I’m with East ridges 3130 errors and our spirit team is hoping to make a sign made of poly carbonate so we can sandblast it and put light in it to make it look cool. I’ve been trying to find a location to buy it but no place I’ve searched seems to have the size I need. the size I need is 20 x 30 with half or 1/3 inch thick. does anyone happen to know the best place to buy this (sorry if something is off with this post its my first time using cheifdelphi)
Plastics International in Eden Prairie stocks polycarbonate up to .375" thick. A 24"x48" sheet is $80. I bet you could order and go to their will call to pick up.
http://www.plasticsintl.com/polycarbonate-sheet.html?page=2&language=1&url=polycarbonate-sheet.html
Otherwise you can dig around on Amazon and see if there’s a supplier for cheaper.
.375 is pretty thick – do you need it to be that thick? 1/4" is fairly rigid.
1/8" is also fairly rigid, 4513 used it on the sides of our 2017 bot to hold electronics with 0 issues. Im not sure where 4513 gets theirs, but McMaster has it for like $40 for a 24"x48" sheet (thanks Tjf for showing me that a few days back)
Thanks and yes we need to have thick enough to put leds on the bottom. our spirit lead wants the led to fit well.
Any reason it cant be on the bottom of the front/back facing panels to save a bit of money? Underglow is cool but thats basically double the price for a little more thickness.
Also, is the sign going on the robot or just being held by someone in the stands? Im assuming the latter but I want to make sure.
I am 95% sure that is not going to work out well for you. Sandblasting plastic is very difficult. If you do a test with some small piece and you get it to work then you can move forward, but I would not buy a large piece hoping to sandblast without knowing for sure.
Other than sandblasting, two other options would be orbital sanding or buying diffused polycarb. Our local plastic supplier carries this so I’m sure it’s available from other sources.
yeah we have tested it on smaller piece and it works just great. As for where its going we will have people on our team holding it.
Okay, just wanted to make sure. You must have some sharp sand for it to work on that stuff.
1/2" polycarbonate is brutally expensive. Check McMaster-Carr for a typical price. It is quite heavy as well, and can probably support a small car.
As noted, 1/4" thick should serve pretty well, but of course you need to judge that for your application. Lighted signs are often very cool.
We’ve used Grainger for polycarb the past few seasons, on thinner sheets they’ve typically been 30-50% cheaper than McMaster. 3/8" thick though looks to be about the same cost from both, and is just going to be expensive overall as others noted.
We are not local to you but a quick search and browse brought back this:
It is almost always better to source plastic local as (as far as I can tell) it is usually cheaper and you do not have to pay for shipping. You can take the search way deeper than I did as you guys probably know the area way better, but I suggest looking for somewhere local and giving them a call to see if they would allow you to order some or even sponsor your team. Good luck.
Your 20x30 piece of .375 poly is going to weigh about 9 lbs, and at .500 thickness will weigh 12 lbs. You might ask your spirit team to stand holding a 9 pound weight above their heads, to see how long they think they can do that. Also think about the safety aspect of waving a 9lb object above people’s heads.
Let’s assume that you want the numbers/logo outlined in color (i.e., the numbers are black). Suggestion:
- use .125 poly
- remove all of the poly where the numbers or logo are
- use an aluminum channel at the bottom to hide the LEDs.
- Put the batteries in a belt pack rather than on the sign
- Put a standard on the sign so that the person assigned to hold it does not need to hold their arms above their head
- Ensure there are no sharp edges
Probably can do all of that in less than 4lbs held in the air.
Looking forward to seeing what you come up with in Grand Forks later this month!