1978 Tri-hull transom rebuild - have question about mixing fillers to lay in the core

[ELoller]

Well I installed my transom core last night. Using some of the great ideas yall gave me I think it went really well.

Its still very hot here so I refrigerated my resin before using it. I also mixed my PB to the thickness I wanted and refrigerated the batches before putting in the hardener. Since the PB was obviously thick I used a power drill paint mixer to zip in the MEKP and make sure it was mixed in there well. Checked it this morning and everything was already cured and rock hard.

Also when I had my helper troweling PB on the inner skin and the inside of the transom core he had two cheap aluminum baking pans. The bottom was deeper and had ice in it and then a more shallow one on top held the resin. This kept his resin colder longer.

I also dumped the PB I was using to fill in the lip around the core into gallon zipper bags like someone mentioned on here. Cut the corner off and used it like a pastry bag. That tactic was so clean and effecient that it was fun! I had about 1250ml of PB just in the lip and about 1000ml troweled on.

I also used about 500ml and a turkey baster to inject some more resin into the top corners where I knew I was going to have some voids. I made the PB slightly runny so it would flow down in all the nooks and crannies. It filled up quite nicely that way. When we drug the trowel over the walls for the final smooth out we made sure to run the trowel lines straight up and down so that if I did have to inject any PB into it, it would run down easily.

I used a .75% MEKP to resin mixture ratio. Taking all of these steps gave us plenty of time to work the PB and get the core in. We were able to line up the clamping boards with the holes we drilled pretty easily as well. Everything went like clockwork!

I got so much squeeze out from all the edges that I had a big mess on the carboard we were working in. I was happy to see that! So now I can move on to strengthening the inner skin with CSM and 1708 to tie it all in a little better.

I will post some pics of how it looks later today.

Thanks again guys!

 

[jigngrub]

Glad to hear everything went well!

Planning, problem solving, and decision making are important parts of a successful boat restoration/repair.

 

[ELoller]

These are from 48 hrs after the transom cured. I sanded down all the squeeze out and filled the areas that still needed some touch up. There were a few areas that didnt squeeze out as much as others but I was able to see a solid line of resin in between the gap I filled. So I made another batch of PB and filled the remaining voids.

All in all it feels pretty solid I still need to wrap csm and 1708 all over the top of the transom to tie it to the moto rwell and then the inner skin on the sides. You cant see it but I have about 3 inches of the back of the core exposed on the inside, on either side of the motorwell. That should let me get a good bite when I lay glass to strengthen the inner skin from the inside.

 

[jigngrub]

Looks good elol!

You've still got your work cut out for you laying everything up, tying it all together, and smoothing everything out... but I'm sure that won't be any step for a stepper.

 

[ELoller]

Thanks jigngrub. I have a question about some biaxial glass I received in the mail.

It is 17oz biaxial glass with a 3/4 oz cloth backing. Whats the purpose of the cloth backing? It came in a separate bag and is not attached in any way to the biaxial... Didnt realize I ordered anything with a cloth backing.

 

[Woodonglass]

Thanks jigngrub. I have a question about some biaxial glass I received in the mail.

It is 17oz biaxial glass with a 3/4 oz cloth backing. Whats the purpose of the cloth backing? It came in a separate bag and is not attached in any way to the biaxial... Didnt realize I ordered anything with a cloth backing.

I'm confused. First you say it's 17ox with 3/4 oz cloth backing then you say it came separate and it's not attacthed. Which is it? If it's 17oz with 3/4oz stitched to it that's 1708 biaxial if you have more of the "Cloth" that looks like the 3./4 stuff only thicker that's called 1.5oz CSM (Chopped Strand Mat)

 

[ELoller]

Thanks for that Wood. The 1708 biaxial came with the backing stitched on but I also got some "cloth" in a seperate container. It looks like cotton or nylon cloth.

I am not sure why Jamestown distributors sent the cloth. I guess I'll give them a call.

But you answered my question.

 

[jigngrub]

Post some pics of that cloth so we can see what you have.

 

[Tarheelsportsman]

ELoller. I saw where you mentioned you got the csm and 1708 from Jamestown, I was wondering if you got your resin there also, I have to purchase some plr and i'm wondering if you are using there totalboat brand

 

[ELoller]

Yes I did get my resin from there as well. It is the totalboat brand. Works pretty well.

