So I need to glue something else on after paint: What are my options?

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Joshua F Thomas

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My "That Tube Rocket!" kit uses the space between the tubes as the launch-lug. After a half-dozen launches I've come to the conclusion that a second launch lug would improve the stability of the rocket during launch.

Since the rocket is already painted, how do I glue the lug on? Do I need to sand all the way down to the tube, glue it, and then repaint? Are there any particular tips/tricks/gotchas with sanding paint?

Thanks in advance.
 
Sanding isn't such a bad idea if you feel the repair is worth the effort meaning it shouldn't be too difficult. I would image that sanding down to the tube is best, but you could probably get away with just roughing up the painted surface and using some CA to attach the launch lug and give it a quick coat of paint after it dries. It really all depends on how much effort you want to go through?
 
My 2 cents...

A dremel tool works great for precise sanding through the paint. Tape off around the area with a double layer of blue painters tape so you know exactly where to sand.

I'd use wood glue if the body tube and the lug are both paper based. CA makes the paper brittle.

Whats the nose cone made of? If it's balsa you could use an eyelet screwed into it...
 
If it's a paper body tube, then you could carefully cut through the paint and first layer of paper, and then peel it off. Blammo, done. Glue and then touch up afterwards.
 
I glued a lunch lug after painting...just scruff it up I bit. I used wood glue that one time........test it afterwards and see if it hold. Assuming this is a model rocket A-D powered.
 
I've had good luck surface gluing fins by drilling a series of 1/16" holes in the body tube along the line where the fin will go. Force glue into those holes then glue the fin in place. As small as a launch lug is, I suspect you could drill just three or four holes, apply glue, and it'd stay in place. Doesn't work for minimum diameter rockets, though.

Best -- Terry
 
Dremel was the way to go on adding my new lug and repainting, thanks for that suggestion.


Masking and fit-testing of the lug

TKBPwkYh.jpg


Small sanding tip with medium grit

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Down to the tube base material

upLIbEih.jpg


Gluing the lug

wLHa2LMh.jpg



Final results after painting

HKIpJkth.jpg
 
On low power stuff, I have trouble keeping sanding with a dremel neat. I usually just tape mark the outline and score the edges with an exacto knife, and peel the paint to the paper. I don't normally get it perfectly clean, but it works if you can get glue/epoxy into the paper.

I actually have installed printed guides this way after painting, but it is tedious, and easy to make a mistake in your paint.
 
If you think the paint will stick to the tube as well as the glue (it usually does just as well or better), just ruff up the paint and glue the tube to that.
 
Joshua F Thomas, not bad, not bad at all. I’m surprised you got it to look the way it is now. Way better than what I could have did. Hopefully there is a strong bond and it doesn’t separate.
 
I think it should hold well. It’s just as if it’s bonded to the base tube, which is how I would have attached one in the first place.

I will probably suggest to the kit maker to add the launch lug. The space between the tubes certainly works, but I feel like it has too much space; the rocket could wobble a little leaving the pad.
 
I think it should hold well. It’s just as if it’s bonded to the base tube, which is how I would have attached one in the first place.

I will probably suggest to the kit maker to add the launch lug. The space between the tubes certainly works, but I feel like it has too much space; the rocket could wobble a little leaving the pad.
I’d like to see a pic of the whole rocket. I would think if there was enough space between the tubes to run a rod, it would be a good place to put a cosmetically nearly invisible lug. Might depend on the length of the tubes.
 
Here’s the whole rocket (before the new lug was added)

396C201F-60E9-4500-8BAE-E7FFA8313A9A.jpeg

The main body and exterior tubes are BT-50 (24mm) size. The triangular spaces between the body and exterior tubes will fit a 1/8” launch rod with some space, but I’m not sure a lug would fit in there; if it did it would be a very snug fit.

The rocket has flown well to-date on A8, B4 and C6 engines, but I dislike the amount of lean it has on the pad when using the between-tube “lug”. The second lug should add some stability, even though I know it will cost me some performance from drag. I would prefer reliability and stability over that performance hit.
 
I’ve always wondered what those extra tubes are for. Boosters? Looks?
 
I’ve always wondered what those extra tubes are for. Boosters? Looks?
Yes it is a Tube-Fin Rocket..been feature in Sport Rocketry the past few years. A few manufacturer makes the kit. Does anyone read their magazine?? Josh who is the Manufacturer, I been considering buying one.
 
ASP Rocketry (asp-rocketry.com). They have an 18mm, 29mm, and a MicroMax version. The 18mm was quite easy to assemble and any experienced rocket modeler should have no problem.
 
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