Epoxy Wing Joining Kit

[Dai Fledermaus]

I tried to use a Delux Materials Wing joining Kit this morning on the wing of my Uno Wot. I say tried because this is what happened;-

The kit had been in a cold garage for a few days and I noticed that one of the liquids was not very fluid, so whilst I had lunch, I placed both bottles containing the epoxy resin and hardener in a dish of warm water in the hope it would make mixing the two much easier.

Back in the garage, having poured all of the contents of both bottles into a container, as instructed, I mixed them very quickly because I wasn't expecting to have too much time to complete the job. Again working as fast as I could I had just enough time to apply resin and tape to the top half of the wing before it started to set off and what was left of the resin in the container went hard.

Now, Delux claim that "pot life of the mixture at room temperature is 8-10 mins but longer 15-20 mins at lower temperatures" I guess my mistake was to warm up the resin and hardener, but if I had known what was going to happen, I'd have mixed two batches, half of it for the top of the wing and the other for the bottom.

Lesson learned

[Bob Cotsford]

yep, it's a chemical reaction so heat speeds it up - as you say, lesson learned

With some resins it's a compromise between getting them warm enough to flow yet not so warm that they set in the pot. I've got to say 8-10 mins pot life isn't much. If youi have some 30 minute epoxy you can try thinning that so that it will flow, I hear that methylated spirits will thin epoxy - or you could warm it up to flow and accept it will start setting quicker. I use Z-Poxy 30 minute and it's just about thin enough to use on a wing bandage at room temperature, I often use it to add glass reinforcing in spats and the like.

ps - I think that the bigger the batch of epoxy that you mix, the faster it will set. Using a wide shallow pot for mixing helps to slow the reaction by reducing heat build-up(?).

[Mowerman]

I had similar problems with my Jocasta wing. In future I will use either slower setting epoxy or poly C.

[Dave Hopkin]

Posted by Mowerman on 01/04/2015 16:06:45:

I had similar problems with my Jocasta wing. In future I will use either slower setting epoxy or poly C.

Dont use Poly-C for wing joining - it doesnt have the strength of Epoxy - its enough to hold lightweight cloth down onto a surface but not as any sort of load bearing component

[Mowerman]

Slow setting epoxy it is then.

[Former Member]

[This posting has been removed]

[Michael Little]

Apologies for bringing an old thread back up but is it ok to use Z-Poxy finishing Resin or would that not be up to the job of joining wings together?

[Former Member]

[This posting has been removed]

[Denis Watkins]

What makes this set up strong Michael, is that the fibres are "wetted" with adhesive, making contact

With both the fibres of the bandage and the fibres of open cells in the wood.

So long as there is adequate adhesive, and overlap of bandage, all in close contact, as Percy states, Aliphatic will

Do the job more than adequately.

Traditionally, we use epoxy type smelly resin as it does penetrate so well, and before Aliphatic, it was in our

Armoury of very strong glue

[Nigel R]

PVA for me, squeegeed in using a bit of balsa or an old credit card or similar.

I use several layers (a wide & a narrow strip) of glass surface tissue, rather than a single thick layer of woven cloth. It's easier to blend the edges (as in, no need to bother). My dad has for years used medical bandage & PVA, again never had an issue.

[Michael Little]

Thanks for the replys, if its better to use pva then i will use that, i just thought as i have some z poxy finishing resin i could maybe use that. Can i just use any pvc glue then from screwfix?

[ChrisB]

To some extent it will depend on the model, its size, weight, design and type of propulsion.

I'd probably use PVA/Aliphatic on smaller, low energy models and good old fashioned 24hr epoxy with bandage on larger, heavier or high energy models. I tend to use Bucks Composites 24 hr epoxy for firewall, tail and wing fixing and pva for general construction and Poly C for finishing.

[Michael Little]

Its for an Acro Wot 58" wingspan with an OS 55AX I'm just itching to join them together now but would rather make sure I'm using the correct stuff first!

[Former Member]

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[Rob Tothill]

Hi Michael, I'm just building an Acrowot too. It's only my fourth build so I'm not very experienced. I joined the wing halves with 30 minute epoxy, and then once joined used skinning epoxy to apply the bandage, which seems to have worked well.

I did find that the tips and roots of the wings were not perfectly aligned, so I spent a lot of time taping the two halves together and marking up to ensure the tips were lined up before I joined the two halves. I then had to fill the surfaces at the root a bit.

[Mike Stevens]

Posted by Rob Tothill on 02/08/2017 23:53:38:
Hi Michael, I'm just building an Acrowot too. It's only my fourth build so I'm not very experienced. I joined the wing halves with 30 minute epoxy, and then once joined used skinning epoxy to apply the bandage, which seems to have worked well.

I did find that the tips and roots of the wings were not perfectly aligned, so I spent a lot of time taping the two halves together and marking up to ensure the tips were lined up before I joined the two halves. I then had to fill the surfaces at the root a bit.

That is what I did with Acrowot a few years back with Z Poxy - not flown it yet ...lol. Interesting to know that other glues can be used though.

[Michael Little]

Thanks for the advise, i have got some Z-Poxy 30 minute epoxy from a friend now who have me about half full tubs but after reading this I'm thinking i may be better off using Alphatic glue as this seems the preferred method nowadays? and rob sorry do you mean you used the Z-poxy to join the flat foam surfaces together before epoxying on the fibreglass along the join on the wings?

[Tim Flyer]

Just a quick tip on epoxy not mentioned. After mixing (smallish amounts best in hot weather as stated) place the mixing tub on a cool bag ice block . That gives much more working time. I put the block in a thin plastic bag first in case I spill resin.

[Mike Stevens]

Posted by Michael Little on 04/08/2017 11:10:27:

Thanks for the advise, i have got some Z-Poxy 30 minute epoxy from a friend now who have me about half full tubs but after reading this I'm thinking i may be better off using Alphatic glue as this seems the preferred method nowadays? and rob sorry do you mean you used the Z-poxy to join the flat foam surfaces together before epoxying on the fibreglass along the join on the wings?

I used slow set epoxy to join wings at root and then used z poxy and bandage to wrap the wing on mine.

[Rob Tothill]

Hi Michael, sorry for the slow response. I used 30minute gluing epoxy, rather than skinning epoxy, when butt joining the two wing halves together. Once that was dried I then prepared the wing for the bandage. I found there were some small gaps in the glue joint between the wing halves, so mixed a little bit more 30 minute epoxy and ran it into the gaps using a hairdryer/heat gun to make it flow.

When aligning the wing tips I kept the misalignment at the roots at the trailing edge, so the leading edges were in line, but there was about 3/16" offsets at the root. I infilled with balsa and then when that was dried and sanded used lightweight filler to get it to a smooth finish. This makes it easier to apply the bandage as it won't conform to a tight radius well, and wouldn't have contacted the whole surface where the roots were misaligned.

Once all was nice and smooth I applied the bandage with skinning epoxy (z poxy).

[Rob Tothill]

Infilling at the root also reduced problems when trying to align the wing to the fuselage to ensure that the incidence and lateral alignment were correct.