Whole house water filter explosion mystery (no injuries)

[durableoreo]

The situation



Background: Yesterday (noon) I set up the Cool Moist with denatured ethanol. Previously I used it with soluble oil---no problems. There's an inline valve to shut off air, which I actuated when I went in for dinner. When I came out at about 9, when I turned the air on, the filter housing broke, sending a liter of ethanol everywhere, but mostly down. There is a regulator upstream of the valve (set to 40 PSI) and I turned it on slowly, which probably reduced the damage.

Any ideas what happened?

 

[woodchucker]

um, I guess you missed the memo.
alcohol and plexi, or lexan is a no no.
it quickly causes the plastic to fail...

 

[mmcmdl]

um, I guess you missed the memo.
alcohol and plexi, or lexan is a no no.
it quickly causes the plastic to fail...

I've heard that about machining some plastics . I've had parts shatter when using whatever cutting fluid I was using . Soapy water is what I use now . I have plenty of stainless units here if you're set on using alcohol .

 

[durableoreo]

I'm not sure what plastic it was made out of. Bought it a while ago, can't find the receipt. I guessed polycarb but that's fairly OK with ethyl and methyl alcohols. One online model said it was SAN and I don't know anything about it.

mmcmdl, can you post a picture of these stainless units? Or send a DM

 

[mmcmdl]

mmcmdl, can you post a picture of these stainless units? Or send a DM

Sure . I have quite a few from working in the filter industry . Give me a minute or 2 , I'll post them here .

 

[mmcmdl]

316L stainless LMO housings and heads . We made millions of these . 175psi at 200 degrees rated . I have them in the house and had them stacked on my air systems . I could use the coalescing filters which removed water in the system or just filtered air or water .

 

[woodchucker]

I'm not sure what plastic it was made out of. Bought it a while ago, can't find the receipt. I guessed polycarb but that's fairly OK with ethyl and methyl alcohols. One online model said it was SAN and I don't know anything about it.

mmcmdl, can you post a picture of these stainless units? Or send a DM

it's not fairly ok with any alcohol that I am aware of. My first experience was with my HF ultrasonic cleaner, it cracked the lens.
Alcohol is not ok with Polycarbonate.

 

[woodchucker]

from: https://www.calpaclab.com/polycarbonate-chemical-compatibility-chart/​

Polycarbonate Chemical Compatibility​

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What Chemicals are Compatible with Polycarbonate?

• Chemically resistant to many acids, oxidizing / reducing agents, neutral and acid salt solutions, greases, oils, detergents, saturated, aliphatic and cycloaliphatic hydrocarbons and alcohols
• Polycarbonate features an extremely high melting point, around 288°C / 550°F
• Autoclavable
• As a thermoplastic, PC can be heated to its melting point, cooled, and reheated without significant degradation
• Superior impact resistance
• NOT compatible with methyl alcohol, acetone, ketones, ethers, aromatic and chlorinated hydrocarbons, aqueous or alcoholic alkaline solutions, or ammonia gas
• NOT ideal for food storage at temperatures above 70° (can release BPA)

Polycarbonate Chemical Compatibility Chart: Check the chemical compatibility of Polycarbonate with various chemicals, solvents, alcohols and other products.

 

[DAT510]

From the color of the plastic it looks like it may be polycarbonate. Polycarbonate can suffer from Crazing which is cracking under stress (both molded in stress and actually stress from something like pressurization.)

As mentioned above, Alcohol can accelerate crazing in polycarbonate.

If you have a polarized lens it is possible to see the stress in plastic, as looking through the lens will show a rainbow like pattern in the plastic in areas of higher stress, as the light passing through the plastic will have ita polarization changed by the stress.

 

[durableoreo]

from: https://www.calpaclab.com/polycarbonate-chemical-compatibility-chart/​

Polycarbonate Chemical Compatibility​

Polycarbonate Chemical Compatibility Chart: Check the chemical compatibility of Polycarbonate with various chemicals, solvents, alcohols and other products.

It's rated B for ethyl and methyl alcohols. No idea what that means but obviously it's not ideal for a pressure vessel.

Anyway, I finally found the receipt. My filter body was made from SAN, Styrene-acrylonitrile.

Can't find a direct answer for SAN. ABS (also a styrene) is badly effected by methyl alcohol. ASA is sensitive to acetone. These could be denaturing agents, depending on the manufacturer.

My supply of alcohol lists isopropyl alcohol and propyl acetate as denaturing agents.

I think I'll get a stainless filter housing.