Need some advice on a Trident duct tube fix

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bernomatic

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I've been accused of just stopping in to the rocketry forum to incite a riot or cause trouble. Well that's a discussion for another day. However, I do have a question which should only cause problems for the mods only if they believe that I am being "snarky".

I've been working on a Semroc Trident Which will be named in honor of Carl, and last night I received another setback.
P6140013_zpsxvdarqlq.jpg



Do others have rockets, that for unknown reasons, just seem to have minor glitches and take longer to finish then they should? My Renegade D was one such rocket. every time I would paint a coat, something would happen, like a clump of dog hair would float on a breeze and land on the wet paint. Frustrating as all hell.

Well this Trident is turning into one of those builds.

Last night after spot painting a patch of a notch (no idea where it came from) in one of the fins, I thought I'd be able to give it the base coat of final silver, then mask for the white. In the middle of the night, I hear a crash thump and meowrr. I knew what it was immediately, fate striking again.

There is a window in the "rocket room which looks out over the roof of the addition to the rear of the house In front of that window I have a stand which I use for spray painting and other assorted activities. The cats of the house also use the stand on occasion to exit through the window when the local servants (my wife and I) are not respomsive to their caterwailing to get out.

of the four rockets sitting on the stand, one was damaged, care to take a guess which one?

1) X-wing fighter
2) Mars Snooper
3) Trident
4) Firefly

Well, since this is the thread for the Trident TPD Carl McLawhorn, you would be correct in your guess of 3. Now as to damage.

a) Total lose, cat boards and other rockets broke there fall by landing on the Mclawhorn.
b) Puncture of one of the ducted tubes by something.
c) Breaking off of a fin.
d) Smashing of the Nose Cone.

Well believe it or not. b. A small hole of about 4mm dia. was somehow punctured into one of the ducting tubes.

So the question I respectably submit is, rather than plugging (which would most likely blow out after some launches) and without cutting and splicing a new section of tube in, How would you handle the repair?
 
Hmm...

I would be tempted to mix up some epoxy, inject some into the hole, cover the hole with tape, and position the rocket so the hole is facing down.
The goal is to let the epoxy you injected into the hole to pool at the hole site.
Once cured remove the tape, probably will need a bit of filler/sanding, and then repaint.

You may also want to reinforce the tube by sanding away the paint and gluing a bit of paper or card stock over the hole. Then use some filler to blend the paper edges to the tube
 
Another option would be to use some thin card stock and cut a sliver about 4mm wide and 12mm long. Curl it along the long axis to match the curve of the tube. Coat the convex side of the strip with a thin coat of epoxy. (If you use wood glue, coat both sides so the strip does not curl up.)

Stab one end of the strip with a sharp #11 blade and work the patch into the hole in the tube. Use the tip of the blade to work the patch into position centered over the hole. I would hold the rocket overhead and work from underneath so that gravity helps.

Once the inside patch has dried, a spot of filler on the outside and you are ready to refinish.
 
Been through this kind of thing before. What les said is about the only easy way to go. I'd make one change. Get a piece of masking tape ,cut it large enough to cover the hole and then some, punch a tiny hole in it, NOW install it and cover the hole in the BT. Inject epoxy into the tiny hole . 5 minute epoxy works great for this. You can get it at wallyworld and it has a removable applicator tip.---Cover the small hole with tape--WORK WITH THE HOLE DOWN. Let sit for a couple days and sand and fill as needed. -------------I do need to stop you in your tracks about one thing you said--------do not, do not, do not, paint the silver as your base coat and then mask over it---the tape will mar the silver unless your using an auto grade paint. Looks like your already silver but you gotta repair it anyway. ---H
 
When it comes time to paint the repair (should you decide not to camouflage it with a decal)... Use a sticky note to mask the area, but have the sticky side facing away from the repair. Make sure that the bottom edge of the sticky is raised off of the rocket, so paint can come in under it and blend with the original paint. The idea is to feather the edge of the repaired area, rather than have a hard edge.
 
