I spent a few days early this year paint stripping and carefully dismantling it.
After much sanding and cleaning it became apparent that the grille was really too far gone. Once apart you could see very deep corrosion in vane slots where one piece slotted into another. This is most probably due to capillary action where water is held in the tiny slot. With time this just eats away at the metal and on my grille it was almost all the way through and on the verge of basically falling apart.
Along with the slot corrosion there was some serious pitting.
This was all hidden under the paint but I suspected it wouldn’t be good news once it was stripped.
I took a few parts to a local anodiser, and even anodising would not hide the corrosion so unfortunately it’s no good. This is obviously an expense I can do without.
After much thought I have decided to make a complete new grille.
Now it would be quite easy to just cut one out with a hacksaw and file it to shape, but I had a better idea. If I get one Laser cut I could make several at once and use them to trade for parts I’m missing maybe?
So after a visit to a local laser cutting business I walked away very disappointed. They wanted an absolute fortune to “write” the program that plots the shapes. The laser cutting takes seconds but they wanted almost a months pay to write the program alone.
After much thought I contacted them again and asked how the plotting program for the laser is done. It is basically X & Y co-ordinates to put into a CAD drawing.
Providing the parts are measured accurately this is just monkey see monkey do repetition to input into a CAD file. Anyone could do it!
So I have decided to “plot” the 330 grille myself.
In this way I can hand over the data which should just mean I pay for just the sheet aluminium and a couple of minutes use of their laser cutter. Based upon a 2.4m x 1.2m Aluminium sheet I reckon I can make multiple grilles for about £15 each.
I also got a price from the Anodising company to silver anodise them upon completion, so all in all I plan to go into production.
So yesterday I started to draw up the plot and get all the dimensions required for the laser cutter. I used my school technical drawing skills to “develop” the curved section of the grill surround into a 2D drawing for rolling once cut. I could have simply flattened what parts I had, but to make the grille properly I need it in its curved form to bend the new parts accurately.
First I needed a sheet of paper large enough, so a neat trick is to call into your local DIY (hardware) store and go to the wallpaper section. They allow you to tear off “samples” of wall paper free of charge. I got a couple of metres (best to use non embossed and not pre-pasted). Next I needed somewhere to lay it out to draw up. Since I only have a tiny table at home the only place I could find was my kitchen floor. The Vinyl floor is ideal to lay paper on and draw! Albeit my kitchen is only 7’6” x 8’ with a free floor space 5’ x 4’6”. But there’s just enough space to do it, even if it is murder on your knees!
So after 3 hours last night and 4 hours tonight I have got about 1/3 of the way through plotting the parts.
