Build an Overhead Water Rocket Launcher Part 3 valve pipe

[robert0joe]

How important is primer?

[sciencetoymaker]

@robert0joe re:using primer on PVC pipe before using the cement. It's a good question. I never use primer, but I do scuff up the surfaces to be cemented a little. I've never had one leak.

Slater

[WRSvideos]

Does anyone know why you need that extra PVC on there? Or is it optional?

[sciencetoymaker]

@WRSvideos Which extra piece? The threaded parts just make it easier to transport and store.

Slater

[pyroman675]

that seems a little long dont it. and were do you get those shredder valves from

[sciencetoymaker]

@pyroman675 Do you mean the launcher is tall? The whole point is to get it overhead so the bottle can't hit somebody on the way up (people rush in to get wet). Valve from any auto parts store.

Slater

[pyroman675]

@sciencetoymaker well ya but you should zip tie a peace of wood to it so it dosent flopp and maybe break

[sciencetoymaker]

@pyroman675 At the end of part 6 at 1:50 it shows how to tape on the leftover 22 inch piece of pipe, both to keep the spring on and so the pipe doesn't flop.

Slater

[pyroman675]

@sciencetoymaker ya i saw that but watch the 7th part of it at the end when thwy fire it's like a snake

[jordyvandewalle]

does the lower 18" piece has a function ?

otherwise i'll don't attach it ..

[sciencetoymaker]

RE the 18" of pipe--good question. When you mount a bottle half full of water on the launcher a bit of water trickles into the pipe. If the air pump hooked in right at the bottom of the launcher, the water will collect there and could back up into the pump--making it very hard to pump. Tire valves have a check valve (one way valve) but they often leak a little. Including that empty 18" of pipe bellow the valve lets the water pool there harmlessly.

Slater

[jordyvandewalle]

Thanks =)

[poopyapple1]

hey im going to do this for extra credit in science and i was wondering what type of valve should i use

[sciencetoymaker]

Go to an auto parts store and get some cheap, common, pull-through stems. Long or short stem does not matter, but if there are two widths get the thinner.

Slater

[MrSwamijim]

In order to ease the re-opening and prevent the drying up of threaded containers of glues, paints etc., I coat the external threads with Vasiline. It works, even on superglue.

[sciencetoymaker]

That is a brilliant tip! Thanks.

Slater

[experimentatori]

Excellent!