What materials to use for mast step repair?

[Project_Mayhem]

What wood or composite material would you use to replace the rotted wood in a mast step? I've heard anything from balsa, hardwood, plywood to an aluminum block.

How many layers and what type of glass would you lay down and in what order? I've done this repair before but I'm interested in a better method of repair

 

[Spindrift NH]

Catalina sells a white oak replacement mast step. You might try the SBO store first.
I replaced the one on my ‘88 with an aluminum screw jack that I had made.

 

[Project_Mayhem]

Catalina sells a white oak replacement mast step. You might try the SBO store first.
I replaced the one on my ‘88 with an aluminum screw jack that I had made.

Thanks for the tip. Is there different grades of white oak? I found this for $11. At that price it's not worth it to hunt down one from Catalina.

That screw jack looks much taller than the wood I would expect to find inside a mast step. I assume that is for a keel stepped mast?

 

[FastOlson]

The answer is G10/FR4 composite. Repeat until memorized. You can usually buy it cut to the general dimensions you need. And/or have a saw on hand with bi-metallic blades.
Also, since thicker versions cost disproportionately more, use thickened epoxy to bind together several layers of 1/4 or 3/8 to reach the thickness needed. McMaster Carr has it, or find a local plastics supplier. While hardwood can suffice, it's really difficult to treat it well enough to keep moisture (and rot) out of it over time.

 

[Project_Mayhem]

The answer is G10/FR4 composite. Repeat until memorized. You can usually buy it cut to the general dimensions you need. And/or have a saw on hand with bi-metallic blades.
Also, since thicker versions cost disproportionately more, use thickened epoxy to bind together several layers of 1/4 or 3/8 to reach the thickness needed. McMaster Carr has it, or find a local plastics supplier. While hardwood can suffice, it's really difficult to treat it deep moisture (and rot) out of it over time.

I have a small scrap of G10 and it is tough stuff! I assume using all epoxy and mat/cloth and no wood would be too brittle?

 

[David in Sandusky]

I used an aluminum plate for mine. The work was done by a fiberglass shop in Cleveland. Total satisfaction with no issues for 24 years now.

 

[Project_Mayhem]

I used an aluminum plate for mine. The work was done by a fiberglass shop in Cleveland. Total satisfaction with no issues for 24 years now.

keel or deck stepped? The C30 is deck stepped

 

[Blitz]

FastOlson suggestion is good

I made one 4-5 years ago for a deck stepped mask to replace the aluminum original that barely last ten years without significant corrosion.

 

[Hayden Watson]

Thanks for the tip. Is there different grades of white oak? I found this for $11. At that price it's not worth it to hunt down one from Catalina.

That screw jack looks much taller than the wood I would expect to find inside a mast step. I assume that is for a keel stepped mast?

Are you talking about the compression block that is in the bilge or the wood in the deck under the mast. To totally different situations and both crop up on a regular basis. For the wood in the deck, I used G10 to replace the wood. I got extremely lucky in that the wet wood extended out to an area about 3/4" less than the size of the Mast Step Halyard Plate that Catalina Direct sells which is about 11" x 8". I cut out the wet wood, bedded the G10 into the void, beveled the deck back to the extents of the halyard plate and laid up layers of glass and epoxy until it was even with the rest of the deck. The end result was a solid base for the mast and the repair cannot be seen unless the mast is unstepped and the plate removed.

 

[colemj]

I have a small scrap of G10 and it is tough stuff! I assume using all epoxy and mat/cloth and no wood would be too brittle?

Brittle doesn't come into play here. It is all compression, and the only requirement is to transfer the compression of the mast on the deck to the bulkhead or compression post underneath the deck. Solid glass/G10 is fine. I wouldn't use aluminum for other reasons, but that is also fine. Hardwood and plywood are OK, but you have much better choices. Even a pour of resin mixed with fumed silica and chopped strand is fine. Balsa or foam is not fine.

Mark

 

[Spindrift NH]

I maybe made some incorrect assumptions based on your questions. I assumed you have a Catalina 30, and that you are talking about the wood block under the cabin sole directly below the compression post. It is very common for this block to rot and need replacement which is why Catalina sells a preformed one.

 

[FastOlson]

I have a small scrap of G10 and it is tough stuff! I assume using all epoxy and mat/cloth and no wood would be too brittle?

G10 is epoxy and fiber cloth. So it's no more brittle than the "FRP" hull of our boats. You can certainly make your own; long ago I determined that he cost of laying up precision thickness pieces - the materials plus my time - was less preferable to just buying it. Having it provided to me in guaranteed perfect thickness is a huge help, also. If I had a vacuum table I might view this differently, but I have never built one. As they say, YMMV.