Foam Filler That Wet Epoxy Won't Disolve?

[rardiH36]

I have a void space between my deck and the ceiling interior liner. Going "top to bottom" the layers are: Solid ~5/16" FRP deck. Then 1.5" void. Then a robust FRP+wood+FRP ceiling liner). For installing a t-track on the deck, I need to make the void space non-compressible. However, over the 4' length of the t-track, it is not possible to fill the entire void space underneath with liquid epoxy such as West Systems. It will run up and down along the void space much further than I need. And I am sure that several gallons would be needed. Much-too-much waste.

But I could inject into void some sort of expanding aerosol foam. Such as one might use for filling large gaps for weather sealing at home. Then I would route out the dried foam from the areas only where my 5/16" bolts will be positioned. Then those routed-out areas can be injected with epoxy to "stiffen the gap" between the deck and the ceiling liner so that I could tightened the bolts with nuts from underneath.

But I am concerned that the foam will be dissolved by the wet epoxy (before the epoxy sets). Making a big mess.

Does anyone have experience or alternative suggestions?

 

[Gunni]

Not real clear on what you are trying to do, but epoxy doesn't dissolve much of anything. You are thinking of polyester resin.

 

[dlochner]

Epoxy is pretty inert, doesn't dissolve much. However, polyester resins contain styrene which will do a number on some foams and plastics.

 

[rardiH36]

Thanks to you first responders. Guess that I might spray some insulation foam on some sort of a test piece on my home's work bench. Then route out a depression in it when it dries. Then fill in the depression with liquid epoxy and see what happens!

In 2014/2015, I participated a lot in the early phases of a wooden tall ship construction project in Sausalito, CA. We used several hundred gallons of epoxy over the course of 4-5 months to layup the ~24 x 2 frames/ribs needed for the 135' LOA vessel. The vinyl/nitrile/latex (don't remember which) gloves we used to protect our hands from direct epoxy contact would hold for a while, but ultimately would start wrinkling then dissolving.

Here's a link to the website to the Tall Ship project: http://educationaltallship.org/

 

[heritage]

I thought all models of the Hunter Cherubini had cored decks and FRP pan liners.

 

[Charlie Jones s/v Tehani]

I've worked with epoxy in boat building for years. The only way epoxy will do anything to foam is if you get it too thick and it gets hot, THEN it will melt the foam, but just from heat.

Here's a link to an article I did for Duckworks mag showing epoxy, glass and foam in use

http://duckworksmagazine.com/13/howto/icebox/index.htm#.WBkmGsm9ldx

 

[rardiH36]

I thought all models of the Hunter Cherubini had cored decks and FRP pan liners.

Hi Heritage:

Yes, that is true! But for the fore-aft ~4' span on the main deck that I want (need) to mount the t-tracks, turns out from my exploratory drill holes there is no core wood underneath. Just the top layer of FRP. On the main deck, the wood core section of the "main" deck spans about 4" from the toe rail to about to about 8" away from where the cabin top starts it's (almost) vertical rise.

In attached photo, which was taken when an AC receptacle was moved away, shows the FRP/wood/FRP layup of the ceiling liner directly below the appx 4"-6" away from the cabin top where I need to mount the t-track. The void space above is the area I need to fill with an epoxy stiffening "plug" so that the compression of the bolt/nut doesn't compress the two surfaces together. The second "deck view" photo (from a ~1980 Cherubini Hunter 37) shows where I want to install my t-track(s).

As an aside, when I bought my boat, the marine surveyor, from his knuckle and rubber mallet rapping, noted possible core rot on forward reaches of my cabin top. I decided the info wasn't a deal breaker. Later, when I replaced the teak hand rails with SS ones, I discovered no wood core at all in the area. Just a void space between the deck and the interior ceiling liner. Further aft, yes, Hunter fitted with a wood core.

 

[Gunni]

There is a method of wood restoration where acetone is stirred into mixed epoxy to thin it and improve wicking into wood. For your project just use West Sys/MAS/RAKA resin neat, no solvent.

However, just re-read your plan. I would consider cutting a spacer from wood to span the space between deck skin and liner...and epoxy that to seal/waterproof it and make it strong, over-drill the track bolt holes, epoxy fill them, and epoxy the piece to the deck skin, then drill in the track bolt locations.

 

[Charlie Jones s/v Tehani]

Agree. In fact the Gougeon's are very against thinning epoxy with Acetone

 

[centerline]

im not sure if this would work in your case, but one thing that can be done to easily fill a void with a non compressive material is to get a dense sponge, like a dish sponge, foam rubber or other dense spongy material, and saturate it thoroughly with well mixed epoxy resin... wring it out enough so that it does not drip and then stuff it into the void to be filled....

when the epoxy cures, the sponge will be hard and non compressive to a very large degree, depending on how dense the sponge material was and how saturated with epoxy it was, but for most purposes, it is a perfect way fill large voids with a semi structural material, or to fill areas that are hard to get to....

in some cases, the spray foam may work, but not in every case...

