Bedding and Backing Plates

t37-panacea · **Joined:** 23 Dec 2006 17:26 **Posts:** 75

Here is a project I am glad to be almost done with. I removed all deck fittings to rebed them and noticed that there were no backing plates on anything! Only ?? washers and these were being bent and pulled into the fiberglass in many places. The holes in most places exposed the balsa or plywood core. Thankfully, there was minimal core damage in only two places.

I took the time to drill the holes a little larger, route out the wood core, refill with WEST System epoxy thickened with 406 Colloidal Silica, then redrill the holes for the correct size machine screws. This project also included the chain plates. I.

I fabricated some stainless steel backing plates using some 4 inch by 4 foot sheets of ??, 304 grade, stainless steel sheet stock. Fortunately, I had the use of a local machine shop to cut the stock to size and drill the holes for the machine screws. I bought my own cobalt drill bits in various sizes. I cut the new backing plates about 20% larger than the hardware I was using it on. The backing plates were bedded in Evercoat Formula 27, a two part plastic filler. This was to smooth out the uneven surfaces in order to provide maximum surface area contact. I drilled the holes slightly larger than the machine screws being used. Either ? -20 SS for most of the deck hardware or 5/16 ? 18 SS for the genoa tracks and bow mooring cleats. All hardware was bedded in either Lifeseal polyurethane/silicone sealant or Life-Calk polysulfide sealant (which I liked better). The Life-Calk seems to hold up better with less shrinkage. Only the winches are left and we?ll be done!

t37-panacea · **Joined:** 23 Dec 2006 17:26 **Posts:** 75

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Down2TheC · **Posted:** 04 May 2007 00:58

Man! That's a job. I know we could use such service but I doubt it's something I'll do real soon. So how much do you charge? Snicker

Tortuga's Lie · **Joined:** 27 Oct 2006 10:32 **Posts:** 827

Panacea, Nice job....I've been rebedding hardware what seems like forever!!! I'm surprised your Tartan did not have any backing plates!! What year is your boat? Mine is a 1977/8, hull #59 and she had either large fender washers or backing plates out of 1/4" fiberglass with washers under the nuts. It is interesting that the construction methods would vary like that. There were some spots that they only used washers: winches, genoa track, grabrails and smaller hardware with little load, but the stanchion bases, pulpit, turning blocks all had backing plates.
It eases the little mindful worries when you fill the holes with epoxy and don't have to think about the balsa coring rotting away!!! While you have the ceiling liner out, add 1/2" foil faced rigid insulation, it will really help keep your boat cooler in the summer, warmer in the winter and has the added benefit of creating a large radar reflector, especially if you add it to the side walls.
Tom

Tartan37.com

Bedding and Backing Plates

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