A person sent in the following query:
>We went to Home Depot today and saw some piping called ABS piping >(it's black). It's very similar to PVC except that it is black, cheaper, >and a bit more flexible. I have never heard of anyone using this for >a structure on the playa, any particular reason? It seems to be sturdy >enough to handle any potential storm. As we are new to the PVC >structure scene, any info would be helpful!
We received two responses, which we present here. The first is from Argyre.
I've been using ABS pipe for the last few years, as the major component of the main center pole of my parachute parasol shade structures.
I liked it because it was black, was available in some big diameters, and actually appeared to be a bit lighter and more rigid than PVC, at least in the big sizes.
Remember, PVC and ABS pipes are designed to be pipes, not structural elements. They are expected to be strapped to other much stronger design elements.
We use them on the playa because they are: light, cheap, flexible, and different. They also need minimal tools and are a forgiving medium. And they don't give you splinters, and fail relatively safely - I'd MUCH rather get whacked by a breaking PVC pipe than by a hunk of metal pipe or a two by four snapping!. But they are NOT a great structural material.
There are some important caveats when using this ABS stuff!!!
It's quite rigid, but when it fails, it fails BIG. PVC is a pretty uniform material throughout. If you read the stenciled text on the ABS pipe, however, the word "foam" usually appears somewhere. If you saw through this stuff, it melts the edges, so it looks solid. However, if hubris has caused you to raise a taller mast than you really needed, and a good gust of wind whacks your structure, you may find that the ABS pipe will fail either with an abrupt fold, and break, in the smaller sizes, or a shatter break in the large size. When shattered, you get to discover that the ABS appears to be lighter because it IS, as most of the thickness is a foamed ABS, with thin solid skin of plastic on the interior and exterior. This makes for a quite light and rigid pipe, but not particularly strong.
I now back up most of the length of the mast with metal pipe, and I usual double up on the mast. Spares are good too.
I may have to bring some four-by-fours to the playa this year...pricey.
Thank you, Argyre. Next, we hear from michaelz:
Argyre can tell you -- uh, I mean your friend -- all about ABS pipe. . .
We both bought some at Home Despot last year (I followed his lead), and we both ran into trouble (luckily for me, mine was on the beach in Alameda, while his was on the playa).
It turns out that ABS is not stronger than PVC. It's not solid plastic -- it has a thin foam core (thus lending some flexibility). It won't hold up to the same load that an equivalent length and thickness of PVC can tolerate.
So now you know.
Just try asking a sales clerk how ABS compares to PVC in holding up a 25' dia. parachute in heavy winds. . . (and bring a camera to capture the expression on his or her face).