Mast step came out, can't access underneath
- Thread starter JAC1
- Start date
Could you cut a hole in that bulkhead and install an access port?
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Amazon.com : 6" White Circular Inspection Hatch Marine Access Port Hatch Cover,Boat ABS Round Non Slip Inspection Hatch,Deck Plate with Screws,With Bottom Seal,Rubber O-rings And Sponge Seal Double Waterproof : Sports & Outdoors
Thanks for your reply. Yeah I was thinking about that as well. My only worry is weakening the mast support.in that area.
I think that's a good plan, but I would modify it a little. I'd replace the rivnuts with something more suitable for use in fiberglass, such as these inserts from McMaster-Carr. And I'd use wood dowels or something like that, in place of the bolts, so that they can easily be removed if the epoxy gets on them. (And then replace them with the actual bolts once set up, obviously.) Or maybe mold release compound on the bolts.
@Tedd I like the look of the insert. It appears to be designed not to turn. A press in fitting. How does it work with the brittleness of epoxy? Will it expand as the bolt is screwed in to the nut? Will it crack the epoxy as you press it into the hole?
It appears that the original design had a weakness. How to overcome the weakness is the challenge.
Before I saw Tedd's inserts I would have suggested fillign the holes with thinckend epoxy and burying bolts upside down in the epoxy while it cures. Perhaps with a nut on the bolt to help give the bolt more mass inside the epoxy.
Then slip the mast base over the bolts to hold them in place and let the fix cure. If you wax the mast base the epoxy should not adhere to the mast base. When you remove the base you will have a nice smooth surface to paint with gel coat.
It appears that the original design had a weakness. How to overcome the weakness is the challenge.
Before I saw Tedd's inserts I would have suggested fillign the holes with thinckend epoxy and burying bolts upside down in the epoxy while it cures. Perhaps with a nut on the bolt to help give the bolt more mass inside the epoxy.
Then slip the mast base over the bolts to hold them in place and let the fix cure. If you wax the mast base the epoxy should not adhere to the mast base. When you remove the base you will have a nice smooth surface to paint with gel coat.
Hi @jssailem ,
The inserts I linked to are designed to be molded into an injection molded part. The don't expand. The whole point of the design is to maximumize load transfer surface area from the very strong stainless steel insert to the far less strong plastic it's molded into. You don't press them in, you place them in the mold and then mold around them.
I should say that I have not used these in fiberglass epoxy, I have only specified them for use in injection molded parts. If they were going to be subject to high pull-out loads, then I'd be less sanguine about them. But for a mast foot I think they'd work well--certainly better than what was in there!
I know that there are fasteners specifically designed to be molded into composites, such as those used on carbon fiber airframes or carbon fiber racing car chassis. But I don't know where to get them and, based on what I've seen, I think they would be difficult to retrofit in the situation @JAC1 is dealing with.
The inserts I linked to are designed to be molded into an injection molded part. The don't expand. The whole point of the design is to maximumize load transfer surface area from the very strong stainless steel insert to the far less strong plastic it's molded into. You don't press them in, you place them in the mold and then mold around them.
I should say that I have not used these in fiberglass epoxy, I have only specified them for use in injection molded parts. If they were going to be subject to high pull-out loads, then I'd be less sanguine about them. But for a mast foot I think they'd work well--certainly better than what was in there!
I know that there are fasteners specifically designed to be molded into composites, such as those used on carbon fiber airframes or carbon fiber racing car chassis. But I don't know where to get them and, based on what I've seen, I think they would be difficult to retrofit in the situation @JAC1 is dealing with.
I like the idea. Certainly the epoxy will withstand the forces. It is getting the insert into the epoxy so that it can cure around the insert and not getting epoxy into the threads designed for the bolts. I guess one could wax/grease the bolt, screw it into the insert (not getting wax or grease on the outside of the insert) then insert it into the epoxy in the holes. That could work in theory. Let the fix cure then remove the bolts and attach the mast base.
I would also want to use the mast base as part of construction, so that the bolts are properly aligned and positioned. Nothing would be worse than to get a solid sub base and not be able to put the mast base on because one of the bolts was leaning out of alignment.
I would also want to use the mast base as part of construction, so that the bolts are properly aligned and positioned. Nothing would be worse than to get a solid sub base and not be able to put the mast base on because one of the bolts was leaning out of alignment.
Sure... I carry one of those in my back pocket... Oh boy another tool I get to buy... Thanks
I think I have a dental pick in my tool box.. I guess I am incomplete in my tools.
@jssailem ,
Thinking about it a bit more, once the waxed bolts come out the threads will probably be fine anyway, even if there is a little epoxy on them--likely no need to clean them up at all, except to remove the left-over wax. After all, Loctite is more or less the same as epoxy, once it sets up. The tap would just be a fall back.
What would be really smart would be to do a trial run not on the boat. Make a hole in a piece of plywood, or something similar, and bond an insert in using this method. Then see if the bolt comes out easily and what, if any, clean up of threads is needed.
Thinking about it a bit more, once the waxed bolts come out the threads will probably be fine anyway, even if there is a little epoxy on them--likely no need to clean them up at all, except to remove the left-over wax. After all, Loctite is more or less the same as epoxy, once it sets up. The tap would just be a fall back.
What would be really smart would be to do a trial run not on the boat. Make a hole in a piece of plywood, or something similar, and bond an insert in using this method. Then see if the bolt comes out easily and what, if any, clean up of threads is needed.
Some overthinking going on here.
Clean it up, slap some 5200 on it, set a block on top with a ratchet strap going all the way around the hull, let it sit for the week before you use it and then forget about it and sail it.
Clean it up, slap some 5200 on it, set a block on top with a ratchet strap going all the way around the hull, let it sit for the week before you use it and then forget about it and sail it.
I guess that depends on whether you want something not quite as good as the original design, which clearly failed, or whether, for approximately the same effort, you want something better.