I am in the process of starting to scratch build some floats for a Dynaflite Super Cub. I have never built anything on floats before and have no experience with their construction. I have a couple of questions regarding my project.

So far, I have a scale drawing of a set of EDO super cub floats. I am planning on making them 48" long and the rest of the dimension will be scaled from that. I plan on making up an internal frame of balsa sticks and light ply formers. The formers that attach to the struts that will hold the floats on will be aircraft grade plywood. I plan on sheeting this frame with balsa sheeting and then fiberglassing the whole structure.

1.) What thickness of sheeting should I use to ensure light weight but will stand up to learning to fly off of floats?

2.) Should I use balsa sheeting on the bottom of the float, or go with a light ply for durability?

3.) What weight cloth should I fiberglass these things with?

4.) What final weight per float should I shoot for? What would be a general ball park, so that way I know if they come out way above this i should redesign and start over.

5.) Should I just save my time and spend the $60 on a set of 46" quarter scale cub floats from SIG?

Thanks for any suggestions,
-Scott-

Consider that you're getting the wood and all of the hardware (IE water rudder) not to mention Plans, instructions, and die cut parts.

Spend the 60 bucks. In the long run it will be cheaper.

Spend the money on the kit and modify it to your likeing..I've built lots of scratch floats and it just isn't worth it. The kits out are pretty good and can look very close to scale with some mods.But I would still cover them with .56 or .75 oz glass cloth and if they are around 48" put an inspection cover on the top and seal it . You never know when you might get a bit of water in the float, and its so hard to get it out of there... if you have any ? feel free to e-mail me or post a message for me....

Check out www.seacommander.com .
Beautiful fiberglass floats that don't leak and look real scale.
A bit pricy but worth it.
Peter

I'd use 2 oz cloth on the bottom of the floats...they take a lot of abuse beaching and launching...

I use a hot wire and cut a foam core. I cover the bottom with 20z cloth and epoxy. I put a spline down the middle for an attachment point. Last, I prime and paint the floats with foam safe paint. I wouldn't waste the $$$ on a kit. I build mine for like 16 bucks a set!

Good luck
Matt

My observation is that built-up floats are heavy.
Blow-molded plastic floats (GeeBee) are kinda klunky, but people either seem to love them or hate them.
Fiberglass floats are pretty and expensive, and get fractured, and frequently leak at the seams.
Foam floats can't fill up with water and sink, and are durable. I have one set on their fifth airplane. SHeeted with balsa, except for the points on the bottom that take the shock loads: inserted 1/16 ply sheeting just in front of the step. They're not unscratched, but they are still serviceable. I don't know of anyone making foam floats commercially, now. BJ was the preeminent brand. I generally charge $35 plus shipping for a set of v-bottom, tapered-side 45" foam cores that look a LOT like BJ floats....kind of a standoff scale EDO float. The nose is not as tapered as an EDO, but that keeps the prop out of the water.

Here's an article about making simple flat-bottom foam floats. You can get 4' x 8' x 2" sheets of foam at Home Depot for $10. Laminate it until it's as thick as you need.

http://www.flyinglindy.homestead.com/skisandfloats.html

There are several other articles on my Florida Float Flyers website: (That's why it's there)
http://jcasey02.home.gate.net/fff.html

I agree with Jim C. Foam core is the best way to go if you don't have the expensive fiberglass ones. Built up structures are difficult to keep water out of but impossible to get water out of. I have seen some foam core floats being advertised but can't remember where, check the magazines. If there is no where for the water to go, it won't go. Just my 3.5c worth. (2c US)
Peter

I've tried balsa built-up, all foam, blow moulded, fibre glass - all have +/- 's - but work well too. It is important to glass cloth the bottom of balsa and foam floats - once had a balsa float holed by a submerged log (might have been a crocodile though !) and it started to sink pretty quick. So they get the F/G treatment now. Whatever type you decide to use, make sure 1/ you use waterproof glues (epoxy, Ca - not white glue) and 2/ all joints are tightly sealed (wing to fuselage joint and tank hatch - smear grease). Enjoy. MalcolmL

Have a look at Niagara Custom Model Products for foam core float kits. Good prices but not as big as 1/4 scale. In 40 to 60 size range - http://www.foamcorefloats.com/