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| Fixed Wing Discuss fixed wing aircraft. |
Topic Review (Newest First)
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| 10-05-2011 08:47 PM | |
| supercub1974 |
Re: Expanding foam in floats? The floats are now retired and hung in the basement, with a new set of hanger 9 ARF floats on the way from Great Hobbies. They are too heavy now and I had a hard time getting off the water with the Gopro camera onboard. If I could change the way I added the foam I would just put a thin layer on all surfaces inside the float and let it stay hollow in the center. That would have made the thin fiberglass layer sturdy enough without the extra weight. Maybe next time. |
| 10-05-2011 03:42 PM | |
| mrrandyman |
Re: Expanding foam in floats? you really need to do it in small increments otherwize it doesn't gas off and the reaction stops. |
| 10-05-2011 03:09 PM | |
| Moosehead |
Re: Expanding foam in floats? Hi guys, I tried to fill the tail section of a fibreglass slope glider with some of that expanding foam. I would fill the cavity and it would look like it was going great. The stuff near the front of the cavity looked like it was expanding out and hardening normally. But something didn't look right in the tail. So I drilled in to have a look and where there should have been foam, was just a very sticky, messy residue. I tried again and again with different foams and different techniques but the result was always the same. I tried both the normal and the low expansion stuff. Does anybody know why this happened? |
| 09-06-2011 07:46 PM | |
| supercub1974 |
Re: Expanding foam in floats? Still haven't tried to fly the plane but I have noticed the places that were swollen are now gone the other way sucking the walls of the floats in? Looks a little strange but should be okay. |
| 09-02-2011 01:00 PM | |
| supercub1974 |
Re: Expanding foam in floats? I cut two square holes in the top of each float (2"x2") and sprayed in enough foam to cover the bottom. Two more applications like this and it was squeezing out the holes. Worked out okay with only some mild swelling in the sides of the floats and they aren't a whole lot heavier. Thanks for all the replies. |
| 08-31-2011 12:40 PM | |
| Tyler P |
Re: Expanding foam in floats? Honestly, a couple small vent holds will do the trick. I used expanding foam to do a repair on one of my foam-cored wings and it worked great! It's super light and did the trick perfectly. It also didn't expand the balsa skin out or anything because it vented back through the entry point. |
| 08-31-2011 12:14 PM | |
| supercub1974 |
Re: Expanding foam in floats? Thanks for all the replies guys, great information. I was thinking i could put the float in a large bucket nose down and fill it with sand or something to prevent the ballooning of the float?? Just adding a little at a time? |
| 08-31-2011 07:55 AM | |
| Big_daddy4902 |
Re: Expanding foam in floats? There is an article write in rcgroups.com written by "jimsp" entitled " Simple DIY Floats " They are super easy to build and the cost was less than $ 10.00. The article tells you step by step with photos how to complete the project. This is the link to the actual article http://www.rcgroups.com/forums/showthread.php?t=147465 Just another solution. |
| 08-31-2011 07:11 AM | |
| proptup |
Re: Expanding foam in floats? Hi I built the 1/4 Balsa USA floats and before I attached the bottom I used foam from a can. It does expand a lot and with a suprising amount of force. Even with the bottom open it broke a bulkhead. I found that keeping the nozel 2" from the top of the float (they were upside down) allowed the foam to expand more and become less dense. I think you may need several holes about 1" in diameter to allow for exantion and to be to apply an even layer of foam through out the float. It did not add much weight and they are much stronger, the flimsy 1/64 ply no longer bends. They are now water tight. However my next floats will be foam, covered with balsa or 1/64 ply and fiberglased with 3/4 oz cloth. Not hollow! If you have hollow floats try adding a vent tube in the top of each float. I have found that when they sit on the dock they heat up in the sun and the air inside expands. When you place them in the cool water the air inside retracts in volume and sucks water into the float where it normally would not. The vent tube allows the expanding air to vent. Cheers Clive |
| 08-31-2011 01:18 AM | |
| Beerwiser |
Re: Expanding foam in floats? The weight of foam is 2lbs/cubic foot at least on the stuff I used on my pump house. The stuff in the cans should be very close to that. It will also float about 60Lbs/cubic foot too lol. If you fill them with foam they will last forever  .
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