Does this look repairable?

[OzHybrid]

What do you think of filling the void between the CR's with 2-part foam to lock the joined area to the motor tube and make everything more solid? It's about 4:2 against in my little poll. I can calculate the volume pretty closely and mix less than needed. You can also apply that stuff in multiple (small) batches, too. It's tricky stuff, but I've worked with it before. Wouldn't it make a nice, solid, well adhered segment that is fully integrated into the rest of the rocket?

You don't get a lot of time to work with foam. You need to make sure your alignment is good. Foam builds up pressure and this could cause missalignment at the worst possible moment. so you're now 5:2 against....

Norm

 

[Orien]

You don't get a lot of time to work with foam. You need to make sure your alignment is good. Foam builds up pressure and this could cause missalignment at the worst possible moment. so you're now 5:2 against....

Norm

I've got you down as a "maybe". Seriously though, eliminating that and the coupler as suggested only make things easier.

 

[OzHybrid]

I've got you down as a "maybe".

I'm a definite NO....

 

[dr wogz]

Is the MAC Performance 'canvas phenolic' similar to the PML phenolic tubes?

Sandy.

No, it's more like a "G10": a cotton (I believe) fabric cloth impregned with phenolic & wrapped around a mandrel. Then sanded smooth. You can see the ends of the cloth in the raw tubes..

 

[icyclops]

Holy Catching up to do, Batman.

Start here: https://www.rocketryforum.com/threa...w-with-a-cti-k675-skidmark-wooooooooo.168904/

Then go here:https://www.rocketryforum.com/threa...-100-composite-materials-build-thread.169007/

And finish here:https://www.rocketryforum.com/threa...oy-project-hurricane-is-go-for-launch.169691/

Or just start here:https://www.rocketryforum.com/threa...rricane-is-go-for-launch.169691/#post-2210023

That's where you'll learn that poor surface prep on a glue joint intersected with a parachute selection that was too small, allowing too high of a recovery speed to occur in conjunction with a landing on a hard road surface.

I simply asked the OP what happened to his roc to cause this….not the history of rocket building…..but thanks.

 

[Sandy H.]

No, it's more like a "G10": a cotton (I believe) fabric cloth impregned with phenolic & wrapped around a mandrel. Then sanded smooth. You can see the ends of the cloth in the raw tubes..

OK. I remember the PML phenolic was amazingly cool until it got an impact and then things went south. It definitely required prep vs cardboard for epoxy, but was really strong and brittle. Back in the day, I think people usually fiberglassed it to add toughness most of the time, but I was very early in my rocket experience back then and might have just absorbed the wrong info. Wasn't sure if this stuff was similar.

Sandy.

 

[Orien]

Repairs are underway. The Dremmel made short work of the extra epoxy and i used a hobby saw on the fincan airframe and a chop saw on the other piece.

I only lost 2” of airframe.

I could probably use this big 6 grain case as an alignment tool.

 

[dr wogz]

what does the underside of that removed piece look like? is there glue on it?

You will likely find, that once you slip teh upper tube into place, that your cut (on the lower, maybe on the upper, maybe on both) are not square. Wrap a piece of paper around teh bottom of the upper / loose tube to ensure it is square..

 

[RocketScott]

You can strap a few pieces of angle around the tubes to keep them in alignment

 

[Orien]

You can strap a few pieces of angle around the tubes to keep them in alignment

View attachment 492953

Good tip, thanks. I could use the big zip ties to hold everything together, check it vertically for plumb with a 4 foot level, then begin bonding by injecting the epoxy fillets.

 

[Orien]

Aeropoxy ES6209 or System 3 T-88 are my fave structural epoxies. I think T-88 can be had in smaller quantities, but it is more particular about accurate mixing ratio. Regardless, if you will be continuing to build rockets, get a scale if you do not have one already.

I found an 8oz. kit of T-88 on Amazon. Is it injectable and will it flow enough once inside the airframe? I may also put four small wood screws radially around the airframe into the forward CR.

 

[Back_at_it]

Or should I just build a new booster? This thing looks pretty effed to me. Worse than i first thought.
View attachment 492662
View attachment 492663
View attachment 492664

Easy fix. Just cut it right in the center of that lower centering ring and add a new tube.

 

[OzHybrid]

Once you complete the repair, resim it to make sure it will fly...... If you're going supersonic, and it looks like you will be, RAS AERO it.

 

[Orien]

Prepping the surfaces for the injected System 3 T-88 structural epoxy.

 

[Orien]

After levelling and plumb bobbing to get the rail buttons lined, i made alignment marks then did a mock-up of the splint.

 

[K'Tesh]

Perhaps too late, but I would try adding lightweight splines between the centering rings to aid in reinforcement of the joint.

 

[Orien]

Perhaps too late, but I would try adding lightweight splines between the centering rings to aid in reinforcement of the joint.

Not too late. This is just a test and dry fit.

 

[dr wogz]

And I would use elastics / elastic bands. not zip ties to hold it all together. Even / constant pressure, and can be pulled apart / adjusted as needed in the process..,

 

[samb]

Perhaps too late, but I would try adding lightweight splines between the centering rings to aid in reinforcement of the joint.

THIS ! ☝
Provides additional glue surface area for the airframe tube. Rather than filling the entire void between the centering rings with epoxy, if that's what you were thinking. Saves epoxy, same structural reinforcement, less weight.

 

[Orien]

Well, she’s locked in place. I measured and leveled and plumbed and checked and rechecked. She is “on-axis”. I used two screws (one of which was an additional rail button) for one axis, then JB Welded the seam. Before it set, i put the splints back on and strapped them tight to lock in the other axis. She will remain in this configuration until after epoxy injections.

 

[Chris_H]

I found an 8oz. kit of T-88 on Amazon. Is it injectable and will it flow enough once inside the airframe? I may also put four small wood screws radially around the airframe into the forward CR.

For injecting, not really. No.


T-88 and Aeropoxy ES6209 are higher viscosity epoxies. A laminating epoxy like Aeropoxy 2032, Raka, or West, mixed with some adhesive fibers is a better choice for injecting. Of these, I think the Aeropoxy is the best. I have used all three. Mix to 'thick pea soup'.

Carefully measure. Mix very thoroughly, for a good long time. Use a good scale. Prep methodically.

 

[rcktnut]

Great job-looking good!!

 

[Orien]

So far, so good I think. I injected 20 cc’s (two full syringes) of the T-88 with a healthy pinch of chopped fiberglass onto the top of the forward centering ring. It was kind of thick but still settled out nicely. I can see how the airframe is "wet" above the epoxy a little - a good sign the sanding and cleaning have broke the surface tension. I then injected 30 cc’s into the void between the centering rings for the lower ring bond. I’ll flip her over and do the same for the underside of the forward ring tomorrow.

 

[Orien]

Good as new!

 

[K'Tesh]

Here's to future better flights!!!

Curious... Did you do the splines I suggested?

 

[Orien]

Here's to future better flights!!!

Curious... Did you do the splines I suggested?

I was going to, but it was so tight in there I was concerned the epoxy (which I knew would be on the thick side) wouldn't flow around them. I could've drilled a hole for each chamber I guess, but she's already starting to look like Swiss cheese. Between the meticulous surface prep, the screws creating a solid fastening point, and a quality structural epoxy with chopped FG reinforcement the whole thing feels solid as a rock today.