Layering LRT & Inner Tubing

Guides and discussions about building water blasters and other water warfare devices such as water balloon launchers.
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Layering LRT & Inner Tubing

Postby TylerK » Wed Aug 24, 2016 1:16 am

So I have read every thread I could find on here and sscentral on LRT, inner tubes, and CPH's; and still couldn't find out how others have dealt with my issue. I will try to detail as clearly as possible with pictures.

I'm building a 'supercps' and my wife and I managed to layer the two layers of LRT without much hassle (3/8 x 3/4 and 3/4 x 1-1/8).
They were cut to the same length (9") but the 3/8 tube stretched during the process and is now 3/4" longer (I think I will cut the excess off???). If I don't cut it off can I use two hose clamps, one for each size. But am afraid the tubing will stretch between the clamps and the LRT will expand more in that gap due to less pressure.
Pic of slippage: ... t.jpg?dl=0
Pic with two clamps: ... p.jpg?dl=0

On the other end of the LRT (where both layers are even), when I tighten down the clamp over both layers the outer layer wants to slip back (or inner layer stretch outward) off of the area that's over the hose barb, thus creating a gap (two clamps again??) I haven't built the rest of the gun so haven't tested everything yet (I understand it will take some tweaking).
Pic: Other end clamp/hose slip: ... p.jpg?dl=0
Pic of what it should look like: ... d.jpg?dl=0

My other question is: when layering the bike inner tubes over the LRT layers do you clamp them down with hose clamps or cut them slightly shorter? Currently I have four inner tube layers (1 full, 2 half, and then the last two layers are in 1.5" pieces) and they are not clamped down. I just don't want any uneven expansion of the LRT and cause uneven wear (I've had LRT pop once before on another project from experimenting with inner tubes).
Pic: Full tube with inner tube layer: ... e.jpg?dl=0

It seems to me that inner tubes to not expand as much in length compared to LRT, which might be tricky (the back of the LRT will pop out once expanded due to less resistance).
Thanks in advance for any suggestions.

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Re: Layering LRT & Inner Tubing

Postby HBWW » Wed Aug 24, 2016 7:39 am

For some reason, I don't think this issue was ever properly documented or addressed. I ended up cutting both tubes to the same length and having them share clamps and that worked. (I used LRT for both layers though.)

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Joined: Wed Aug 03, 2016 11:14 am
Location: AZ

Re: Layering LRT & Inner Tubing

Postby TylerK » Wed Aug 24, 2016 10:14 am

Last night I replaced one of the hose barbs with a longer one (3/4" diameter, yeah that took a while and talk about flow!) and that seems to fix the unevenness & slip issue (there's more space for the hose clamp to grab. Still curious about the inner tubing though.

BTW, just using silicone and 'elbow' grease works fine for layering LRT layers that have the same OD/ID, 3/4").

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