Pressure pot or vacuum chamber?

[rkm rdt]

I was wondering if I can use a vacuum chamber to cure acrylic instead of a pressure pot?
Is there any difference? My old pressure pot is toast and a vac chamber is half the cost.

 

[bigj1972]

I was wondering if I can use a vacuum chamber to cure acrylic instead of a pressure pot?
Is there any difference? My old pressure pot is toast and a vac chamber is half the cost.

No....works the opposite, You'll put more porosity in.

You could retro a pressure cooker, or just buy a paint pot like Harbor Freight.

Or just Ebay

 

[rkm rdt]

No....works the opposite, You'll put more porosity in.

You could retro a pressure cooker, or just buy a paint pot.

So it would suck air out of the model and into the acrylic?

 

[bigj1972]

So it would suck air out of the model and into the acrylic?

Well, in a vacuum air expands. Not only in solids but liquids. Test a marshmallow or balloon. Water will "boil" in a vacuum.
A vacuum has opposite effect of pressure.

Why the scuba diver in Jaws 2 got an embolism. "Came up too fast"

 

[rkm rdt]

Well, in a vaccum air expands. Not only in solids but liquids. Test a marshmallow or balloon. Water will "boil" in a vacuum.

I’m reading a similar comment on a separate site explaining that micro bubbles will expand under vacuum which does make sense.
Thanks for the suggestion

 

[zero_zero]

I was wondering if I can use a vacuum chamber to cure acrylic instead of a pressure pot?
Is there any difference? My old pressure pot is toast and a vac chamber is half the cost.

A vacuum chamber will boil off the monomer before it could polymerize, it is better use to de-foam casting epoxy resins. You can make a pressure pot for cheap from a regular old-style pressure pot, for under $50 CAD in no time. All you need is a cheapo pressure pot, some hose, 2x small hose clamps, 2x 1/4" NPT ball valves, 1x 1/4" NPT T-fitting, a 1/4" NPT pressure regulator and some fitting to connect it to your air supply.
Here's a sketch, pretty self explanatory

Or you could convince Crob to lend you one of his vulcanizers perhaps...

 

[bigj1972]

Or you could convince Crob to lend you one of his vulcanizers perhaps...

 

[rkm rdt]

A vacuum chamber will boil off the monomer before it could polymerize, it is better use to de-foam casting epoxy resins. You can make a pressure pot for cheap from a regular old-style pressure pot, for under $50 CAD in no time. All you need is a cheapo pressure pot, some hose, 2x small hose clamps, 2x 1/4" NPT ball valves, 1x 1/4" NPT T-fitting, a 1/4" NPT pressure regulator and some fitting to connect it to your air supply.
Here's a sketch, pretty self explanatory
View attachment 44602
Or you could convince Crob to lend you one of his vulcanizers perhaps...

So I tried making one from a cheap pressure pot from Amazon but the gasket was too flimsy and it leaked at 20 psi. I just sprung for an aqua press so no more frigging around.

 

[bigj1972]

So I tried making one from a cheap pressure pot from Amazon but the gasket was too flimsy and it leaked at 20 psi. I just sprung for an aqua press so no more frigging around.

Well they're a pain too, but better than nothing. Maybe try a quality pot. Go to the stores. Or like I said a hardware store for a paint pot.
Can also troll eBay for used. Just be sure to plan ahead for replacement gasket.

 

[zero_zero]

So I tried making one from a cheap pressure pot from Amazon but the gasket was too flimsy and it leaked at 20 psi. I just sprung for an aqua press so no more frigging around.

Get one of these type, has a simple compression seal vs. the expanding silicone seal of the newer types which can rip quite easily...

You don't need more than 10 PSI, BTW...

 

[Doris A]

Pressure Pots | Harris Discount Dental Supply

www.harrisdiscount.com

 

[rkm rdt]

You folks forget I live in a 3rd world dictatorship now. It takes years to order the good stuff now.

 

[Denture Dude]

Pressure Pots | Harris Discount Dental Supply

www.harrisdiscount.com

Dang, I just bought a new pot, these guys have it for $100+ cheaper. Plus it had a bad regulator out of the box.

 

[Denture Dude]

Be careful retrofitting your own pressure pot. Can get dangerous.

 

[zero_zero]

Be careful retrofitting your own pressure pot. Can get dangerous.

Worst case it blows the hose off... I have a DIY for 10+ years already

 

[Denture Dude]

Worst case it blows the hose off... I have a DIY for 10+ years already

Worst case is someone neglects to put a blowoff valve and over pressurizes and blows the lid through the roof.

 

[tuyere]

I know someone who blew all the windows out of their kitchen because they modified a pressure cooker in a way that removed the burst disc failsafe. That stuff is no joke. A proper pressure pot isn't nearly expensive enough to jury-rig something to save a few bucks, imo.

 

[Denture Dude]

Rkm I’ve got an old coe pot (unheated) in my giant pile of ‘can’t throw out lab s$&t ‘ in my basement I’d be happy to send to you if you want. Just needs a new gasket. Although I don’t know what restrictions there might be sending pressure pots thru ups to Canada. Things kinda got weird when folks started making bombs out of them. I hate to throw stuff away but that’s where it’s destined. Along with about 12 old hanau fully adjustable articulators. Time to clean up.

 

[Doris A]

Dang, I just bought a new pot, these guys have it for $100+ cheaper. Plus it had a bad regulator out of the box.

Send it back and get one from Harris.

 

[rkm rdt]

Rkm I’ve got an old coe pot (unheated) in my giant pile of ‘can’t throw out lab s$&t ‘ in my basement I’d be happy to send to you if you want. Just needs a new gasket. Although I don’t know what restrictions there might be sending pressure pots thru ups to Canada. Things kinda got weird when folks started making bombs out of them. I hate to throw stuff away but that’s where it’s destined. Along with about 12 old hanau fully adjustable articulators. Time to clean up.

Thanks for the offer but I sprung for an aqua press.