Airsoft M72 LAW rocket launcher

Step 8 Control Box and Locking Mechanism

Figure a way to make some sort of control box on top of the outer tube. I used sections of a 1 inch square pine dowel. I epoxied it to the top and reenforced with more fiberglass and felt.

Once the epoxy cures, paint your choice of colors.

EDIT: Picture 2 & 3 - The Locking mechanism (13 seconds into the video)

This is a strip of plastic glued to the side of the launcher.
Nothing special needs to be purchased. Look around your house/environment for a strip of plastic at least 1/8 of an inch thick and about 3 inches long. It needs to flex without breaking. Look around and use creativity and imagination.

Drill a hole on one end for the screw in STEP 6 to go in to. Glue the strip of plastic to the side of the tube in such a way that when the launcher is extended the screw goes into the hole in the plastic. put a layer of fiberglass, felt or duct tape to make sure the plastic does not come off or shift (see the green square in picture 2). a flexible strip of metal will work too.

Edit: People still don't get how to make locking mechanism. I still get messages about it. I think the trouble is people are trying to make it more complex than it really is. The rule is K.I.S.S. Here is a video of the locking mechanism.

Comments

[airsoftchase]

what is the greenish tape stuff?and where can i find it?

[MrTinkerer]

Green self adhesive felt.

[pablotheillegaltaco]

What is the locking mechanism for is it to hold the metal bar in place?

[MrTinkerer]

no. It is to lock the tube in the extended position.

[yourworstnightmare]

the blocks on top are 1inch, 2inch,and 4inches right? they are your control box right?

[MrTinkerer]

Yeah, that sounds about right. But again, use dimensions that makes sense for your build.

[Bonadas]

Hi Can you help me and explain what is the Proflex shielded coupler used for? it's because I am portuguese and i cannot understand what is that so i was wondering if you can help me because i wanna but that piece i dont no the name of that in portuguese. Thank you.

[amk10]

its used to put the mad bull grenade in place and to hold it there while in use

[thisishaggard]

How do you form the fibreglass over the trigger to make the control box? This could be a dumb question, but I havent worked with fibreglass cloth before and I'm unsure how to go about making the control box.

[MrTinkerer]

The control box from version one was really hard to make. Which is why I came up with version 2. To make a covered control box, i built a form out of wax. I then covered the wax in fiberglass. Once the resin has hardened I melted the wax out. Again VERY complicated process, so I made version 2.

[thisishaggard]

That's an amazing idea. I never would have thought to do that. Is it so complicated that it's just not worth doing, or is it do-able, but just takes a lot of time and patience? I would love to be able to have the covered control box. Is there any other possible ways that I could build an frame for the fibreglass to go over the trigger? Even if it was just a metal or wood frame and that way I could stretch the fibreglass over. I was also going to ask you if it was possible for me to use the proflex shielded coupler part number 3000-215? I know that you say to use the 3001-215, but I looked everywhere, and I wasn't even able to special order it. I guess it's because I live in Canada. So I bought the 3000-215, and 36 inches of 2 Inch ABS, then put the coupler on the end, tightened it, and it's a perfect fit. I believe that the 3000 and 3001 are almost exactly the same, maybe a pressure rating? They are both 2 inch - 1.5 inch, and used for coupling all of the same materials (plastic, steel, and so on). Are you planning on making a V3.0 any time soon? I'll let you know how mine turns out.Thanks for your help.

[MrTinkerer]

Not, sure if the 3000-215 will work or not. Only way to find out is to try it i guess. As long as the fit to the pipe is snug and the fit to the grenade is snug, you are good to go. The pressure involved is low, so different pressure rating should not matter. For the control box, i am sure there are other methods, i just used the wax method becuase it was materials I had readily available. What ever method you use, just make sure the control rod/bar/cable can move freely inside the enclosed control box. I recently relocated to another state. I no longer have a garage to do projects, so LAW v.3 will have to wait.

[thisishaggard]

Are you just using paraffin wax? I'm sure the best way is to buy it in blocks from a grocery store. As for the coupler, I figured it would just have to fit snug, and since it is 2"-1.5", if the grenade is 1.5" wide, it should work. Thanks again.

[MrTinkerer]

i used a large block of parafin. I cut it to a rough shape using a fine hot wire, then carved to it's final shape with a sharp knife.

[tg456]

does it have to be velvet or could i use duct tape

[MrTinkerer]

I never said anything about using "velvet". I have stated in the video to use duct tape.

[red_october]

wow you have a very creative mind in order to think of something this big(project wise not the actual size) but i have a question i read about how to make the locking mechanism what exzactly do you need to do? do you need to drill a hole into the inner tube so that when it gets extended it locks itself in or what becuase it was very confusing

[MrTinkerer]

Hi. Thanks. OK, this is how I did it. other methods are possible.

Go back to step 6. Step Six is needed because without it when you extended the tube, without the screw the inside tube will pull out completely.

Now, the locking mechanism "Captures" the screw in Step 6.

[MrTinkerer]

I have created crude animated pictures of how the locking mechanism works. Instructables does not seem to play nice with animated gifs so please click on the link I provided. if this still does not explain it for people then I do not know how else I can describe it...

[geoffpeplau]

do we need that locking mechanism and if we do how do we make it?

[MrTinkerer]

Please review Step 6. Then review picture 2 & 3 of Step 7. The locking mechanism is required because without it when you push the trigger forward the launcher wants to collapse. The locking mechanism is a piece of flexible plastic. Please see my edits in Step 7.