Other solutions for keeping your nose cone weight in place.

[kuririn]

From the OP's posts on other threads I'm assuming we're talking low power here.
If I'm wrong then please forgive me.
So why make this more complicated than it needs to be?
Fill the cavity with PU foaming glue, let it cure overnight, problem solved.
KISS
Takes the same amount of time as using yellow glue, with the added benefit of locking the weight in place mechanically with the expanded foam if the adhesion should fail.
No brainer.
Rant over.

 

[BABAR]

Keep in mind that this will tend to tug on the weight at ejection, trying to pull it loose.

I thought about that. On the other hand, at launch the force is all going to be on the interface between the weight and the nose cone as well. I am thinking you need two attachments for the shock cord one for the nose cone and one to the nose weight

 

[jrap330]

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!!)


View attachment 422489 View attachment 422490

DR Wogz..thanks for explanation of Gorilla glue. I will try this in future. To Original poster, my Sizzler nose cone with 5 min epoxy and fishing weighs still is holding 10 years later. Again only time I tried weights.

 

[MALBAR 70]

I'll +1 Gorilla Glue. I've been using it for years to keep nose weight in place. Usually, I pour in the shot, hose in the GG and give it a little shake and tap to get the glue to the tip. Add little splash of water and in a couple of hours it'll have foamed up. I learned to let the nose cone sit for a day or two, just to ensure the glue has cured completely, I have had it ooze out and gum up the inside of a rocket. I have also, on one occasion had Gorilla Glue expand and burst the tip of the plastic cone (Estes Conquest) at the seam.

To the OP, I think you are overthinking the nose weight issue, there are LOTS of rockets are perfectly stable without any nose weight whatsoever, especially in low power.

 

[SecondRow]

I have also, on one occasion had Gorilla Glue expand and burst the tip of the plastic cone (Estes Conquest) at the seam

Why were you adding weight to the Conquest? Did you mod it or did the stock kit need more? I’m in the middle of building one right now.

 

[MALBAR 70]

The two pats of clay that come with the kit are sufficient, I was using the Gorilla Glue to hold in the supplied clay weight.
I think the seam on that particular cone was weak, I ordered a new one and it held up fine.
The Conquest is a great looking kit and, surprisingly, it flies excellent.

 

[School of Rock'et']

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.

I've been thinking of using this idea, only I have a 5:1 Ogive TWFG NC that forms aft towards the payload by a 7.75" diameter coupler. I'm wondering if only 2 nails will work as I have about 14.5 lbs of weight to add to my level 3 project. I suppose I could add more. Does the pml foam weigh anything significant as well?

 

[bjphoenix]

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.

I did something similar years ago- I had some spare 4" LOC parts so I built a real stubby 4" dia. rocket to use G motors. I stuck 3 roofing nails into the front part of the nosecone, I just drilled small holes and pushed the nails in. Then I poured in lead weight and epoxy. Now I have 3 small disks around the nose cone a couple of inches back from the point. On a 4" diameter nose cone they aren't very noticeable.
Even if a person wanted to use dowels or rod, cut and sand flush and putty the holes, this is still a lot less work than we typically put into balsa or plywood fins before painting.

 

[Bowman]

For Mid and High-power.
I don't try to secure weight into the forward part of the nosecone.

I bore a ~1/2" hole through the shoulder.
Using that I install a screw eye into the back and secure it with a fender washer and self-locking nut through the hole I bored.
Now I have a secure attachment point for the shock cord. Never had one fail in over twenty five years of doing it.

Next I add sufficient lead shot and round balls through the hole to achieve the weight I need. They're just loose at this point.
Finally I pour in sufficient epoxy to fill the shoulder to the depth of the shot, keeping the nosecone tilted so nothing runs out.
Lastly I put a piece of masking tape over the hole and stand the nosecone up until the epoxy cures. Then just pull off the masking tape.
The weight is now secured in the shoulder to the the threads on the part of the bolt that extends past the self locker nut and the nut itself by the epoxy. It is also the shape of the shoulder so even if it did come loose it could not move much because of the taper of the nosecone.
Yes I know the weight is not quite as far forward as it could be but the difference is negligible and compensated by going a tad over with the lead shot.

I've never had the weight come loose and never had a eye bolt pull out of the nosecone.

 

[DaHabes]

I've been thinking of using this idea, only I have a 5:1 Ogive TWFG NC that forms aft towards the payload by a 7.75" diameter coupler. I'm wondering if only 2 nails will work as I have about 14.5 lbs of weight to add to my level 3 project. I suppose I could add more. Does the pml foam weigh anything significant as well?

The foam can add some weight, but how much depends on how dense you make the foam, since it's variable density (I love the stuff and have used it several times).

I wouldn't use nails for 14.5 pounds, but you can use any sized metal rods you need to make it work (they are just a part of the weight needed, after all), and you could do a lattice (multiple rods at 90 degrees to each other) to provide a stable structure for the length of epoxy/weight you need in the nose cone. Just make sure you adequately design your recovery system for a NC has weighs that much. It will definitely come down nose first and the recovery system design needs to account for it.

 

[DaHabes]

For Mid and High-power.
I don't try to secure weight into the forward part of the nosecone.

I bore a ~1/2" hole through the shoulder.
Using that I install a screw eye into the back and secure it with a fender washer and self-locking nut through the hole I bored.
Now I have a secure attachment point for the shock cord. Never had one fail in over twenty five years of doing it.

Next I add sufficient lead shot and round balls through the hole to achieve the weight I need. They're just loose at this point.
Finally I pour in sufficient epoxy to fill the shoulder to the depth of the shot, keeping the nosecone tilted so nothing runs out.
Lastly I put a piece of masking tape over the hole and stand the nosecone up until the epoxy cures. Then just pull off the masking tape.
The weight is now secured in the shoulder to the the threads on the part of the bolt that extends past the self locker nut and the nut itself by the epoxy. It is also the shape of the shoulder so even if it did come loose it could not move much because of the taper of the nosecone.
Yes I know the weight is not quite as far forward as it could be but the difference is negligible and compensated by going a tad over with the lead shot.

I've never had the weight come loose and never had a eye bolt pull out of the nosecone.

Good method. I prefer the NC tip because for anything MPR and HPR, I cut off the shoulder, build a 2 piece bulkhead and use the NC for any tracking avionics (assuming either no AV-Bay or a traditional DD AV Bay). Keeping the tracking avionics separate from the metal rods in a traditional AV Bay is the primary reason.

 

[Back_at_it]

Lots of interesting methods and I'm sure I will use more of them someday. At point I have only used three methods. The first was the old clay in the nose cone. This simply doesn't work long term or in any kind of cold weather. Even on an A motor I've had this come loose on two rockets when flying in the cold.

Second method is the one that I use most often. If I can get to the inside of the nose cone I rough it up with sand paper. If I can't get in there then I pour rubbing Alcohol into the cone and use a bottle brush to clean it then let it dry. Next I mix BB's in 30 min epoxy and pour them in. I've heard that this might not work in every application but I have not had one fail even under G power. Even the notorious LOC cones that nothing seems to stick to has worked perfect with this method

The last was the foam method. I build a short almost Goonie style using a BT80 Super big bertha nose cone. The base of the cone was removed to give me a little more room in the tube so I had access to the back of the nose cone. I added my nose weight then used the old stand by "great stuff" to fill the void. Let that sit outside for a day then capped the bottom with a bulk head.