Another one bites the dust!

YAHOOOO!
This past weekend dad got his level two certification!
He took the test and got a perfect 100% and then later in the day we flew the Eclipse to 2960' on a J350W.

Unfortunately, it managed to land in the one spot we didn't want it to...a 15' wide gravel road! Ouch!

Luckily , the only damage is a couple of scrapes and one small crack in the quantum tube about 1" long. It will easily fly again w/o any repair but to make sure the crack doesn't spread I want to fix it. So, a question to you guys, what would be the best way to fix this w/ the least amount of damage to the finish?

Dave

Can't offer a suggestion on the crack but....

CONGRATS on L2!!!

From the inside

or Wick in CA

or use clear epoxy

- Being brief, but thorough (I think)

Nick

Mav,

You are in a tough spot...here is why...

First Choice:

About the only way to save the tube, keep the strength, integrity and finish is to cut the bad 1" off...if you can.

Downside: PML has some pretty tightly packed kits and you will shorten a side with either a drogue or main, so make sure it can be done and still assemble ok.



Second Choice:

One wrap of 2oz glass cloth on the outside of the plastic Quantum will work. Use West Systems Epoxy...it sands like butter.

Downside: It requires re-finishing the end and you also may restrict the piston from functioning correctly with weather changes, since that end will not be allowed to expand or contract with the rest of the tube. However, a good cold weather fit would work fine in warmer weather, so do it in a Warmer environment.



Third choice:

Glue the crack.

Downside: Unfortunately, the glue must not enter the tube if you are using this method. Also, Quantum, since it expands and contracts, doesn't glue very well. I lost a rocket due to a small crack, 1/8", that caused enough play for the nosecone to come loose at max thrust...A good epoxy should be used, or a good CYA and it should be tested for strength before flight.

Carl

One more thing...some Chrome or whatever color Self Stick Monokote wrapped at the end a couple of times will also add some support. The stuf is tough like mylar and should help add some strength.

Yo Mav,

First off, congrats to your dad on the 100% score!!! Also, did they consider that launch successful since it sounded like everything worked fine?

Now to the fix. Personally, I would smear epoxy on the crack outside the tube and let it dry then wrap the end in a nice Monokote color. That should be strong enough. I wouldn't use CYA cause it may "eat" the quantum tube.

Hmmm, CA on Quantum Tubes. Yep, here it is:

PML Tube FAQ

It basically says, CA is okay in small amounts, but maybe the amount to fill a crack would be deemed a lot and that is said to be back.

PML doesn't recommend fibreglass

PML does recommend epoxy

I like what was said a bit earilier, about fix from the outside, but rather than refinish, maybe a strip or decal would be a good way to cover without have to refinish the whole thing.

Nick

Thanx for all the suggestions on how to fix the crack.

I am leaning towards a different method I thought of last night. It goes something like this:

First, dremel out half of the tube thickness around the crack on the inside so that you have a 1/4" wide groove in the tube, where the crack is. Sand the inside of the tube thoroughly in this area. Then, using 30 minute epoxy, work a little epoxy into the crack itself by holding it open a little. Then, allow the crack to close up and squeeze out the excess epoxy. Level the excess on the outside with the tube so it is hard to notice. Then, on the inside, place epoxy into the groove so that it fills in the the groove and makes the tube level again. Place tape over the crack on the inside and outside to be sure it sets correctly, right in the groove and levels out nicely. Remove tape when dry and test integrity of joint.

So, will this work?

Dave

BTW- The flight was successful.

Originally posted by MaverickLV


Luckily , the only damage is a couple of scrapes and one small crack in the quantum tube about 1" long. It will easily fly again w/o any repair but to make sure the crack doesn't spread I want to fix it. So, a question to you guys, what would be the best way to fix this w/ the least amount of damage to the finish?

Dave

Click to expand...

I haven't used Quantum tubing, but seeing it in the kits at the hobby store makes me wonder:

Maybe drilling a small hole at end of crack will help to prevent it from spreading (kinda like a windshield repair)?

Unless a rocket is really short, I tend to just cut off cracked or zippered ends of tubes.

I would tend to agree with drilling out the crack at it's termination point.......then spread the crack, fill it with epoxy and let off the pressure as the epoxy dries.