Coupler wedged in tight after lawn dart, how to remove?

The ejection charge on the motor on my Jart 5 failed to fire and the rocket lawn darted. Pulled it out of the ground and first thought was that it was in remarkably good condition, at least on the outside. The inside was a different story, the AV bay was pressed forward, we could not take the rocket apart despite several strenuous efforts.

We ended up sawing the rocket apart and then were able to remove the broken bulkheads and sled. The coupler tube, however, remains tightly wedged in two pieces, half in the nose cone, half in the airframe. Any thoughts on how to get the coupler out? Can't fit a hacksaw inside to cut it out, maybe need some kind of small mini-saw? Could possibly pull it out if there's a way to get more leverage.

Any ideas?
Thanks, Bill

First of all, my condolences. Second, I confess I had to chuckle at the statement of a Jart "lawn dart", since of course the original Jart was the original lawn dart toy.

Anyway, I"d suggest breaking, tearing, or cutting the coupler up and removing it in pieces. I couldn't tell what the material is. If it's cardboard then just slip a knife point in, cut toward the centerline, and just pull pieces out. It it's fiberglass get some sort of saw on the inside, cut carefully so you don't reach the body tube, and break off pieces. You could use a saw blade wheel for a roto tool, a "single ended" hack saw, or anything else that will get inside. Or a chisel-like tool to chip it out. Just don't try to go for an "all at once" solution and you'll get there eventually.

X-acto Razor saw, or japanese style pull saw?

Stick it in freezer overnight, possible the inside piece might shrink more than than the outside and pull loose.

If that doesn’t work, and all the parts are water compatible, try soaking in hot water

What are the parts made of? With all due respect to BABAR, if it's a cardboard coupler on a cardboard tube, or a fiberglass coupler in a fiberglass tube, etc. then freezing it won't work. If they're not the same material, try looking up the CTEs and then put it either in the freezer (if the coupler CTE is greater) or the oven (if the tube CTE is greater).

Thanks for the replies. It is all fiberglass, looks like I'll need one of those small saws.

jqavins said:

What are the parts made of? With all due respect to BABAR, if it's a cardboard coupler on a cardboard tube, or a fiberglass coupler in a fiberglass tube, etc. then freezing it won't work. If they're not the same material, try looking up the CTEs and then put it either in the freezer (if the coupler CTE is greater) or the oven (if the tube CTE is greater).

Click to expand...

If the coefficient of thermal expansion is the same, placing ice inside and heating the outside quickly might cause the two parts to contract and expand differently and be able to pull apart.

AAir pressure,use a blow gun between the sides.

Modify a slide hammer with a hook atachment

Couplers can really get impossibly stuck in tubes unless you can apply force precisely along their axes. With a 3 or 4" tube, using a motor case to push the coupler sometimes works, can't do that here. I'm not sure if there's a way to get a bulkhead in there so you can push on the center of the bulkhead, but that might work.

I'm not sure that airframe is really salvagable, you might want to cut that away instead, from the outside with a Dremel cutoff wheel or something.

Yikes I'd be tempted to give that nosecone a Viking Burial and cut the fincan below the coupler and salvage just that. I'm keeping an eye on this thread to see how/if this works out.

For fiberglass, a Dremel with carbide bur ( https://www.mcmaster.com/burs Click on burs). I prefer the round end cylinder. Carefully grind a groove through the coupler. Once through, the coupler will come out easily. A small amount of cutting into the body tube or nose cone won't hurt anything.

Call Wildman and get a new cone or complete kit. Coming in hot there must be other damage.

Give me a call on Monday and we will get you taken care of

Thanks Tim, and thanks to all for the replies. I was able to cut out the coupler using a single-ended hack saw like the one pictured above by Joe. I'll also have to cut off the bottom 1.5" of the nose cone, the fiberglass was damaged. Airframe looks brand new, no damage at all.

Does that mean I win?