 

[Brian S]

Ok, so I'm no big boater, with all those liners and such, but wouldn't it be better to cut out an access panel in the interior liner, that you could trim with nice teak or something and replace? Then, once you've got the section removed from the liner, you'd have full access to glass in some proper backer, drill and bolt, then put the section back in place to cover the nuts and stuff. Because overall, I don't know that you'd want or need the liner to take the load. Certainly, as you point out, the void between deck and liner causes the problems of through bolting through the deck and liner.

 

[rardiH36]

im not sure if this would work in your case, but one thing that can be done to easily fill a void with a non compressive material is to get a dense sponge, like a dish sponge, foam rubber or other dense spongy material, and saturate it thoroughly with well mixed epoxy resin... wring it out enough so that it does not drip and then stuff it into the void to be filled....

when the epoxy cures, the sponge will be hard and non compressive to a very large degree, depending on how dense the sponge material was and how saturated with epoxy it was, but for most purposes, it is a perfect way fill large voids with a semi structural material, or to fill areas that are hard to get to....

in some cases, the spray foam may work, but not in every case...

Centerline:

Something along your saturated sponge suggestion also did occur to me, but I wasn't sure if epoxy would chemically "melt" the sponginess before the epoxy set thus take away the sponge's "fill the gap" characteristics. So I discarded the idea into the category of "dustbin of unworkable imagination". But with your prompt, I will do a test tonight at home of a sponge stuffed into a beer can and let you know how the sponge (and the beer can) fairs. And yes, this could be a solution for my project.

 

[rardiH36]

Ok, so I'm no big boater, with all those liners and such, but wouldn't it be better to cut out an access panel in the interior liner, that you could trim with nice teak or something and replace? Then, once you've got the section removed from the liner, you'd have full access to glass in some proper backer, drill and bolt, then put the section back in place to cover the nuts and stuff. Because overall, I don't know that you'd want or need the liner to take the load. Certainly, as you point out, the void between deck and liner causes the problems of through bolting through the deck and liner.

Brian: Good points. Yes, a fore/aft 4' cut in the interior ceiling liner to match the same length of the t-track and say 1.5" wide would give great access. I have stared, and thought, for quite some time. I am convinced that the liner is important to the cross-beam rigidity of the entire boat. And also that I need to through-bolt all the way through the interior liner rather than just bolting to underside of the single frp layer deck.

Alternatively for access to the 14 bolt/nuts needed on each port/starboard sides, I can drill out 1" opening adjacent to each without really damaging the liner's contribution to the boat's designed strength. Into these holes I could insert epoxy saturated sponges as per Centerline's idea.

For the long cutout, yes I could probably re-glass to restore the full strength of the liner. But then I would lose access to the nuts underneath when they will need to be cinched up at some point. I not sure that just a decorative trim piece screwed onto the liner would provide the same strength.

This project has morphed into one of the more vexing ones for me. A solution will be found!

 

[centerline]

Centerline:

Something along your saturated sponge suggestion also did occur to me, but I wasn't sure if epoxy would chemically "melt" the sponginess before the epoxy set thus take away the sponge's "fill the gap" characteristics. So I discarded the idea into the category of "dustbin of unworkable imagination". But with your prompt, I will do a test tonight at home of a sponge stuffed into a beer can and let you know how the sponge (and the beer can) fairs. And yes, this could be a solution for my project.

remember it takes a couple weeks for the epoxy to come to full strength, but in a warm temp it will harden up enough for you to see the result in 24 hours....

ive drilled 1/2" holes in a laminate that had a slight warp and an oil can effect, then poked larger pieces of saturated sponges into the hole thru a funnel spout with a piece of dowel, then blocked the laminate doen til the sponges set, to keep it from oil canning and to hide the warpage.... I probably could have used a sealant, but my thoughts were that if the sealant didnt bond, the epoxy sponge trick would probably fail against the sealant, whereas if the epoxy failed, I could still try the sealant.... the sponge worked.
Ive also used it on older boats where a void needed to be filled so it either keeps out insects, or so there is a firm backing for something else against it.
it can also be used for taking shapes from other objects to make molds from....
it is about the cheapest large volume filler that will last the life of the boat ...

