H02: Build A Box! | ENGI 210: Prototyping and Fabrication

Cost Estimate: $156.01

Time: 30hrs

Work/ Labor time =6hrs

Filler drying time = 24hrs

Materials: $39.91

Sixteen #6- 3/4 phillip flat head wood screws
1. Item Used for Estimation: Everbilt #6 x 3/4 in. Phillips Flat Head Stainless Steel Wood Screw (3-Pack) =$0.57/pack
2. Total cost: 0.57*6= $3.42
Elmer’s Wood Filler
1. Item Used for Estimation: Elmer’s E855 Carpenter’s Wood Filler, 3.25-Ounce Tube, White = $4.67
Wood
1. Item Used for Estimation: Home Depot 11/32 in. or 3/8 in. x 4 ft. x 8 ft. BC Sanded Pine Plywood=$16.93
  1. Wood Cuts:
    1. Two 5 5/8″x 5 1/4″ x 3/8″ wood pieces
    2. Two 5 5/8″x 6″x 3/8″ wood pieces
    3. One 6″x6″x 3/8″ wood piece
Spray Paint
1. Gray Primer Spray Paint
  1. Item Used For Estimate: Rust-Oleum Painter’s Touch 2X 12 oz. Flat Gray Primer General Purpose Spray Paint (6-Pack) = $23.88
  2. Total cost= 23.88/6=$3.98
2. Blue Spray Paint
  1. Item Used For Estimate Rust-Oleum Stops Rust 12 oz. Protective Enamel Satin Sapphire Spray Paint (6-Pack) = $25.62
  2. Total cost= 25.62/6= $4.27
3. Silver Spray Paint
  1. Item Used For Estimate: Rust-Oleum Stops Rust 12 oz. Hammered Silver Protective Spray Paint (6-Pack) = $37.08
  2. Total cost= 37.08/6= $6.18
Razor Blade
1. Item Used For Estimate: TITAN 100-Pack of Razor Blades = $7.53
2. Total cost: 7.53/100= $0.08
Sponge brush
1. Item Used For Estimate: Wooster 1″ Foam Sponge Flat Sash Paint Brush = $0.38

Labor: $116.1

According to PayScale, the average hourly pay of a machinist is $19.35/hr so the labor cost is 19.35*6= $116.1

Disclaimers:

Lack of information on the screw metal composition could have skewed my cost estimate value. However screws are rather inexpensive across the range of materials so the effects are not drastic. The cost value used for the estimate is for stainless steel screws. Moreso, I chose to omit the cost of the equipment for this estimate.

The Journey:

Image: The sides of the box.

First I cut two 5 5/8″x 5 1/4″, two 5 5/8″x 6″, one 6″x6″ pieces of wood from a 3/8″ thick sheet of wood ( I do not know the type exactly because the wppd was not labeled in the OEDK) I also cut one ~6″x~4″and one ~1′ x ~6″ piece of the same wood to use for testing.

Image: Test wood. I used this piece to test the Kreg Jig and to test the wood filler idea, seen as a white spot on the bottom right corner which hides the screw underneath.

Next I tried to use the kreg jig on the smaller piece of test wood but found that no matter how I changed the length on the Kreg Jig and/or the position of the collar on the drill bit, the holes were angled so that the screw would always come out the side of the wood making it impossible to put my box together with the Kreg Jig. This was because my wood sheet was too thin for the Kreg Jig.

Image: Initial box Assembly with deeply countersunk holes.

I now had to find a way to put my box together without making the location of the screws too obvious.I considered using flat head screws with countersinks on my box but this would not hide my screws. I then decided to use both a countersunk and a counterbored holes deep enough that the screws could recess into the wood so I could fill up the holes with white wood filler and completely masks the screws. This would also make the paint job look nicer. (Note: I used a countersink also because the screws I used required them) This was a nice idea in theory that was surprisingly difficult to actuate in reality because my wood was too thin. The thinness meant I had to be much more precise with where I drilled the hole so that the wood would not crack. The countersunk holes actually turned out nicely on the sides of the box however I had trouble with cracking the wood at the base of the box and had to redrill one hole.

Image: Routed edges.

After drilling all the holes and placing the screws to ensure that everything fit together, I removed all the screws from the base of the box and routed the edges of the box.

Image: Counterbored holes covered in white wood filler before sanding.

I then added all the screws back in and filled the countersunk holes with white wood filler to dry over two nights. The filler was applied suing my hands, a razor bald and a sponge brush. I also used wood filler on any gaps I saw between the wood on the outside. I did not fill in gaps on the inside however and this was a mistake and they are cracks on the inside of my box.

Image: Outside of painted box.

Once the filler was dried I spend at least 1 hour sending the box and making all the corners smooth and continuous. I then spray painted the box with a gray primer and let it dry. Then I painted the outside of the box blue and used a cup to create a small circle of gray paint.

Image: Cardboard used to protect the outside paint while painting the inside of the box.

Lastly, I used a piece of cardboard and some painters tape to protect the outside of the box while I painted the inside silver.

Image: Finished Box.

Lessons Learned:

The main lesson I learned is that sometimes it’s better to start over when you make a mistake and sometimes its worth exploring those mistakes. I made the mistake of choosing a thin piece of wood from the start of this assignment and it consistently created issues when building. However it was because of this issues that I was pushed to use wood filler and was able to come up with the idea to almost completely hide all of my screws.