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Comment by ryandrake | Hacker News Reader

Yea, Home Depot PVC doesn't belong anywhere near compressed air. I knew a guy who wanted to outfit his garage with several compressed air drops for air tools and used plain old white PVC. Big mistake which he realized when one of the fittings shattered and launched a metal quick-disconnect through the garage door and out into the street. Thankfully nobody was in the line of fire. Please don't use PVC for air under pressure.

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Id love to make more potato cannons but my main issue is exactly this. I have no idea what the pressures are, what materials would work, etc. It's all folklore and bravery

Not really.. you can find standard ratings for pipes all over the place. I just ran air lines in my garage and it was fairly simple for me to get online and see that I needed type m copper based on the pressure I'm at. Wasn't cheap, but neither is aluminum pipe and now i have a nice reel in the center of the garage. There's a bit more to calculating the pressure when exploding hairspray in an enclosed vessel, but I'd be willing to bet just as easy information to find.

I worked in a PCB shop that had a network of 1 1/2" PVC pipe for compressed air. When Tees failed we would lose production for the remainder of the day. We finally replaced the entire network with type M copper.

Maybe wrap it in a ton of duct tape, then it can't shatter too dangerously.

Depending on the circumstances, that can also make it a more powerful bomb.

what if you house it in a pool of acid, and place it near a baby for safety

Hrm :-/ okay, please disregard.

Again - neither of these are much more than moderately held opinions.

That strengthening a pressure vessel with tape might raise the pressure at which it fails? Does that really need a citation?

One example: https://www.cbsnews.com/news/texas-teen-gravely-injured-by-h...

Well there's two of many possible outcomes, which are covered under your "depending on the circumstances", which make your comment universally true, and therefore not so informative:

1. We strengthen the pressure vessel enough so that it gives way at higher pressure, making a "stronger bomb"

2. We strengthen the pressure vessel enough so that it doesn't give way, making it not a bomb at all.

It's not at all clear if the duct tape will do 1 or 2 or something else, and this first-order logic / first-impressions design doesn't smell to me like a rigorous solution.

So I'm aware that wrapping a pressure vessel in tape has the possibility of making things worse.

I thought, for safety reasons, it was worth replying to the comment suggesting to wrap "a ton of" tape around it. At the time I replied there were no other replies.

Not trying to win a debate with you. Just trying to share that it could be a bad idea. Rather than just assuming that making the shards less sharp or fragmented was the only possible outcome.

Fair!

You're replying reasonably and I'm dragging that into my top-level comment about rigor. Impedance mismatch.

Then use steel or aluminum pipe.

Home Depot sells many grades of PVC and pipe, it's up to the buyer to select the grade they need for their application.

This is something I would suggest buyers do at every store they shop at.

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