"Stabilizing" a kraft body tube

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

jahall4

Well-Known Member
Joined
Jul 21, 2014
Messages
1,241
Reaction score
217
Excuse me if this has been asked many times before... Does anyone make a product to "stabilize" a body tube prior to construction?

By stabilize I mean at least make the tubes surface outside (and possibly inside) somewhat more durable and less susceptible to humidity
 
I sprayed the inside with clear lacquer or used sanding sealer.

Also sanding sealer on the outside, but usually whatever paint you coat with will have the same effect.

Edges that will contact couplers such a payloads that are removable or that receive the nose cone, I seal with thin CA and reach inside an inch or so and do same.
 
Excuse me if this has been asked many times before... Does anyone make a product to "stabilize" a body tube prior to construction?

By stabilize I mean at least make the tubes surface outside (and possibly inside) somewhat more durable and less susceptible to humidity

Once our models are painted they become pretty much weather resistant unless left hanging in a tree for a week or so or landing in a Pond or lake.

I have models that were made as much as 35years ago in the DC, Maryland High Humidity area without ever having a problem with susceptibility to our sometimes 80-90% humidity. Further my models are stored outdoors in an uncontrolled Shed.
I have a HUGE stock of raw Thin walled body tubes that stay in the same shed without any moisture absorbing problem over more then a decade. These are in fact Estes, Centuri and some Quest body tubes which may be different then what you are asking about. but even the heavier NCR and a few Loc tubes have not shown any unstable behavior.
 
Once our models are painted they become pretty much weather resistant unless left hanging in a tree for a week or so or landing in a Pond or lake.
I have models that were made as much as 35years ago in the DC, Maryland High Humidity area without ever having a problem with susceptibility to our sometimes 80-90% humidity. Further my models are stored outdoors in an uncontrolled Shed.

This is very good to know! Does the quality/source of the tubes make a difference? I ask because my rockets are a combination of Estes kits and scratchers built from recycled/garbage-picked tubes. If I can store them in an outdoor shed it will solve a few spouse-related problems for me ;)
 
Based on the posts so far it does not sound like a product exists for the purpose.

Unfortunately humidity in the Tennessee valley is a real problem for anything that can absorb moisture from the air… 80%, 90% humidity…. I wish that was all. It is quite common to have 100% humidity, in the mornings for several days in a row for much of the year. There are days in the summer where humidity and the temperature are too high to spray paint.

I would never store unpainted paper tubes outdoors here in Tennessee, no way, no how.
 
Based on the posts so far it does not sound like a product exists for the purpose.

Unfortunately humidity in the Tennessee valley is a real problem for anything that can absorb moisture from the air… 80%, 90% humidity…. I wish that was all. It is quite common to have 100% humidity, in the mornings for several days in a row for much of the year. There are days in the summer where humidity and the temperature are too high to spray paint.

I would never store unpainted paper tubes outdoors here in Tennessee, no way, no how.

Your Probably right. these isn't a specific product cause there isn't a Real Problem.
We had a solid week of 90-98% humidity just a few weeks ago. During that time it was in fact Way to humid to paint but that really doesn't effect tubes stored in their shipping box (2'x2'x4' heavy cardboard). Matter of fact I has to get a BT-55 from one of them to build a model finished on Saturday.

I'm still trying to understand why you think you have a problem in the first place. Have you had tube swell up or get soft from absorbed moisture? As mentioned in my previous post the ONLY time I've ever had an swelling or softening issue was when I put a model in the trees that stayed there through a rain storm or two, or splash down in a pond or lake. Shoot even one of those I managed to get the swollen spent motor casing out of and the model still flys today.

Most of the Mod-Roc manufacturers use glassine coated tubing. Perhaps that's why we've had absolutely no problem with moisture over the years.
 
Your Probably right. these isn't a specific product cause there isn't a Real Problem.
We had a solid week of 90-98% humidity just a few weeks ago. During that time it was in fact Way to humid to paint but that really doesn't effect tubes stored in their shipping box (2'x2'x4' heavy cardboard). Matter of fact I has to get a BT-55 from one of them to build a model finished on Saturday.

I'm still trying to understand why you think you have a problem in the first place. Have you had tube swell up or get soft from absorbed moisture? As mentioned in my previous post the ONLY time I've ever had an swelling or softening issue was when I put a model in the trees that stayed there through a rain storm or two, or splash down in a pond or lake. Shoot even one of those I managed to get the swollen spent motor casing out of and the model still flys today.

Most of the Mod-Roc manufacturers use glassine coated tubing. Perhaps that's why we've had absolutely no problem with moisture over the years.

If you are going to categorically dismiss the question, because you don't think it is about real problem them why did you even take the time to reply?

If there are others in this forum who are interested in my experiences with kraft tubes I'd be glad to go provide more detail, if not then there is no need for me to elaborate.
 
