Sciencemadness Discussion Board

Easy Custom Heat & Temperature Resistant Seals?

VeritasC&E - 16-7-2022 at 09:15


I'm looking for a solution to make custom sealing/gaskets for home & chemistry applications involving either vacuum or pressure.

I'd like it to be:
⤑ Inert (as much as possible)
⤑ Non-Contaminating (most important)
⤑ Fairly Temperature Resistant ( -30C to +200C is enough)
⤑ Fairly easy to make, work with and clean

My initial idea was that I'd just take a bathroom/kitchen/window silicon sealant tube and work from there but it seems that there's many undisclosed additives in there that makes me afraid of contamination.

My first project will be to make a new seal to my wife's pressure cooker (she has a great 20L pressure cooker which is fairly hard to get but it's unusable because the seal for the lid is gone).

Could I easily make my own silicon sealant? How inert is that for chemical applications? Do you guys have any other ideas?

Rainwater - 16-7-2022 at 09:47

Rtv meets most of these requirements. What type of reagents are you looking to expose to your seal

VeritasC&E - 16-7-2022 at 10:47

Quote: Originally posted by Rainwater  
Rtv meets most of these requirements. What type of reagents are you looking to expose to your seal


Thanks a lot for your answer! Can I be safe about ocntamination from RTV? Is there an easy way to make my own?

In terms of reagents: HNO3, H2SO4, Cl2, HCl, H2O2, Ethanol, Methanol, Ether, Acetone, and saturates solutions if mild bases (alkali metal carbonates).

Rainwater - 16-7-2022 at 12:31

https://lmgtfy.app/?q=rtv+chemical+resistance

Herr Haber - 16-7-2022 at 13:20

Quote: Originally posted by VeritasC&E  

My first project will be to make a new seal to my wife's pressure cooker (she has a great 20L pressure cooker which is fairly hard to get but it's unusable because the seal for the lid is gone).
Quote: Originally posted by VeritasC&E  

In terms of reagents: HNO3, H2SO4, Cl2, HCl, H2O2, Ethanol, Methanol, Ether, Acetone, and saturates solutions if mild bases (alkali metal carbonates).


You should worry more about the pressure cooker than the seal.

Rainwater - 16-7-2022 at 20:17

I have had success using a pressure cooker to contain an apparatus and take advantage of the increased solubility and higher boiling points of solvents. But safety is a major concern. Pressure explosions are no joke. Even mentos and diet soda can remove fingers. Without secondary containment and the ability to vent the system remotely, it should not be attempted

VeritasC&E - 18-7-2022 at 02:52

Quote: Originally posted by Herr Haber  
Quote: Originally posted by VeritasC&E  

My first project will be to make a new seal to my wife's pressure cooker (she has a great 20L pressure cooker which is fairly hard to get but it's unusable because the seal for the lid is gone).
Quote: Originally posted by VeritasC&E  

In terms of reagents: HNO3, H2SO4, Cl2, HCl, H2O2, Ethanol, Methanol, Ether, Acetone, and saturates solutions if mild bases (alkali metal carbonates).


You should worry more about the pressure cooker than the seal.



Luckily my wife doesn't use the same ingredients in her cuisine (thus with her pressure cooker) as I do with glassware for chemical applications (with the exception of Ethanol).

VeritasC&E - 18-7-2022 at 02:55

Quote: Originally posted by Rainwater  
I have had success using a pressure cooker to contain an apparatus and take advantage of the increased solubility and higher boiling points of solvents. But safety is a major concern. Pressure explosions are no joke. Even mentos and diet soda can remove fingers. Without secondary containment and the ability to vent the system remotely, it should not be attempted


That's interesting! Not that I'm equipped to be able to do this (nor that I find it likely I could be in the future), but can you favourably use this for improving the yield of purification by recrystalization or would that be too much of a hassle?

A lot of stuff has growingly interesting solubilities in water at high temperature but it's hard to use because (1) crystals form too fast in very saturated solutions, (2) near BP the loss of water, which is hard to control, makes things harder to predict and rather erratic.

[Edited on 18-7-2022 by VeritasC&E]

VeritasC&E - 18-7-2022 at 03:02

In case it can be useful to others, thanks to the search recommended by Rainwater, I found the following document with a rather good summary for the stability of RTV vs common chemicals:

https://www.reinhardoil.dk/PDB/Momentive%20PDB%20OG%20SDB/Ch...