Sorry for the late response as I was out of town for a few weeks.

 

[ELoller]

Post some pics of that cloth so we can see what you have.

Jamestown made a mistake in sending the cloth to me. Of course it confused me. I wasnt supposed to get it!!

I laid up all of the internal 1708 pieces before I left on my trip. Man laying up vertical pieces while in a cramped space with my hands above my head was HARD. But we thorughly wetted both sides of the 1708 and I wetted the mating surface as well. This made it easy to "stick" on the 1708 but you have to get it stuck on almost exactly in the spot you want it to setup or it can be a pain to move it around because of the "stretchiness" of the 1708. My precut pieces became more deformed the more I slid them around. Luckily it looks like I minimized voids by using an aluminum glass roller and a few old plastic gift cards for smoothing things over.

Now that I am done working inside the bilge area I can move to the outer skin and into a more comfrotable working space and position... I will update as things come along. August is going to be a busy month for me even without the boat repairs.

 

[jigngrub]

Did you ever get this put back together E?

 

[ELoller]

Well its been months since I had time to post my progress. While I was rebuilding the transom I was also rebuilding the 1983 70hp Evinrude I run. Motor is rebuilt and oiled, waiting to be mounted...

After laying in the core and taking the time to sand and look around for anymore potential weak spots I finally felt comfortable moving forward. The first thing I did was prep the old skin to be stuck back on. I wanted to use the old skin because it was still in good condition and would give me a better idea of how far out to build up my new glass to fill the cut I made.

After sanding down the back of the skin and already having sanded the transom core I was ready to re-install the old skin. I made some fairly think resin butter and smoothed it over the back the skin being sure to drag my spreader in multiple directions to fill any voids from the factory glass. I laid it on pretty thick because I knew the squeeze out was only going to help me,

I used the same clamping system of 2x4s and all thread that I used to clamp in my core. After I tightened all my all thread pieces There was alot of resin squeeze out so I smoothed out and tried to make my future sanding job easier.

Once the skin cured, I went to work sanding and prepping all of the surfaces around the outer edge that I needed to glass in. I also layed several layers of glass over the top of the motorwell and down the back of the transom for strength. I also did the same process on either side of the motorwell and tied in the new inner layer with the top and back with several layers of 1708. I know this helped add strength because I glassed about 10-12 inches down the inside of the reinforced inner skin and the back of the transom.

I used 50yds of 4 inch wide 1708 to go around the outer edges and fill in the cut I made. I basically did the left side and then the right side in 4 separate stages. I used all but about 2-3yds of the 1708 tape. I found the 4in wide tape was really easy for this application because it was about 1in wider than my cut. Much less cutting of dry glass rolled sheets. I made sure to overlap the fiberglass edges as far out as they would allow and of course brush it all on with clean resin. I found that flexible gift cards were great for spreading wetted fiberglass and getting out the air bubbles. Then going back over and brushing more clean resin on with cheap chip brushes.

All in all this process worked out really well. I did two separate layups on both sides and sanded in between. I found that spreading some resin butter over the area I just let cure and sanded down, helped me smooth the marrying surface that much more. Of course I always sanded and wiped with acetone before laying up glass or butter. I didnt use thick amounts of butter just enough to fill any small pinholes or uneven spots before laying on the next layer of glass. I layed about 8-9 layers of glass during this buildup process.

After I was satisfied with filling in the cut with glass and butter I sanded and prepped one more time. Then all in one session I spread some butter to again help smooth things and then layed up more glass that was precisely cut to not over lap but to cover as much area as possible. This layer was done around every corner of the transom to tie in the rear to the side. Of course I sanded and prepped the sides that were still gel coated from the factory, Once again I had already filled my cut but I wanted to add more layers around the sides as someone suggested in this thread to help tie in the transom with the sides.

Now I just need to reinstall the rear upper pieces of the body cap I cut off but kept whole. I cut these off to let me slide in the core at the beginning of this install. Those pieces arent structural so they shouldnt take nearly as long. I then should just have to use some light butter and basically smooth everything as much as possible in multiple stages of sanding and resin butter until Im satisfied, Its just an old fishin boat so Im not gonna be SUPER picky but I dont want it to look like wrinkled dog butthole like someone described the other ones they see on here installed like I did.

Then gel coat! Working on getting pics posted.

 

[ELoller]

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