Swim ladder step repair

shank

shank

.
Apr 20, 2016
125
Catalina 27 5231 Lake Champlain
Hello sailors,

I'm refinishing the steps on my swim ladder and I found some rot on one of them where the screws secure it to the ladder itself. The wood is teak and the integrity of the rest of the step is very good so I want to try and repair rather than replace it. Any ideas on what to use to fix it? Thanks
 

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PaulK

PaulK

.
Dec 1, 2009
1,355
Sabre 402 Southport, CT
It looks like a rope ladder with teak steps? Though it may be strong enough, epoxy filler is going to look weird. Can you cut off the ends of the steps and re-drill holes? The ladder would be a few inches narrower but would look better. Test out a narrower tread with a 2x6 first, to make sure it works for you.
 
D

dlochner

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Jan 11, 2014
12,769
Sabre 362 113 Fair Haven, NY
The one side looks beyond repair. If this a rope ladder then I would not trust an epoxy repair as it will essentially be a big chuck of thickened epoxy butt jointed to the wood. The shear forces might not survive being stepped on.
 
dLj

dLj

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Mar 23, 2017
4,296
Belliure 41 Back in the Chesapeake
dlochner said:
The one side looks beyond repair. If this a rope ladder then I would not trust an epoxy repair as it will essentially be a big chuck of thickened epoxy butt jointed to the wood. The shear forces might not survive being stepped on.
Click to expand
With all due respect @dlochner - Flexural strength of west System epoxies are typically over 11,000 psi. So if that step is 1/2" thick and say 4 inches wide, that would be 22,000 pounds that joint would support on a straight joint. I wouldn't do a straight joint, I'd make a scarf joint. I'd cut the joint between the top surface and the back surface at an angle. Depending upon what seemed easier, I'd likely do about a 65 degree cut (just because that's an easy cut on one of my saws). That would make that joint strength over 24,000 pounds. And that's only on one side. I would have 0 concerns over strength of that joint.

dj

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D

dlochner

.
Jan 11, 2014
12,769
Sabre 362 113 Fair Haven, NY
dLj said:
With all due respect @dlochner - Flexural strength of west System epoxies are typically over 11,000 psi. So if that step is 1/2" thick and say 4 inches wide, that would be 22,000 pounds that joint would support on a straight joint. I wouldn't do a straight joint, I'd make a scarf joint. I'd cut the joint between the top surface and the back surface at an angle. Depending upon what seemed easier, I'd likely do about a 65 degree cut (just because that's an easy cut on one of my saws). That would make that joint strength over 24,000 pounds. And that's only on one side. I would have 0 concerns over strength of that joint.

dj

Compare Epoxy Physical Properties | WEST SYSTEM Epoxy

We compare WEST SYSTEM Epoxy physical properties using ASTM scientific tests, with specimens cured at room temperature for two weeks.
www.westsystem.com www.westsystem.com
Click to expand
@dLj I strongly suspect that you have more engineering background than I do, however the chart gives the strength of the epoxy but doesn't specify the application. It seems quite possible that the epoxy itself wouldn't break or a block of epoxy wouldn't break. That is not the application here. The question I alluded to was the strength of the bond to the rotting teak. How strong is the bond between the epoxy and the wood? Because the condition of the wood is suspect and teak is an oily wood, the bond strength may not be all that great.

A quick search shows these values for the tensile strength of G-Flex epoxy. According to West, G-Flex is formulated to have the "highest adhesion values." In tension only, G-flex has an adhesion value of about 1400 psi with teak. In the step application the forces will be in shear not not tension, the values for that are not reported. West notes, "It is also rare to have all the components assembled in such a way that the load path is purely tensile. A slight off-axis load can induce significant peel stress." This is the concern I have for the repair.

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DArcy

DArcy

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Feb 11, 2017
1,768
Islander Freeport 36 Ottawa
shank said:
Any ideas on what to use to fix it?
Click to expand
A teak board.
Honestly, that will be way easier to replace than repair and maybe not much cost difference considering the amount of epoxy you would need.
 
dLj

dLj

.
Mar 23, 2017
4,296
Belliure 41 Back in the Chesapeake
DArcy said:
A teak board.
Honestly, that will be way easier to replace than repair and maybe not much cost difference considering the amount of epoxy you would need.
Click to expand
Agreed, but that wasn't the question....

shank said:
so I want to try and repair rather than replace it.
Click to expand
 
dLj

dLj

.
Mar 23, 2017
4,296
Belliure 41 Back in the Chesapeake
dlochner said:
@dLj I strongly suspect that you have more engineering background than I do, however the chart gives the strength of the epoxy but doesn't specify the application. It seems quite possible that the epoxy itself wouldn't break or a block of epoxy wouldn't break. That is not the application here. The question I alluded to was the strength of the bond to the rotting teak. How strong is the bond between the epoxy and the wood? Because the condition of the wood is suspect and teak is an oily wood, the bond strength may not be all that great.

A quick search shows these values for the tensile strength of G-Flex epoxy. According to West, G-Flex is formulated to have the "highest adhesion values." In tension only, G-flex has an adhesion value of about 1400 psi with teak. In the step application the forces will be in shear not not tension, the values for that are not reported. West notes, "It is also rare to have all the components assembled in such a way that the load path is purely tensile. A slight off-axis load can induce significant peel stress." This is the concern I have for the repair.

Home | WEST SYSTEM Epoxy

The home of WEST SYSTEM marine-grade epoxy resins and hardeners for boat building, boat repair, home repair, and restoration.
www.westsystem.com www.westsystem.com
Click to expand
I wouldn't use Gflex in this application. I'd use the 105 and the appropriate hardener for the temperature along with the 404 high strength filler. If you look in the tables I linked, you'll find that that values for the Gflex would not match those of the epoxies. The 105 was formulated for excellent adhesion to wood. You do bring up a good point as to the specific wood species, teak. It may be a good idea to actually call the help line and find out if they have specific information on adhesion to teak.

As to your point of the rotting teak, well you can't reliably attach to rotten teak in any way that I'm aware of no matter the system. The OP would have to cut back to get to solid wood in any case.

Actually I think @DArcy has hit the nail on the head, just buy teak and redo the steps. That's likely the most direct way to fix these and least coast method in the long run. But if the OP doesn't want to do that, the only other method that I feel would be even remotely satisfactory would be epoxy with structural fillers.

dj
 
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