Small Balsa Core Damage - filler vs foam?

[JBP]

Originally Posted by nfbr

I'll try this. Do you find it has a little flex? The current adhesive filler in the boat is strong but brittle. It doesn't act like wood / foam.

I'm wondering about Flex epoxy from West

I find that all microballons has slightly more flex than silica, but I wouldn't worry about it. For your repair as described, any marine epoxy will do. I would not bother with the flexible kind, they are for more specialty flexibility needs.

[smj]

Originally Posted by nfbr

Last place someone did that was the deck.

The difference in flex cracked at the join, and water got into the ply, rotting out about 2 sqr ft

So I’m anxious to find a filler that acts like balsa for flex.



Once glassed over, its not a big deal, but keeping water out of balsa is a hassle.

Sounds like someone didn’t do the correct prep or grind the correct bevel if the joint cracked.

[slowpoker]

Dig out rotted part, put a piece of wood to fill most of the hole, fill the voids with regular wood filler, sand smooth and oil paint the whole surface of the locker. Prevent further water leaking by fixing what caused this in the first place, Done !. It's only a 2"x 4" on an inside locker floor.

[wingssail]

I use blocks cut from pine boards. It is almost like balsa cheap and easy to work with. Epoxy paste goes in first, then the blocks (previously cut to fit) then thin epoxy to fill all the voids. Finnish with thickened top epoxy layer and glass over. sand smooth. paint. ( have always saved the old top layer of glass which then plunks right back into place

[garyfdl]

Originally Posted by thinwater

I'm with Choto on this. It's just not going to matter

Me three. I wish that the biggest thing I had to worry about on my boat was an 8 square inch soft spot... in a locker!

[Chotu]

Originally Posted by garyfdl

Me three. I wish that the biggest thing I had to worry about on my boat was an 8 square inch soft spot... in a locker!

Same here! I dream of a day when this type of thing is high on my boat list. Currently, it’s the composite chain plates and hopefully getting the mast extension and forward cross beam done before I die or get put away into a home (or asylum??) Lol

[garyfdl]

Originally Posted by Chotu

Same here! I dream of a day when this type of thing is high on my boat list. Currently, it’s the composite chain plates and hopefully getting the mast extension and forward cross beam done before I die or get put away into a home (or asylum??) Lol

Right there with ya! There's a lot more sand in the bottom of the hourglass than the top.

Tomorrow is replacing all the (40 y/o?) fuel lines, installing new fuel filter and separator with shut-off valves, reconnect the exhaust hose, install rebuilt injectors and their fuel lines, two or three things I'll think of later, and firing up the engine (I hope )

[Mike Banks]

I have used a mixture of cotton fibres, Cabosil, epoxy resin and polystyrene beads (the small ones). Use a slow cure resin, and first wet the entire interior and walls of the space with epoxy resin, before tamping in your mixture.

Mix the resin in correct proportions first, then stir in the Cabosil and cotton fibres, then add the styrene beads last and mix REALLY well. Add enough ingredients to the resin so that it does not flow but goes where you put it and stays there.

Take your time, you are using slow cure resin, then start adding your mix to the cavity to be repaired, using a plastic spoon or trowel and a bit of dowel as a tamper to get the mix to cover all surfaces, even tamping it gently in place to be sure. Fill the cavity to just less than level. The epoxy will cure, shrinking a tiny amount, and the resulting filler is strong and will accept more epoxy resin and when you have glassed over the repair, (which might need a little chiselling to get a suitable even surface for the glass repair which will cover it in the usual way,) use overlapping layers and a ground-back area each side of the repair for a tapered bond.

The styrene only exists to be coated with Cabosil and cotton and glue which sets to a flexible linkage of egg-shell stuck to one another spherical structures forming a honeycomb of considerable strength, far superior to the original balsa and having perfect glue-covered fit.

[Rumrace]

Micro balloons in a proper weight for mix and application is rigid and offers absolutely no flexibility. The micro balloon point is to create mechanical connections replacing removed glass. System West is rigid offers no flex. TPU or TPE polymers are flexible and I can’t think of a worst plastic for the application save styrene.
If you want a soft landing to protect a glass surface add a chunk of a rubber car mat.
Or get a tray 3D printed in TPU.
End grain balsa can support a transport truck. It supports your mast if it’s step mounted. If it’s a Jeanneau it will have Kevlar roving in the area to back up the balsa. Boats which used plywood are in the free boat row.

[Rumrace]

The C4 Corvette has a terrible flaw. The fibreglass rollbar cover is independent of the rear quarter and the flex from the new drive line made the two parts hit. Like prop walk it’s more obvious on the drivers side.
The only solution short of tapering the edge of the roll bar cover is Systems West with 15% micro balloons. West alone will crush the glass under the damage area. You also replace a small piece of weather strip between them with a slighting fatter profile borrowed from Camero. With out the micro balloons or any fibreglass resin patch fails and destroys paint jobs in 2 years.

