69 Woodson Tri-hull with 68 Johnson 55hp

[Woodonglass]

The relief holes in the transom wood are not required. I like em cuz they do a couple of good things. 1.) they help to ensure there are no air pockets in the PB when you clamp the transom in place, and 2.) they allow the PB to ooze thru and act like glass rivets to keep the wood from delaming from the outer skin. It's your decision but I really like the results. Might be overkill but it only takes a few minutes to drill the holes and a bit more PB. Good luck on your Transom Install.

 

[Hab]

Thanks Wood, Im still trying to figure out how im going to get all the steps completed in a day to make the full install wet on wet. How much PB does it generally take to get an outboard type transom in. My rough square dimension is 66"X26". I assumed 0.25" layer of PB over the whole area and that adds up to like 2 gallons of PB.

 

[Woodonglass]

Uhmmm, I'm thinking more like 3-5 Quarts. Mix it @ 1% catalyst so you'll have more time. Also Plan it for EARLY in the morning for cool temps and extending working time. use a 3/8" notched trowel and mix one quart with the catalyst and spread it quickly. This will give you an idea of how many more you'll need. Mix the rest and apply. Make sure to do a dry run first with your install and clamping so you'll discover any issues prior to the real thing. It REALLY helps if you have a Helper during the actual installation.

 

[Hab]

Ive been digging around trying to double check on a number of things. I'm stuck on the filler mixes. I'm reading that in some instances I would only need resin and cabosil and others i would also add the milled or chopped fibers. Im planning to put CSM and Roving over the transom skin of the hull and CSM on the transom. I will spread a filler between the CSM over the transom and the roving over the skin and clamp together. I am wanting to attempt this all in a single run so the resins and fibers are essentially applied wet on wet. For the filler or PB mix between the transom and skin, can the mix be cabosil and resin only? Can a thinner filler layer be used if the application is wet on wet? Say 1/16"-1/8" layer of filler? I think I only have 2 lbs of cabosil roughly half a paper grocery sac full.

 

[Woodonglass]

For gluing the transom to the outer skin I recommend Mixing resin, Cabosil AND chopped milled fibers to the consistency of Mayonaise. Ratio is close to 1-2-1/2 1 part resin w/catalyst, 2 parts Cabosil 1/2 part CMF. i.e 750 cc of resin, 1,500 cc of Cabosil, 375 cc of CMF. Add additional Cabosil as needed to obtain the right consistency. Add The CMF at the very last

 

[AShipShow]

I don't think I ever made PB without the chopped fibers... They add a lot of strength to the PB and in most cases, it is a structural application. Even fillets are structural, they eliminate stress risers at sharp corners... Theres really no downside to using it all the time, its cheap as mud and easy to add.

 

[kcassells]

Chopped fibers with poly is a major YES. Supposed not necessary with EEEEpppoooxxxyyy but I do it anyway sometimes.
Oh yea I add the fibers first and let settle to the bottom and then add the resin then cab. As long as they are wetted out.

 

[Hab]

Got my fingers wet last night. Made some small test fillets with filler between the hull and transom skin, and then covered them with CSM and resined them over. Well.... more or less sloped some goop at them, and then tried to comb down the hairy mess. Honestly I was nervous and was pretty sloppy for attempting a small amount of vertical and horizontal corners. I didn't baby sit it long enough. I waited till late in the evening to start, there's plenty of bubbles to dig back out. All in all it was a good learning effort, the working time was better than I expected. for the filler i used 1:1:1/2 ration of resin:cabosil:milled fiber, worked up to a descent anti-gravitational mayo and seemed to work fine for the vertical fillets. Below is the proof. I gots to go see the glass man today to get a few more supplies to make sure i have enough on hand to complete the transom install. Going to get some PVA or gel to finish the last coating.I dont have a shop and my tarp wont keep any significant amount of rain off of it. I got the clamps made and finished the rest of my prepatory cut outs of glass. should be good for a dry run on saturday, then i can start coating the dry wood for install on sunday.

 

[kcassells]

You have to start somewhere ya see and get the feel for it. I would suggest to let the pb dry then go ahead with glass. :joyous:

 

[archbuilder]

I just caught up on your thread, nice job.

 

[sphelps]

Looks good . It’s not really rocket science ...
Just some more practice and you’ll be screwing things up like the rest of us ..:lol:
You will get pretty good and confident and think ya can handle any layup then you will really screw up .
Maybe forget the hardener or something on a big layup . Get mad snatch it all out , make a mess , resin everywhere even on the dog , say some choice words then regroup and do it right next time ..
At least that’s my experience ...

 

[nurseman]

Looks good . It’s not really rocket science ...
Just some more practice and you’ll be screwing things up like the rest of us ..:lol:
You will get pretty good and confident and think ya can handle any layup then you will really screw up .
Maybe forget the hardener or something on a big layup . Get mad snatch it all out , make a mess , resin everywhere even on the dog , say some choice words then regroup and do it right next time ..
At least that’s my experience ...

I was bedding stringers and forgot to add catalyst to one batch...:frusty: Had to dig it out from under the stringer, which isn't as much fun as it sounds like it would be.
Didn't get it on the dog, but sure as heck got it on everything else.

 

[kcassells]

I did the same thing...….el pisso dumbO says I but lol
But I did shoot the dog.
He survived....no worries guys... Shoulda used Silver bullets.

 

[Hab]

Its official, I am a fiberglass No-Go.I did manage to get the transom in, but it isnt pretty. Ive got a ton more glass over the wood than the factory used, but the layup is just as imperfect. Ive got to say that tabbing and CSM is by far the worst part of the job.

 

[Hab]

Ive still got another layer of tabbing to add to the transom, but ill have to get some more grinding done before i can get that in. the install went all-right except for the one pot of resin that gelled on me. I guess im just going to have to slow down and baby sit each square foot till it hardens before moving on. Running fiberglass with temps in the 90s is not for beginners. Anyway its in and it holds water, got a couple showers the very next night.

 

[strokendiesel002]

Good job sir from everything that I've read the hardest part is just making yourself do it,k then keeping your spirits up when it doesn't go quite as planned

 

[oldrem]

Most important is that it's strong and waterproof

 

[kcassells]

The more you do the easier it gets!! It really does. Look at me...I can finally do it.

 

[nurseman]

Some guys measure out their resin, then put it in the fridge or a cooler with ice to help slow it down when it's hot out. The lay ups get better as you do more of them. Take your time and plan your moves out before you mix the resin. Sometimes I would even do a dry run just to make sure I had all the ducks lines up. The transom install is probably the hardest part. Now that that is done, there isn't anything in the boat that you can't handle. She is lookin good!

 

[Hab]

I appreciate the encouragement guys, i was needing it. Ill grind out the biggest of the bad spots in the corners where i more tabbing to do, but the rest I will leave.... for science. I'm going to get my bilge drain installed and then toss the cap back on to test the fit of the transom and check warpage before installing the stringers. Ill have some time in building bulk heads and testing final fitment of the stringers, but I'm hoping to be setting them before long. God willing by the time i finish another 72ft of tabbing for the stringers, ill have this fiberglass stuff about half learned.