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Standard tube sizes?


OldMarine

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I've read this and every other pyro site I can find and have yet to see any standards for tube internal and external diameters. I see terms such as NEPT bandied about but no definitive descriptions.

I see a lot of tooling geared to these tubes. What is the difference and is there a standard sizing?

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Standard id`s typically run from 3/8" to 1-1/4" in 1/8" increments, then jump 1/4" to 1-1/2" id for 6lb tubes. Wall thickness on the smaller tube diameters can be quite variable but from 3/4" (1lb) upwards its typically 1/8", 3/16" and 1/4". NEPT tube id/od`s are/were more consistant than most.

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As I have come to understand, there is no definitive standards.

And those there are, changes with the regions of the world.

 

What's available to you would be the standard ;)

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There are actual standards used by tooling makers here in the US. The actual ID of say 3/4" tubes isn't actually 0.75". They tend to be around 0.765" IIRC. There was a long, and somewhat pedantic conversation/argument about this on another forum not too long ago. I'll see if I can find it. Your best bet might be to contact a tooling supplier like Rich Wolter or Ben Smith, and see if they have specs they make their tooling for.

 

I'm not sure if you're asking, but NEPT is New England Paper Tube, which is a supplier of some of the nicest tubes in the US. There are other suppliers of similar quality however. NEPT tends to be somewhat difficult to work with at times.

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Hmm, I'm beginning to understand why so many folks manufacture their own tooling. I can also see why many roll their own tubes. It's not too critical for me yet as I am starting with gerbs, smoke and strobe pots but I'll eventually have to shoot the moon and build some aerial effects.

I'll definitely need to hone my rolling skills before then it seems.

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Most "3/4" tooling will fit most "3/4" tubes, there are a few outlaying exceptions (SLD makes his tooling basically scrape the inside of NEPT tubes), but thats not a big enough problem to worry about.

 

 

I asked Wolter what dimensions he uses for his tooling, and this is what he sent me:

 

 

"Ok, here is the list.
These will fit my tools:
Original I. D. and O.D. dimensions of the NEPT tubes.
4 oz I.D. =.515 O.D=.698
8 oz I.D. =.638 O.D. =.907
1 lb. Thin wall I.D. =.765 O.D. =1.018
1 lb. thick wall =.765 O.D. =1.143
2 lb. I.D. .890 O.D. =1.280
3 lb. I.D. 1.015 O.D. =1.380
4 lb. I.D. =1.265 O.D. =1.765
6 lb. I.D. = 1.515 O.D= 2.0000
Thanks,
Rich Wolter"
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Thanks! That's more info than I've found in a week of searching. They have a great reputation on this site so I'll more than likely go with them for my first rocket tools.

 

 

Most "3/4" tooling will fit most "3/4" tubes, there are a few outlaying exceptions (SLD makes his tooling basically scrape the inside of NEPT tubes), but thats not a big enough problem to worry about.

 

 

I asked Wolter what dimensions he uses for his tooling, and this is what he sent me:

 

 

"Ok, here is the list.

 

These will fit my tools:

 

Original I. D. and O.D. dimensions of the NEPT tubes.

 

4 oz I.D. =.515 O.D=.698

8 oz I.D. =.638 O.D. =.907

1 lb. Thin wall I.D. =.765 O.D. =1.018

1 lb. thick wall =.765 O.D. =1.143

2 lb. I.D. .890 O.D. =1.280

3 lb. I.D. 1.015 O.D. =1.380

4 lb. I.D. =1.265 O.D. =1.765

6 lb. I.D. = 1.515 O.D= 2.0000

 

Thanks,

Rich Wolter"

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I asked Wolter what dimensions he uses for his tooling, and this is what he sent me:

 

 

"Ok, here is the list.
These will fit my tools:
Original I. D. and O.D. dimensions of the NEPT tubes.
4 oz I.D. =.515 O.D=.698
8 oz I.D. =.638 O.D. =.907
1 lb. Thin wall I.D. =.765 O.D. =1.018
1 lb. thick wall =.765 O.D. =1.143
2 lb. I.D. .890 O.D. =1.280
3 lb. I.D. 1.015 O.D. =1.380
4 lb. I.D. =1.265 O.D. =1.765
6 lb. I.D. = 1.515 O.D= 2.0000
Thanks,
Rich Wolter"

 

 

Great list. Now one only needs a conversion chart for mm, and, a guesstimate for tube drying shrinkage, and then your set to go, making your own tubes for some of the best tools in the trade.

Thanks.

B!

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The Id can be set by drying the tube on the mandrel, the od can be set by making the tube slightly oversize and sanding it after its dry.

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There is that. But it would be harder to get it of the mandrel, and you either have a load of mandrels, or really slow production.

An upside is of course that the tubes would be straight and truly round. Sometimes i have to discard a tube due to it being out of shape after drying.

B!

