1lb Rockets Failing - I Need Help

[joeyz]

Thanks chief! I spent a hour trying to find tubes online. Here is a video i made for you on the paper for tubes, can i use it?

 

I found like 10 of these in the dumpster 6 years ago while emptying my office trash can and pulled one out. its heavy as hell and i could only carry one out of the parking lot dumpster, like 60+ pounds. i originally picked it out of the trash to use as a painting drop cloth to repaint the kitchen and bathroom, not to get paint on the floor. Now i use it for packaging etc.

 

Edited August 17, 2016 by joeyz

[NeighborJ]

Everyone who rolls their own tubes seems to have their own ideas for the best material, best glue, and best method.

Personally I use 30% recycled heavy file folders from Staples and Elmer's wood glue max. I just wrap the edge around a dowel on a flat table and put a thick bead of glue across the entire sheet and roll it out. I press down hard and the bead squeezes out ahead of the roll as I progress. I need to use two folders because the paper has grain and only rolls nicely in one direction. I have had issues using craft paper such as yours because it shrinks as it dries and will wrinkle like a rasin. I know some people preglue the paper and let it dry flat, and then reglue and roll out to counteract the shrinkage but I've found that to be a pita. Your paper will be useful for making can shells and I use it to roll out on my work bench for easy cleanup.

[joeyz]

okay chief, sounds like i will be going to the store to buy some file cabinet yellow manila folders. at least their about 13-14" and satisfy the 7 1/2 length requirement for tubes. how thick should i roll it? 1/8" for 1lb end burner and core burner? do you have a routine standard of eye estimating thinkness? or you just take one folder, depending on type (if need two) open wide, start glue rolling, cut excess when dry? does one folder give you enough length to get two rockets out of it? sounds pretty close.

[OldMarine]

I use Phil's tubes. They're spiral wound but hold up very well.

 

http://www.ihaveadotcom.com/cart/index.php?main_page=index&cPath=72_118

[NeighborJ]

I think I get 1 7-1/2" tube from each folder which makes 2 tubes. I roll one side let it dry for 30 min then roll the other half over top.

And yes OM is right Phil has good tubes but I have had burn thru on his larger tubes 4# but I can't speak for the smaller tubes. I've had very good luck with the tubes Jim sells at hobby horse but I have noticed inconsistency with the I'd. So it is hard to say what the best choice is. That is why all my endburners use homemade tubes.

[joeyz]

thanks marine. but the only ones i saw was the tubes with 1/4" wall thickness. i have a case of 3', 3/4" ID, 1/4" thick walls that im skeptish in using after testing one rocket. i was trying to go thinner and lighter as possible in case a rocket strays off my 20 acres of land. those thick tubes are monsters, like a hollow wooden dowel spear coming down from the sky, and im trying to be safe as possible. i also using 1/4" sticks to reduce weight to increase safety. if best practices and risk mitiigations arent used, it could be bad. i fear someone knocking on my door, "excuse me, is this yours?"...pointing to his skull with an arrow like tube/stick stuck in his head. lol

 

thats definately a great resource and appreciate it. his prices are pleasing in contrast to other sites.

Edited August 17, 2016 by joeyz

[OldMarine]

The 1/8" walled tubes are at the very top of the column.

[joeyz]

hmmm, top two are 1" ID

 

i think i found it... third one .765 ID, the pictures through me off because its showing incorrect demensions. when i click on the full description i see it is says .125 thickness which means to me 1/8". is this the one --> http://www.ihaveadotcom.com/Tubes/tubescart.html

 

btw, i love phil's comments, "If your wife complains about spending more money on "your silly fireworks hobby", send them back and use your refund to start divorce proceedings." hahahahaha

[Phildo]

The tubes in the photos look like the fuzzy, pulpy tubes that some vendors offer. They're made with cheap paper, only a few layers, and poorly glued. I'm afraid you're going to find their uses to be pretty limited. You might try shaving the edges of your support so that they don't quite touch when tightened and use more pressure when pressing your fuel.

 

The page you referenced is outdated and I need to either remove it or modify it. Whoops!

 

I've never had a report of burn through in the 10 years I've been offering these. Neighbor, are you sure you were using my tubes? I've never offered a 4# tube.

 

These tubes been tested and retested by the experts and all have been surprised at their strength. There has been several lengthy discussions on Fireworking dot com using different fuels and pressures without any issues with the exception of side split when the support is removed with spongy whistle fuel. That problem was resolved by simply using a proper support and reducing the amount of pressure on the ram. SLD went so far as to report that these were the only tubes he would buy if he didn't already have a lifetime supply of NEPT.

 

There's no question that NEPT tubes are strong but they're also very expensive to produce and the tolerances vary from batch to batch.

[NeighborJ]

If that ain't addiction then what is? She's one firecracker I don't want to light. if my wife ever said " it's either me or the fireworks!!!!" I'd consider asking her for the lighter.

[dagabu]

The tubes in the photos look like the fuzzy, pulpy tubes that some vendors offer. They're made with cheap paper, only a few layers, and poorly glued. I'm afraid you're going to find their uses to be pretty limited. You might try shaving the edges of your support so that they don't quite touch when tightened and use more pressure when pressing your fuel.

