Vacuum chamber seal keeps splitting under heat

[gnetix]

I bought a vac chamber from a local headshop as well as a Pittsburgh Automotive 3CFM 2 Stage Vacuum Pump. The seal of the lid keeps splitting in half when I leave my chamber on a skillet at low temps (120-130). Is there a specific reason that is causing this or is it just because the chamber lid is poorly built to fit the chamber? I'm living in California, and I only get to 25inHg sometimes 26.

here is some pics of the seal

 

[Gray Wolf]

That looks like a seal made by cutting a length of extruded round stock, and gluing the ends together; with the glue joint breaking.

I have flat gaskets cut out of Viton at Paramount Supply, which are one piece and don't do that.

 

[gnetix]

That looks like a seal made by cutting a length of extruded round stock, and gluing the ends together; with the glue joint breaking.

I have flat gaskets cut out of Viton at Paramount Supply, which are one piece and don't do that.

So I'm new to this, sorry for any obvious or stupid questions but is there any local stores that may sell a flat piece of viton plastic so that I may cut into? Because I'm not sure what to buy on the paramount supply website since there is so many dimensions that I do not know which one will fit my lid exactly.

 

[Rickys bong]

Go to an industrial hydraulic seal or O-ring supplier. They can either supply you with a standard O-ring that may work or they can make you a square section ring to fit. Get a few spares...
They'll ask you about material. Buna (Nitrile) is most common and cheap.

RB

 

[Gray Wolf]

So I'm new to this, sorry for any obvious or stupid questions but is there any local stores that may sell a flat piece of viton plastic so that I may cut into? Because I'm not sure what to buy on the paramount supply website since there is so many dimensions that I do not know which one will fit my lid exactly.

Don't know where local is to you, but Paramount Supply will probably also sell you the sheet material without cutting it.

I just gave them an ID, and OD, plus what thickness I wanted it.

If you measure the length of the broken one, and divide by 3.14159, it will give you the diameter, or take it with you to the hydraulic store that RB suggested, and let them do it for you.

 

[gnetix]

Don't know where local is to you, but Paramount Supply will probably also sell you the sheet material without cutting it.

I just gave them an ID, and OD, plus what thickness I wanted it.

If you measure the length of the broken one, and divide by 3.14159, it will give you the diameter, or take it with you to the hydraulic store that RB suggested, and let them do it for you.

I'll head over to a rubber/hydraulic supplier today then, thank you for the help! Also was wondering do you purge while it's on a skillet or heat up the chamber then take it off the skillet then vac?

 

[vapor]

I got a tube of Dow corning high vacuum grease that came with my glass chamber for my gasket.

 

[gnetix]

I got a tube of Dow corning high vacuum grease that came with my glass chamber for my gasket.

Do you just put that on your gasket before using the vacuum for a run and how so does it help?

 

[vapor]

The dude at the glass supply/science gear shop i go to. Told me to just put a wee bit on my fingers and then slide the seal through my fingers. When adding heat low and slow. no problemos so far///

 

[Gray Wolf]

Do you just put that on your gasket before using the vacuum for a run and how so does it help?

You very lightly coat the o-ring. It helps more if you are twisting an o-ring to seal it, than it does if you are just pressing straight down.

Spendy stuff, but a tube goes a looooong way.