LRT McMaster-Carr alternatives and optimal tube diameter/layering

Guides and discussions about building water blasters and other water warfare devices such as water balloon launchers.
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SoakerScotia
Posts: 7
Joined: Sun Nov 10, 2019 5:47 pm

LRT McMaster-Carr alternatives and optimal tube diameter/layering

Post by SoakerScotia » Mon Dec 16, 2019 1:50 pm

Hello everyone!

First I have to say it's great that the community, while smaller than in the heyday, is still around. I used to have an account on SSC back in around 2007 and while I never really posted much I remember what an easy going and welcoming community it was, especially in comparison to some others :cough: Nerf :cough: It's also great that a lot of the more prominent members of the forum appear to still be active (congratulations on the Phd Ben).

Now, some older UK based guys might be familiar with this phenomenon but recently the cost of living has meant that after being three years out of uni I've had to return to the nest. Whilst home I decided it would be a good opportunity to sell off some of my old things to clear some room and that's when I stumbled across the box containing super soakers, or at least a box containing parts of super soakers; mainly a xp110, flash flood and ww expedition. These were the soakers I was working on fixing/modifying when I began to lose interest in the hobby and they were all broken or missing parts. This discovery, however, prompted me to venture out to the shed to find the rest of the collection only to be dismayed to find them not in the shed but rather stuffed behind it in a pile of broken garden furniture and covered in mud. On testing I discovered that out of 2 cps 1000s, a cps 1200, a SC 600 an xp 105 and a xxp275 only 1 cps 1000 remained in full working order, the rest having succumbed to the Scottish winters and the SC600 being gone completely. I hate throwing things away and decided to fix what I could and sell them on, in the process on doing this, well, I fell back in love.

Whilst nerf has come on leaps and bounds since the late 2000s, water gun technology has completely stagnated and regressed with the 20 year old CPS line still the pinnacle of development (apart from Tim's POPCAP which looks completely insane). There is something very fallout-esq about the way that everyone now covets these ancient pieces of aquatic artillery from a bygone age whilst making tentative steps to recreate the technology in homemade form; and I love it! Whilst there is very little scope for new development in nerf nowadays there is so much we could be doing with water guns. I have currently fixed the CPS 1000 and 1200 and the xp 110, the flash flood and expedition were too far gone (completely the fault of my younger self) so were broken down and stripped for parts. I have since also added several more to the collection in various states of disrepair (access to money and alcohol has definitely played a big part in increasing a collection of things I was meant to be selling) which I intend on fixing and modifying for longevity.
I also plan on finally building a homemade, while PVC was practically impossible to get in the UK back in 2007 it is now far more obtainable. LRT, however, still is not. This brings me to the purpose behind this thread.

Whilst scouring the web for alternatives to McMaster-Car I found myself on that well known internet auction site and found an American vendor selling LRT with international shipping. Although they only offer tube with 1/8 inch thickness, by layering the tubes I could achieve a 3/8 ID 1-1/4 OD final tube. I have several questions about this:

1: Does anyone have any experience buying LRT from anywhere other than McMaster-Car? I recall from reading articles on SSC that certain types of LRT are unsuitable for multiple expansion and retraction cycles.

2: Are there any disadvantages to Layering LRT? In order to get from 3/8 to 1-1/4 I would have to layer 4 tubes, I have read the posts from Killer 7s homemade which layered 3 tubes of matching ID to OD tube to achieve 1/2 ID 1-1/2 OD. Two of the tubes that he used where the same as ones I plan on buying so I believe the four should be possible however Killer 7s bladder did eventually burst.

3: Are there disadvantages to layering matching OD to ID tubes? As mentioned Killer 7s bladder eventually burst whilst Ben, and I assume his brother's, non matching OD to ID bladders have been fine.