Been through this kind of thing before. What les said is about the only easy way to go. I'd make one change. Get a piece of masking tape ,cut it large enough to cover the hole and then some, punch a tiny hole in it, NOW install it and cover the hole in the BT. Inject epoxy into the tiny hole . 5 minute epoxy works great for this. You can get it at wallyworld and it has a removable applicator tip.---Cover the small hole with tape--WORK WITH THE HOLE DOWN. Let sit for a couple days and sand and fill as needed. -------------I do need to stop you in your tracks about one thing you said--------do not, do not, do not, paint the silver as your base coat and then mask over it---the tape will mar the silver unless your using an auto grade paint. Looks like your already silver but you gotta repair it anyway. ---H

I'll second Hornet Driver's post above.

He is exactly correct about your silver paint. Silver & Gold metalics should ALWAYS be the Last color applied as they can not be masked without damaging the metal flake on the surface of the model. It's just the nature of the beast:;)
 
Bernie,

Really sorry to hear of your trouble with the Trident but there are some really wonderful people that can help with just about any problem that comes up. I hope you will be able to repair it.

Sheryl
 
Thanks Sheryl, it is just another little hiccup on the path to a beautiful build, I am sure.

To everyone
Here's a pic of the damage


As of right now, I have sanded the paint around the puncture and was thinking of trimming the hole to an even edge, or should I just leave it rough?
 
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Hmm that hole is not too big really...I'd be tempted to just 1) sand all the paint off around the hole; you need adhesion 2) mix up a batch of epoxy and microballoons (good epoxy, you need it to be sandable) to thick consistency, 3) slather it on and put a piece of tape over it, turn upside down to cure. Remove tape and sand it out when done. I don't think you need to worry about getting a patch inside the tube.
 
The reason the patch should include the inside is because that is a pressurized tube for the venting of the ejection charge to the upper section. Any patch which is not totally secured will pop out like a cork, causing recovery system failure and lawn dart.
 
Hmmm. I would edit your original post and delete the first sentence - then proceed like a normal member of the forum rather than drawing attention all over again. That should help fix the problem.
 
Bernie, is that a highly reflective metallic, or the Rustoleum Painters Touch Aluminum? I haven't tried masking over the Aluminum, but it sure goes on differently from the other silver and gold metallics I've tried.
 
That is the Rustoleum 2X Painter's Choice Primer + Paint. While I am not enthralled with Rustoleum anymore due to problems with most of their cans, I did at one time think it was a lot better than the Krylon. Now I'm just using up what cans I have. I have switched over to airbrushing and butyrate dope for most jobs.
 
Sorry. Painters Choice. I'll have to start saying IIRIC - if I recall incorrectly.

Based on threads here and on YORF, I've started saving the good nozzles. I've had a couple in a row that 'blow snow'.
 
I bought several of the extra size cans in black (get so many ozs. free), only to toss them after using about a third of the can. It wasn't the nozzle IMHO but the whatever allows it to spray at "any angle". I would invert the can, and the paint would spray out somewhat well, but would then drip all over my hands, the floor whatever.
 
The reason the patch should include the inside is because that is a pressurized tube for the venting of the ejection charge to the upper section. Any patch which is not totally secured will pop out like a cork, causing recovery system failure and lawn dart.

I think in this case the patch would hold easily since the hole is very small and the PSI is split between 3 tubes. I've done similar external-ish patches on much bigger holes in single tubes without failures. Sanding all the paint off is crucial.
 
I finished repairing the tube, I used portions of some of the ideas some offered here and I thank you all for your ideas. Well that's irritating. just tried uploading an image of the repair and it wouldn't let me upload it.:sad:
 
Nope, trying to upload from my computer isn't allowed, no buttons appear.

P8070015_zpskpsf2avj.jpg


With the patch applied

P8100022_zpsw3wyubsl.jpg

Still needs a bit more sanding, but the obvious blemishes aren't as bad as they appear here. The divot and pinprick are along opposite edges of the patch. After a touch more sanding and the final coats I think the repair will be unnoticeable.
 
Yes, I did try the advanced option but it still didn't show the upload buttons. but I can also upload to photo bucket, then to TRF
 
In Advanced, try using the "Manage Attachments" button a bit below the text input and post icons section. It's in "Additional Options"

Post Picture.jpg

Choose the +Add Files button at the top of the window that comes up, then "Insert Inline" once the upload is done.
 
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