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View Full Version : Finally had to rebuild my sponson



Capt. Crash
05-11-2009, 02:58 PM
After repairing all the cracks with band aid repairs like CA glue due to a lot of abuse...I finally had to do surgery.

The prep sanding completed, I went ahead with the glassing. I first mixed 1/4oz each part Z-poxy but found out that was way too much as you can see from the rock hard left over in the pic below. I mixed half that the next time. I decided to use 2oz cloth vs. the 3/4oz, both of which I already had on hand. I laid the side and back of the sponson with the 1st piece of glass…let it set up for a 2 hours…lightly sanded the back of the sponson and laid the bottom and back a 2nd time with the 2nd piece of glass. I added a layer of additional resin to the outside (after the glass set up) for additional strength. I let this all dry for 2 hrs then flipped her over and went inside.

I finally made the decision to not add a new turn fin backup plate of any kind. (Oh…it was after I glassed that I was able to see that the stock back up plate was waffled with 6 holes…not just the 2 that are used.) The reason for this decision was the difficulty in getting the third bolt to actually do some good. It goes down into the corner of the sponson and there was not enough clearance on it or the other bottom bolt to thread on a retaining nut with out grinding down the side/sides of the nut that goes up against the bottom/side of the sponson. You can only feel the bolt if you have long skinny fingers, I had to use tape on my finger tip to hold the blind nut.

So…I went ahead and glassed the inside of the sponson….I used 3 layers of 2oz cloth and a generous amount of resin. I covered the bottom rear edge, the back (completely covering the backing plate) and the outside rear of the sponson. The pieces of glass were about 1 ½” x 2” each. I also added a piece along the inside top were I had a crack as a result of the buoy impacts.

So what I ended up with was 5 layers of 2 oz cloth and plenty of resin on the entire rear of the sponson.

I drilled the holes again and added the 6/32” hard ware. I used a flat washer, lock washer and standard nut for the top bolt but used the ground down “blind” nuts for the other 2 bolts. They dug into the thick glass just enough to hold without having to pour resin on them….I snugged them up pretty tight, but not enough to crack the glass…they are still removable. I also added silicone sealant around the bolts between the bracket and back of the sponson to prevent leakage.

I added the fin to the fin bracket having to again grind down the fin retaining nylon lock nut to get it to fit. 6/32” allen bolts were used on the bracket and they gave me even less room for the 4/40” fin retaining bolt.

I didn’t a get perfectly smooth paint job on the side or back but the ride pad is perfectly smooth and square and the sponson is rock solid. I don’t care that much about the looks after all the damages. Even the paint does not match the rest of the stock paint…it is what I used topside however, so I used it on the sponson too. You can really see the difference where the 2 colors meet. There is a lot more detail and pics on the whole rebuild over at RCGroups.

She is ready for action again. :popcorn2:

longballlumber
05-11-2009, 03:55 PM
Looks Great!!!!

Thanks for sharing with everyone!!!

egneg
05-11-2009, 04:12 PM
Yea ... nice save.

Capt. Crash
05-12-2009, 12:29 PM
Thanks guys...I pretty much followed in others footsteps on this repair. I'm hoping the additional weight in that sponson will help the boat handle better too...it should at least help in the corners. This weekend we will see. :popcorn2:

Flying Scotsman
05-12-2009, 01:02 PM
That fin bracket from Kintec racing is a winner and the prop ballancer, couplers which I also own are of a very high quality.

Douggie