Props4ever

I recently got myself an unusual part of a vintage aircraft. It is actual nose cone/redome piece that was used on the airliner and was taken off after it sustained high speed rain damage while flying many years ago.

Its a honeycomb structure moulded as one piece unit.
Now problem is, there are couple of areas the are very weak and can be easily pressed in as i believe honeycomb is badly cracked from inside of wall. Now when i say inside i don't mean underside of the redome but inside of the honeycomb wall.

I want to keep outside original as it's chipped and its authentic this way, so what can i do to fix this part without damaging both underside and out side surfaces.

I was thinking of getting automotive fiber glass repair kit from Canadian tire and lay the mat on the underside while apply resin on it. Now once its fixed, i am planning to turn it into coffee table or make a model display shelf out of it. Your advice and help will be appreciated.

TeamSeacats

If you like the way the exterior is, why would you worry about a few soft spots (or is it THAT soft?).

Honeycomb cores, once damaged, are very difficult to fix if a lightweight usable repair is sought. If you don't care about weight, I would pierce the inner surface of the structure with a drill in a semi-elaborate matrix. Then, using an inexpensive plastic syringe from Home Depot or Lowes, inject resin into the crushed areas through the drilled holes. Start in the center and work your way out. If this is going to hang on a wall somewhere, Bondo brand polyester resin will work just fine (but note that it has some stability / shrinkage issues if used in some applications that probably won't be enough to be concerned with here.

Props4ever

Tameseacats,

Just to give you bit of idea how soft the top, top left and left side of the ring is presently. I have not yet fully decided what i will turn this redome into, a coffee table or display shelf. I sure do want to fix it properly that if i decided to do it as display shelf then ring should be strong enough to take the load of glass doors hinges on it and also the glass shelves i will installing in side of it. I also noticed the bottom layer of the honeycomb wall is split that i can easily fill in with resin and clamp it to fully cure.

Since it will never fly again, weight is not an issue yet i don't want it to a ton either after repairs are done.

I also talked to me dad about it and he said to keep the outer surface the way it is presently as it's authentic. So considering all are saying the same i am thinking to take it to auto paint shop and get semi-gloss sprayed on it so outer surface will stay the same and become bit more secure and sealed.

Props4ever

Here is the split in the wall as i mentioned earlier, would this split help in pouring the resin in the honeycomb structure between the walls. Plus what will be the good resin for this repair, i have Aeropoxy resin still left from my S Connie fiber glassing job.

sensei

Drill a series of # 40 holes on the interior side of the radome, and all in the delam area. Utilizing a syringe; inject a thin slow setting resin in all of the holes. Maybe something like EZ Poxy 10 and 84 hardener and allow to cure.

Bob

Props4ever

Hi Bob,

Seems as this is the only way to fix it by drilling bunch of holes and then injecting resin mix into them..How long would it take for EZ poxy 10 and 84 hardener to fully cure once injected and should i clamp the walls for re lamination or tape will do the job also?

ergocentric

Cool project, my wife would take my head off if I brought home one more 'project'.

My I suggest (after you fix the delaminations) to add a ring of carbon on the inside to really stiffen it.

Smithcraft has what you need.

Let me know if you come accross a cool looking small but long piece, I have a project started.

sensei

With the system I spoke of, it would take around 12 hrs. at ambient 70 F. You want it to take a long time to cure so it won't go into thermal runaway and distort everything in the area..

Bob

TeamSeacats

Wow, that thing is large! The delamination is the weakness so you need to figure out someway to reattach the core to the skins. Adding additional material to the inside will help but without darn-near filling it, it won't do much to strengthen it. Given the large areas of delamination that you are working with, I would first rough sand the entire inside of the cone. Then use a dremel tool and a diamond or carbide cutting disk to cut a series of 'slashes' completely through the inside skin to the core. I would then squeegie in a copious amount of resin...since it is not a structural repair, I would probably save a few bucks over epoxy and purchase a good quality "laminating" polyester resin with a slowish cure time (http://www.uscomposites.com/polyesters.html - B440 is what I would use). The slower the cure, the less heat generated...you probably wouldn't be able to feel the heat generated from this resin in this repair. With the resin in and everything saturated as much as possible, I would work the soft spots around, roll the unit around and let gravity and motion work the resin into all the bad areas. Then I would wipe up as much resin as possible from the inside of the cone, allow that to start to gel, and then lay in two layers of 6oz fiberglass on the inside to cover up the slots created with the dremel.

daven

My Feedback: (1)

I would make several (varying diameters) rings (formers) out of 1/4" plywood. Start near the bottom work your way out to the top. Three or four rings would probably be plenty. That should really stiffen the overall shape, then you could do some epoxy/glass work in areas that still needed stiffening.

skin6061

From your pics the core doesn't look to be crushed or damaged at all. I think the hweakness in the radome is from sitting outside in the rain to long. the fiberglass slowly soaked in the water, and once it started getting warm the moisture started building up and had no place to escape except for delaming the peice. i suggest fixing it like everyone else said, drill some holes and using a syringe start injecting with resin. i would not use a polyester resin, i would use a epoxy resin, since that is the type of resin that was used to make it.

Props4ever

I went and bought the epoxy and hardener today to do the de-lamination repairs on all the weak areas of this redome. Soon as weather clears and we get couple of nice warm clear days i will start doing the repairs. I'm thinking on doing composite repairs first then add some sort of structure inside to stiffen the whole redome. I have decided that i want to make coffee table out of this piece, i am also looking for the source where is can get 10mm thick tempered glass for it. It would be be on expansive side i think but this is very unique transformation and creation once its all done.

Here is how i came up to keep this piece in my hanger...It's Sig's Beech Bonanza F33 besides the redome...

Thanks guys for your assistance and help fixing this piece..