FrankFuss

I have an ARF with a complex plywood framework (EF Yak 74”) that is lacking glue in many of the joints. What is the best way to add glue to this structure? There many gaps where gap filling CA would not work well. I am thinking about using CA where the gaps are small and Titebond and a glue syringe to fill in the large gaps. Do you guys have any advice for me since this is probably a common problem? Thanks.

Frank

styk

Hi Frank
I have just finished the EF Yak 74 and what i did and i suggest you do is buy 1/4" Triangular stock balsa and go round the inside of the frame in the corners of the formers and engine box glueing them I used epoxy for around the engine box and F1 and thick CA for the rest You can see what i mean if you look at the front of the firewall where they have already done the same thing This method really reinforces the joints with not a lot of weight gain By the way you'll love this plane Absolutely lovely to fly
best of luck
Styk

Rodney

A lot of hardwoods (plywood included) is somewhat acidic and will not bond well with CA. To make a good bond with CA just dust the area very lightly with plain old baking soda (from the kitchen) first. You will find that the CA will make an instant bond if the acid has been neutralized by the soda.

foodstick

You might want to do some experimenting with Elmers Ultimate glue, or Gorilla glue, both expand and make a nice strong gusset of glue, I think it pretty light when dry as well. It doesn't sand well, and if you are real picky about how the insides of your plane look you might not like it. I am SOLD on the product though and use it all over the place.. just don't get it where you will need to sand. If you get a blob you need to remove, a dremel with sanding drum works best for me.

daven

My Feedback: (1)

I agree with Rodney, sprinkle baking soda in the gaps and hit with thin CA. It will form a rock hard bond, just watch out for the fumes.

It does work very well. Fine saw dust works well also.

FrankFuss

Thanks guys. That gives me some ideas.
Frank