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Re: China made still - thoughts

Posted: Mon Aug 03, 2020 2:31 am
by charcoal
I have a very similar still.

viewtopic.php?f=6&t=76373

Works well.

I have changed the configuration to a VM still now. And yes, all the Australian sellers source from China and charge a huge markup. Most of them are out of stock now.

Re: China made still - thoughts

Posted: Mon Aug 03, 2020 3:48 pm
by MartinCash
I think you're building a straw man with your argument and experiments on ethanol, gwizard. We don't work with pure ethanol. Here are some of the ratings of silicone according to the link you posted, with some of the components that come through on a batch distillation. The highlights are mine.

Ethanol: B - Good
Ethyl Acetate: B - Good
Acetaldehyde: A - Excellent
Acetone: D - Poor
Acetic acid: C - Fair
Butyric Acid: D - Poor

Ratings:
A - Excellent
B - Good: Minor Effect, slight corrosion, or discoloration.
C - Fair: Moderate Effect, not recommended for continuous use. Softening or loss of strength, and swelling may occur.
D - Severe Effect: Not recommended for any use.


And this is for normal storage, and makes no mention of the effect of hot liquid or vapor, which is more corrosive than cold liquid. Some of these, particularly acetone, come through in significant amounts at stages of the distillation. There is a reason rule 8 is in there. We are hobbyists and the budget pressures of commercial producers are not our concern. Our safety is more important.

Re: China made still - thoughts

Posted: Mon Aug 03, 2020 4:12 pm
by Hambone
Good info Martin.

What does everyone think of EPDM for gaskets? I replaced some of these with PTFE, but using that link they didn't look like a problem for our purposes.

Thinking I may keep them for replacements if I need them....

Re: China made still - thoughts

Posted: Mon Aug 03, 2020 7:21 pm
by Deplorable
This is one of the threads that inspired me to go look for myself for the effects of Ethenol vapor on "food grade silicone". What I found, was that FDA silicone, or food grade silicone, is only considered food safe at 20C or 68F. at temperatures above that it's( I beleive the word they used was "limited"). Considering the vapor temperature of Ethel Acetate, There is no flippin way Id leave a silicone gasket in my still, let alone the vapor path. In preparing my new still for running, I replaced all the 2 inch silicone gaskets with PTFE, and the 1.5 inch gaskets were double wrapped in PTFE tape.

Re: China made still - thoughts

Posted: Mon Aug 17, 2020 2:10 pm
by Hectorlandaeta
Deplorable wrote:
Mon Aug 03, 2020 7:21 pm
This is one of the threads that inspired me to go look for myself for the effects of Ethenol vapor on "food grade silicone". What I found, was that FDA silicone, or food grade silicone, is only considered food safe at 20C or 68F. at temperatures above that it's( I beleive the word they used was "limited"). Considering the vapor temperature of Ethel Acetate, There is no flippin way Id leave a silicone gasket in my still, let alone the vapor path. In preparing my new still for running, I replaced all the 2 inch silicone gaskets with PTFE, and the 1.5 inch gaskets were double wrapped in PTFE tape.
I don't believe there should be but trace amounts of ethyl acetate in a parametrically correct fermented wash. If you exclusively do nutrient-deprived sugar washes or UJSM, and ferment them at higher temps than the yeast recommended then perhaps you should worry.

Re: China made still - thoughts

Posted: Mon Aug 17, 2020 9:54 pm
by NZChris
Hectorlandaeta wrote:
Mon Aug 17, 2020 2:10 pm
Deplorable wrote:
Mon Aug 03, 2020 7:21 pm
This is one of the threads that inspired me to go look for myself for the effects of Ethenol vapor on "food grade silicone". What I found, was that FDA silicone, or food grade silicone, is only considered food safe at 20C or 68F. at temperatures above that it's( I beleive the word they used was "limited"). Considering the vapor temperature of Ethel Acetate, There is no flippin way Id leave a silicone gasket in my still, let alone the vapor path. In preparing my new still for running, I replaced all the 2 inch silicone gaskets with PTFE, and the 1.5 inch gaskets were double wrapped in PTFE tape.
I don't believe there should be but trace amounts of ethyl acetate in a parametrically correct fermented wash. If you exclusively do nutrient-deprived sugar washes or UJSM, and ferment them at higher temps than the yeast recommended then perhaps you should worry.
That is correct, but it comes over concentrated in the foreshots and heads, not evenly spread throughout the run. That is one of the reasons my gasket supplier recommended I should use PTFE.

Re: China made still - thoughts

Posted: Tue Aug 18, 2020 2:36 am
by shadylane
gwizard
That's a nice looking rig :thumbup: