Hi guys,
I bought hk super glue ca thick(stored in fridge) and used it on  coro for making wings. i left the joint after applying ca for 15 to 20 mins, but the bond is not strong . Should i get HK ca thin?
Same happens with hot glue, but after a week.I think the paint on coro board(from advertisment boards) is responsible for weak bonds.i also washed the board with water first and let it dry but stil nthing.

Finally ,how to glue coro(note that ad paint on coro, how to remove it) and what to apply for stronger bonds?
 
Thankyou
Snehal

Sandpaper the coro before applying glue. The other teshnique is to flash the coro using a butane torch. Sandpaper is easier. Just roughen the surface so that the glue can adhere better.

Should i completly sand the paint or partially will work?will thick CA work with coro?

How to apply hot glue on coro? Should i heat the glue so much that its viscosity decreases?

Any alternative for butane torch?

I have used Fevikwik tubes and Industrial CA (Thin) with coro. You don't need to sand off all the paint, only the areas where you plan to apply CA. There may be other alternates to a butane torch, I know of people who use cheap cigarette lighters, but they are experts. I would advise you to use sandpaper to start with.

You could also make your own CA accelerator or kicker by dissolving half a teaspoon of baking powder in half a cup of water and spraying the liquid into the joint after applying the CA. This will cause the CA to set fast. However, be careful, this may also compromise the strength of the joint.

The hot glue should flow easily onto the coro, the consistency of the heated glue should be like toothpaste. Ensure that the hot tip of the glue gun does not make contact with the coro.

Thankyou Vikram sir for the information.
Should i apply bead or drops of CA or hot glue (inch interval)?

After lightly sanding both surfaces of the coro to make the surface dull, clean it with iso propyl alcohol. avaialble at all electronic stores for around 15rs for 100ml. This gets the oil off.
Then stick it with little cyano. don't use too much. one drop per 2cm of length of joint. Hold the edges together with many clothes clips. applies more uniform pressure without crushing the coro.

You are welcome. Btw., its either VC or Vikramaditya and cut out the Sir!

One golden rule with CA on coro - Too much is too bad. Use as little as possible, or else it will just refuse to dry out, it will ooze out and create a mess. Worse, the wing will get stuck to the surface and in trying to pull it out, you risk damaging the entire wing.

Can rubber based solution be used I assume it will give very good joint .......bonfix available easily?

Yes, however, that may add some extra weight to the model.

Yup but thin layer on both surface will be very strong.....

Actually u are forum hero and i have developed high respect for you coz u truely help others and put ur hard effort to maintain Rc india and its status(one latest example stuart one) . Saying sir is not intention but it comes out auto, from ma heart.

P.S. Mai makkhan nahi lga rha.

@ratsaurabh
what is a rubber based solution?would like to try it.
From where can i get?any brand name wil help a lot. I am guessing that cobblers use that. Am i right?

If anybody used rubber based soln on coro before, then plz share your experiences.

Thanks

Dendrite is a rubber based solution. But I finally found Industrial cheap CA(Thin) is the best.
After using the process as adviced by VC, this gives the bond which cannot be opened but torned into pieces under testing.

While applying CA, I even not sqize the bottle. The cold bottle expands with the heat from my finger and CA comes out normally and just applied like a Zig-Zag line with 1" apart. Just then the upper surface is attached and left with ruller at upper surface for uniform pressure.

But I stiill prefer single layer coro wing. It's lighter and better for slow flyer. But if you prefer high speed, you have to go for duel layer 2mm Coro wing with reinforcements

Yes I have used Dendrite on my Hovercraft builds. However, you need to buy the industrial Dendrite that is available in tins. The ones that are available in tubes are for light use and do not have the requisite strength. Having said that, I was not too happy with the results and switched over to CA / Epoxy.

Epoxy, like Araldite or Fevitite, is very good but adds extra weight which is not desirable for aero builds.

So what i infer is that CA is best for sticking coro pieces.But only THIN one, and not medium or thick. I tried thick CA with coro and failed.

So i guess Rs.10 tube of feviquick(Is it thin?) wil be best for coro wing. Am i right?

Yes... the best.

I used FLEX KWIK , i my bonds are very strong. you can have it from any hardware shop for just rs 30/-  15gms bottle.
But before applying sand the coro slightly, and you will get best results  .just try it once.

Thanks for the info Swizera. I should try dat. Is flex kwick a CA or some other material? I might need to tell the shopkeeper what is it actually used for.

Just ask for any glue like fevikwik or CA in your nearest hardware store and ask for large quantity use like 2 x 20ml botthe or 2 nos 15 gm bottle. You may be cheated first with torn MRP tag. But you will know the local BrandName.
I use VegaQuick of Resinova Chemie Ltd of Kanpur.
http://www.indiamart.com/amar-traders-bidar/products.html

I follow this, and it works well

- Use CA Glue - Industrial Strength. Available with someone who sells sunpac sheets (coro).
- Clean the sheet before sticking - use colin or similar, clean both surfaces that need to be joined
- Lightly sand using 100 no. sandpaper, don't rub in too hard. Use circular hand movements for best results. Once sanded, use a cloth to wipe off the area.
- Use dots of CA glue spaced almost 1 inch apart. There will be no time for measuring, so estimates are good. Too much of CA is bad, so only use dots of CA glue
- After sticking, lightly press together and hold for about 30 seconds. Pressing too hard might collapse the flutes inside.

Hope that helps

Snehal It is specially used for sticking FLEX sheets. just ask for Flex kwik .
i am attaching its pic . u can show him the pic from ur mobile too.