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Fiberglassing a Balsa Nose Cone

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Estimado

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Hello All,
I would like to apply a light 5/8 glass weave cloth to a balsa nose cone of a Cosmodrome Nike Smoke using finishing epoxy. since most of my experience is with fiberglassing fins, I am new to doing this with a conical (a very pointy one at that !) surface. One thought I had was to make a template by rolling the cone on a flattened piece of putty in one full revolution in order to use the impression to make a pattern. I would then use the pattern to assist in cutting the glass cloth and placing it fully around the cone's surface. I will tack it down with a glue stick prior to applying the finishing epoxy.

Is there another way to make a pattern, and apply glass cloth to a balsa nose cone, that will result in an the most optimum smooth finish?
 

cosmodrome

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You could use the template that I include with the kit. Trace the template on a big piece of paper, extend one end to a point and the other end maybe 2-3 inches. Cut out the new template and wrap it around the cone to make sure that it is correct. When you wrap the glass around the cone, move it up or down to get the right amount. Slide the glass up if the cut was too narrow and down if not enough. If you need a new template it can be found at: http://www.cosmodromerocketry.com/Instructions/NikeSmoke/instructions_NS.pdf

Let me know if this helps.
 

stantonjtroy

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There are a couple of options available to you.
To utalize the glass gloth you have, you can cut triangles and apply them in sections. There are three major advantages to this method. It gives you multiple smaller pieces which are easier to work with and if you mess up with one, chances are it won't effect the others. Smaller pieces mean less chance of wrinkles and bubbles. Finally (and most importantly) this method keeps the bias of the cloth weave lined up (more or less) in the same direction which improves the strength where rolling it around the cone will change it with each degree. This is done by taking the circumfrence (max diamiteter) of the cone and deviding it by the number of triangles you want to use ( 3 or 4 is useally enough). Add a half inch for working overlap. This will be the base of the triangle. Take the length of the cone and add a half inch. this will be the height of the triangle. An equalateral triangle using these dimentions will be your pattern. Align the pattern with the cloth so the bias runs 45 degrees to the base. this will give good strength and allow the cloth to better conform to the cone. Lay up as you normaly would from here.
The second method involves using tubular cloth. It is available in different size ranges. Check here: http://www.sollerpaddles.com/composites/carbon fiber sleeves.html#fiberglass and http://www.cstsales.com/braided_glass_sleeve.html .The Cosmodrome Nike Smoke has a max cone dia of just under three inches so you'd want a 3" max expansion sleeve. Open it to it's max dia; Slide the cone in then pull the ends tight. Wet out as usual. Due to the long taper of the Smoke cone, two different sizes may be needed or cut wedges in the fabric as you near the tip. The advantage of this method is it eliminates, or at least reduces, the number of seams and keeps a more continual glass thread which improves strength and is easier to fair and finish. Best of luck.
FWIW
 

Estimado

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There are a couple of options available to you.
To utalize the glass gloth you have, you can cut triangles and apply them in sections. There are three major advantages to this method. It gives you multiple smaller pieces which are easier to work with and if you mess up with one, chances are it won't effect the others. Smaller pieces mean less chance of wrinkles and bubbles. Finally (and most importantly) this method keeps the bias of the cloth weave lined up (more or less) in the same direction which improves the strength where rolling it around the cone will change it with each degree. This is done by taking the circumfrence (max diamiteter) of the cone and deviding it by the number of triangles you want to use ( 3 or 4 is useally enough). Add a half inch for working overlap. This will be the base of the triangle. Take the length of the cone and add a half inch. this will be the height of the triangle. An equalateral triangle using these dimentions will be your pattern. Align the pattern with the cloth so the bias runs 45 degrees to the base. this will give good strength and allow the cloth to better conform to the cone. Lay up as you normaly would from here.
The second method involves using tubular cloth. It is available in different size ranges. Check here: http://www.sollerpaddles.com/composites/carbon fiber sleeves.html#fiberglass and http://www.cstsales.com/braided_glass_sleeve.html .The Cosmodrome Nike Smoke has a max cone dia of just under three inches so you'd want a 3" max expansion sleeve. Open it to it's max dia; Slide the cone in then pull the ends tight. Wet out as usual. Due to the long taper of the Smoke cone, two different sizes may be needed or cut wedges in the fabric as you near the tip. The advantage of this method is it eliminates, or at least reduces, the number of seams and keeps a more continual glass thread which improves strength and is easier to fair and finish. Best of luck.
FWIW
Mike and Troy,
Thank you both for your replies. I will try your suggestions and see how it turns out
Rich
 

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