 

The page you referenced is outdated and I need to either remove it or modify it. Whoops!

 

I've never had a report of burn through in the 10 years I've been offering these. Neighbor, are you sure you were using my tubes? I've never offered a 4# tube.

 

These tubes been tested and retested by the experts and all have been surprised at their strength. There has been several lengthy discussions on Fireworking dot com using different fuels and pressures without any issues with the exception of side split when the support is removed with spongy whistle fuel. That problem was resolved by simply using a proper support and reducing the amount of pressure on the ram. SLD went so far as to report that these were the only tubes he would buy if he didn't already have a lifetime supply of NEPT.

 

There's no question that NEPT tubes are strong but they're also very expensive to produce and the tolerances vary from batch to batch.

 

Phil even got ME hooked on his tubes! He brought a section for me to try, it fit perfectly into my NEPT build tube support, pressed it to 9000LPI and stuck a 2" festival ball on top (endburner) and lit it up!

 

11 seconds of flight time, HOT BP, no burn through. I'll be looking to do a bulk buy from Phil very soon of the #1 tubes!

 

BTW- Phils tech grade KNO3 is the very best KNO3 I have used.

[NeighborJ]

Phildo I am so sorry, I looked up the invoice in my email and the 4# tubes were from skylighter. I've been using them up on zippers because they aren't good for much else and I have no need for such large core burners.

[DavidF]

Joe, I don't think that is a burn through at all. That is a blowout, IMHO. Also, it seems to me that it did split along the 'swirl'- the inside swirl! I did suggest that you don't use ball-milled 70-20-10. That's for the nozzled core burner. The charcoal for that rocket should be airfloat, or mostly airfloat with some slightly coarser charcoal added. But adding the slightly coarser charcoal is to make a pretty spark trail at night.

With an end burner, you want a faster-burning powder for sure. You should use a faster charcoal for that, like the spruce you used. Also, ball-milling is good for end burner fuel (75-15-10). Adding a small amount of water and screening it in helps consolidate it better, as you saw. Those spiral tubes are not ideal for rockets. Phil's tubes are also spiral tubes. But, they are hard and strong as everybody agrees. The spirals are tight. I've used Phil's tubes for every kind of rocket I make, successfully.

Waxing those cheap tubes will help. I believe your chuffing is caused by fire running up the spirals from the top of one increment to the (less dense) bottom of the next increment. Waxing will prevent that. So: ball-milled 75-15-10 for the end burner, ball-milled potassium nitrate and straight airfloat 70-20-10 for the coreburner. Moistening both fuels would help both rockets.

Waxing is helpful in many cases, because it helps overcome defects in production. I agree with NeighborJ though, that waxing the tube should not be the first thing folks try when they have failures. The defects in production need to be worked on first. I do wax all my tubes, but I am biased. I had major chuffing with a Phil's spiral tube end burner. The next tube was waxed and the chuffing was gone.

I have before and after pictures of the thrust curves from my Acme, but I'll be dog-gonned if I can figure out how to get a picture from my computer to this post. Copy and paste doesn't work. I wish I was better with computers! The chuffing (on my rockets) corresponds to the increments.

http://www.pyrobin.com/files/run%2059%2C%201lb%20Wolter%20end%20burner%20with%20unwaxed%20Phil%20tube%20.750inch%2C%204hr%20paulownia%20BP.jpg

 

 

http://www.pyrobin.com/files/run%2060%2C%20same%20as%20run%2059%2C%20with%20waxed%20tube..jpg

EDIT: I figured out how to post the thrust curves I mentioned. The chuffing was very audible, as Run 59 implies

Edited August 17, 2016 by DavidF

[joeyz]

The tubes in the photos look like the fuzzy, pulpy tubes that some vendors offer. They're made with cheap paper, only a few layers, and poorly glued. I'm afraid you're going to find their uses to be pretty limited. You might try shaving the edges of your support so that they don't quite touch when tightened and use more pressure when pressing your fuel.

 

The page you referenced is outdated and I need to either remove it or modify it. Whoops!

 

I've never had a report of burn through in the 10 years I've been offering these. Neighbor, are you sure you were using my tubes? I've never offered a 4# tube.

 

These tubes been tested and retested by the experts and all have been surprised at their strength. There has been several lengthy discussions on Fireworking dot com using different fuels and pressures without any issues with the exception of side split when the support is removed with spongy whistle fuel. That problem was resolved by simply using a proper support and reducing the amount of pressure on the ram. SLD went so far as to report that these were the only tubes he would buy if he didn't already have a lifetime supply of NEPT.

 

There's no question that NEPT tubes are strong but they're also very expensive to produce and the tolerances vary from batch to batch.

Phil, got a better link? which one do i order? i have 1lb 3/4" Rocket tools. i would like 3 sets of your 3/4" ID, 1/8" thick tubes. do i select the .765 i see on your site? thanks.

