Important note for those teams making their own CORAL game pieces from PVC pipe!
There are two kinds of readily available Schedule 40 4" white PVC pipe at places like Menards. One of them is exactly what you are looking for, and the other is almost twice as heavy!
Make sure to buy CPVC i.e. Cellular PVC/Coextruded-Cellular Core PVC. Do not buy solid PVC - it is out-of-spec with regards to weight. I’ve attached photos of both types of what is in stock at the Saint Paul Midway Menards. Be sure to read the print on the pipe itself!
Findings and writing by fellow 2491 mentor @63hz who is too busy building our field to get on here himself. Light edits by me
Yep. Luckly it is the cheaper of the two as well as lighter.
That said, I just went and ordered 120 from AndyMark. 10 foot lengths of the proper stuff are $50 or so at the home stores. That works out to $5 per coral. It’s ending up costing about $25 more for AndyMark to cut and deliver them to me than it would be to make 120 myself.
That saves ARC’s fabrication time and money for the reef scoring pipes. The FIRST pipes are incredibly overbuilt. They’re made from schedule 40 steel pipe and are 20 pounds or so each. Our current plan is to make the upright out of 2" square tube and cut the 2023 “cone poles” which are the right diameter for the branches. Should end up as rigid as the FIRST elements with the same critical dimensions where coral will be placed but significantly cheaper and lighter.
What was the total cost shipped to you from AM? I got $695.96 quoted from AM for 120 Pieces.
Home Depot has them for $230. Maybe I have the wrong pipe?
im not well versed in pvc, but the stuff we got was 4.5" outer diameter. is this one of those things like wood where the number is one thing but actual is different?
When it comes to pipe the dimension is the Inner Diameter(ID), then the “Schedule” is the thickness of the wall, so the OD is the ID+that thickness, getting you a weird measurement on the OD.
I always remember this by just thinking about how pipe is conventionally used, you care about thrings running through it, not around it, and then the thickness is all about how strong it is.
Aluminum and welding. The poles FIRST is building could support multiple robots climbing on them. The worst they should be subjected to in a match is a robot getting caught on the topmost branch and trying to pull free.
Hi all,
We bought 4” PVC from Home Depot hoping that it would be correct. It looked right but a 12” segment weighs 0.85kg when the official Coral piece weighs 0.55kg. We will need to return it and keep searching.
Below are images of the product.
The nominal pipe size determines the OD of the pipe.
4 NPS SCH-40 pipe (of any material) is 4.026" ID and 4.500" OD.
4 NPS SCH-10 pipe is 4.260" ID and 4.500" OD.
4 NPS SCH-80 pipe is 3.826" ID and 4.500" OD.
PVC is a quick and dirty way to get a simulacrum of the actual element and I suggest every team build one to prototype against. You can even glue plumbing 45 degree wyes into it which aren’t that far off the actual field.
But…
A six foot tall PVC post is going to have a lot of flex to it, so practice against it will behave differently to how the poles will function in the real game.
There’s also the issue of coefficient of friction between PVC to PVC and PVC to powder coat.
PVC is perfect for prototyping to verify measurements and angles to the robot. For my goal of building two entire reefs that behave as close to the real field as practical, PVC isn’t enough.
I’m actually curious if shoving a piece of cheap 3/4" steel conduit inside the PVC will adequately stiffen it up. You could 3D print reducers to get a snug fit.
edit: 1" doesn’t leave much room, so 3/4" might be the better call
When buying 120, I think AM is $3.95 per not including shipping, Home Depot is $30.77 for 10’ (so 10 coral if you don’t mess up). That’s $0.87 per coral.
I was looking at Home Depot yesterday, vs Andymark, and ordering any amount made andymark close to Home Depot (not even including NY tax). When adding a larger amount it became cheaper for andymark, and no hassle of needing to cut pieces perfectly in half (if you buy a 2-foot piece) This might have to do with Long Island being a pricey area? not sure if teams in other areas might have different pricing. $12.81 per 2 foot section.