[Spot]

Originally Posted by wingssail

I use blocks cut from pine boards. It is almost like balsa cheap and easy to work with. Epoxy paste goes in first, then the blocks (previously cut to fit) then thin epoxy to fill all the voids. Finnish with thickened top epoxy layer and glass over. sand smooth. paint. ( have always saved the old top layer of glass which then plunks right back into place

For non-structural I would do this as Wingssail describes above, and coat the wood once with normal mixed epoxy, enough to soak the surface, before sticking it in the hole with any other epoxy and fillers being used for the repair. And as mentioned before, if there was a root cause for the leak/saturation address that too.


-Another member of Overthinkers' not-so-Anonymous


PS thought about it some more...hehehe...you could add a little fumed silica to keep the goop in place while the initial repair sets and any fill layers that you need to sand will go easier with an add of glass micro-spheres. If you don't have either it is not mission-critical, sometimes using what you have on hand is satisfying too.

[pbmaise]

Oh! I read the OP wrong. I thought you had an area 2 ft by 4 ft.

Below I write up an explanation of an area I repaired 3ft by 3 ft. This type of repair is more of a repair of a large non-structural area. The area I repaired was above the water line in an ama.


I think people that recommend micro balloons have no idea how much epoxy and balloons it would take to fill an area 2ft by 4 ft and 1.25 inches.

The repair I had to do was on a curved wall within an ama. The size was about the 3 ft by 3 ft on a curved vertical wall. Fortunately it was not an area you normally see and so I wasn't too concerned about making the repair perfect.


I found a firm that made custom refrigerators. They made walk in coolers etc. They had what I think was a urethane foam...it turned yellow and solid when mixed. Closed Cell. They sold me a few jars of the liquids that when mixed together turn into a solid foam.

If you are in the USA you can order from Amazon.

https://www.amazon.com/Expanding-Pol...12137891&psc=1


I first cut out the interior fiberglass, and the cut out the problem balsa core.

I then used a little epoxy to seal the good core area. Next I shaped my glass mat over the area. I left an area at the top to pour in the mixture using a funnel and tube. The foam expanded like crazy and came out a vent hole. I cut away the foam when solid and then glassed the pour and vent points.

[smj]

Originally Posted by pbmaise

Oh! I read the OP wrong. I thought you had an area 2 ft by 4 ft.

Below I write up an explanation of an area I repaired 3ft by 3 ft. This type of repair is more of a repair of a large non-structural area. The area I repaired was above the water line in an ama.


I think people that recommend micro balloons have no idea how much epoxy and balloons it would take to fill an area 2ft by 4 ft and 1.25 inches.

The repair I had to do was on a curved wall within an ama. The size was about the 3 ft by 3 ft on a curved vertical wall. Fortunately it was not an area you normally see and so I wasn't too concerned about making the repair perfect.


I found a firm that made custom refrigerators. They made walk in coolers etc. They had what I think was a urethane foam...it turned yellow and solid when mixed. Closed Cell. They sold me a few jars of the liquids that when mixed together turn into a solid foam.

If you are in the USA you can order from Amazon.

https://www.amazon.com/Expanding-Pol...12137891&psc=1


I first cut out the interior fiberglass, and the cut out the problem balsa core.

I then used a little epoxy to seal the good core area. Next I shaped my glass mat over the area. I left an area at the top to pour in the mixture using a funnel and tube. The foam expanded like crazy and came out a vent hole. I cut away the foam when solid and then glassed the pour and vent points.

The people that recommended the micro balloons read the post correctly and realized it was a 2”x4” area not 2’x4’

[Summmitgrpinc]

Here is a link to a product called injectadeck. It has been designed by a NASA chemist and is a fabulous product to cure soft or rotted core. It is easy to use and works amazingly.

Product will actually push the water and rotted material out of the holes where you inject it, leaving a structural foam core between the substrate and the top gelcoat material with minimal cosmetic repair.

It is trully amazing.

Take a Look: https://injectadeck.com/

Captain Daniel Kiefer
M/V: Miss Ann

[garyfdl]

Originally Posted by Summmitgrpinc

Here is a link to a product called injectadeck. It has been designed by a NASA chemist and is a fabulous product to cure soft or rotted core. It is easy to use and works amazingly.

Product will actually push the water and rotted material out of the holes where you inject it, leaving a structural foam core between the substrate and the top gelcoat material with minimal cosmetic repair.

It is trully amazing.

Take a Look: https://injectadeck.com/

Captain Daniel Kiefer
M/V: Miss Ann

Seems like overkill for a dodgy area of 8 square inches...