Fin alignment.

[johnnyrockets]

Hi everybody!

I'm new here! This is my first post. I tried searching the forum for this, but came up with nothing.

Is there a jig that can be purchased to ease fin alignment and gluing?

Also what is the best glue for fins? I have found super glue to not be so super!


Any suggestions?


Thanks,


From Tecumseh, Michigan

 

[Micromeister]

Hi everybody!

I'm new here! This is my first post. I tried searching the forum for this, but came up with nothing.

Is there a jig that can be purchased to ease fin alignment and gluing?

Also what is the best glue for fins? I have found super glue to not be so super!


Any suggestions?


Thanks,



There are a couple different fin alignment jigs out there depending on what your building.
All have their strong and weak points and range from a few bucks to $350.00.
Personally I believe buying or making a "good" set of fin attachment point marking guides is a much more important early purchase.
Getting the body tubes marked properly the starting point for just about every thing and those darn paper guides are notoriously inaccurate and cumbersome to use. Once you have a set of fin marking fixtures, any number of fin attachment fixtures can be constructed to aid in holding wet glued fins in place.

Personally I like Yellow carpenters glues for attaching fins and motor mounts. some perfer white glue.
I think one of the most important things to learn concerning fin attachments it the use of the "Double Glue Joint". once you get a little practice with this method the alignment jig become less of a need.
The trick is to apply a line of glue to the root edge of the model and press it firmly onto the line for your fin. Once this line has been added to the body tube line set the body and fin aside allowing the glue to completely dry with the two pieces apart. We then apply a second line of glue to the root edge of each fin in turn and press it onto the previously glued body tube line. the fresh glue reactivates the dried glue film and almost immediately grabbs the fin securing it in place. You can still swivel it a bit to sight along the body tube to ensure it's aligned properly and at 90° to the body tube. now stand the body up-side-down on a dowel or something while the second glue line setups up completely.

Here are some fin making fixtures and the old fin attachment/alignment jig Estes used to offer. both currently discontinued from Estes but are still sort of available in some hobby shops or on line...& E-bay, at much higher costs. Last is that 350 buck attachment jig that's really designed for Internat competition flyers. ITs a wonderful jig but for most, it's just a little to expensive. Making your own isn't that difficult also. I understand someone is now offering a 50.00 or so magnetic/steel fin alignment fixture but I don't have any info on it. The One I have seen looks very good.
Hope this helps some.

 

[gpoehlein]

You know, for standing the rocket upright while the fins dry (yet, I too use the double glue method with white glue - as John said, it grabs almost immediately and the joint is super tough when it dries) I use another of John's tools that he posted here at one time. Take an expended motor and cut out a strip of paper or cardstock that is 1/4" wide and long enough to go around the motor at least 3 times (cardstock) or 4-5 times (paper). Glue the strip around the nozzle end of the expended motor so it forms a lip. Once dry, it makes a great counterweight for standing up minimum diameter rockets (I made one 13mm, one 18mm and one 24mm). Also, and this is the task John created them for, it is perfect for seating motor thrust rings. Apply your glue inside the tube at the right depth with a stick (I use a bamboo skewer), insert the thruse ring into the end of the tube and push into place with the motor tool - it always places the thrust ring so that 1/4" of the motor will stick out the back of the rocket.

 

[johnnyrockets]

Guys,

Thanks, all of the info is super helpful! I had never even heard of double gluing! Great idea!

Micromeister,

As I said, I'm new to everything! But my son and I happened upon the micro rockets portion of the Fliskits website. We were very excited with this idea.

I see from your reply that you might know something about micro kits?

Any pointers? We were actually looking at the "Big Honk'in Rocket" kit on their site? Any ideas or thoughts here?


Thanks to all who have helped a lot with their replies!


John

 

[Micromeister]

Well yeah: I might know a little about Micros! :roll:
I've been building and flying Micros since there release in 1999. My current micro fleet stands at 161 different models. I just recieved my "Big Honkin rocket" kit from Jim over the weekend.