[OldMarine]

Dave, how do you post the ACME results without them being low resolution? Mine looked like childhood scribbles last time I tried.

 

I've got a couple that are almost identical to your test #59.

Edited August 17, 2016 by OldMarine

[DavidF]

Haha, I just got lucky! I bet you posted yours on Fireworking.com? Whenever I post mine there they look like crap. I copy and paste, but that didn't work for me on this site. This time, I uploaded them to Pyrobin, and then copied the shortcut to show them here.

[NeighborJ]

David this is genius. It's getting the gears turning. I believe this also happens on parallel tubes as well. For the past month I've noticed that my end burners have needed very little compaction in order to compress them, in fact I've made 1# motors using body weight alone to press them except for the nozzle and bulkhead, I have never made such smooth burning reliable motors. This can only be done on endburners with super milled bp and ungranulated. I couldn't figure out why until now. I need to let this sink in a little.

[DavidF]

NeighborJ, the only time I ever experienced that strange chuffing was with that motor. I was testing Phil's tubes during the NEPT drought. The propellant was 75-15-10, milled. I've made and tested a few end burners, before and after. Never anything like this. I feel like I caught the essence of what was going on, but not sure I understand it completely.

[NeighborJ]

David when I was making chip board tubes, it had a large lip on the inside. When it burned the flame would "quick match" from increment to increment, only pausing when the flame front reached the compacted side of the increment. The result was not chuffing but a slight surge. I did not understand entirely what was happening.

When I only press with body weight the increments do not have this compacted side of the increment. The burn has been smooth and consistent.

And you are right about the spiral tubes having this same issue but more pronounced. The propellant would have a scouring action across the lip causing premature burnthru, this would not happen on the parallel tubes. The problems you've uncovered on this spiral tube appear to me a combination of two forces causing failure. First scouring accross , then surging due to that quick match effect. This problem is further exacerbated by the fact that when the fire follows this channel it will expose a lot more propellant because of a much longer channel between increments. So what might be a slight surge on a parallel tube becomes a repeated over pressurization (chuffing) with a spiral tube.

I'm not sure if I expressed the whole concept properly but it should be the main gist.

Disclaimer: the tubes theorized about in this hypothetical scenario are generic tubes with large interior, overlapping layers or troughs between layers.

Edited August 18, 2016 by NeighborJ

[Phildo]

Guys, can we differentiate between generic spiral tubes and the tubes I carry?

[dagabu]

Phil, can you take a quick pic of the interior of one of your tubes for us? I think the spiral trough is the "lip" being spoken of.

[NeighborJ]

Phildo I'm just trying to confirm that we are all understanding this concept the same. Your tubes are not suspect.

[DavidF]

Phildo, I already differentiated between your tubes and other spiral tubes in post #38.

 

" Those spiral tubes are not ideal for rockets. Phil's tubes are also spiral tubes. But, they are hard and strong as everybody agrees. The spirals are tight. I've used Phil's tubes for every kind of rocket I make, successfully."

 

Here it is again in case anybody missed it

[joeyz]

team, thanks for your guidance....

 

- ordered 3 sets of 3/4" ID, 1/8" thick tubes from phil. the shipping cost just as much as the tubes but its a start until i find a better solution.

 

- switching bp fuel 70/20/10 to my 1lb burner use only.

 

- made a new batch of 75/15/10 for my end burner nozzled 1lb. corrected moisture level to reduce dust and allow better caking/compacting.

 

- bought 4 blocks of parrifin wax. making a 2" x 10" pipe with cap so i can heat wax in it with propane torch and dip tubes to coat them.

 

- bought mag wheel polish to polish spindles.

 

- ordered press pressure guage, 10,000 pd from woodys. i originally submitted for 3,000 lb gauge but woody contacted me and recommended 10k one and stated thats what he uses on all his rockets so i i took his advice as a me being a novice.

 

- i need a rocket clamp tool, guess i have to make a 7.5" one, woody's $155 clam is just to far out of my ballpark. right now, using a pvc pipe with hose clamps on my 5" end burner cases.

 

going to do more expirements with rockets soon.

 

thanks.

Edited August 19, 2016 by joeyz

[joeyz]

white paper project....linked up with my neighbor thats a master mechanic in hydraulics. he repairs and builds hydraulics for cars. engineering a design bar push button press where the first button is a hopper dispenser (up side jar or bottle with neck but opens at top) that feeds 1 teaspoon in cat litter amount into a funnel. a dial would be cool to control amounts for different size motors. to where you place the tube under the bar, funnel end and fill it correct amount. second is a nozzle rammer, 3rd is another dispenser for bp, next two columns are other rammers. pressure system with inline gauge for correct amounts of pressure. engineering a dial or switches and indicators that says selection 1lb, 2lb, 3lb etc. going to start that project this fall. final system should make it fun to build rocket motors.

 

there are gun cartidge reload kits that have auto dispensers for relaoding shells, same concept here for cat litter and bp dispensers.

 

will post a diagram for you guys to see and correct concept. should be a low cost high efficient rocket press system.

Edited August 19, 2016 by joeyz