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Other solutions for keeping your nose cone weight in place.

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Senior Space Cadet

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Finding something to use for a nose cone weight is pretty easy. Clay, BBs, lead shot, etc.
Getting it to stay in place is the problem. If the weight comes loose on liftoff, that's a problem.
A possible solution, for some nose cones, is to fill in the space behind the weight with something low mass, like foam, thus preventing the weight from moving back.
Some of my nose cones are two piece. One piece being a cup shaped base. Apogee make ejection plugs that will fit perfectly into some sizes. You could make your own from blue foam insulation.
Another possible solution is spray foam insulation. An issue there might be that it needs exposure to air to dry.
I'm guessing you can buy small Styrofoam balls, that you might be able to drop through a hole in the back of the nosecone, then seal the hole.
Point is, if your nose cone has a cap, on the back, you just need to find something light to fill the void between the weight and the cap.
 

Nytrunner

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Many rocketeers like to use two-part foam either in the nosecone volume, or in their through-the-wall fin units. The two-part will cure wherever it is once its mixed, unlike the spray foam that van remain gooey forever if ita in an enclosed area
 

lakeroadster

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I tend to build short rockets that need a lot of ballast to be stable. What works well for me is to make my own wood nose cones and for ballast I drill and tap the nose cones, then use a bolt for ballast.

You simply calculate the diameter and length of the steel mass you need, then proceed accordingly.
 

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dr wogz

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the most common method for securing lead shot nose weight in lager NCs it so to drill a hole or two thru the near tip of the NC. The hole will fit a dowel. Insert dowel, then mix epoxy or whatever glue-du-jour and the required mass of shot, then pour in. once cured, cut / trim / sand the dowels to the surface of the NC. presto! weight secured to the NC..
 

o1d_dude

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the most common method for securing lead shot nose weight in lager NCs it so to drill a hole or two thru the near tip of the NC. The hole will fit a dowel. Insert dowel, then mix epoxy or whatever glue-du-jour and the required mass of shot, then pour in. once cured, cut / trim / sand the dowels to the surface of the NC. presto! weight secured to the NC..
I frequently use bamboo skewers for that purpose.

Same concept, different method of execution.
 

Senior Space Cadet

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the most common method for securing lead shot nose weight in lager NCs it so to drill a hole or two thru the near tip of the NC. The hole will fit a dowel. Insert dowel, then mix epoxy or whatever glue-du-jour and the required mass of shot, then pour in. once cured, cut / trim / sand the dowels to the surface of the NC. presto! weight secured to the NC..
I'm aware of this method, and it sounds great, and if I were going for 20,000 ft. or something, that's what I'd do, but it doesn't sound that easy. Drilling the hole in a hard, curved surface doesn't sound easy. Gluing the dowel in place and sanding it flush doesn't sound that easy. Getting just the right amount of BBs and epoxy doesn't sound easy.
What sounds easy is to keep adding putty or clay, till the rocket balances at the right point, them putting something like foam or balsa behind it so it can't move back.
 

o1d_dude

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As @Nytrunner said, two part expanding foam is also a method that doesn’t involve drilling, skewers or dowels, etc. and has been used by many builders. Just don’t use insulation foam. Use the two part stuff.

In the words of JFK, “We do these things not because they are easy, but because they are hard.”
 

Senior Space Cadet

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I tend to build short rockets that need a lot of ballast to be stable. What works well for me is to make my own wood nose cones and for ballast I drill and tap the nose cones, then use a bolt for ballast.

You simply calculate the diameter and length of the steel mass you need, then proceed accordingly.
I'm not set up to make my own nosecones. It sounds like Balsa Machining is a good source, but they don't give a lot of info. It's not that easy for a novice to figure out what to order. I ordered some balsa nosecones from some other company. They weren't as cheap, though not bad, and I wasn't happy with some of the cones.
I've also considered using a balsa nose cone as the thing I put behind the weight in a plastic nose cone. Sand it down a bit and cut off the tip for a perfect fit.
I'm not seeing that many photos, on this forum, of rockets with parabolic (rounded) nose cones. Seems like you are one of the few that uses them. An aesthetics thing? I'm not fond of the look either and they are hard to find in anything but balsa, but the superiority of the aerodynamics, in a subsonic rocket, is hard to deny. As a compromise, I've been ordering short ogive nosecones.
 

