How to make a blister.

Things you will need:

Aluminium Sheet

2 x MDF template
4 x Sets of nails

Laser or CNC cutter

Mallets
Wood offcuts

Sand paper (optional)

Polisher (optional)

Instructions:

STEP 1. Once you have created a desired shape of blister using your chosen program, use the laser cutters or the CNC cutters to cut out the blister shapes from the MDF material. You will need two identical pieces as well as 4 holes that are slightly smaller that the screws to be used to lock the two pieces together. 

STEP 2. Sandwich the aluminium sheet between the two mdf templates and with the screws bolt together. As you will be continuously hitting the blocks, make sure that the two templates are tightly bolted together. Make sure the metal is in the center.

STEP 3. Place the blocks on a sandbag or clamp it to a vise to make sure that the target does not move as you hammer it. Start hammering gently with a nylon mallet around the middle area of the blister. Slowly work your way to the sides until you get an overall blister shape.

STEP 4. To create creases in the sides, use different off cuts that have rounded (so you don't get indents from the corners). Lay these off-cuts near the edge of the blister and tap upon it using a hammer. This will create the sharp fold of the metal.

STEP 5. To smooth out the uneven bumps on the surface of the metal, you can rub the rounded, wider side of the mallet on the metal. This will have a slight polishing effect also.

STEP 6. Continue to stretch the metal until you have the desired depth and curve. Once you are satisfied, you can unbolt the woods to release the metal. You can also do some touch ups in this state if you feel the need to.

Results: