I have built several foam board planes from plans. And designed several of my own for fun and FPV. Over the months after several flights in the winter or from just handling my designs, the paper can start to roughen or peel from the foam on exposed foam edges. Many people wrap the edge of wings or belly with extreme packaging tape. This makes a nice seal or stronger edge for sure. But in some spots it isnt all that practical. Sometimes its hard just to cut the tape to fit all your contours. And it just adds weight! So try this on your next build.
I have found using a few drops of wood glue or contractors glue works wonders. Simply add a few drops every other inch to the 3 layers and smooth with your finger. When dry, it forms a smooth clear bonding seal. It also makes the panel more rigid. If you do put it on thick it can dry to a yellow or light brown color so be carefull.
Sometimes it is a better bond than hotglue. I might have a alieron that needs installed and start with hotglue. But only just to hold it till the carpenters glue is set up. By putting wood glue in places panels might have little reinforcement and flex is a must.
Notice in this pic I used hotglue to hold the panel 90 degrees upright while the carpenters glue dries over night.
Just be aware these panels are now married and will not seperate with a knife like with hotglue!!!
Here the motor mount is permanent and lighter than hotglue. Yes I could have used a wet paper towel to clean up the excess but I forgot to in this one area.
By the way..... This is not normal foam board. It is the higher grade brand sold at places like Hobby Lobby. It's 3 times the price. Whats the expensive Foam Board like? This quality stuff is harder to cut, the foam is more rigid. And the paper is glossy and thicker as well. Weight? Well, yes heavier too. Regular foam board is something like 47 grams for a full 20 x 30 Dollar Tree sheet. This stuff is about 253 grams a full sheet. But i love being able to use less of it to be able to make something very strong.
If you preffer to paint the glossy brand be sure and scuff it with very light sandpaper or painters scuff pads to get the proper paint adhesion.
Happy Landings!
Also not using tape on the leading edge of a wing and using glue to penetrate and seal all three layers makes for a lighter and stronger design. Sometimes more appealing to the eye as well since the glue dries clear. This makes the edge somewhat moisture proof if you fly a lot in the winter as I do.
Another unmentioned point.... This expensive brand f foam board also comes in 3/8" and 1/2" thick sheets as large as 40"x 80". They are not cheap by any means. But if you want that 80" wing to be one piece the is the way to keep it simple. Larger scale scratch builds can be made out of thicker foam board instead of the standard flexible blue and pink insulation at hardware stores.
Enough said..... Happy landings!
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