I must caution you: MICRO's ARE Addictive! they can infest your entire house. but they are so small who cares!
How often can you go to a Club launch and carry your entire model-Rocket fleet with you? I do it almost every month!
I urge you and your son to come on over an join us at the MicroMaxRockets yahoo group. please note the upper/lower case letter and spelling. Once you join the group, log on to the group and check out the file section and the photos sections. We have about 120 pg plans for micro models you can download. Great info in the FAQ files and tips and places to get everthing micro. OH! that is besides Fliskits who has now got one heck of a line of micro parts as well as some pretty darn good kits.
the board has been a bit slow recently as many of us have been pre-occupied with other things in this ecomony.. but i'm sure as things start to get back to normal, will pick up again. I've been so busy with 1/8A helicopter models I haven't done anything else since January.

As for the Big Honk'in Rocket. you get three in the kit. why! beauce they are pretty small and are likely to be lost.
I've been flying my smallest creation.. actually a downscle of another Flis model from year back. That I call the Nano-Dot. pic below. the one page plan at sets you up to make a dozen of these is also in the files section
If you need help finding anything Micro just say the word.
Here are just a couple micros to get the thoughts flowing. We even have micro Night, Payloads and RC gliders

 

[powderburner]

I see from your reply that you might know something about micro kits?

johnnyrockets, I'm not picking on you or anything, but you just got connected up with a guy (Micromeister) who has a house overflowing with rockets, including a bujillion micros. I think he buys MMX motors by the trainload.

As to using superglue on model rockets (and micros), it may seem tempting to use something like superglue that sets quickly, but these CA-type glues have their own problems that make them sort of unsuitable. They can be a bit dangerous to use. They make it easy to make mistakes just as much as they make it easy to build. They tend to cure into a brittle form that cracks relatively easily (IMHO).

Plain old white and yellow glues (water-based stuff like Elmers) is more than strong enough for model rockets. It is cheap (the "back-to-school" sales are coming soon!), easy to use, fairly non-toxic, and easy to clean up after. It will usually dry into a glue joint that is stronger than the cardboard or balsa that it is joining together. Dry joints will also be a little tougher than CA joints.

You can search the old TRF posts using keywords like "glue", or "Tite-bond", or anything associated with making glue joints. And when they get the older posts from TRF1 put back online, there is a TON of discussion and advice in those threads too.

Welcome to TRF!

 

[johnnyrockets]

Wow!

You guys have helped me SOOO much!

I cannot thank you enough!

I thought maybe Micromeister might know something about micro rockets!


Thanks, thanks, thanks for all of your awesome ideas!


Right now I'm building a big rocket with my son, but next comes the Micros!

Those little kits are right up my alley!


John

 

[jflis]

John,

Welcome to rocketry and to TRF. You're going to love it here, but I think you already figured that part out

I've attached an image for a very simple fin jig that I have used for decades. Basically you glue a spent motor casing to a stiff (flat) piece of cardboard to hold your rocket up on. Then you pinch your fin between two paint bottles to hold it straight as it dries on the fin.

The "double glue" method is a wonderful tip and should be used nearly every time

Also, with regard to micro models, I would shy away from the "Big Honkin' Rocket" as your first foray into micro models. No sense getting your self frustrated loosing rockets... Until you have a chance to experience just how fast these little buggars can really go, you should look into some more conventional kits.

I would recommend the doo-Hickey as a great beginner introduction to the micro world (very easy to build, but doesn't go very high - maybe 70 feet). After that I would look at models like the Crayons (very nice flyers), Teeny Triskelion and/or the Dead Ringer. All great kits and will give you some good experiences with the sport.

