FoamCoare Board VS Depron or CellFoam
 

Being self crowned "King of Chincey" , I have experimented with a lot of different new materials that pretty much replace the use of Balsa and save money (don't take me wrong, Balsa still has a lot of uses trumped).

What I have found is pretty serious in building and can bite you in the b*tt as it did me..so here goes

I "discovered" this cool new material called foamcore that everyone seemed to be building with ...bought typically at Hobby Lobby craft stores (not the RC Hobby (dash) Lobby)).

By itself (unpeeled) it has two slick thick paper faces that are sort of heavy for our "normal" use (its pretty stiff and strong unpeeled, and can be used that way fine and is not as strong but lighter than lightply).

What is not known is if you buy this stuff and peel it (many tricks to do this and other threads describe how), it ends up looking and working sort of like Depron, only a little softer.

Here's the problem. I thought WOW, I'll build several planes of this stuff and laminate the edges of the tail surfaces with a 1/16" brich dowel (soaked) or a 1/8" balsa strip to give it some integrity and stiffness. Well that worked...BUT (doncha just love it)...on every one of them...(5 in all) about a week later the surfaces began to look like tulip petals....YUK...I mean YIKES!!

Here we have several models built and ready for finish (I prefer acrylic ) and the tail surfaces are all warped horribly....not even iron on covering could get the warps out....nor could a heat iron or heat gun.

At first I thought it may have been the disimilarity of the shrink of hardwood or balsa to the foam core... but then I tried the same on Depron and CellFoam available at RCFOAM.

No problem...never a warp...no matter what the humidity or time left unpainted/unsealed.

So...

Never use FoamCore for anything you would add stiffening to (ie laminating edges, stiffening carbon fiber strips, balsa reinforcement strips)

It's a good material to use "as is" with its facing as this actually controls the shrink of the foam material...but don't try to use it after spending a lot of time stripping it of those faces. I posted some pics of this "phenomenon" on other forums on a couple of build projects that got seriously delayed trying to solve this mystery.

My advice...don't waste time with foamcore...just buy depron or *cellfoam (*which is just as cheap as foamcore) and same all the grief of stripping it and discovering this anomaly later.

I found cellfoam here to sample

http://rcfoam.com/cart.php?target=ca...ategory_id=107

RE: FoamCoare Board VS Depron or CellFoam
 

Sorry to hear of your problems with the Hobby Lobby foamcore. I have been using all three thicknesses of this stuff and havent had trouble with it warping on me. I dont face the wing leading edges with the wood, I just use hard balsa for spars at the hingeline on the tailfeathers and lately have been useing those dowels at HL in the wood stuff area for spars in the wings. They come in several sizes and I glue them on to the bottom of undercamber wings and then put strapping tape over the dowel to kind-of smooth it out.
Have you found out this foam has a grain? It is several times stiffer bending one way then the other. Always run the stiffway, longways for all your parts like wings, fuse sides and horizontal stabs. Also I have found over the years that if you paint the top of a wing, paint the bottom also because the painted side will tend to draw it up, dont know why but it does....What kind of glue are you useing, maybe that is a problem, but I have used about all the water base glues out there and have been OK.

Maybe you just got a bad batch of foamboard, I have used HL and Dollar Store stuff for about 4-5 years, maybe 25-30 planes built. Fly em till the get rough looking and them hang them up of give them to the neighborhood kids to hang in their rooms......

Good Luck
Bob

RE: FoamCoare Board VS Depron or CellFoam
 

The clearer type Gorrilla glue is best...but have used foamsafe cyano , spray contact, epoxy and low temp hot glue...all same results.. Yes , i know it has a grain.


Ok, we've heard a "no problem"...and you've seen my case...let's hear from others..

anything...good....bad....indifferent.. let's compare notes