Acrylic Fabrication Q & A

Good question. acrylic itself is good at 180 degrees to -40 degrees. it what about the seams? I'm going to shoot this question to my scigrip connection and see what he says.

Anyone know how old an empty acrylic tank can get before the seams get compromised? Like leaving in an unheated garage over the winter, etc...
 
Anyone know how old an empty acrylic tank can get before the seams get compromised? Like leaving in an unheated garage over the winter, etc...

Not a direct answer but a timely anecdotal response. I happen to have an old Sealife Systems Pro Series acrylic wet-dry sump I obtained about three years ago. It has literally been sitting in my garage in Southwest Florida (aka very, very hot summers) for those three years. It had sat empty for nearly a year before I got it.

Had a local looking for one so I threw some water in it last weekend and let it sit all week. I was actually surprised but absolutely no signs of leakage. Not even from the old bulkhead in it that I capped for this test.

Based on this little experiment, maybe the answer to your question is longer than we think. And I did say maybe!!!
 
It would be interesting to find out if the actual bond is effected by extreme temps. how will it hold up long term? that would be my concern.
 
Making a tank or sump out of acrylic sounds awesome. I have learned how to cut acrylic, but that's the extent to my knowledge
 
He said essentially what I had thought, 32F. When water hits 4C is begins to expand and this could cause the material and seams to expand and affect integrity. I suppose there is a chance that it wouldn't, but pressure vessels are a pretty specific subset of acrylic manufacturing. Basically there are many below-zero applications of acrylic and while this is undoubtedly true:
Good question. acrylic itself is good at 180 degrees to -40 degrees
It's too hard to say whether or not an acrylic tank would be affected or not.

It is was a brand new tank (never seen water) then maybe. But if it was a used tank, even one that had sat dry for a while (months) there likely is still latent water content in the acrylic
I just learned Plexiglas g's Max water absorption is at 28 days and 0.8%.
...which might not completely offgas.

So I guess I would err on the side of caution
 
I have no real science to add to the shelf life of frabicated acrylic tanks. That said I delivered them year round and many times the temps were way below freezing in the Northwest as the tanks traveled around in my un heated box truck. Since the failure rate was so low over the 20 plus years of acrylic tank manufacturing (one or two that I can remember) I would venture to guess that an empty tank would not experiance any problems. Acrylic is used in commercial aircraft windsheilds that travel at over 33,000 feet where temps are much colder than at most of our elevations. These are pressurized aircraft and the acrylic performs quite well for many years. Think about that next time you are in a commercial aircraft. I would not see any problem as long as the tank is emptied and dried before the onset of freezing conditions.
 
Yeah I have a local guy building 180+ gallon tanks using the capillary method & building from the base up (so, bonding ends to bottom first, then the front panel to the bottom while simultaneously bonding the front-to-end vertical seams), said he learned everything from Joey Mullen - he told me that the pins method is only needed for 3/4" and above (as Joey does mention in this video)...I suppose if you had enough practice, you could put tanks together that way, but it's not like the pins method is super expensive and highly complex or anything, and it's been proven without a doubt to give you a stronger bond, so why not use it?

I smh whenever I see videos like this, and I've seen more than one. People seem to be OK with using a technique that is guaranteed to give you a lower bond strength.
 

IF YOU HAD TO TAKE A REEFING EXAM, WOULD YOU PASS?

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