1930s Amilcar

Bonnet louvres
In order to achieve the look of the inspiration car, we needed to work out how to create louvres in the side panels of the bonnet. Some research online suggested a few potential methods. In the end we opted to use a punch and die set in a manual press. The punch is made of aluminium plate which we welded together to get the required thickness. The punch was shaped by hand to give the inside profile of the louvre. The die is a piece of steel with a long 'D' shaped hole in it. The die ha about 3mm of clearance around the punch (when the end of the punch is about 4mm below the top surface of the die). We rounded the top edge of the die somewhat and polished out and surface roughness so it didn't transfer to the aluminium sheet. To press a louvre we needed to cut the sheet for the opening of the louvre with a thin cut off disk in a grinder. Trail and error showed us that the length of the cut was key to getting the louvre to press cleanly. We also discovered that the radius of the ends of the punch needed to be enlarged as a tight radius resulted in the aluminium tearing. A larger radius on the ends stretches the sheet less. We found that it was useful to fix wooden blocks each side of the punch to hold the sheet flat when the punch was at maximum travel. This helps produce a more defined bend at the edges of the louvres. Once we were happy with the set up, we set a fence that we could run the panel along to ensure all the louvres were a consistent distance from the edge and at the same angle. Once we were set up it didn't take long to press the actual panels. 90% of the work is required to make the first louvre.