Lacquer sanding sealer is what I, and many use on Blue tube, which has very real, known humidity issues. What I use: https://www.idealtruevalue.com/servlet/the-15045/Detail?gclid=Cj0KEQjw4uSgBRDZveXz9M-E1aoBEiQA2RMP6k_xcc2h9XbKu2J7W1GfYGVb3_cY5LZPZmkx3xNiyvcaAg-I8P8HAQ

I have never used this on Estes or LOC tubes as I'm unaware of humidity being a real problem with them. If you have first hand experience of this I'd be very glad to hear about it. That being said Micromeister has probably build more models than a hundred other of us on this forum combined, if he hasn't seen it where he lives I can't imagine having a problem with it. However, I have been wrong before. Again, if you have examples I'd like to hear about it.
 
Hey new guy, don't let Micromeisters use of the royal "we" upset you; he's a pretty knowledgeble fellow :). Other than sealer and paint of your choice I do nothing special with rockets stored in the garage. And unlike many posters I don't have a big stash of raw tubes sitting around for any length of time. I don't think humidity conditions here are as difficult a yours. I guess we need some Tennessee Valley TRFer's to weigh in here to give you some better context.
 
First, there have been several comments referring to completed rockets, but my question was never about them. Second, humidity has become a focus of the thread, but only one potential source to “destabilize” the tube. I use that term to describe any undesirable change in the tube.

I have noticed 4 problems with the LOC tube I used in a build this past month:

1) The outer layer wanted to unravel some at the ends (not unexpected).
2) The integrity of the tube degraded during construction, not as rigid.
3) The outer layer became “not smooth” (hard to describe). This was the only one I thought might be attributed to the high humidity.
4) The tube became fuzzy.

None of these are unexpected, after all a paper tube, is well… made of paper, but after 30 years I thought there might be a product I was unaware of that could be used to prepare the tube prior to construction. The hobby has changed drastically (e.g. simulators and laser die cutters) there are construction techniques I’m trying today (e.g. webbed centering rings) that I never imagined as a kid.

I have dealt with all 4 of these issues using various techniques during construction or as part of finishing, but not prior to construction. So getting back to the original question asked in a different way…

What products and/or techniques do some of you use to prep a tube prior to construction?
 
I feel your pain.....

Living in Savannah Ga. where 95-100% humidity can last 30-45 days continuos , it devastates anything cardboard or paper based. Mildew will destroy stuff stored outside in shed or garage, not climate controlled,or the bugs will get it.

I stored a 7.5 in phenolic....yes phenolic rocket wrapped in carbon fiber in my shed. It was impossible to separate the parts.
After bringing inside the house [airconditioned], and checking every few days....2 weeks later I was able to get things separated.

On vacation for a month & sometime during my absence the AC quit. Upon my return & opening the front door I was in shock......my immediate reaction was...... who painted the stair rail white. It was THAT covered in mildew. It felt like a sauna inside my house.

Anything leather....chairs or belts, wallets etc in drawers were totally destroyed. It covered walls and ceilings, even got INSIDE my paintings hanging on the wall. Many of my AT and Estes rockets were like mush and covered in mildew....they were toast. I had Serv-Pro come and clean the house, even then there were many books & magazines that could not be fixed.....well they could at 75-100.00 @ that was just too much for me.

So I have had first hand experience with what you are speaking of.....just seems humidity down south carries lots of spores and fungus Northerners do not get. It can be devastating .

I switched to building mostly fiberglass or fiberglassed paper tubes since. Although I do have quite a fleet of Micro's and a few
estes kits still.

Now when I leave, I have a dehumidifier that gets turned on for back up......just in case.LOL
 
Wow! that's bad, can't even touch that here in the TN valley. Even northern KY where I grew up is much different than down here.

anyways...

What I'd like to do a spray (much like priming) a paper tube outside (and possibly inside) with a "surfacing agent" for lack of a better term that was:

1) Thin so it would penetrate the paper.
2) Sand-able (but the thinner it was the less I sanding would be a factor)
3) Glue-able (epoxy and CA must stick well)
4) Opaque (preferred)
5) Filler Primers (must stick well)

Typically I would apply to the whole tube before it was cut and slotted.

You (and others) mentioned using lacquer sanding sealer. How does lacquer based sanding sealer sand? Does epoxy have any issues sticking to it? What about filler primers?
 
Wow! that's bad, can't even touch that here in the TN valley. Even northern KY where I grew up is much different than down here.

anyways...

What I'd like to do a spray (much like priming) a paper tube outside (and possibly inside) with a "surfacing agent" for lack of a better term that was:

1) Thin so it would penetrate the paper.
2) Sand-able (but the thinner it was the less I sanding would be a factor)
3) Glue-able (epoxy and CA must stick well)
4) Opaque (preferred)
5) Filler Primers (must stick well)

Typically I would apply to the whole tube before it was cut and slotted.

