Fin Alignment

On my first scratch build hpr I made a homemade tri fin alignment jig. Each section maybe wasn’t spaced perfectly at 120*, but was really close. On my second build, the Madcow Torrent, I didn’t use my jig after reading on the site that I bought it from that the pre-notched body tube would help align the fins. So, I trusted the slot to keep me perpendicular with the body tube and didn’t use my jig. Alas I don’t eyeball it look I should have and I didn’t notice after gluing my first fin that it was cocked to the side by a few degrees until the epoxy had already set. I ended up setting the last two fins the same way to keep all the fins at 120* with each other. I am wondering if you experienced builders use a jig for setting fins or just eye ball them, and if so which jig do you recommend? Maybe siting them in is close enough? Sometime I wouldn’t mind getting a more user friendly one than my homemade jig if necessary. Tks for advice

I use a jig for most. Payloadbay.com and you can print out your own, glue them to card stock and cut them out. Last night I did a 4 fins rocket, made a jig in about 10 minutes. Took heavy card stock, used the stock straight edge, cut out 2 pieces the same, glued a 2x4 on one part, then glued that to the other all the while I had it standing on a flat surface so they would align. Cut out a notch for my body tube, did not even have to the right size as the card stock holds the fins flat and aligns the body tube doing so. Out of breath now.

Low power rockets-angle iron, straight line, eye ball
Medium and high power rockets-3D fin alignment jig

Same as above. Go to payloadbay.com . Print-out a template. Tape it to foamboard, use a ruler to draw the fins to the right length (if needed). Carefully cut it out with a hobby knife. Literally only takes a few minutes.

I always use a guide. Actually, I always try to hold anything in place while the epoxy is curing to avoid coming back to a surprise.

Not that it matters much; I think your rocket will fly fine.

Like John said, it will likely fly fine... I did the same thing when I built my L1 rocket. I didn't tack the fin before I epoxied it and it shifted while the epoxy was curing. Most people would not even notice it unless they were looking for it. Rocket flies fine but I'm annoyed with my mistake.

I've used the payloadbay fin guide ever since. Nice thing is that you can make it once and use it a number of times. Just remember to cut notches to prevent yourself from glueing the guide to the rocket accidentally.

The problem with printing a jig, even tough it may be "perfect" does not necessarily mean it'll align with pre slotted tubes, which are rarely "perfect". I prefer to just transfer the pre existing slots to the jig material...

The Macklin Guillotine Fin jig is your best friend