Water Rocket Forum

I built a launcher some years back with a one price pipe. I cut a groove into the pipe for the o ring to seat. I think I use 3/4 inch pvc. And now my o ring had final failed do to age. And I can't for the life of me remember what size o ring I used when I built it. I do know that it only works with Pepsi bottles, not coke because the coke bottles are to tight. It has a Clark cable tie release on it. I real don't want to have to cut the launch tube in half to put a ring on. I just need to know what size I can slide down the tube to the groove to seal the bottle. I live in the middle of no where and will have to order one because the closet stores are 2hrs away. So any help would be greatly appreciated.

I recommend you sand your launch tube down a bit so it fits more bottles. The o-ring will take up the slack and provide a nice seal for all of them. I believe you have a 1/2" launch tube, if you are launching 2-liter soda bottles.

As to a replacement, I believe you will find it in one of these kits: http://www.harborfreight.com/catalogsea ... t?q=o-ring

It's okay if you have to stretch the o-ring over the launch tube, so long as it fits in the groove you have cut and is thick enough to seal against your rocket.

Good luck!

Thanks for the reply. And I do believe your right about it being 1/2 inch tubing I hadn't thought about sanding the tube but that's a great idea. Once again thank you.

Would it be best to get SAE or metric sizes? And can any one please tell me right size I need. I know o rings come in different sizes. Out side and inside diameter and different #'s like #2 #3 ect. So I can simplify my buying. Sorry on a very strict budget here. Thank you very much in advance.