You (and others) mentioned using lacquer sanding sealer. How does lacquer based sanding sealer sand? Does epoxy have any issues sticking to it? What about filler primers?

Have to admit those are the two worst humidity stories I've ever heard. My apologies if my earlier posts seemed to dis the problem. just never heard of anything that bad.
Can't really help you with your particular problem but perhaps others can.

Have used a far amount of Sanding Sealer over the years, just not for your intended reason. It's water thin with very light super fine filler solids. Sands very well on wood and outer tube surfaces but does not fill grain or seams without many coats.
Interior a Polybrush or mop might be the easiest way to apply. Smoothing inside there is always the old sandpaper rolled around a dowel trick, but man what a job that would be. Perhaps you'd only have to sand the interior at the forward end to fit the NC shoulder?
 
Last edited:
Have used a far amount of Sanding Sealer over the years, just not for your intended reason. It's water thin with very light super fine filler solids. Sands very well on wood and outer tube surfaces but does not fill grain or seams without many coats.

How does epoxy glues and primer fillers do over top the Sanding Sealer?
 
How does epoxy glues and primer fillers do over top the Sanding Sealer?

For epoxy I always scuff up any coating that is present. The best bond is the one that the adhesive can penetrate as deeply as possible into the materials. I wouldn't epoxy over any sealer/paint. As for primer, I use Rustoleum automotive primer, and it sticks great to the lacquer sanding sealer. I don;t see why other primers wouldn't work fine too.
 
How does epoxy glues and primer fillers do over top the Sanding Sealer?

Most any of the usual White, Yellow, Brown woodworking glues work well with Sanding sealer once roughed up with 120grit paper. CA's also but due to their brittle nature over time do not recommend CA as a primary adhesive unless it's for a very short life expected Competition model.

Normally I use epoxies for Fillets & larger MPR motor mounts Only. Have experienced no adhesion problems when applied to sanding prepared or Epoxy rivet method attachment surfaces.

As I've stated all over the forums. I use the Cheapest Auto Grey, Black & brown rattle can primers I can get my hands on. Currently .88/12oz can ColorPlace from Wal-Mart as well as quite a few others over the years. None have had any problem adhering to Sanding Sealer or Balsa Filler (higher Solids content for grain filling) prepared surfaces.
 
Most any of the usual White, Yellow, Brown woodworking glues work well with Sanding sealer once roughed up with 120grit paper. CA's also but due to their brittle nature over time do not recommend CA as a primary adhesive unless it's for a very short life expected Competition model.

Normally I use epoxies for Fillets & larger MPR motor mounts Only. Have experienced no adhesion problems when applied to sanding prepared or Epoxy rivet method attachment surfaces.

As I've stated all over the forums. I use the Cheapest Auto Grey, Black & brown rattle can primers I can get my hands on. Currently .88/12oz can ColorPlace from Wal-Mart as well as quite a few others over the years. None have had any problem adhering to Sanding Sealer or Balsa Filler (higher Solids content for grain filling) prepared surfaces.

Thanks very good to know...

At this point I'm considering a specific process for "stabilizing" paper tubes not glassed:

Prep
1) Storing them in an environmentally controlled area until...
2) Spraying them outside (and possibly inside) with a thin sanding sealer.
3) Spraying them with a filler primer following spiral and obvious defects.
4) Sanding and reapplying filler primer as necessary to hide spiral and other defects. Essentially sanding back down to sealer to keep tube as light as possible.

Construction
5) Cutting to length and other modification (e.g. slotting)

Any one else perform a similar procedure?
 
Most any of the usual White, Yellow, Brown woodworking glues work well with Sanding sealer once roughed up with 120grit paper. CA's also but due to their brittle nature over time do not recommend CA as a primary adhesive unless it's for a very short life expected Competition model.

Normally I use epoxies for Fillets & larger MPR motor mounts Only. Have experienced no adhesion problems when applied to sanding prepared or Epoxy rivet method attachment surfaces.

As I've stated all over the forums. I use the Cheapest Auto Grey, Black & brown rattle can primers I can get my hands on. Currently .88/12oz can ColorPlace from Wal-Mart as well as quite a few others over the years. None have had any problem adhering to Sanding Sealer or Balsa Filler (higher Solids content for grain filling) prepared surfaces.


I had to switch away from the cheap primers that WallyWorld has. 3-4 years ago the quality was good, lots of solids in the paint. Over the years the paint has turned to crap, not enough solids to do a good paint job. Thinner is cheaper than solids and that's what they did to increase profits instead of simply raising a few cents to cover the cost of making a better paint. I don't want to shoot primer in 2-3 coats when 1 is enough with good paints. I'm using Rustoleum 2X all the way now, best stuff in a can right now. Yeah at $3.77 a can it's a bit spendy but they have 4 primer colors, 4. White, gray, red, and black primers, you got the perfect undercoat for just about every color then. Flip side to this a thin primer will soak much deeper into the wood, adding toughness. Paints like Rustoleum do soak in a bit but nothing like the thinner primers.

