How To Laminate 3/4 Ply Transom

[mspring]

I am almost ready to cut and install my new transom. This will be the first thing I have cut or sanded that doesnt blast fiberglass all up around my ears and elbows.

My transom will be two pieces of 3/4 plywood. Can someone walk me through the process of glassing it in?

It is going in a fiberglass hull that will have at least a 90 hrs Johnson on it. The deck and stringers are ripped out at this point and I will be using polyester resin. The outer skin is in good condition but has alot of holes from various accessories that were on there from the previous owner.

How will I fill the holes?

 

[rockyrude]

Re: How To Laminate 3/4 Ply Transom

Everybody here uses an adhesive known as "peanut butter" , it is resin with cabosil and chopped fiberglass fibers mixed to the consistency of "peanut butter". Once mixed you trowel it on to a uniform thickness and clamp the pieces together. You can also use the stuff to glue your stringers in place before glassing in.

 

[tashasdaddy]

Re: How To Laminate 3/4 Ply Transom

i use "PL poly construction adhesive", Home Depot, paint dept. it is 100% poly, comes in a caulking tube, you don't have to mix. it is thick, put is on and use a notched trowel to spread it, like you were laying tile. clamp together. i have also used it to fill holes in the hull, above water line.

 

[mspring]

Re: How To Laminate 3/4 Ply Transom

Can I use that to glue down the stringers also?

What about the holes in the outer skin?

When I install the transom I guess I should coat all sides with resin and glass in totally with mat then a layer of roven on the inside?

 

[tashasdaddy]

Re: How To Laminate 3/4 Ply Transom

it is 100 % poly, you could use it to place the stringers, and then glass over them, i have just shot it into the holes, let it dry, and sand off. correct of transom. also lap on the gunnel's.

 

[mspring]

Re: How To Laminate 3/4 Ply Transom

If I fill the holes with the caulk I can sand it then paint over it because later I plan to paint the entire boat.

 

[drewmitch44]

Re: How To Laminate 3/4 Ply Transom

tashasdaddy, what is that stuff called you are talking that comes in the tube?? I work at lowes and if home depo has it we most likely carry it too. You said its 100% poly? Ill be looking for it when i go to work tonite. Im just wondering what its called? And would i find it near the caulks? We have a huge selection of construction calks and what not so if i knew what it was called I could find it easier! Thanks

 

[drewmitch44]

Re: How To Laminate 3/4 Ply Transom

is it this stuff??? http://www.amazon.com/Henkel-10-2-Ounce-Polyurethane-Construction-P73948125/dp/B0002YVJG8

 

[tashasdaddy]

Re: How To Laminate 3/4 Ply Transom

that's the same stuff. i worked for Home Depot for 3 years after i retired. as a Lumber cashier, ringing $10,000 a day. it was a fun job, and got me out of the house. was great until one of the still wet behind the ears, assist. mgrs, got smart with me. i told him i should kick his --- right there, then he tried to make it miserable. Fired me, tried to keep me from drawing unemployment. i made a fool of there whole cashier, and cash account system, at the unemployment hearing.

 

[mspring]

Re: How To Laminate 3/4 Ply Transom

What should I use to glue the transom in to the outter skin? Resin or the poly caulk?

 

[erikgreen]

Re: How To Laminate 3/4 Ply Transom

For my transom (on my first boat, which still isn't in the water) I used a peanut butter consistency mix of epoxy and wood flour... basically the wood flour is a powdery sawdust, which I bought online.

I also used that to laminate the parts of the transom together. Very solid. I used it to fill the gaps at the edges between transom and hull, and then laminated glass over it - first roving (24 oz) then two layers of 8 oz cloth.

All done with epoxy, wood flour, and glass.

Erik

 

[drewmitch44]

Re: How To Laminate 3/4 Ply Transom

Thats cool tash, is wish i would get fired! LOL I think i told you that i work at Blowes. Sometimes its kinda of a joke there. I closed last nite and i dont know how that place affords to keep the lights on with as little business they do. Im starting to be lucky to get 40 hours. Its almost to the point where if i were to get fired i would make more on unimployment. I couldent just not work though thats just how i am. Id go nuts. Thanks i looked at the stuff last nite. They have that elmers resin with hardner that was normally 36 bucks a gallon for 6 dollars. I got 5 gallons of it. Thats what im going to use now i think. That stuff has the wax in it but i think it will bond to itself between layers if i grind it between layers. Anyways thats what im going to use for the rebuild im working on now.

 

[tmcalavy]

Re: How To Laminate 3/4 Ply Transom

You may already know this, it was posted in a similar thread on this board some time ago. When you layout and cut both pieces of ply to make the transom, cut them so they will be cross-grained when bonded together. In other words, the grain(s) should be perpendicular to each other rather than parallel. Imparts more strength. I did this when replacing the transom on my early 60's aluminum v-hull runabout that I am restoring. It's a light duty pleasure craft and I am on a budget due to downsizing at work, so I didn't glass my transom or deck. Just waterproofed both with a good latex primer and paint (3 coats) before the install. Also made sure that the back panel in the deck is removable, so I can pull it out and vacuum or drain out any water that gets in there and goes to the rear bilge...before I stow/park it after each lake use/trip. That may be heresy to some who advocate fiberglassing all surfaces, but in my experience it's easier to keep/service/maintain an aluminum boat when the floor/deck is engineered for easy removal. My last smaller aluminum fishing boat had a home-made wooden deck, made of interlocking panels. Never a problem with getting off balance when moving about in the boat, easy to maintain, and made cleaning the boat out a breeze. I toyed with that idea when working out the details of how to put a new floor in my current restoration project, but decided that plywood panels screwed to the aluminum stringers would be just as durable/serviceable and was ultimately more affordable on my current budget. I've drifted off topic again...remember to build your transom so the wood grain is cross-grained.

 

[BillP]

Re: How To Laminate 3/4 Ply Transom

mspring,
The outer transom skin has little strength so don't get too hyped up on the glue joint giving much, if any, structural increase. All you need is a tight fit for the wood against the skin it so there isn't a pocket to hold water. New boat mfgs use straight resin for glue and clamp it...same as between the transom plys, straight resin and clamp. I use their method and it works fine. Also, remember that when the motor is bolted on it gives tremendous clamping strength to the whole transom assy. Glassing the edges of the transon ply to the inside of the hull are the most critical places.

The post on not glassing the transom might be confusing. Aluminum boats bolt the transom wood in and don't use glass...glass won't stick to aluminum. Virtually all fiberglass boats glass the transom wood in.

Like mentioned already by tmcalavy, cut multiple pieces at diagonals so the SEAMS are across each other. Mine are usually cut at maybe 30-40 degree angles across the beam (alternating each from floor to deck) and I use screws to pull them together instead of clamps. I leave the screws in and glass over them. The motor holes can also be used with bolts though them for clamping.