Tip to tip fiberglass

[aaronvanhorn]

The is a new process for me, and I have several questions. Since the fiberglass will be on the booster section (I am doing minimum diameter) will the epoxy be able to withstand the engine temps? What epoxy do I use for the fiberglass? Is the picture below the correct cloth to use?

thanks for the help!

 

[Orien]

I did my first tip-to-tip this year. I used the same cloth as you and this resin. Can't remember where I ordered it, but it worked great. Just remember, there's nothing you can mess up that can't be fixed with sanding. Have at it!

 

[Titan II]

https://www.rocketryforum.com/threads/doing-a-tip-to-tip-fiberglassing.169196/
https://www.rocketryforum.com/threads/tip-to-tip-or-not.167071/

 

[manixFan]

I’ve used System Three since I started in HPR over 20 years ago. It’s great stuff - you can buy one resin with different speed hardeners, as well as a variety of fillers. I ordered mine directly from their website. The other popular system is West System. Both work very well.

The big question is why are you doing tip to tip? Over the years I’ve found it is rarely needed if the fins are designed and built correctly. It’s a lot easier to fiberglass the fins before they are attached to the rocket.

Good luck!

Tony

 

[n3tjm]

I personally wouldn't recommend using that Bondo fiberglass. First it's heavy. Second, it's usually not in the best of shape when opening the package. Lots of fraying and "stretch marks". Also that fiberglass is on the heavy side. I usually order my finerglassing supplies from US Composites. Reasonability priced, they don't tightly pack the glass which can damage it.

Sometime early next year, I plan to order several yards of 4 oz glass, some 2" kevlar strap (anti-zipper bands), half a gallon epoxy resin, pumps, and some fiberglass sheers (pricy but worth it to be able to cut fiberglass without it falling apart), and maybe some rollers. Going to glass my 7.6" LOC/YANK Patriot.

 

[JimJarvis50]

If you can weigh the cloth that was provided in the package, you can calculate the weight per unit cloth in oz/yd2. A weight around 6 oz/yd2 is good for tip to tip, and a couple of layers or a 1/3, 2/3 pattern can be used. More than 10 oz is harder to work with.

Heat from the motor won't be a big deal, but you don't want the epoxy softening just due to the sun. An epoxy such as West shouldn't be used for that reason (a Tg around 120°F). Use an epoxy with a higher Tg. Aeropoxy is one, and there are many others.

Whether or not you need tip to tip depends a lot on the material used for the tube itself. Tip to tip helps to keep the fins on the tube, but more importantly, it keeps the tube from deforming. If you are using a fiberglass or carbon air frame, you might not need tip to tip unless the fin span is more than perhaps 3" or so. If the tube is cardboard or blue tube, then tip to tip will strengthen the tube itself.

Jim

 

[aaronvanhorn]

I’ve used System Three since I started in HPR over 20 years ago. It’s great stuff - you can buy one resin with different speed hardeners, as well as a variety of fillers. I ordered mine directly from their website. The other popular system is West System. Both work very well.

The big question is why are you doing tip to tip? Over the years I’ve found it is rarely needed if the fins are designed and built correctly. It’s a lot easier to fiberglass the fins before they are attached to the rocket.

Good luck!

Tony

Learning it for my Wildman mach 3 build

 

[Chris_H]

Probably do not need T2T.

Aeropoxy ES6209 with good prep,careful mixing, some adhesive fiber and colloidal silica, sufficient radius, and you should be good. Good prep. Accurate mixing. Careful about introducing too much solvent if you are using something like alcohol to lubricate the pulling. E6209 is a structural epoxy, not for cloth.

With a 75mm rocket with a reasonable fin design, stellar fin epoxy prep, and stellar epoxy execution, if your fins are ripped off during flight, the lesson might be as valuable as the rocket.

With your question about which resin to use.... definitely keep researching epoxy systems and how to use them.

Here is one of the online resources you will have crossed with sufficient research. I did not check to see if this is the 'part one' or the 'part two'. Find both.

https://www.raketenmodellbau.org/repository/archive/167792?view=true

 

[Kelly]

If you can weigh the cloth that was provided in the package

I've weighed that Bondo stuff, and it comes in at right around 6oz.

 

[JimJarvis50]

I've weighed that Bondo stuff, and it comes in at right around 6oz.

OK. If you mean 6 oz/yd2, that's fine. If you mean it's actually 6 oz, then the package says 8 ft2, which means 6x9/8=6.75 oz/yd2. That's fine too.

Jim

 

[tfish]

Tony

 

[Kelly]

OK. If you mean 6 oz/yd2, that's fine.

Sorry, I meant 6oz/yd²