As you can see, feel free to ask questions and don't be shy about offering advice

jim

 

[mjennings]

I only have one micro model at the moment, the Tog that I got from Fliskits it's a great little rocket, but hold off on this one till you've built a few. As for alignment guides a simple piece of right angle stock with a few inches of the corner cut out works well for making sure you get 90 degrees to the body tube.

Welcome. Oh the unwritten rule around here is post lots of pictures.

 

[johnnyrockets]

Thanks again everyone!

My sons and I (9 and 7) just looked at the doo hickey and we think that would be a great starting place!

Thank you all for your great, great advice!

Thanks for such a great forum!


John

 

[Trident]

Hi everybody!

I'm new here! This is my first post. I tried searching the forum for this, but came up with nothing.

Is there a jig that can be purchased to ease fin alignment and gluing?


Thanks,


From Tecumseh, Michigan

John,

Our Fin Wizard is currently out of stock, but I am hoping to have another production run in May. My partner with the mill is busy with some other machining jobs. We currently offer the Fin Wizard for Estes tubes sizes from BT-20/50/55/60, and a few of these handle the equivalent Centuri/Semroc sizes (please check out the website). More sizes coming in the future, also. We have decided to concentrate on low-power, so nothing extremely small or large (for now!). Have fun and savor all the great info you'll find here.

 

[TheAviator]

As to using superglue on model rockets (and micros), it may seem tempting to use something like superglue that sets quickly, but these CA-type glues have their own problems that make them sort of unsuitable. They can be a bit dangerous to use. They make it easy to make mistakes just as much as they make it easy to build. They tend to cure into a brittle form that cracks relatively easily (IMHO).

Plain old white and yellow glues (water-based stuff like Elmers) is more than strong enough for model rockets.

Hah! I'm glad I read this, I've been doing improper double joints for years! I do agree that CAs are definitely not something to start with. I'm into competition, so I use a lot of CA to keep the models lighter. They also do have their place in the hobby (IMHO). However, when I do use CA with a regular model, I make sure that I fillet the joint with white or wood glue. Also, I'm still somewhat impatient with getting fins attached, so this is kinda my weakness.

If you want to get into the micros check out Art Applewhite's website. He has some free micro saucer-style type plans that print on 110# cardstock and and can be completed with a pair of scissors and some glue. They fly really great and have an apogee of about 20-40' depending on wind. I launch them in my back yard when I need a rocket fix, but can't get to a field. If you print them on bright orange or bright pink cardstock, you'll be able to find them really easily. They also make great night fliers; you'd be surprised at the complete difference in effect! If I weren't at college, I would go outside right now and take some pics so you could see it!

Have fun!

 

[hardinlw]

Here's an approach I have used from Estes to high power.

Take a piece of 1/4" foam board (Walmart or craft shops are sources) and mark a center point. This needs to be larger than the tip diameter of your fins by at least a couple of inches. Now, draw radial lines at the appropriate angles for the fins (120 degrees for 3 fins or 90 degrees for four). A plastic protractor does fine here. Use a compass to draw a circle with a diameter that matches the outside diameter of your body tube. Cut out the center hole and slice out fin slots. Now cut off the corners where the fins will touch the body tube (otherwise you'll glue the jig to the rocket). Slide this onto the body tube so when you glue the fins on it will hold them straight. You still need the alignment lines on the body tube to keep them from twisting at the root, but this ensures they will stick straight out from the tube.

 

[TheAviator]

Here's an approach I have used from Estes to high power.

Take a piece of 1/4" foam board (Walmart or craft shops are sources) and mark a center point. This needs to be larger than the tip diameter of your fins by at least a couple of inches. Now, draw radial lines at the appropriate angles for the fins (120 degrees for 3 fins or 90 degrees for four). A plastic protractor does fine here. Use a compass to draw a circle with a diameter that matches the outside diameter of your body tube. Cut out the center hole and slice out fin slots. Now cut off the corners where the fins will touch the body tube (otherwise you'll glue the jig to the rocket). Slide this onto the body tube so when you glue the fins on it will hold them straight. You still need the alignment lines on the body tube to keep them from twisting at the root, but this ensures they will stick straight out from the tube.

