Fiberglass kit assembly question

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Well-Known Member
Jul 11, 2010
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In another thread I got some good guidance regarding my very tight fitting Aeropack adapter.

I have another question.

On the cardboard HPR rockets I have built, I extended the fin slot to the end of the tube, this way, I can remove the motor mount/fins before final assembly. This makes adding internal fillets much easier, since you have full access to the fin to MMT joint. Is there any reason not to do this?

...... I extended the fin slot to the end of the tube, this way,

I do it often on FB rocket.. If the space is too long, you can add a piece of coupler to the center ring, and then fill the slot with Bondo
Nope, no reason not to do it.
I do it nearly all the time. And if need be I add the coupler piece mentioned bt Q-Aero.
Great. Looks like I need to stock up on reinforced dremel cut off wheels. And ensure I have saftey goggles and dust mask. Fiberglass sure is nasty.
It's a matter of personal preference, but there 's a technique to get good internal fillets by injecting epoxy, and I've always used this method on fiberglass rockets rather than extending the slots.
Save yourself some money and stress and get one of these Dremel bits, they work equally well in FG, CF and cardboard and wood.

View attachment 319384

+1 for what Rich posted-works well on CF which eats everything else alive. I t cuts G-10 rather than melts it first-so everything is cleaner and you don't have to worry about structural degradation along the edges. FWIW-look for turkey flavor injectors during (or rather after) the holidays for injecting as mikec mentions. Most have metal tips you can cut off and inject thru a #30 hole. I usually pay about a buck a piece and then just toss 'em afterwards-look in your local Dollar Tree/99 cent/Dollar General discount stores and stock up. Easy-peezy injector! There is a lot to be said for sloting the fin can as you can control the mass a little better with the structural fillets. Straight smoke and good chutes!