I was wondering why you need such an immense resin trap. Even if I am infusing a whole seven-style hood, wich is basically a third of the whole car, there are only a few drops, if any. I use the ec resin trap more as a safety device for my pump. I have to say that I am always degassing the resin, so there are no airbubbles I need to let through the resin trap. But even if I did, the 400ml seem like plenty of volume for the task. I mean, this are 400g resin for nothing.

Pressure multiplied by area results in force. Force (without an opposing force (lid failure)) divided through mass results in acceleration. Considering that the lid endures aboutique 7000N (700kg) and weights about 2kg this means acceleration peaks around 3500m/s^2 wich ich around 350 times gravitational acceleration! Obviously only at the very first moment. But this shows that vacuum contains a lot of energy, and that save equipment should be used.

I understand how strong the atmosphere is, but consistent pressure doesn't necessarily mean rapid acceleration. I can perfectly understand how vacuum could break the lid. But the acceleration required to bounce those pieces down and scatter them around a workshop? I can't visualise it. 

Actually 1 Ato "overpressure" will create a significant force on the acrylic lid ..  You could visualize it like this -- on top of the lid place a 76 cm high column of mercury, with a diameter like the lid itself ...

It should be obvious that very significant stress is placed on the acrylic .. which is a brittle material .. not tough like Polycarbonate/Lexan 

When you drill holes in it, or use a router to shape it, you will get tiny radiating cracks If you are not using VERY sharp cutters or drills and going VERY slowly in the machining.  These cracks will act as fracture initiators.

The end result will most likely be a build up of stress on the lid, resulting in an abrupt and catastrophic release of all the forces acting on the lid .. Styrene vapours may well be accelerating the building of the cracks.

@finnluxury:  Where in the lid did you drill the hole -- in the middle? (Where forces would be the greatest .. )

"Sapere Aude"... Dare to KNOW!

The written word is the only truly efficient vehicle for transmitting a complex concept from mind to mind...

103% of all people do not understand statistics...

Do not adjust our mind, theres a fault in reality :-)

So it was your own design lid?   I guess a stress fracture is possible depending on the holes.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

I will take some photos tomorrow if I remember. The lid were shaped with router and then the hole were drilled. I use degassing chamber as catch pot, because it allows more resin to be suck out if need. Also the same chamber works for degassing job. One reason is also that I can use two different vacuum Gauge. Basic one and digital micron meter. I would never work anymore with just Glycerin filled vacuum Gauge. The micron meter is life changing product. My personal guess is that the hole has something to do with the happening. as 25mm thick acryl is quite strong. its either the polyester resin, or the drilling of the hole. or maybe both helps each other. Largest pieces of the lid were 1 meter away from the lid. Only smaller pieces were inside the lid. Also the resin were already cured before this happened, as the acrylic pieces were not glued in the resin, they were over the dry resin inside the chamber. I will check the pieces more carefully tomorrow. 

It's a common mistake that an implosion does not lead to broken prices flying away from the center. After accelerating inward, the prices have a high momentum, bounce against each other, or the chamber, and then take their way away from the center. Also an explosion doesn't make sense, since the chamber is not designed to take any pressure from the inside. The lid would just pop up.
It could be, that your lid was not styrene compatible. Just my suggestion. Weakened bis the hole the styrene softened the underside a bit, until it could not stand the pressure anymore.

You should really pick up and collect all the pieces of the Acrylic lid, at take a few pictures ..

My theory is that you have drilled the hole for your vacuum hose yourself, and drilling in thick Acrylic can create pre-stressing in the material if not done correctly-

Where did you find the largest pieces of the lid?  any shards inside the chamber?

"Sapere Aude"... Dare to KNOW!

The written word is the only truly efficient vehicle for transmitting a complex concept from mind to mind...

103% of all people do not understand statistics...

Do not adjust our mind, theres a fault in reality :-)

Hi Finnluxury,

Was this the catch pot or the degassing chamber as only the catch pot comes with a hole in the lid.  We would be very interested to know what has caused this as obviously we do not want such equipment failing suddenly in this way!  Please do keep us updated on what happened so we can take any action if necessary.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant