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  #1  
Old 07-20-2011, 02:15 AM
Dr.Jeckyl Dr.Jeckyl is offline
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Default Almost perfect fin alignment

I was sitting at my hobby desk trying to figure out a way to get all my fins in alignment to each other on my Quest Harpoon AGM kit# 3008 when I realized I had some scrap balsa I could use. With that and the clips from the Estes fin jig I thinks it's a pretty good idea. The results are better than freehand that's for sure.


I'm horrible with descriptions so I'll let my pictures do the talking.
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  #2  
Old 07-20-2011, 04:44 AM
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Nicely done!
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Old 07-20-2011, 07:50 AM
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Good thinking! I used a similar method on my last high power rocket with split fins. Only I used pieces of aluminum angle as the guides. For the large lower fins, I used one of my homemade fin alignment jigs.
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Old 07-20-2011, 10:04 AM
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Nice job...

Yep been using that trick for awhile myself... I bought some light aluminum angle and cut it in 1 and 2 foot pieces for tube marking purposes and it's a nice backup for that sort of thing, or balsa, or a ruler... usually use clothespins for clamps. Works like a champ.

I don't bother with fin alignment jigs. I prefer four fins, and use an "L" shaped piece of balsa scrap, or a mini-carpenters square (thin steel "L" shaped 90 degree tool I picked up somewhere along the line) and use double glue joints to attach the fins in opposing pairs, one pair at a time, and then put the "L" shaped piece over the end of the rocket like a "V" and using clothespins clamp it to the opposing fins-- holds them perfectly aligned to each other while the glue dries, making them perfectly straight to each other. If the fins are swept back behind the body tube, you can do the same thing using a ruler or flat balsa strip like you did here, going across the aft end of the tube (assuming the motor mount isn't sticking out too far... that's why the "L" is nice...

Later! OL JR
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Old 07-20-2011, 01:21 PM
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Quote:
Originally Posted by luke strawwalker
I don't bother with fin alignment jigs. I prefer four fins, and use an "L" shaped piece of balsa scrap, or a mini-carpenters square (thin steel "L" shaped 90 degree tool I picked up somewhere along the line) and use double glue joints to attach the fins in opposing pairs, one pair at a time, and then put the "L" shaped piece over the end of the rocket like a "V" and using clothespins clamp it to the opposing fins-- holds them perfectly aligned to each other while the glue dries, making them perfectly straight to each other. If the fins are swept back behind the body tube, you can do the same thing using a ruler or flat balsa strip like you did here, going across the aft end of the tube (assuming the motor mount isn't sticking out too far... that's why the "L" is nice...

Later! OL JR


What I like about the fin alignment jigs, either the Estes version or my homemade version, is that they square the fins to the body tube, and also keep them in line with it. No matter if you have three or four fins. As far as I can tell from your description, with your method the fins get squared to each other, not the body tube. If one fin is out of line, the opposite one will be too.
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Old 07-20-2011, 03:00 PM
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Good idea. I have two unrelated questions:

1) Is the BT of your 'poon partially crushed?
2) Why is your mat so clean? I don't see any coffee and/or whisky rings, paint drops, glue smears, cuts, or stains from blood or tears. What's your secret?
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  #7  
Old 07-20-2011, 03:09 PM
Dr.Jeckyl Dr.Jeckyl is offline
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Quote:
Originally Posted by jeffyjeep
Good idea. I have two unrelated questions:

1) Is the BT of your 'poon partially crushed?
2) Why is your mat so clean? I don't see any coffee and/or whisky rings, paint drops, glue smears, cuts, or stains from blood or tears. What's your secret?



1: Yes. Just a tiny bit. I didn't notice it until I took it out of the bag. Must have been a careless person at the hobby shop I got it from.

2: I'm just neat that way. My hobby desk is pretty tiny so it gets cleaned after each step in the build. I also put down scrap paper when I glue/paint to keep it off the mat since they're so expensive.
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Old 07-20-2011, 03:11 PM
Dr.Jeckyl Dr.Jeckyl is offline
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Quote:
Originally Posted by luke strawwalker
Nice job...

Yep been using that trick for awhile myself... I bought some light aluminum angle and cut it in 1 and 2 foot pieces for tube marking purposes and it's a nice backup for that sort of thing, or balsa, or a ruler... usually use clothespins for clamps. Works like a champ.

I don't bother with fin alignment jigs. I prefer four fins, and use an "L" shaped piece of balsa scrap, or a mini-carpenters square (thin steel "L" shaped 90 degree tool I picked up somewhere along the line) and use double glue joints to attach the fins in opposing pairs, one pair at a time, and then put the "L" shaped piece over the end of the rocket like a "V" and using clothespins clamp it to the opposing fins-- holds them perfectly aligned to each other while the glue dries, making them perfectly straight to each other. If the fins are swept back behind the body tube, you can do the same thing using a ruler or flat balsa strip like you did here, going across the aft end of the tube (assuming the motor mount isn't sticking out too far... that's why the "L" is nice...

Later! OL JR


Any chance you have a picture or diagram of this technique?
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  #9  
Old 07-22-2011, 02:23 PM
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Quote:
Originally Posted by qquake
What I like about the fin alignment jigs, either the Estes version or my homemade version, is that they square the fins to the body tube, and also keep them in line with it. No matter if you have three or four fins. As far as I can tell from your description, with your method the fins get squared to each other, not the body tube. If one fin is out of line, the opposite one will be too.


Hasn't been a problem... I just leave extra line on the tube and carefully glue the fins on straight...

Course I also use double-glue joints-- all the convenience of CA with the strength of yellow glue. No problem getting the fins aligned with the tube, and clamping them to each other ensures they're aligned with each other...

Later! OL JR

PS. Not opposed to fin guides, but haven't personally seen the need for them.. whatever floats yer boat!!!
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Old 07-22-2011, 02:25 PM
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Quote:
Originally Posted by Dr.Jeckyl
Any chance you have a picture or diagram of this technique?


I'm on vacation so I'll have to check when I get back...

Might have a pic of the fins gluing up with this method in one of my build threads-- if you want to do a search for it...

Later! OL JR
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