Thursday, 29 April 2010

Instructable- Sandblasting

Glass Beads

Glass beads produce a much smoother and brighter finish than angular abrasives such as sand or steel grit. Glass beads can be recycled approximately 30 times. Grit sizes range from 50-325 and are round in shape

Bead blasting is the process of altering the surface finish of any material by applying fine glass beads at a low pressure without damaging the material

The Sandblast Gun

Abrasive blasting is supposed to be a scrubbing action, not a damaging process. Therefore, the gun should always be aimed at a 60Ў to 45Ў angle to the surface being treated. When the gun is aimed at 90Ў, damage occurs and, due to the abrasive particles colliding with the abrasive bouncing off the surface, a very high rate of media wear occurs.

The gun in a blasting cabinet should be kept at least 20 cm from the surface being blasted. This allows the spray to spread out and cover a larger area. Blasting a larger circle allows for better overlap of the pattern and you achieve a more even and appealing finish.

Wednesday, 28 April 2010

Creating the bag structure- Former

To create the bags, a former had to be made to ensure the same size of bag each time. This makes it easier to produce the bags quickly and efficiently.

The 'teardrop' section of the former was manufactured using the bandsaw to cut the rough shape, then planed down using the planing machine and sanded by hand.

To create the base of the former, the wood block was cut using the router. The size of the router blade was the same radius as the bottom of the teardrop shape

The dopamine pattern was marked out on to the aluminium using a biro to avoid it smudging. I then used a jewellers hacksaw (1mm blade) to accurately cut out sections of the pattern.

The holes for the stitching were marked out and drilled individually by hand.

When testing out ways to link the layers of wood, metal and leather together, sections of the dopamine pattern were cut out and folded through the lasercut wood.

Further testing was done to see how well the layers sewed together. This was done by hand, although pliers were used to pull the needly through the materials to avoid strain on hands.

After working through several prototypes, the decision was made not to have the aluminium sections folded through on to the wood to avoid compromising the strength of the materials.