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As @Nytrunner said, two part expanding foam is also a method that doesn’t involve drilling, skewers or dowels, etc. and has been used by many builders. Just don’t use insulation foam. Use the two part stuff.

In the words of JFK, “We do these things not because they are easy, but because they are hard.”
Good comeback. A challenge is good. A lot of nosecones, like the ones I ordered for my 33mm rockets, make the putty and foam method nearly impossible.
 

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Many rocketeers like to use two-part foam either in the nosecone volume, or in their through-the-wall fin units. The two-part will cure wherever it is once its mixed, unlike the spray foam that van remain gooey forever if ita in an enclosed area
I used two part foam to make a floatation chamber on the boat I built. I can't remember, but doesn't it get really hot, like epoxy? I've been reluctant to use epoxy in my nosecones, for fear of melting the nosecone. Apogee suggest setting the nose cone in water, while it cools. I'm going to have to try it pretty soon.
If you have an airbrush, you might try two part paint. I used it on the exterior of my boat. Tougher than regular paint. Not very cheap, though.
 

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Senior, the stick method is easier than you think / make it out to be.
  • you re drilling into plastic. drill at least one hole (two usually) near the tip, thru the NC. it doesn't have to be precise, at 90°, etc..
  • push the dowels skewers, twigs into the holes.
  • you know how much shot to add because you calculated how much you need. Weigh out what you need. You then add epoxy to your mixing cup & mix. then put teh mixing cup on the scale and add shot until you reach your desired weight (minusing the cup of course..)
  • pour epoxy / shot mixture into the NC.
  • Tap down
  • set aside to cure
  • sand dowel ends flush..
  • paint
 
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kuririn

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For low power I use original Gorilla glue and a few drops of water.
After a few hours it foams up and dries solid.
I've done about 8 nose cones and still have 2/3rds of the bottle left.
Cheap, easy and effective.
0628200454[1].jpg0628200454a[1].jpg
 

tOD

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I used two part foam to make a floatation chamber on the boat I built. I can't remember, but doesn't it get really hot, like epoxy? I've been reluctant to use epoxy in my nosecones, for fear of melting the nosecone. Apogee suggest setting the nose cone in water, while it cools. I'm going to have to try it pretty soon.
If you have an airbrush, you might try two part paint. I used it on the exterior of my boat. Tougher than regular paint. Not very cheap, though.
I've used the two part foam from PML in nosecones. It does get hot as it cures. I suspend the cone in a glass of water. It cures pretty fast, so no need to keep it submerged for long.
 

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kuririn

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Never really used gorilla glue before. How much of a volume increase?
Sorry, can't give you an actual number or %.
But take a look at post #7 in the thread below to get some idea.
I just go by feel and add more later if needed.
 
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BABAR

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Wow, I never thought of adding water to make it cure faster. Thanks!
Gorilla glue won't cure without water actually. Gorilla glue in an enclosed space in a dry climate won't cure much at all. I've also used it to attach a BT/CR inside a plastic nose cone to provide more space inside a small rocket. Probably only good at LPR weights/loads though.
 

jrap330

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I'm aware of this method, and it sounds great, and if I were going for 20,000 ft. or something, that's what I'd do, but it doesn't sound that easy. Drilling the hole in a hard, curved surface doesn't sound easy. Gluing the dowel in place and sanding it flush doesn't sound that easy. Getting just the right amount of BBs and epoxy doesn't sound easy.
What sounds easy is to keep adding putty or clay, till the rocket balances at the right point, them putting something like foam or balsa behind it so it can't move back.
Again..overthinking it...if you do not care about altitude..than put more weight via BB's and epoxy than required. Clay is expensive (Estes procure source). Forget about getting to the gram.....or fractions of an ounce. Use whole ounces as you guide. Again plan epoxy is heavy..you can weight it before putting it into nosecone.
 

neil_w

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For routine LPR flying, the clay is sufficient. Everything else is overthink.