4: Has anyone discovered an optimum Tube thickness for performance vs pump weight in 1/2 and 3/4 pumps? In Wayne Schmidts CPS repair he used a 1/2 ID 7/8 OD tube which appeared to closely match a stock bladder, given this 3/8 to 1-1/4 seems overkill but I plan on trying various combinations of these tubes: 3/8 to 1-1/4, 3/8 to 1, 1/2 to 1, 1/2 to 1-1/14 ect. Anyone done any testing?

5: Has anyone managed to get 3/8 ID LRT over a 1/2 tubing barb? I recall Ben attempting to figure out a method for achieving this, has anyone managed it yet? The decreased dead space would definitely be an advantage but would there be any disadvantages?

Whilst I have already trawled through the forums to find the answers I do apologise if these questions have already been answered elsewhere and I missed them. Throughout the process of my repairs I have been taking photos and plan to write up some guides in the spring, I've also completed a homemade pump replacement in a Monster X which I am currently working on modifying/fixing and I have plans for the xxp275 too which I look forward to posting about.

The LRT seller on ebay is called zwgoods, a search for thick latex tubing should find them.

Cheers!

CDMT
Posts: 36
Joined: Mon Oct 20, 2014 11:35 pm
Location: Washington

Re: LRT McMaster-Car alternatives and optimal tube diameter/layering

Post by CDMT » Wed Dec 18, 2019 4:48 am

I haven't messed with LRT for awhile but you could alternatively use a 1.05 quart Jabsco accumulator tank. I've used mine for years and it is very reliable.

https://www.amazon.co.uk/Jabsco-30573-0 ... 165&sr=8-3

SoakerScotia
Posts: 7
Joined: Sun Nov 10, 2019 5:47 pm

Re: LRT McMaster-Car alternatives and optimal tube diameter/layering

Post by SoakerScotia » Wed Dec 18, 2019 6:12 pm

I had a look at accumulator tanks as pressure chambers but it was the price and the fact that I couldn't find any links to someone successfully using one that put me off. That's interesting that they do work though, the one litre one is a tad expensive but there is a 0.75 litre one on amazon that is more in my price range which I might try out. Shame it uses NPT but you can even get that here too now.

SSCBen
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Re: LRT McMaster-Car alternatives and optimal tube diameter/layering

Post by SSCBen » Wed Dec 18, 2019 7:58 pm

Welcome back! Sorry for the relatively brief message as I'm currently focused on other things but wanted to post something before I forgot.

Bladder/accumulator tanks might be a better option for many. I recall someone back at SSC made a fairly powerful water gun using a large bladder tank in a backpack, though I can't find the link right now. I bought a 1 gallon tank a while back myself just to test and I found it to be fairly powerful.

As for the specific questions.

1. I was going to buy LRT from Primeline Industries (who ship internationally and have better variety than McMaster-Carr) but never did. I tried some of the thicker tubes from McMaster-Carr but found that they burst and are extremely loud. These tubes will damage your hearing. I think that's probably true for all tubes over a certain thickness. My enthusiasm for LRT has decreased greatly after this.

2 and 3. I'm not sure if there are any major disadvantages aside from it being annoying. I think having a gap between tubes might decrease performance but I'm not certain.

4. I don't think anyone has done this.

5. I think Killer 7 had some method but I don't recall what it was.

Looking forward to any guides you can make. As you're aware, repairs are becoming more and more important in water guns.

Also: I don't have a PhD yet.

Tim
Posts: 122
Joined: Wed May 11, 2016 4:05 pm

Re: LRT McMaster-Car alternatives and optimal tube diameter/layering

Post by Tim » Fri Dec 20, 2019 8:04 am

Read this and other TylerK posts...

viewtopic.php?f=126&t=6974&p=62836&hilit=Barb#p62836

SoakerScotia
Posts: 7
Joined: Sun Nov 10, 2019 5:47 pm

Re: LRT McMaster-Car alternatives and optimal tube diameter/layering

Post by SoakerScotia » Tue Dec 24, 2019 11:11 am

Ah sorry Ben I thought I'd read somewhere that you were graduating, still congratulations all the same, I actually did fluid dynamics as my advanced higher physics product in my final year of high school (although I dropped out of the class about half way through so didn't actually do any meaningful note taking) It's pretty cool how the hobby has had a hand in maybe steering you on to your career path.