There is an online application that will make a PDF of this for you if the rocket isn't too large. For that go to here. This makes it as simple as entering the values, printing it out, gluing it to a sheet of foamboard or somesuch and cutting it out. Just make sure your PDF reader doesn't scale the drawing for printing.

 

[troj]

Also what is the best glue for fins? I have found super glue to not be so super!

As others have said, CA does end up brittle and won't hold for the long run.

But I often tack fins into place by putting a thin line of thick CA along the fin root, then pressing the fin into place. If you're not happy with where it is, whap it once at the fin tip and pop it loose, then do it over again, to place it where it belongs. Otherwise, let it sit for 15 - 20 seconds and the glue will fully set up.

After things have set up, apply proper fillets with a good quality glue. I use Titebond II.

I've found that fins glued on this way hold up just as well as fins glued on with Titebond II or white glue in the first place, and it's a lot easier, as I don't have to make sure things don't get bumped while a slow-setting glue is drying.

If you try it, make sure you use thick CA -- thin stuff will soak into the balsa, run all over, and just generally make a mess. It's also a case of "less is more", as you don't want a huge bead.

My experience is that a fin is as likely to break as it is to come off when glued on this way.

-Kevin

PS: The so-called "double-gluing" method is actually the way wood glues are designed to be used, although the first coat is typically given 10 - 15 minutes to set up, but not allowed to dry fully.

 

[peter_stanley]

A method I just started using is printing an alignment guide with VCP onto cardstock paper. I then cut that out with scissors, line the slots up with my fin lines, and tape to the body tube. It looks cheap and flimsy, but seems to work well. It's also quick to make on the the fly. Here's a pic,

For model rockets I like to use Elmer's Carpenter glue, or any general type of good quality yellow glue. I first apply it to both contact surfaces and allow to dry. Then apply to the fin root and attach. The fins grab really well using this method.

 

[RimfireJim]

PS: The so-called "double-gluing" method is actually the way wood glues are designed to be used, although the first coat is typically given 10 - 15 minutes to set up, but not allowed to dry fully.

That statement surprises me. I've done a considerable amount of woodworking over the years, both carpentry and cabinet making, and have never used the "double-gluing" method in that work, nor have I ever seen it recommended in magazines or manufacturers' application guidelines. I think it would make a mess of the work.

Titebond does suggest using a "sizing" mixture of one part glue to two parts water for the unavoidable end grain woodworking joint, letting it soak in for no more than two minutes.

The big difference between woodworking and rocket building is that in woodworking, one never relies on a end-grain glue joint for strength, whereas in model rocketry, the fin-to-body tube joint is always a (mostly) end-grain joint for the balsa side of things. Plus, we can't follow the clamping recommendations given for the usual use of woodworking glues. I agree, "double gluing" is the hot ticket for attaching fins.

 

[Gus]

John,

I see you are from Tecumseh, MI.

You are located very near a fabulous group of people who fly every month near Jackson. The group is called JMRC and their website is here.

If the weather holds tomorrow (May 9th) they will be flying at a place called Gumbert's farm (see the map on the website). If you miss that launch be sure to get to one this summer at Michigan International Speedway. The group launches everything from the tiniest Mosquito all the way up to some very large high power rockets. You and your kids will love it.

If you'd like any further info feel free to contact me either by email or PM.

Steve

 

[RangerStl]

Where's "Standard Rockets"? LYLE!!! Your fin jigs are needed out here!!!

https://www.rocketryforum.com/showthread.php?t=2102

N

 

[troj]

That statement surprises me. I've done a considerable amount of woodworking over the years, both carpentry and cabinet making, and have never used the "double-gluing" method in that work, nor have I ever seen it recommended in magazines or manufacturers' application guidelines. I think it would make a mess of the work.