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The drying mandrels dont need to have much of a wall thickness, its better if they dont. Sort a drying box that can provide 70C and the tubes will dry from the inside out thanks to heat transferred through the thin walled former. Once the innermost layers are dry (<30mins), they create a moisture barrier which forces the rest of the moisture to move outwards. At that point the tube is set and you can remove it from the mandrel and the drying box.

To get stubborn tubes off a mandrel use a piece of thick plastic with a hole in it the same size as the mandrel, If the mandrel is smooth, the tube will submit no matter how tight it is :)

Edited by Col
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One more thing to consider, is that NEPT seems to run pretty wide tolerances, many pyros have found that their supports work for one batch of tubes, but not the next (either too small, or too large). The tube supports themselves also have varying dimensions, not nearly as dramatic as the tubes though.

 

If you plan on using a wolter/firesmith support, I would get it in your hands, measure it, and then roll your tubes to fit that specific tool.

 

 

and when you start making rockets, GET VIDEO!! :)

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Just received my Wolter 1" gerb tooling. It's so gorgeous I'm ashamed to whack it with a mallet. But?...

This is my pyrotechnic red line.

Single use tooling is a commitment.

 

Edit: Am I wrong for starting at 1"/3 lbs? I have experience that only qualifies for the forbidden forum so I can't start too small...

Edited by OldMarine
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the only issue with that size is going to be getting the composition consolidated well enough; gerbs are much more forgiving than rockets though, so you should be fine. Of course pressing, (opposed to hand ramming), will circumvent that problem.

 

You will be very satisfied with that set, the difference in performance is substantial between 0.75" and 1"!

 

Get video!

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Hehe, I'm already shopping for a press and I haven't pounded anything stronger than smoke.

I have a game plan: Smoke-strobes,gerbs-fountains then rockets.

Over-ambitious isn't in there.

I'll post fail and success videos and I expect all due criticism!

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Oldmarine you seem to be a pretty cool chill dude. Welcome. Your choices here are good ones, ones I should have made a few years back as far as tooling goes. I make 1/4", 7/16" and 5/8 rockets and mini fountains/gerbs. I can agree that you going with a 1" off the line is awsome. The difference between the sizes is amazingly large for thrust/pressure capacity, speed and height. Cool factor weighs in heavy as well. So far I have'nt had the need to buy tubes as I learned to roll them many years back. Kraft paper and 70/30 water to wood glue only now. (I was adding wheat paste to the mix :( Titebond, gorilla, or elmers wood glues make rock hard, burn resistant with only a 1/8" wall thickness up to 5/8 or 8oz. As far as the rockets go anyway. When making tubes for noisy freds back then and now they get a 3/16 wall. So far after a dozen or so cato's only 4 went to peices with the remaining good for a reload. Your going to have a good time with the tooling.

Edited by Sparx88
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I plan to perfect my tube rolling skills before I need them. This thread has taught me the value and necessity of that! By the time I progress to rockets I don't want tube failure to be the leading cause of CATO's.
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With quality tooling, support sleeve and a press you`ve got most of the bases covered. Roll the tubes with virgin kraft and high solids glue and you shouldnt have many cato issues. 3lb rockets cost more to make so ideally you want them to fly not cato :)

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  • 5 weeks later...

With quality tooling, support sleeve and a press you`ve got most of the bases covered. Roll the tubes with virgin kraft and high solids glue and you shouldnt have many cato issues. 3lb rockets cost more to make so ideally you want them to fly not cato :)

 

Hmm..an answer always leads to new questions. I was looking at a Firesmith tube support that accepts 10" long tubes. I've eyeballed that thing over and over and can't see how it could be used on anything shorter without some extra something. It's the one with 2 slip rings. Need enlightenment please!

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One issue with big fireworks is that they can travel long distances. If they go the wrong way you still need clear space there.

 

I remember a 3" whistle rocket with 12" ball shell being written about here. An estate agent would be proud of the "stick" (10ft of 2x2 )! You have to think where it will land.

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I'm torn between the Wolter clamshell 3# support and the Firesmith slide lock model. Both have good reps for accurate sizing. Any preferences?
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One issue with big fireworks is that they can travel long distances. If they go the wrong way you still need clear space there.

 

I remember a 3" whistle rocket with 12" ball shell being written about here. An estate agent would be proud of the "stick" (10ft of 2x2 )! You have to think where it will land.

 

 

I believe you're thinking of cplmac's rockets. I was fortunate enough to see several of them in action. For being so huge, they go surprisingly low. They really howl though. The first one only went maybe 5 or 600 feet. Even when he got the design nailed down, they went 1000-1200 feet I'd guess. The stick and tube actually drift quite leisurely back to earth as well.

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I can't picture a 10 ft 2x2 coming down leisurely! I'd look like a squirrel in traffic trying to get away from it.

 

 

After sage advice from an esteemed forum member I went ahead and ordered the Wolter clamshell support. Now for a press and I'm done buying for a while...Hehe...right...

Edited by OldMarine
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