Fin slots

[Jonsayler]

Hi Guys,

I just received a fiberglass rocket and everything is tight fitting! I can’t even get the nose cone coupler in. Has anyone used a dremel to open up the fin slots and if so what attachment did you use?

TIA

 

[David Schwantz]

I have worked with glass for a long, long time. I would not use a dremel on the slots. I like to use an emery board, sanding stick of some sort. Dremel is to easy to mess up with. You can get emery boards at Walmart in the nail section. That is in nail polish for girls section. For the NC shoulder, wrap a strip of sandpaper around the shoulder and use a back and forth motion.

 

[user 30299]

I have worked with glass for a long, long time. I would not use a dremel on the slots. I like to use an emery board, sanding stick of some sort. Dremel is to easy to mess up with. You can get emery boards at Walmart in the nail section. That is in nail polish for girls section. For the NC shoulder, wrap a strip of sandpaper around the shoulder and use a back and forth motion.

I "2nd" those suggestions. Emery board is perfect for the fin slots.

 

[Jonsayler]

Great suggestion thank you!

 

[Rocket86]

I like to sand just one side of fin slots, so there is always a true factory surface to align the fins.

 

[mtnmanak]

All good suggestions. If you want something that will last forever and be usable on any size FG rocket you ever work on, check out perma-grit hand tools. You can get them from Aircraft Spruce. They are not cheap, but, like all good tools, they are a sound investment.

https://www.aircraftspruce.com/catalog/topages/permagrithnd.php?clickkey=13743
I have pretty much a complete set of every hand tool and sanding block they make. I have never regretted the purchase and I have never had to replace a single tool yet.

 

[David Schwantz]

I have had some of their rotary files for 20 years.

 

[Handeman]

I use a Smooth Cut 10" flat file to file one side of each slot as @Rocket86 said. It cuts through fiberglass quick, but not as fast as a Dremal can if you mess up with one of those.

 

[K'Tesh]

I like to sand just one side of fin slots, so there is always a true factory surface to align the fins.

And it's important to be consistent... Personally, I always use the left side (based on nosecone end being up) as my factory edge... Left as in "left alone". This way will help keep your fins aligned. If you don't, things can go "willy-nilly" pretty easily. Just don't ask me why I know this.

 

[SolarYellow]

I use a Smooth Cut 10" flat file to file one side of each slot as @Rocket86 said. It cuts through fiberglass quick, but not as fast as a Dremal can if you mess up with one of those.

Unfortunately, Nicholson has been competing in the downward spiral of lower cost. File production moved from 'murica to Mexico, then to Brazil. I haunt surplus and old tool sales looking for the good old ones. The cheapened ones (and they are less good, not just cheaper) still work, but not as well as they used to.

 

[OverTheTop]

Remember to wash all the fiberglass parts before you put your tools onto them. The mold-release gets onto the tools and gets spread around, potentially weakening bonds.

https://www.rocketryforum.com/threa...our-government-doesnt-want-you-to-know.58389/

 

[Biodragen]

No Dremel tool needed. I have used tongue depressors or popsicle stick with sandpaper. Home made emery board in a pinch.

 

[Dan Griffing]

Hi Guys,

I just received a fiberglass rocket and everything is tight fitting! I can’t even get the nose cone coupler in. Has anyone used a dremel to open up the fin slots and if so what attachment did you use?

TIA

I used a 2” x 2” square of 100 grit sandpaper.

I’d echo the word of caution that it’s real easy to take off too much and have the fins loose.

And I used foam core board to make fin profile templates to hold the fins in alignment after tacking them to the motor mount with epoxy.

 

[rharshberger]

I used a 2” x 2” square of 100 grit sandpaper.

I’d echo the word of caution that it’s real easy to take off too much and have the fins loose.

And I used foam core board to make fin profile templates to hold the fins in alignment after tacking them to the motor mount with epoxy.

Foamboard combined with the Payloadbay.org printouts glue to it are awesome fin guides and cheaper than 3D printing them.

 

[Handeman]

I used a 2” x 2” square of 100 grit sandpaper.

I’d echo the word of caution that it’s real easy to take off too much and have the fins loose.

And I used foam core board to make fin profile templates to hold the fins in alignment after tacking them to the motor mount with epoxy.

Dan, you look way too enthusiastic as you're wrapping that pull cord around those fins!

 

[Dan Griffing]

Dan, you look way too enthusiastic as you're wrapping that pull cord around those fins!

My 29 year old daughter was visiting from Seattle and was taking pictures for my L3 construction document.

My enthusiasm is because I really like working in my shop to build rockets.

 

[Dan Griffing]

Foamboard combined with the Payloadbay.org printouts glue to it are awesome fin guides and cheaper than 3D printing them.

Thanks. This is the third rocket I've used Payloadbay.org printouts glued to foam core board for fin alignment.

 

[waltr]

Foamboard combined with the Payloadbay.org printouts glue to it are awesome fin guides and cheaper than 3D printing them.

Yes, I use these on most of my build.
And when the fins are thru-wall, which does the axial alignment, these fin guides simply ensure the fins are square.