my first 2 stage rocket

[beginingrocket]

hello im beginingrocket, im new I got not much experience I enjoy building and constructing new rockets so far I got 2 fuel tanks and working on a 2 stage rockets I need help with a small nozzle and its coming out good I made a coupling and its basicly 2 caps glued with silicone drilled out and Im also woking with my 2 best friends the are helping me and I almost done I will put on picture soon and im new don't judge me please

[beginingrocket]

this is what it look like soo far and its glued with silicone and will connect together with a coupling and its a kinda skinny bottle

[bugwubber]

Welcome to the forum and good luck on your rocket!

The best cheap glue to use is PL Premium which is a construction polyurethane glue. Silicone will fail at much lower pressures than PLP.

[Blenderite]

I am going to have to agree with bugwubber there. I made that same mistake myself when I started. Problem is that the silicon is strong enough on it's own, but it can't grip the plastic well. It is too slippery, kinda the nature of silicon if you think about it.

[beginingrocket]

ok ill try and get the glue

[beginingrocket]

The problem is that when I started I used the heavy duty liquid nails and it seemed like a good idea but it took forever to dry and on launch day I took it up to 60psi and it failed I agree I need PLP I'm working on that how much is it I have 2$ and 30¢ in my pocket and when I have built and finished my rocket ill take. a video of launch I'm thinking of first 60 then 80 and so on keep increasing til 120 plan is a 6ft tall rocket

[Blenderite]

I should have told you this before hand, but Liquid Nails will not work. Liquid Nails is a rubber based adhesive. PL Premium is a polyurethane based adhesive. The polyurethane adheres much better to a bottle than a rubber adhesive will.

As for cure time, I always let my bottles cure for at least a week before I touch them. After about a week, you should be good. What ever you do, please do not think that the 24 hour cure time on the container is accurate. It is accurate for construction purposes where there are porous surfaces. Plastic isn't porous so it takes much longer.

This is a time when waiting a week is the difference between a successful rocket and a rocket that blows apart. Patience will reward you.

[skysaber89]

Hey, good to see that someone else has given the 24 is bottles a go.
Well I thought I may give some input, so you can take it how you will. First, I agree with bugwubber in the glue. PL premium is a great glue to use. An alternative to that would. Be some form of high strength two part epoxy, but pl premium is easier to work with.
Second, I don't know if you did or not, as the picture isn't necessarily that clear, but sanding. Before you glue the joint, you should sand the area. Both the inside of the outer bottle and the outside of the inner bottle. This makes the glue stick better.

Third, I see that there is still some of the label plastic leftover. A great way to remove the label completely is to fill the bottle with warm water and wait a minute. This heats up the adhesive and makes it easier to remove. Then you can take some lighter fluid on a paper towel or some adhesive remover and take of the glue leftover. This will help when it comes to gluing, but it also just plain looks better.

Hope this helps

[skysaber89]

The problem is that when I started I used the heavy duty liquid nails and it seemed like a good idea but it took forever to dry and on launch day I took it up to 60psi and it failed I agree I need PLP I'm working on that how much is it I have 2$ and 30¢ in my pocket and when I have built and finished my rocket ill take. a video of launch I'm thinking of first 60 then 80 and so on keep increasing til 120 plan is a 6ft tall rocket

I did the same thing that you are planning to do, but mine was a single stage. You can go here for pictures of my last rocket viewtopic.php?f=28&t=2735

That rocket was pressurized to around 200 psi, but the coupling sprung a small leak.

I would recommend aiming for higher pressures, possibly reinforcing the bottles with fiberglass strapping tape. The extra pressure in the smaller bottles definitely helps to get the rocket going. The extra height makes liftoff slightly more difficult for the rocket.

Cheers

[Blenderite]

I would also like to warn that at higher pressures, a rocket is more dangerous so make sure that you are far enough away from the rocket. If you don't, a single explosion will teach you that.

[beginingrocket]

ok I decided to switch because I didn't have enough bottles but I still have the idea and so far I have a gardena launcher and a 7 bottle high rocket with no coupling to make it bigger . its a single stage and it is inter changeable with gardena and clack cable tie (if aren't all rockets) and I used pl preiem .

[Blenderite]

Good job! Hopefully it will work! Did you use the 3x PLP or the 8x PLP?

[beginingrocket]

i have no idea but this rocket is huge!

[beginingrocket]

i checked it is 8x

[Blenderite]

Excellent. I was going to say that the 3x would fail sooner than the 8x.

We want to see pictures of it put together!!!