Ah those are some great posts! I don't know how I missed that. The fact that so many people have had bursting tubes is slightly alarming though... I've decided to just go ahead and order some, I'm thinking that starting as close to standard stock cps chamber size and tube width/diameter and then trying out things from there is perhaps the best way to go.

Although there are perhaps better pc options for homemades, LRT still seems like the only option for repairing stock soakers which is something I'm quite interested in so hopefully these ebay tubes will work. If they don't at least it will stop anyone else making the same mistake.

I've definitely been surprised by the longevity of stock cps bladders, I remember reading ten years ago about theories of the pcs hardening with time and rupturing but I've still never actually had one burst myself.

Wonder if it would be possible to make a cast for a spherical pc at home and cast one with liquid latex used in mask making?

SSCBen
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Re: LRT McMaster-Car alternatives and optimal tube diameter/layering

Post by SSCBen » Tue Dec 24, 2019 4:20 pm

SoakerScotia wrote: Wonder if it would be possible to make a cast for a spherical pc at home and cast one with liquid latex used in mask making?
I vaguely recall people talking about this a long time ago, but I don't think anyone actually did it. It's worth a shot.

I think the main problem with the durability of bladders would be the number of cycles you can put them through. I don't imagine an unused bladder stored in a dark room would have any major problems.

Killer7
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Joined: Wed Mar 04, 2020 11:05 pm

Re: LRT McMaster-Carr alternatives and optimal tube diameter/layering

Post by Killer7 » Sat Mar 14, 2020 10:04 am

Hello,

I am the original Killer 7 from the forums all those years ago, and I'd be happy to answer the questions that pertained to me.

The only disadvantage I saw to layer lrt was the cost and the difficulty in doing it. My bladders did ultimately burst, but I was able to fix that in my next iteration. The problem I believe was that I was allowing the lrt to over expand. Once I put the lrt into a smaller chamber the bursting problem went away. it did cut onto my capacity somewhat, but it was a pretty small price to pay compared to haveing to rebuild the bladders. That got expensive pretty quick.

As far as using layers of lrt that match od to I'd of the next layer. I didn't notice any downsides once I fixed the bursting problem. I suspect that layering lrt in a state of constant stress like you would get by layering non matching ID and OD would over time tend to cause the outer layers to fail, but I dont have any evidence to support this actually happening. I was very happy with my cps homemade once I made the chamber smaller and they quit letting go.

Also if you have any questions about the assembly process I used to make the three layer matching id and od bladders, I'd be happy to answer them. I wrote an article for sscentral back in the day, but if would like I'd be happy to talk you through what I remember doing.

I hope this helps, and have fun with your homemade.

Killer7
Posts: 2
Joined: Wed Mar 04, 2020 11:05 pm

Re: LRT McMaster-Carr alternatives and optimal tube diameter/layering

Post by Killer7 » Sat Mar 14, 2020 10:12 am

I did have a method for getting a small piece of lrt on a bigger hose barb. I shaped an ice cube on the kitchen sink to make a cone that had a base diameter a little larger than the hose barb then I melted it into the hosebarb until the cone base met the hose barb then you just push the lrt over the cone. It goes on very easy. The only downside I found was that the lrt tended to initiate expansion somewhere along its length, and that spot was very consistent. If it didn't start from the front you would end up having a flow restriction in the lrt because the I'd of the lrt was the smallest thing the water had to pass through. Super soakers for around this by making th bladder thinner at the spot they wanted expansion to initiate from. I never found a good fix to make it start expanding from the front when I did this.

I hope this helps, and if you have any questions feel free to ask away.

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