but it is the first one I've done in an all metal housing. Assembling the parts for a computer and installing them in a computer case is not a difficult task -- the challenge comes when you put the parts into something that wasn't designed to hold them. With a careful approach to layout and careful cutting of the required cut-outs, however, this can be a fun and interesting challenge.