Hi Guys,

This is my first test before building planes. I plan to do many more such tests in the future and post it here. Any comments will be helpful.

I used the following glues to test and tore the pieces apart after 12 Hrs of settling(Not actually required.) A very thin layer of glue were used to rule out the side effects of heavyness.

1)Foam Safe CA from Hobbycity with Insta Set CA for quick drying on the residue CA.(I sprayed the Insta Set for the excess that came out.)
http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=7525
http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=8456&Product_Name=Insta-Set_CA_Accelerator_2._oz
Also available with LHS.

2)very Thin layer Hotmelt glue(I have a glue gun that will help me set the temperature from 140 to 220 degrees - 100 watt power, Chinese make). I have used 180 degrees.

3)A LITTLE thick layer of hot melt glue.

4)Fevitite. Here I placed the foam on the base foam and slightly moved the top foam 'to and fro' to spread epoxy a little.

After applying the glue I let it dry for 12 hrs.

For Result comparison:
From what I have experimented before, A very THICK layer of foam safe EPOXY like fevitite or HOT GLUE gives ultimate strength. In fact its stronger than the foam itself. So considering the strenght of such joins as 100 percent strength, the strength of the individual joints is given below.


1)Foam safe CA with Insta CA setter for excess glue:70 to 75 %

2)Thin layer Hot melt:75 to 80%

3)A little thick layer hot melt: 80 to 85%

4)Fevitite:85 to 90 %

I did not use any spring balance to rip it off. Its just based on the strength I put to break these. SO these are estimates only. I don't have a precision scale to measure weight of the pieces but all were 2 grams except for the CA joint which was oscillating between 1 and 2 grams.

From this I conclude that

1)The Strength of the CA joint was JUST as strong as the foam itself. Too much CA is bad, it eats/brittles foam unless you quickly spray the setter on the excess CA. Foam safe CA is expensive, but considering how LITTLE is required, a small bottle can be used a long time and is very light. But you need to consider the setter cost as well. I have tried without setter but a little excess CA also that comes out of the joins wont dry soon and causes a little brittleness near joins reducing the strength to 50%.

2)The hotmelt is the cheapest, convenient and heaviest (From what I have read).

3)Very strong, but you need to apply within 2 mins for best results, you cant just mix the epoxy and apply after 3 mins. Heavier than CA, Expensive as you need to use a thicker layer than CA.

Final Choices:
1)CA on large area joins, Where you cut the foam into shapes to get maximum contact area(don't know what that process is called.)
2)Fevitite on stronger joins - like rudder-tail of an f22 raptor. Where you need barely 15" joins to build the whole plane.
3)Hotmelt Glue, If you dont care for the weight and want robustness and ease to applying.

Hope this helps.

Vinay.

Commendable effort Vinay 

BTW, if you are working with epoxy, it makes the whole process a lot easier if you do the mixing strategically on a piece of paper, and then roll it like it is done for cake decorations (cone shape, like how it is used for Mehandi also), secure the cone with some tape and cut a small hole at the tip.  This makes applying small amounts of epoxy very easy.  Just squeeze the top of the cone, and the required amount of epoxy flows out of the tip.  No messy on the hands !

Thanks Anwar bhai, I searched many sites and got many answer. But I was never satisfied with any. So I thought before I start building a plane, I will experiment it my self. After the test was over, I thought I'll put it up here so that its useful for beginners. .