Maybe the trick is to shoot the cheap primer first, sand and follow with a second coat of Rustoleum for leveling purposes. I know the 2X paints hang heavy on the rocket but they give good coverage.
 
I don't have a humidity problem in this dry climate, but I've used this on MDF items I've built to toughen their surfaces and water-proof them (from spills, not immersion):

https://www.homedepot.com/p/Deft-1-...-Wood-Finish-Brushing-Lacquer-01004/100142803

It easily soaks right into the MDF producing a very evenly shaded darker surface that looks great and is fully sealed against water spills.

It would probably soak even more easily into kraft paper tubing, used on the inside surface of a built rocket, at least as far as your arm can reach into a 3.9" ID airframe since this stuff is brushed on. Added weight would certainly be a result, but it might have an added benefit beyond humidity-proofing of strengthening the tubing and producing a lower friction surface for recovery system ejection.

Coating FLAMMABILITY due to ejection charge gases and embers might be a problem. I'll be testing the weight gain and coating flammability on a short (scrap) length of 4" paper tubing.
 
I'm using Rustoleum 2X all the way now, best stuff in a can right now.
Same here. Switched over to it completely. Some nice very bright colors have been introduced just recently. For anything other than priming, however, the spray volume is pretty high. I have to laugh at their "multiple light coats" instructions. Yes, multiple coats, but not what I used to think of as "light." If your nozzles clog which some have complained about here but which I've only had a problem with with the clears, go to their web site, send them feedback complaining about it happening multiple times (as it did with me and the clears), and they'll send you a bunch of replacement nozzles for free, I think it was 24 in my mailer.
 
I have noticed 4 problems with the LOC tube I used in a build this past month
I recently bought a 4" LOC coupler that was noticeably and considerably lighter and flimsier than another one I'd bought several months back. I measured it and confirmed that impression. It was too thin in my opinion. If I ever get another one like that, I'm returning it and providing the weight and wall thickness measurements in an email to LOC. I hope this and your issues aren't the result of some change in their paper product supplier(s) or that supplier's quality control. If it is, it is not acceptable.
 
This is a weird but cheap one. I have seen people use panty hoes that act as a fabric sock. slide it over the tube and coat with resin the strengthen and coat it.
 
I don't have a humidity problem in this dry climate, but I've used this on MDF items I've built to toughen their surfaces and water-proof them (from spills, not immersion):

https://www.homedepot.com/p/Deft-1-...-Wood-Finish-Brushing-Lacquer-01004/100142803

It easily soaks right into the MDF producing a very evenly shaded darker surface that looks great and is fully sealed against water spills.

It would probably soak even more easily into kraft paper tubing, used on the inside surface of a built rocket, at least as far as your arm can reach into a 3.9" ID airframe since this stuff is brushed on. Added weight would certainly be a result, but it might have an added benefit beyond humidity-proofing of strengthening the tubing and producing a lower friction surface for recovery system ejection.

Coating FLAMMABILITY due to ejection charge gases and embers might be a problem. I'll be testing the weight gain and coating flammability on a short (scrap) length of 4" paper tubing.
Results of the application of a single coat of the above to the inside of 4" LOC paper tubing:

1. 4% increase in weight
2. Noticeable increase in tube rigidity
3. Rougher surface upon drying, like very bad sandpaper with very widely spaced sand grains; easily removed with 320 grit sandpaper; second coat would probably provide friction-reduced surface for recovery components
4. Flammability test: no noticeable increase; 5 second butane flame at various angles produced only the very beginnings of charring.
 
Interesting, that sounds like a good way to provide more life for sliding surfaces made from paper tubing (couplers, BT ends).
I was aiming more at a solution to the OP's paper tubing humidity issue with the possible added benefit of lower friction for deployment components. However, when it comes to two surfaces treated with lacquer sliding against each other, I have noticed in cases where I've slid two spray-can lacquer treated paper surfaces against each other that there was definitely some "stiction" whereas the softer paper surfaces slid smoothly over each other. It probably has to do with how hard the resulting lacquer coating surface is with the more "plastic" varieties having that problem, so other brands/types might work better.

To be safe, on couplers used, for instance, to hold an ejected payload section in the lower airframe tube, I only treat the coupler with spray-on lacquer and reinforce the leading edge of the lower airframe tube with soaked-in CA sanded smooth. The coupler is sanded to slide smoothly and evenly within the lower tube. The aim of treating the coupler is to achieve greater dimensional stability from avoidance of moisture absorption and provide greater abrasion resistance. Plus, it looks very professional.
 
Back
Top