50's elgin 14ft redo

I am new to boat building. this boat is probably not worth the repair but it was my gradfathers boat. i've read on posts about the epoxy sealers and the west system. I just wanted some info on how this stuff works. I know you put it between boards when installing them kinda of like a glue. but they talk about sealing the whole boat. is this what makes it waterproof. and what is the best stuff for the money. and do you have to do inside and out or just one coat on the inside and three on the exterior. I'm going to use 1/4" lauan.

one other question some of the solid wood on the interior like seat backs and the dash board and transome are mahogany. is the any alternitive woods that I could use on the interior that would work well with the lauan. that would be cheaper. and the framing is 2 sheets of 5ply mahogany put together could i use a pine plywood instead since it isn't seen. to save money.

any help would be appreciated dont know much about wood boats but this one has sentamental value to me
by the way it is a 14ft elgin plywood construction

 

If I were you, I would go to http://www.westsystem.com/

I am not posting this link so I won't need answering, and I guess I could answer a few (with my limited knowledge), but there are so much information that is is good to know, and some that you _must_ know (safety), so the best place to start would be west epoxy's site.

Also, how "rotten" is it? Is it in good condition? If so, maybe you don't need to meddle with epoxies?

Epoxy is a sorts of plastics (when fully cured), so by "sealing" it, you are in fact encapsulating it in it's entirety in plastic. It _can_ be good, but not always - for instance, you don't want to put it over something that is moist..

I can understand it has sentimental value, so maybe, if at all possible, then the rotten plywood should be replaced by marine plywood (better glue etc.) That way it will last longer.

Also, when sealing with epoxy, make sure you encapsulate the "rear" too (the back of the seams), before you stick them together. Otherwise your "plastic bag" may have an open end where moisture can be led. In that case, having the other sides covered so the moisture can't escape might not be such a good idea.


Anyway, I'll stop ranting now.

Good luck

Andre

 

thanks for the reply I have to totally redo whole boat top to bottom. I just finished tonight tearing it down. there is only a few top braces that are selvagable. i'm going to be using marine lauan plywood. I talk to a boat builder in person he said with plywood all he does is uses a marine type of liquid nails to put together then primes it sands it a varnishes it with about 5 coats my new question is what makes it waterproof. the varnish?

 

Yes, the varnish does that. But epoxy is stronger and if you varnish on top of epoxy you will get the best of both worlds (the epoxy making it real waterproof, making a much stabler base for the varnish, and the varnish with UV protection in order to protect the epoxy against UV-degradation.


Especially make sure that the end grain is closed. around any edge of plywood you have 50% endgrain. That you will need to be sure is closed.

Andre

 

so if money was a absolute issue you could just varnish all the end grains before putting together and then varnish the whole boat.

also what could be used for framing instead of mahogany. it is exspensive and not very avalible where I am located.

do You also know where I could get any info on how to piece two pieces of plywood together to get my 14ft length.

 

yup, you could basically use anything that will stop water from ingressing.

I'm hesitant to say what can be used for framing, as it kind of depends where you live what will be best (and cheapest). But cedar is good (naturally rot resistant) and you might be able to scavenge it from a house being torn down. Larch could be another one (I am using that for my boat - it's cheap and traditionally used here in Scandinavia), but there are many reasonable cheap choices, it kind fo depends what is available at your place.

What you're looking for is "scarfing". I will see if I can find a link. You will need some glue for this, though.

Edit: Here we go:

http://www.oneoceankayaks.com/stitchglue/plyshophtm/scarfjig2.htm

I like the diagonal one the best.

What you do is put them together, and move back the top one the 8-12 times the thickness. And you need an ekstra piece (can be any old scrap of wood) on the bottom, also the 8-12 times from the middle one (so you get a sort of ladder). Then you use your plane and go diagonally down, and when all is smooth, you can turn one of them, and it will fit. And be very strong.

 

thanks for all the info in my area douglas fir is avalible and I see many others use this with lauan for the sheathing and fir for framing and interior peices. but cedar might be an option for me to

 

Any time, Oldspower

Douglas fir is often used, so you could certainly use that as well. However, all things being equal (i.e. if you can get the cedar at the same price and in your vicinity) I would go for the cedar. Simply because of it's rot-resistance and saving a little money on the "encapsulating".

I have seen cockpit floors made from untreated cedar, so it ought to work either way. And cedar is beautiful, methinks

 

new question sorry for all the questions. if I use cedar for the interior. and lauan 1/4" ply for the sides does this have to be marine grade or since i'm varnishing it will be sealed and okay. thanks for all the help

 

Hehe, that's okay, Oldspower

Do you mean the cedar being marine grade?

Because cedar is "real" wood, so "normal" will do.

The plywood, though, should preferably be marine grade, for longevity. Ordinary ply is really not worth much (longevity- and strengthwise), especially if sealed with just varnish or oil paint.

 

The cedars do not compare favorably to Douglas fur in strength and I would strongly advise against recommendations of swapping out different species at the drop of a hat. Larch in Europe is very different then the western larch we have in the states. Western larch compares very favorably with Douglas fur and can easily be a substitute. If using a cedar, scantlings dimensions will have to be upgraded to accommodate the different strengths and properties of cedar.

Varnishing the whole of a boat was common practice until epoxy came along. I know of no marine version of a Liquid Nails type product, so check out what this boat guy is using.

Marine grades of plywood are necessary in the hull shell. You can get away with exterior grades of plywood for use inside the boat, in cabinets, shelves, seating and other furniture, but I would use marine plywood in all the bulkheads. Marine plywood is stronger, much better quality construction and lasts longer. The structural pieces of the boat should be made out of it.

Douglas fur does not finish well. It turns into a washboard as soon as it is sanded. The more you sand, the worse it gets. As a framing piece, it works well. Cedar for trim pieces will look nice and finish well, but lacks the strength of Douglas fur.

You best bet for lumber substitutes would be a trip to the local wood supplier to see what is available. With this list in hand, better recommendations can be made, that will not sacrifice strength or other properties, if the replacement piece is built to the same dimensions.