Is the ‘back’ side of your MDF kit badly blackened, charred or burnt? This can happen on kits available from Knights of Dice or any other provider of laser cut MDF model kits. The short answer? The laser bed of the machine that kit was produced on needed a good clean!
I wish I had some better photos to share in this article but I only thought about writing this today as I was looking at the laser beds and getting ready to clean them, but we shall carry on.
MDF kits have two sides, the ‘face’ and the ‘back’. Other studios might use different terms but this is what I use. The Face is the side of the MDF that is visible when you look into the laser .. it is the side that the laser punches through the MDF. The Back is therefore the underside, it is the side of the MDF that is touching or sitting on the honeycomb bed of the laser.
When MDF is laser cut the majority of the material is vapourised and extracted out of the machine as smoke, however not all the resin (the binding agent used to manufacture MDF) or the sawdust is vapourised, some of it collects and builds up on the laser bed.
As the laser runs and burns through the MDF, the laser beam will strike the metal honeycomb bed as it travels around, and if the bed is dirty and there is lots of resin on the bed, it will begin catching fire, briefly before the air-assist puts it out, but enough that it will start creating scorch marks and leaving carbon on the underside (the back) of the MDF. Regular maintenance makes it much easy to avoid this problem.
Now I’ll be the first to admit that I do not clean the laser beds in the studio anywhere near often enough! It is certainly an area where I can make significant improvements! Too help with that, I’ve built a new wash tray out of some corflute.
Typically I will spray the beds with the orange cleaning product I use and then spray them off with my petrol powered high pressure sprayer. It usually takes around an hour to thoroughly clean a laser bed if it is not regularly cleaned, it takes multiple applications of cleaner and spraying to remove all the built up resin.
Obviously the first thing I need to do is clean the beds more often, but what I’ve never been able to do is give the beds a good soak overnight and then simply spend 5 minutes spraying them off the next day … I simply never had a big enough and shallow enough tray to fit the 1000x600mm laser beds in!
A nice clean laser bed is critical to ensuring that the back side of the MDF remains as clean as possible. Some scorching or charring on the back side isn’t really a big problem, other than looking nasty, but too much can start causing problems with painting, let alone smelling even more pungent than laser cut MDF already does!
So, if you’ve bought a laser cut MDF model kit and it has a dirty, burnt, charred backside it’s simple because the laser bed needs a little maintenance!