 

[heritage]

Your wood cored pan looks plenty strong enough to carry the load of the 4' T track, with bolts every four inches. All you need is a way to keep the thin top deck from compressing when the nuts are tightened. Why not drill 3/4 inch holes through the deck centered on where the bolts will go, then fill the cavity with epoxy thickened to the point that it will not sag and spread away from the cavity. Bring the thickened epoxy slightly above the top of the deck, let it set up, grind level with sander, and drill your bolt holes all the way through both deck and pan.

 

[Solarfry]

I would not cut thru the interior to fill with epoxy absorbed anything. It will drip. It is easier to cut the cored decks upper laminate and retain the lower laminate removing the coring. Then you can place anything there with epoxy without having to worry about the overhead. Gravity works in your favour.

 

[Charlie Jones s/v Tehani]

I would not cut thru the interior to fill with epoxy absorbed anything. It will drip. It is easier to cut the cored decks upper laminate and retain the lower laminate removing the coring. Then you can place anything there with epoxy without haicely than under decksving to worry about the overhead. Gravity works in your favour.

Sorry, disagree, Topside(decks etc) is MUCH harder to repair than under sides. And epoxy, properly used is not that drip prone. Have done more than one deck repair, and always try to do from below, unless decks are really trashed.

 

[Gunni]

You could do this install by having a machinist mill you 3/4-1" spacers with center holes out of stainless or aluminum round stock, drill bolt locations down from on deck, and then enlarge them in the liner to allow the spacer to be set into location, flush with the inner liner, then back the nuts with a backing plate that holds the assembly in place and webs the load across the liner. I did something similar for my dock cleats.

 

[rardiH36]

Centerline:

Something along your saturated sponge suggestion also did occur to me, but I wasn't sure if epoxy would chemically "melt" the sponginess before the epoxy set thus take away the sponge's "fill the gap" characteristics. So I discarded the idea into the category of "dustbin of unworkable imagination". But with your prompt, I will do a test tonight at home of a sponge stuffed into a beer can and let you know how the sponge (and the beer can) fairs. And yes, this could be a solution for my project.

Well, my experiment doesn't seem to be a success. See the attached pics showing that the "epoxy" sponge hasn't gone very solid after 24 hours and a day in the sun. Yesterday evening, I mixed some West Systems epoxy resin with the approximately correct amount of 205 hardener. Put the sponge into it. With gloved hands, I soaked, squeezed and soaked the sponge a few times to get the epoxy into it. Then gently squeezed out the excess. I could feel through the vinyl gloves a bit of warmth, confirming that the epoxy reaction was happening. Then I wetted out two small pieces of FRP pieces cut from some fiberglass strip I had on hand. Then pressed them up against the wet sponge to make a sandwich. Then gently wedged the two pieces together a bit so they would stay in contact with the sponge. Then walked away until the next morning. The left over epoxy in my mixing container was "hocky puck" hard. The sponge was well adhered to the fiberglass strip. But the sponge material itself, albeit having only gone through it's initial cure, still was flexible with just minimal finger pressure. I used a razor knife to cut the sponge even with the fiberglass strip (to make the assembly "pretty"). Then I put the sandwich assembly on the black dashboard of my car in the sun all day. (75 degree day so easily 90-100 in the car. Still the sponge remained quite pliable even after I have let it cool to room temperature. Maybe it will cure rock solid in a few more days, but so far doesn't look like it will ever be strong enough for the intended duty. Possibly I should have left more epoxy in the sponge. But also, the sponge/epoxy combination does have an unusual odor. So maybe the epoxy did react with the sponge chemistry. (It was a synthetic sponge of course.)

I have now decided on an alternative method that should be neater to implement and will be more precise to install. Somewhat along the lines of Gunni's idea. But with a total of 28-30 bolt/nuts, paying a machinist to custom make the parts isn't viable for me. Instead, Tap Plastics has a fiber reinforced epoxy tubing product. Visiting my local store today, one size is exactly 5/16" inner diameter (my bolt size). The outer diameter of this size fits perfectly/snuggly into the inner diameter of their next size up. See attached pic of the tubes. Inserted together and adhered with epoxy, the two in tandem should work excellent as the spacer I need so that tightening the nuts from below the interior ceiling liner won't pull/deform the deck downwards.

 

[heritage]

How are you able to gain access and set the fiber tubes between the deck and pan? I'm asking all these questions because I'm about to install new teak rails on my Hunter 27 and have decided to use bolts from below instead of attaching with screws from above. I have a cored deck and single layer frp pan and will probably cut a 3/4" access hole in the pan to enable installing the bolts. Then snap in plastic covers over the holes. In my case, a spacer isn't needed, unless I decide to use a longer bolt and secure on bottom of pan. As a side note, I'm using Ez-Lok inserts in the hand rails. See pics: