light balsa

[anthony_marquart]

I know the best material for cores would be one of the hard foams that are available. These materials can be expensive and sometimes tought to get in small quantites. I've been using contest grade balsa for cores. I know it's a little heavier than the cheap pink or blue foams available but it's much stronger also.

Have any of you guys had any issues using balsa for sponson cores?

 

[Mark Poole ModVP]

I have made several different "things" out of balsa that are on the bottom of a boat. Never made an entire sponson out of it but I know people who have and it seems to work well. Long grain balsa will not have the compression strength that end grain will but I have encapsulated it in different things including plain fibergalss and it did ok. When I make plugs out of balsa I give the wood many coats of resin and the surface ends up being very hard. Still, a small area impact will dent it. If I were making a hydro sponson out of it I would skin it with thin ply (that might be what you already have in mind). That type of construction bonded with epoxy resin is quite tough.

 

[mercguy]

I know the best material for cores would be one of the hard foams that are available. These materials can be expensive and sometimes tought to get in small quantites. I've been using contest grade balsa for cores. I know it's a little heavier than the cheap pink or blue foams available but it's much stronger also.
Have any of you guys had any issues using balsa for sponson cores?

Anthony

I made a couple of Pinkerts Gator outrigger hydros using balsa on the sides of the tub with 3/4 oz. fiberglass over it. Mark is quite correct in that it dented very easily. For sponsons I too would recommend covering with thin plywood.

Bill

 

[tnrcboatracer]

As already noted, grain orientation is critical. The balsa will tend to split along the grain. Balsa is no heavier than the higher density foams.

 

[anthony_marquart]

I have been laminating 1/2 pieces of balsa together, then I shape it and cover with with 1/32 ply. Seems to be working very well so far.

I was just wondering if anyone had any experiences I should look out for.

Thanks guys,... I'm going to keep using it.

 

[warlokboats]

anthony

i used balsa in my warlok boats from the begining. front and rear and had no problems. used 4/6lb contest balsa.

jon

 

[Ron Zaker Jr]

I know the best material for cores would be one of the hard foams that are available. These materials can be expensive and sometimes tought to get in small quantites. I've been using contest grade balsa for cores. I know it's a little heavier than the cheap pink or blue foams available but it's much stronger also.
Have any of you guys had any issues using balsa for sponson cores?

Make sure you router them out as MUCH as possible. Leave only enough wood for tube support,sides,back,top and bottom. Turn fin sponson needs to be a little stronger depending on your fin mounting, example... turn fin spar behind sponson (Ninja) or standard 2 hole on sponson inside.(Crapshooter).

 

[jeff baham]

anthony, ive been useing balsa for sposon for over 15 years with no problem, i ran my twin for the first time this weekend and when i came in in to the launch area, the motor would not die and i ran into the the only pipe by the launch , broke the fiberglass boom tube and the aluminum stub boom in the sponson, the front of the sponson had a little indentation . ifxed it and ran the next round. so go for the balsa, don't have to rebiuld everytime you hit something.

 

[Ray Sametz]

OK, My 2 cents. Besides the weight factor, the hard wood blocks for the boom tubes a stronger with balsa. Also think you get a better edge when you skin them using balsa, more forgiving when cutting on the band saw.

 

[Charles Perdue]

I use balsa for prototype parts including sponsons. Fast and easy to form and try different shapes quickly. It also gives you more design lattitude and allows you make more aerodynamic top surfaces, you are not limited to corners and sharp edges. Air hates sharp edges, they create more drag and erratic air flow over the surfaces.

I also use balsa for plugs to make molds. For me it is much faster than any other material that I have tried. Just my opinions.

 

[Dan_Cousin]

The one thing I don't like about balsa core sponsons is if you get water in them they will swell and not dry out back to the original size. This means that if you get a leak say at the boom stud, the inside edge of the sponson will crack the corners of the sponson at the glue joints. When it dries, it doesn't retract all the way and leaves a crack in the paint. You then have to square it up with epoxy and sand to finish.

Other than that is a dream to work with. make sure you have dust collection on your power tools.

 

[time bandit]

Balsa is a great medium to work with for a multitude of purposes. I don't think I'd use one solid piece for something as large as a front sponson. I use solid blocks for the rears but the fronts I essentially build a box, where the inside is 1/4" balsa 1/64" ply lam (1/8" ply turn fin side). Top and outside 1/2" balsa no lam and the bottom is 1/16" ply. The boom sockets are set into internal blocks.

Hollow sponsons will be less effected by water damage and heat. They're also much stronger and do a way better job of absorbing vibration and punishment.

Think if a full scale boat were made from solid wood. Besides weighing ten tons, it would beat you to death

my 2 cents

gh