Stuck Sponsons on Tubes

[Andy Brown]

Andy, you described the brass tube as held in by large dowels. I assume they have a near same od to the aluminum rods. How are the dowels built into the sponson? I need the picture painted in my head before I rationalize a restoration attempt, or I heed the safe play advice. Thanks!

Thomas,

A 1" O.D. wood dowel with a 17/32" hole bored into it for the brass tube is glued into the foam core. It is sandwiched between the inside sponson plate and an internal (not visible) sponson plate that is similar to the inner plate.

So there are a total of 3 sponson plates or formers . The inner, the internal, and the outside chine plate. The top of the round 1" dowel is sanded flat before the sponson is decked. Therefore the dowel is also secured to the deck. The 1" dowel is as long as the bottom of the sponson is wide. The brass tube, which has a plug in the end to keep glue from entering into it is glued into the sponson after the sponson constructing is complete with 5 min epoxy. The brass tube passes through a 17/32" hole in the internal plate. Everything is assembled with 5 min epoxy.

It is a strong structure. Have never seen one total destroyed beyond repair, even after crashing into concrete wall.

 

[Brian Sorgente]

Yep the more I look at the pics the more I see what Andy means. Clean it up and paint it. Depending on how you tape off the tube when you spray it, you might be able to hide the cracks. You know they aren't going to com apart, would be a lot less work too.

Brian

 

[ThomasMoroney]

So I went down to The Hammers shop and we threw caution to the wind. We cut the rear tube, applied heat, twisted, and out came all the brass. No damage resulted in the brass removal. I can also now repair a cracked dowel nearest the turn fin. Upon removal we could see the dowel split as did the sponson skin due to the expanded brass I guess. Easy fix.

Now the only oversight was the loss of aluminum rod due to the galvanic reaction. The front aluminum rod measures in at .498x? I will need to double check that later. A brand new .5015 ID brass tube has notable play.

So Andy, how is the front rod pinned in the solid block up front? As one of the plays here is remove a thin rectangle of ply sheeting and de pinning the rod. Heat, twist, new rod. Or perhaps drill out the pins with out touching the sheeting, other than hole repairs.

 

[Ray Sametz]

So I went down to The Hammers shop and we threw caution to the wind. We cut the rear tube, applied heat, twisted, and out came all the brass. No damage resulted in the brass removal. I can also now repair a cracked dowel nearest the turn fin. Upon removal we could see the dowel split as did the sponson skin due to the expanded brass I guess. Easy fix.

Now the only oversight was the loss of aluminum rod due to the galvanic reaction. The front aluminum rod measures in at .498x? I will need to double check that later. A brand new .5015 ID brass tube has notable play.

So Andy, how is the front rod pinned in the solid block up front? As one of the plays here is remove a thin rectangle of ply sheeting and de pinning the rod. Heat, twist, new rod. Or perhaps drill out the pins with out touching the sheeting, other than hole repairs.

Slow down! We got real lucky with getting the sponsons off, lets not push it. I Would not mess with that front boom tube in the nose. Call me I have a solution.

 

[ThomasMoroney]

Ray, yes I will give a call asap. I took a quick measurement of the rod this morning. Its range is from .4900 to .4940. Those are also outlier measurements, as I measured .4915 to .4925 more frequently. The new rod measures .5015 to .5025. That’s inches for anyone who is wondering.