BYYB Forums

I'm using MarinEpoxy from Boat Builder Central (2:1 mix).  I plan to encapsulate all the plywood, and glass the "wear and tear" and wet surfaces.  6oz. glass cloth.  Can anyone give me a ballpark figure for coverage by square foot of the epoxy for encapsulating and glassing?  I don't want to mix a gallon when a pint will do!

Thanks.  Dave

I used small mixed  margarine tub sized batches, Best to get a reliable helper, they can mix batches as you continue applying them. I left the inside of my boat without glass & epoxy. I used white solid deck stain, I wanted wood moisture to have a place to go, as it aged. My fear was that the moisture would be trapped, and eventually cause rot issues.

Greg 

Yeah Dave, I was advised to 'glass the outside of the boat, and not the inside, so the plywood has fibreglass on one side and not on the other. My boat has fibreglass over all the exterior areas, more for uniformity of finish than any other reason, but it's just painted wood on the inside.

Don't actually mix up a whole gallon at once! It will get really really hot and you'll end up with a terrible mess. Individual margarine tub sized batches is the way to go. I recall initially using 4 litres of resin total, but it was a long time ago. I can't really remember. If you buy a gallon, you'll have some left over for inevitable touch-ups and repairs.

There seems to be controversy about this point.  It unanimous to not glass the keel, because of the differential expansions of the solid lumber causing delamination of the glass..  But plywood should be dimensionally stable and delamination (and water gaining entrance) should not be an issue.  Has anyone who encapsulated the entire boat had any problems or regrets?

Dave

As everyone else said, use small batches. Otherwise it sets up and you have this gelatinous mass you can't use.  I don't exactly know how much per square foot. I built a 12 foot row boat and used about 1 1/2 gals of epoxy.  That's pre coating the wood, wetting out the glass (only on the outside) a second coat on the glass, and two coats on the exposed wood inside the boat.  The designer said one gallon but I think they were basing that on them having built a lot of these boats.  After a while you get better at it and use less.

Anyway if you use small batches you don't have to worry too much about mixing up too much and wasting it. If you get near the end and run out you can go buy a pint or half gallon and finish up.  Having a helper is great. My wife did a lot of the brushing the epoxy on while I mixed up the next batch, but if you use small batches and mix the hardner in the correct amounts the first layer will stay tacky long enough to mix another batch, so you get a good chemical bond between the first and second layers. If you wait and it sets up hard, wash it down to get rid of the amine blush before you apply another coat. Plain old water will remove the amine.

It's depends on how uniformly you apply epoxy, which is technique dependent.

The most economical method is with a plastic applicator or squeegee. This will apply a uniformly thin sheet of goo to the surface. You can spread out a small amount of epoxy over a large area this way, which is the whole point.

Brushes, either foam or chip are not a very good way to apply epoxy. Unfortunately, they can at times, be the only way to get epoxy into corners and cutouts. Brushes tend to create pools of epoxy with feathered out edges, not a uniform coating. You'll easily use twice as much goo with a brush.

As has been mentioned, working small batches is the only way. As you gain experience, you'll increase the size of the batch, until at one point, you'll "smoke a pot". Everyone has to do this at least once, just to learn how much they can work with.

Temperature and humidity (viscosity) has a lot to do with how much you can apply as well. If it's fairly warm, you can lose "working" time, because it gels before you're finished. Also the epoxy you've selected can affect the amount you use. For example, if you're using a regular hardener, but the temperature is at the high end of it's working range, then it will kick off faster then you may have time to apply it.

Generally use a hardener that is slower then you need. You can always wait a few more hours for it to cure, but it's hell to pay if you waste it, because you mixed too much and it kicks off in the pot.

A gallon of epoxy should cover about 250 to 300 square feet of surface. Porous surfaces will absorb much of the first coat, so subsequent coats will cover larger areas then first coats.

Again, as you gain experience you'll get a feel for how much you can work in one shot under the current environmental conditions.

A trick I use when coating large areas, using multiple batches is to have a container (mason jar) of lacquer thinner or acetone.  I  keep the brushes or rollers in it while mixing the next batch.  

Pull them out of the jar when ready and dry them with a rag....almost as good as a new brush.  This retards the curing on the brushes and you get much more use out of them.  Use natural bristle brushes not nylon or polyester brushes.

Hay, Peter, I just realized who you were. Welcome aboard Ike . . .

Well bless my soul.  You do get around don't you!  I was looking around at other forums and this sounded like a good one so I signed up.  Glad to be here.