Posts Tagged ‘EPP Covering’

Hello

My name is Jon McCarty, some of you have seen me flying with Paul and Frank out at the Hermann Airport. Paul and Frank asked me to share a product I recently started using as an EPP plane covering. Its called Doculam (Well it used to be, I think it changed names). Its a laminating film, meant to run through a large laminating machine.  The film i am using is 1.7 mil CP, Its a low temp film perfect for foam use. The adhesive is heat activated so it only sticks where you want. The 25″ width on the rolls means you can use one piece and cover most park fliers. The company I ordered from sells this in 2 roll minimum’s but for a small surcharge they will sell one 500′ roll. which if your like me is more than you will probably ever use.

The film starts out a milky white color with a dull side and a shiny side, the dull side is the glue. I found a small craft iron at the local Wally world called the Tulip (Its pink, but it works and is $10) which after a few min. gets up to an almost perfect temp to apply the Doculam. I have also used the wife’s clothes iron, which heats up faster and is a bit hotter, caution the the low temp doesn’t need high heat, I use the big iron at about half temp.

Doculam before and after applying

One of the reasons I wanted to try this film is the fact that it can be painted. I have tried several types of spray cans,  from Wally world cheap stuff to Krylon Fusion, which I hadn’t found a way to use that on or even near foam. The Krylon Fusion works very well as a base coat with no chipping or peeling even when I folded a test piece 180 deg back on itself.

As far as strength goes, I recently had an opportunity to test the strength of the Doculam on my version of Franks Sky Fighter. at this time I believe I had the ESC fail which caused total control loss while I was traveling nose down at around 100mph!!  there were a lot of firsts in this crash:

First time I stripped servos in a crash, I got both of them.

First time I did that much damage to a battery and had it stay in the plane.

First time I had an ESC look like that after a flight.

First time I lost total control of a plane let alone one moving that fast.

First time I have had a plane hit the ground that hard and be mostly flyable, the major airframe was fine except for 2 small cracks in the lower fuse. there was some damage to the non EPP parts but the EPP survived and will fly again, the Doculam held up great.

If you would like to get some more info on Doculam here is a link to RCGroups thread:

http://www.rcgroups.com/forums/showthread.php?t=274520&highlight=doculam

I did some testing on the Doculam, I took 3 – 10″x5″ pieces of EPP. One I left bare of any covering as a control, one I covered in Doculam, and the 3rd I covered in fiberglass weave and Doculam.

3 test pieces

I then set my hanging scale so that the part would be suspended 3″ from my table top from its center. I measured how much force it took to flex the part so that both edges touched my table. I also weighed each part to get an idea of how much weight was added. here are my results:

Bare EPP:                                              weight- .5 oz                         force- 3.64 lbs

Doculam covered:                            weight- .6 oz                         force- 5.22 lbs

Doculam/Fiberglass covered:    weight- .7 oz                        force 7.08 lbs

Now the bare EPP and Doculam covered both took as much force to flex it as it took to maintain it, but the Doculam/fiberglass covered took more force to flex it but didn’t require as much to maintain it, it was 7.84 lbs to flex it but only 7.08 lbs to maintain it. Also something else I noticed that was surprising was that the Doculam/fiberglass covered piece bounce back closer to flat than the other two pieces did.

Warp after test

So my findings were as I suspected, that covering your EPP in the Doculam added strength but the addition of fiberglass as Paul and Frank recommend added much more rigidity.

I hope you find this information helpful in your future builds.

If you would like to try a small amount I have 500′ and will sell some at $.50 a ft plus shipping. email me at sales@bloodymicks.com and we can work out the details. This is for US, lower 48 states only no over seas shipping at this time please.
Jon