Interesting. I know a number of folks who will spread on a very thin film over both surfaces, give it a few minutes to set up, then put another thin film over that, clamp, and let it sit.

-Kevin

 

[DM1975]

A method I just started using is printing an alignment guide with VCP onto cardstock paper. I then cut that out with scissors, line the slots up with my fin lines, and tape to the body tube. It looks cheap and flimsy, but seems to work well. It's also quick to make on the the fly. Here's a pic,

For model rockets I like to use Elmer's Carpenter glue, or any general type of good quality yellow glue. I first apply it to both contact surfaces and allow to dry. Then apply to the fin root and attach. The fins grab really well using this method.

This is what I do as well, except I print my fin guids on regular paper and glue them to either cardboard or foam core.

 

[peter_stanley]

This is what I do as well, except I print my fin guids on regular paper and glue them to either cardboard or foam core.

I tried some new material this weekend that I like. It's Staples Illustration Board, 1/16" think compressed cardboard. Three big sheets is about 13 dollars, but should last a while.

 

[CharlaineC]

one of the thigs that I have foud to help me emencely is by glueing the fins just to the right of the lines i have made this allows for you to like the fin to the line and gives a great finish. This tip was once in the old estes mrn mailings I just do not remember witch one, it is also eplained by semroc on their golden scout kit..

 

[Larry Curcio]

Michaels sells Aleene's *Fast Grab* Tacky Glue, which does grab faster than normal Tacky Glue. Never tried it with the double gluing method.

This is definitely NOT for gluing cardboard rings to the insides of body tubes. (FWIW, the way to do that is with an *excess* of regular glue applied to the *inside* of the body tube. Prevents premature grabbing.)

 

[MarkII]

I was going to come to the defense of CA as a fin adhesive, but Kevin (troj) beat me to it. I follow the same method that he outlined. The key to using CA is to use THICK CA, either the gap-filling variety (like Bob Smith Industries Insta-Cure+, which is what I mostly use) or the slow-curing kind (e.g., Bob Smith Industries Maxi-Cure). You won't find these varieties at your local stationary store or hardware store - you will almost always only find them in hobby shops. The good news is that they are not expensive. Buy them in small 1/2 oz. or 3/4 oz. bottles at first. It is possible to save money by purchasing the larger bottles of it, especially if you know that you will be using it a lot, but these require special care and storage to insure that the CA doesn't harden in the bottle long before you use it up. (This has been the subject of more than one discussion thread on this forum.)

The other key is to use another adhesive in conjunction with the CA, as Kevin discussed. On some very lightweight models, I have created joint reinforcements (fin fillets) with BSI Maxi-Cure CA, which I then hardened with Insta-Set accelerator. Otherwise, I use either yellow carpenter's glue or 30-minute epoxy.

There is some great advice in the previous posts about getting fins aligned straight. I want to especially point out Micromeister's advice about getting the fins properly spaced around the tube. His flat marking guides are probably the best overall method for marking the tube in the right places for fins. Unfortunately, I have trouble keeping the tube precisely centered and steady while I stand it on its end and place marks around the circumference for the fins when I use this method. Wrap-around guides do need to be properly sized for the tube in order to produce accurate results, but that is the method that I use. I make customized fin wrapper guides for each project using either Gary Crowell's free VCP program or his free VCT program. Over the past couple of years, through trial and error I have compiled a list of measurements that I enter into the form to size the wrapper precisely for the body tubes sizes that I use. When the proper dimensions are plugged into it, VCP and VCT produce very accurate and precise fin marking wrappers. This process is not at all hard; if it was, I wouldn't be using it!

Once I mark the fin locations on the tube, I use a length of aluminum angle (you can buy it cheap at your local hardware store) to draw straight lines up the tube. Charlaine's advice is very pertinent here: place each fin on the tube by aligning one side of the fin root along the drawn line. In other words, do not try to center the fin over the line - place the fin next to the line. Just make sure that you place each fin on the same side of each line (e. g., place each fin to the left of its marked line).

