Filling voids in keel with resin

[gstewart]

I would appreciate a recommendation for the appropriate resin to use in my relatively unusual situation.

I have a sailboat with a shoal draft keel made with a fibreglass outside and filled with cement as ballast. There are many voids in the cement and damage to the fibreglass has occurred when water found its way into the bottom of the keel and froze. I have drained the keel through holes that I drilled in the bottom and have be pumping in warm air to try to dry out any moisture that remains.
I need a resin that I could pour into the keel that would work its way into cracks and voids in the ballast thereby filling any space where moisture or water might pool. The resin would need to have low viscosity and cure at a slow rate. Strength and other properties usually associated with resin are not important. I can’t tell what volume I need to fill but expect that it would be at least 2 gallons.

I would like to keep the cost down and thought that a polyester resin might be fine if the viscosity can be reduced and cure rate can be slowed down.

I also wondered whether pouring alcohol into keel and draining it out might remove remaining moisture – especially if any remaining alcohol would mix with the resin.

 

[jbcurt00]

Low viscosity and slow cure rate would be descriptive of Epoxy resin NOT polyester resin. Poly resin isn't a good choice anyway, IMO, as it's weak and brittle w/out added fiberglass reinforcement.


Having no experience w/ ballast keels or concrete in sailboats (wth?) I have NO idea if epoxy would accomplish your goal or how well it would accomplish it, even if it was thin enough to pour and fill in all the cracks and voids as you'd hope. But Poly resin definitely wouldn't.

 

[Scott Danforth]

your situation is unique.

the idea of alcohol is a good one. Alcohol will mix with any remaining moisture and help remove it. Remember, it is also flamable

is your shallow draft keel only GRP and cement? or is your keel also made up of a balsa core? if so, did the water get into the core?

is your thought to use the poly resin because you may be doing other repairs with poly? or are you intending to do other repairs with epoxy?

The reason I ask, you could use a 2-part epoxy paint and simply pour it in for a low viscosity solution. you will need a catalyzed paint. do not rely on solvent dry or air dry. you can slow the cure rate of polyester by using less catalyst to a point. However for a specific low viscosity you will be looking at epoxy.

 

[undone]

Epoxies are high in viscosity unless they are thinned with solvents, which weakens them, polyesters and VE's are low in viscosity to start with and need to be thickened to use as a laminating resin. The repair could easily be done with either resin type though, typically the voids are small and even though polyesters are weaker, the volume is so small it doesn't make much of a difference. A long gel time infusion resin, VE or polyester would cost less and work fine, but finding 2 gallons locally at the retail level would be difficult in many parts of the country, but it can be purchased online. I would use whatever very low viscosity resin I could find that had a long gel time.

Epoxy paints tend to shrink a great deal as they cure due to the solvents evaporating, and in a mass they can crack, plus stay rubbery for a long time.

 

[minuteman62-64]

Gluvit?