Air tight Plexiglass box?

Question

Is it possible to make an air tight box of plexiglass using acrylic glue that could hold argon gas at 1 Atm for a long period time?

Answer 1

i am anal so i would make it a work of art! here are some over-engineered sugestions:

you said something abut a coil in passing, it is always better to by them than to make them. locutus gave you all of the basics you need to know. sand the edges so that they are clean. use about a 80 grit sand paper on a soild block. 80 grit will clean the edges but leave a surface just rough enough for the epoxy to stick. the long an epoxy takes to cure, the stronger it is. try to avoid that 30 min c**p.  unfortunatly i have never seen clear in anything over 30 min. i am not exactly sure why you want the box but if it has something to do with moisture aswell as safty, see if you can hide a piece of this in the box out of sight: http://www.agmcontainer.com/desiccantcit...

it would be good to cut a grove into both sides of the material and use a seperate piece of thin material for a tounge. this will increase the contact area of the glue, reducing the chance of leaks. it will greatly improve the strenght too. i have not figured out how to do that( although a router. roto-zip, biscuit cuter and table saw should all work). maybe you can if you would like. concider having the top mechanicaly mounted to a base larger that the sides. this will alow you to place a final seal outside of the box, sevice the inside and conpleately seal the other five pieces togeather.

after you have constructed five of the sides and allowed them to cure, to full set. it can be romoved from the table claps 30 min after working time. cut a grove in th bottom of the top piece. run a bead of aquairuim caulk around the inside of the cube covering all of the epoxy. aloww it to sit long enough to skin (5 min). caulk does not stick to windex. if you spraya little on the caoulk and run your finger down it, it will look very proffesional. next place a tiny anount of culk in the grove. set a rubber bead used to hold in screens (lowes/home depot) into the groove. place a small bead ontop of it. make sure what you want to be in the box is secured where you want it to be! flip the top over and s***w to bottom. fill with air to about 5 psi. this will put pressure on all of the caulks skin, forcing it into any gaps in the epoxy. allow to sit for an hour and bleed off the pressure. run a fianl bead of calk around the outside of the base. allow to reach full cure before repressurizing. you can go to a hobby hop and buy decritive brass edging. it looks good.

also instead of plexiglass (it is ok and it is cheap) concider lexan which is much higher quality or Polycarbonate which is used for isolation of high voltage systems. both get expensive fast so only buy precut piecies. both can be found here:

http://www.tridentepp.com/Materials.html

for introducing the argon concider HVAC quality schrader valves. they hold presure very well. if you use this type of valve, concider having an HVAC guy hook a vacume pump up to the box. this will evacuate the air and alow you to check for leaks. dont let it run too long, -5psi sould be good. once the valve is disconnected, the argon can pe introduced (again about 5psi). adding a second valuve for a gauge can be done too. you can buy the gauge at a latter date or remove the gauge when not in use so that the box retains its pressure longer.

http://en.wikipedia.org/wiki/Schrader_va...

was that too much?

Answer 2

In theory yes.  Practicality is a different story.  I think you will find there will be a bunch of small spots where the glue doesn't seal completely.  This will be due to several factors including variations in the thickness of the panels and how much glue is applied.  If you are using it at 1 atm then there should very little difference at sea level between the gas inside and the outside air pressure.  Another thing to factor is how do  you plan to evacuate the chamber after you build it.  Everything that breeches the side should be sealed.  An epoxy that is compatible with plexiglass would probably be better, and I would use it liberally so that when you press the sides together it will flow out and fill in the small variations.  Use lots of clamps and make sure it is cured completely before moving on to the next step.  Percission in your measurements is another key factor.   With out knowing how you plan to obtain or put the argon in the chamber I can't offer any ideas on how to seal that area.