I don't use a physical guide to get the fins on straight and perpendicular to the tube. To align them straight, I use the aforementioned drawn lines. To get them to be perpendicular to the tube, I use a very reliable and accurate gauge - my eyeball. When in doubt, I find a reference point, such as the edge of a door or the side of a cabinet, that is vertical, straight and in the background. Then I hold the tube up and look through it until the opening at the far end is centered in the opening at the near end, and my fin is at the top. I line it up so that when the tube is perfectly horizontal (far opening is centered in near opening), when I glance up, the fin is lined up perfectly with the reference point in the background. (This is an old artist's and crafter's trick.) Using Insta-Cure+ (gap-filling CA) or Maxi-Cure (slow-curing CA) to initially bond the fin to the tube really helps here. Both of these products give me a little bit of working time to allow me to reposition the fin before they set up, but they set up fast enough that I don't have to hold up the tube for a really long time. I take my time, though, and glue one fin on at a time, and I don't rush things. I never have any trouble getting my fins on straight and perpendicular with this method.

The methods that others have described are fine too, especially if you have steady hands and deep wells of patience, and I don't mean to knock them by any means. The procedures described above are the ones that I use, though.

MarkII

 

[FatBoy]

A "Must-Have" for any rocket builder is the Standard Rocket Assembly Tool. This fixture allows you to mount all your fins at the same time, no matter how many fins you have or what your fin configuration is. It uses magnets to hold uprights in place and to hold your fins to the uprights. It is totally adjustable and very versatile. The uprights even have cradles cut into them to lay your rocket horizontally while your extra fillets dry.

www.standardrockets.com

 

[standardrockets]

A "Must-Have" for any rocket builder is the Standard Rocket Assembly Tool. This fixture allows you to mount all your fins at the same time, no matter how many fins you have or what your fin configuration is. It uses magnets to hold uprights in place and to hold your fins to the uprights. It is totally adjustable and very versatile. The uprights even have cradles cut into them to lay your rocket horizontally while your extra fillets dry.

www.standardrockets.com

Thanks Jeff,
I have to add one of my suppliers is now back in town so I can get more made.

I'm working on getting the paypal ordering setup at this time to get integrated into the website the weekend after NSL.

I'll also have one or two of these at NSL for anyone to try out if there is any building onsite. I'm planning on putting together either a Zooch Sat V or Alway one for Monday's launch.

 

[powderburner]

This is definitely NOT for gluing cardboard rings to the insides of body tubes. (FWIW, the way to do that is with an *excess* of regular glue applied to the *inside* of the body tube. Prevents premature grabbing.)

Yeah, lotsa glue works, at least to get an internal part slid inside a BT before the glue grabs and locks up. But then it takes a long time to dry, and you run the risk of having excess glue run to places where you don't want it, or drying in a big scab and shrinking as it dries and pulling in the BT contours with it. It works, but there are other ways I like better.

Swab the insides of the BT (where the internal part is going to seat when installed) with white or yellow glue and LET DRY. A Qtip works well for this and can be thrown away when done (for deep reach, hold the Qtip in some needle-nose pliers, or tape the Qtip to a bamboo skewer). Swab the joining face of the other part likewise and LET DRY. Assemble the parts WITHOUT any additional glue. After the parts are in their proper position, use another Qtip (or a cheapie school watercolor brush from the dollar store) to swab some water on the joint, or if you don't trust the water to re-activate the glue, paint some thinned glue onto the joint (thin the white or yellow glue 1:1 with water). It only takes a few drops, worked into the joint, and the previous glue will grab.

Actually, 99% of the time you can simply assemble the parts without any pre-gluing or without any added glue during the assembly. After the parts are in their proper position, use a Qtip or cheapie brush to work some thinned glue into the joint, then follow up with a few drops of full-strength glue and spread it around the joint too.