Thursday, 19 April 2018

Repair Tip For Broken Plastics

As the plastics on our vintage machines become more brittle with age, coupled with the rigours of transportation and general handling, some breakages are inevitable.

Commonly liquid cement is used for plastic model making but I’ve found it is equally up to the task of repairing old computer casings, peripherals and even floppy disks. I generally find the bond to be superior to most glues and more importantly, if done properly, the repair will be almost invisible.

This is because of the way liquid cement works. Essentially it melts the plastic and welds the two surfaces together. It won’t work with all plastics and is not recommended for bonding dissimilar materials, but is handy to have in your toolbox for when the time is right. I generally use Tamiya Extra Thin Liquid Cement which is available from most hobby shops and online. It is applied with a small brush and the gap is filled through capillary action.

Here is a floppy disk that was broken during shipping:

The broken piece is held in place and the cement applied. Wait a couple of seconds for the plastic to start to melt and then squeeze the parts together. A raised bead of melted plastic should appear along the seam. This bead can later be sanded if required. 

Likewise on my Amiga 1000. A common issue is that the internal clips will break off from the stress of repeatedly removing the case lid. The A1000 case is notoriously difficult to open without damaging these tiny clips as the entire lid assembly essentially hinges on them. 

This was my first attempt at repairing the clip and it is misaligned. I pulled it apart and had another go and the repair now looks seamless (unfortunately I forgot to get a photo of the final repair!) A pair of tweezers is also a good investment for holding these small parts together and applying pressure to the join. 

Hopefully this was helpful to someone!