Commander Compression Post Discussions

[Commander 147]

John

A normal sized router should do the trick just fine. I like the little one but would certainly use one of my other routers if I did not have the little one. Also you will find that the top skin of the deck is closer to 1/8" thick than it is to 1/4" thick. The balsa core in the center of the deck is 3/8" thick and then you have the bottom skin of the deck that is close to 1/16" thick.

As far as the suggested repair I will draw a picture as soon as I can get some time later today and post it for you. But here are a couple of things I can tell you now. First, the tickened epoxy only goes between the top and bottom skins around the perimeter of the 5" hole you will cut through the top skin. And that assumes that the balsa core is degraded in a larger area than the 5" dia. cutout. While I'm on the subject, you need to know the only way to give the thickened epoxy body so that it will not sag out and run out of the area you are putting it into is to use cabosil (also known as fumed silica). You will want to use micro fibers or 1/4" glass strands to give the epoxy strength after it is cured but you will also need to mix in cabosil to thicken it to a peanut butter consistacy so it will stay where you put it.

Then in the area where you have the 5" cutout you will wet out possibly as many as 8 layers of 1708 biax cloth one at a time to build the core area up to the 3/8" thickness that that original balsa core took up. Then when you are built up to the the point where the glass is filling the core area and even with the bottom of the top skin you will lay down the 8" circle of glass first to get a complete bond with the entire beveled area and the glass you put in the core area. After that you will follow with the 7" circle of glass and then the 6" circle of glass and if the center is still slightly below the surrounding deck area one more layer of glass 5" in dia.

When all of this sets up use the grinder to knock down any high spots and mix up some more epoxy to use as a fairing compound and this time you will need to use cabosil and microballoons. Probably about twice as much microballons as cabosil. The cabosil once again gives the epoxy body and keeps it where you put it and the microballoons will make sanding it later much easier.

Does this help or would you still like the picture? I'm happy to do it but I have some work I need to get done before I can.

[John]

Jerry,

If I understand what you are saying, once I have cleaned out the bad core, I fill the void until I have a 5 in. hole from deck to ceiling. then I proceed to lay in glass matting until I get to the deck level. At that point I start using increasing sizes of mat to rebuild the deck as it was. I can then grind to match the deck, fill if needed and stand back and admire my work. Oh, yes, then I can remove the Gator tape (great stuff by the way) and re-drill the holes to mount my mast step.

I plan on placing a soda straw over my mast light wires and hopefully leave them so they can be removed or fished if needed. This does mean that the glass will have to be layed gently with a slit on one edge to accomodate the wires. Also, if the ceiling does not rebound around the compression post cap, my plan is to cut 2 semi circles of 1/4 plywood and gently jack up the ceiling until it matches the surrounding area an the compression post has a litlle wiggle to it.

[Commander 147]

John

I believe you are following but just to make sure I will post a picture later possibly as late as this evening.

[Commander 147]

John not sure if this picture will do more to explain or confuse but anyway here you go.



If this confuses I will try again.

[Commander227]

John,
Jerry's above repair is very proper and the best and most permanent fix. Here is a quick and dirty repair that should get you at least another 40 years out of the mast step.
Use a 5" or 6" hole saw to remove the top skin, scrape out the bad core and dig it out from the edges until the balsa you are pulling out looks clean and dry. Using the same hole saw cut out a plug from 3/8" plywood. Draw a 8" circle around your hole and taper the edges out to that. Pack thickened epoxy into the void between the skins and lather up the bottom of the hole, stick in your plywood plug, butter everything up with the thickened epoxy and apply your repair plys of glass mat wetted out with epoxy. Pre cut your repair plys, mask off a large area and have every thing laid out and ready to go 'cause your going to be a sticky mess. If you put on 4 or 5 sets of rubber gloves you can keep peeling them off when they get too messy and you want to pick up a tool or something. The repair could be done with polyester resin instead of epoxy if cost is a factor, its not as good, but thats what the rest of the boat is made of.
.02 cents
Mike

[John]

Repairs have gotten more complicated. You can see pictures in the Mast Step discussion. I now have an open area of about 8" x 8" underneath the mast step. The compression post/wedge has already broken through the cabin ceiling. I am faced with raising the roof (really) and then rebuilding the entire structure. Also I did slip and there is a 1" puncture in the cabin ceiling. Fortunately, I am using a 1/4" bit in the router. Rather than continue duplicate discussions, I will continue the discussion in the Mast Step, as most seem to read both. Suggestions are welcome.