Still awaiting an ORK file to see why so much nose weight is actually needed on a scratch design.
 

dr wogz

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Or if something else can be added instead of 'nose [dead] weight' (like: larger fins, more fins, a longer BT, or.. assuming the design is open to refinements to make it all "useful")
 

jrap330

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Thank you Neil and DR Wogz......this whole tread has gone overboard.
 

dr wogz

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Gorilla glue is a polyurethane glue. it needs water to activate (it says to spray one side with water to ensure bonding)

And, just so everyone knows, "Gorilla" glue isn't perfect either. (This is LePage's version: a Polyurethane glue; a Canadian manufacture of glues) This is a few ounces that came loose one flight (after a few). It was the weight in my Binder 2.6" Aurora. I've since gone with the shot, epoxy & dowel method. And yes, I didn't really sand the inside all that much..

(We really, as a collective, need to pressure our kit makers to use something other than whatever Poly plastic they use to make NC. Glues & paints never really stick!!)


20200123_180607.jpg 20200123_180520.jpg
 

kuririn

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The reason the drilled holes/dowel/epoxy method was devised was because most adhesives, including epoxy, will not stick to some plastics, like HDPE (polyethylene). If you just fill it with weight and pour glue on top it will eventually fall off. Usually during boost.
Clay, wood glue, epoxy will not stick to it, and you cannot scuff it up if it's inside the nose cone.
Using Gorilla glue with a little water will mechanically lock the weight in place so even if the adhesion fails the foam will keep it in place. This is true for low or high power. Just make sure the foam fills the cavity.
This is not overthinking. It is a cheap, easy and effective way to lock your weight in place.
 

mpitfield

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Drilling a hole horizontally through the tip of the nosecone, inserting a piece of brass rod, and pouring mixed epoxy with lead-shot works well. It is a bit more work but the weight will not move and the brass rod can be filed level, filled and painted as if it was never there.
 
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kuririn

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Here's an Apogee video of the method referred to by dr. wogz and mpitfield:
 

BABAR

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Seems like while you are gluing you nose weight it place it would make sense to attach a kevlar loop to a washer and shove it into the tip with your BBs or fishing weights or whatnot.

Run this out the middle. And use it as a dual attachment to shock cord along with whatever your other nose cone attachment site is. Redundancy is usually a good thing.

To my knowledge polyurethane glue doesn't degrade kevlar. I have read that CA does.
 

Mike Haberer

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I drill holes in the nose cone to insert 2 nails at 90 degree angles to each other (we're adding weight, right? why use sticks?). I use Rocksim to sim out how much weight I need for the biggest motor I think I'll use so I get 1 caliber separation between the CP and CG, weigh out 80% of that weight in BBs and 20% in epoxy. Mix, pour, let set. Trimming the nails off is easy with a Dremel (everyone should have a Dremel). Trim them a little deep, fill with spot putty and sand. I do this rather than PML expanding foam because on birds 2.6" and bigger, I fashion my own two piece bulkhead so I can use an Eggfinder in the nose cone; otherwise PML foam is the bomb.
 

neil_w

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Seems like while you are gluing you nose weight it place it would make sense to attach a kevlar loop to a washer and shove it into the tip with your BBs or fishing weights or whatnot.
Keep in mind that this will tend to tug on the weight at ejection, trying to pull it loose.

To my knowledge polyurethane glue doesn't degrade kevlar. I have read that CA does.
CA wicks into the Kevlar and makes it hard, not what you want in your shock cord.
 

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