JAE Sponson Build Idea

[Blackout]

I think I figured out a good way to make sure the sponson tubes don't pull out from lack of epoxy. As mentioned in the instructions, you have to make sure there is enough epoxy on the tubes, but at the same time keep the epoxy out of the inside of the tube. This can be tricky because some of the epoxy is cleaned off when you slide the tube in. I decided to drill holes in the top of the sponson foam and fill the holes with 30 min. epoxy. Let gravity bring the epoxy down and around the tube a bit. Use a toothpick to get any air bubbles out. Add enough epoxy so that the hole is filled atleast 1/4" above the tubing or fill it all the way if you are not concerned about weight. Below are pictures. Any thoughts are welcome.

 

[opio]

that is a slick idea. I like it, looks like you can get a lot of epoxy in there!

 

[Ron Olson]

I'm building 2 more sets right now and gave it some thought also but using a V groove all the way across to help tie in the tubing and sponson sides a little better. The way that I'm thinking it probably would have been easier to cut the foam before epoxying the sides on.

 

[bzubee]

You can also run a die on the tube to lightly score the tubes and give the epoxy something to grip.

 

[Blackout]

When epoxying metal to wood I always rough the metal surface with medium grit sand paper and clean with laquer thinner. Laquer thinner is nice because it evaporates quickly so the part does not need to be dried.

 

[Ron Olson]

After posting last night/this morning I went downstairs and dug out the foam above the tubes which was unfortunately easy to do, that meaning that I found out how poorly the epoxy had worked in helping to hold the tube in place. I mixed up a small batch of 6-minute and put it in there. The cheapo in me would have placed the tubes in a drill and roughed them up with coarse sandpaper to add some grip to the tubes. The exposed parts of the tubes would have been in the chuck.

While doing this it made me wonder how the other big 'rigger builders hold theirs in place.

I just did the .12 sponsons but the .21's are going to get the same treatment.

 

[Blackout]

I think the big riggers use wood blocks in the sponsons. Holes would still help with wood blocks.

 

[Wes James]

This is all good to read, as I am going to be doing my JAE .21 sponson's soon... Thanks for taking the time to make posts such as this, guys!

 

[John Knight]

I think the big riggers use wood blocks in the sponsons. Holes would still help with wood blocks.

Craig,

You are correct. Most every rigger builder places wood blocks inside of the sponsons and the sponson stub holes are drilled and then the stubs are inserted. If you knurl (place bidirectional grooves or cuts) the stubs they will hold much better in the sponsons.

 

[TCHedOff]

Last yr I made 3 sets of sponsons w/o the foam core…. just 1/16” ply sides, and used a toothpick to really pile up the epoxy around the insides of the holes before I slid the roughed brass tubing into place. I experienced 1 instance of a tube letting go from the side. I also had to repair my sponsons a few times from hitting bouys…. Used a soldering gun to heat the brass until the epoxy soften and pulled out the bent tubes…. I was surprised by how much epoxy had actually adhered to the tubing…. You don’t want so much grip that you cant remove the brass inserts?

So on this yr’s build, I took some oak doweling and drilling it down the center lengthwise, and then cut this into 1/8” sections - Which I then epoxied to the inside walls of each sponson side for reinforcement. I am making both “eggcrate” (hollow) sponsons and foam cored sponsons…. Man the foam core way is WAY faster/easier! J