1987 170 Rebuild

[AquasportEd]

Quick update: I bought some PVC board to make the dam. I first put on some of my mold release on a scrap piece and let it cure for an hr. Then i cut a piece of 1708 and mixed up some epoxy and wet it on. I wanted to test out the materials first before i tried laminating the whole skin. The next day after the epoxy fully cured, i was able to remove the glass from the PVC.

I also traced out my transom on the PVC and mocked it up (pic below). I plan on reinforcing the PVC with a couple 2x6's to make it more rigid. Haven't purchased it yet, but found some 1.5in composite material for my core not too far away. Also bought some 1.25in PVC pipe for the drain. Looks like the original drain was much smaller, likely 3/4. Think Im going to go w/ a 1in diam PVC for the drain, seems like that size expandable drain plug is readily available as well.

I also bought some cabosil + milled glass and made a test putty for the corners/drain. Can I lay that stuff on well in advanced, or do i still want it a bit tacky when i actually lay the glass for the skin?

Hoping the weather holds up this weekend to finally get the outside skin created.

[RickK]

The PVC board template looks great Ed. The more you can do "wet on wet" the less you have to sand between layers. You did some test runs, so you have an idea of how long it takes the resin to kick off. Down here in FL I use slow resin because it is usually warm here. I tried using it once when the temp was in the 60s and it took a couple days to kick off. The beauty of epoxy resin is you usually have plenty of time to apply it, you just have to get it out of the mixing pot quickly and into a roller tray (use the disposable paint tray liners from big box stores).
So, you would want to have the three layers of glass cut, trimmed for the corners where they overlap and also the 4,8,12 overlap (or whatever overlap you chose) and then flipped back out of the boat. Then mix your thickened resin and lay in the fillet. You let it kick enough so it doesn't deform if you touch it and then it is time to start the 3 layer lamination of the 1708.

[AquasportEd]

The 3 layers of 1708 got laminated today, hope to pop off the mold tomorrow. For the first time dealing with that much glass and epoxy it was quite the learning experience. Overall i think it came out pretty good, but there were a few areas i wasnt 100% thrilled with. Ill have a spot or two where i want to add some additional glass. Should have the pictures to post of it in the next day or so.

[RickK]

Good for you Ed - sometimes you need to get help mixing while you're in the boat laying the glass and rolling it in.

[larsli68]

Looking good! Great progress! 

//Lars

[AquasportEd]

I definitely had my doubts throughout the process of securing the dam, cutting the glass and laying out the epoxy. But when i popped the mold off today, i was pleasantly surprised on how it all came out. Obviously there are a few areas that need some attention, but overall i think it came out pretty darn good.

Bad news is the store that has my core material isnt open weekends, and is far enough away ill have to take a day off of work. So not sure when Ill have a chance to grab it, but hoping less than 10 days.

[RickK]

Good job - looks great.

[AquasportEd]

I was hoping to use a composite material for the transom, but acquiring it is taking some time and presenting a roadblock. On the flipside, it seems i can easily acquire some marine plywood locally. So im thinking thats the route im going to go, so as to not stop progress (and save alot of money).

I can get 5/8 marine plywood, as they are out of 3/4. So the questions are: will 2 layers 5/8 be sufficient (i would think so)? Also Rickk, i noticed you laminated the two pieces of plywood with glass inbetween. Will one layer of 1708 be good for that? And should i use straight epoxy when laminating them or make a thickened mixture w/ cabosil? Thanks again

[Fishhead]

The supply problems continue! Same problems on west coast.

[Fishhead]

With the out of sight prices on plywood, it’s probably more expensive than coosa but that’s not available. Crazy

[RickK]

I would not use 5/8" the actual size is just a little over 1/2". You want to end up with 1.5" minimum - so maybe 3 layers of 5/8"  I got my 3/4" marine plywood at Lowes.
As for the layer between I would use some CSM, maybe 1.5oz (2 layers of 3/4oz) between each layer. Epoxy doesn't melt the CSM like poly does but it does give the wood something to grab onto. I think at that stage of my rebuild I was still using poly resin. Make sure you are laminating on a flat surface and to keep the layers aligned you can drill a wooden dowel into/through the layers and then grind off the excess. 2 dowels in opposing corners will work. I always used cheap plastic painters drop cloths to cover what I was doing, above and below and weigh down the lamination with cinder blocks

[AquasportEd]

Sorry for the lack of updates, but unfortunately not much progress has been made. Hoping to make some strides this weekend. Last weekend I picked up the core material, a 4x8 sheet of 1.5in Coosa.

Plan is to fist grind some of perimeter on the inside of the transom to get it square, some of my thicken epoxy made for some interesting angles. Then mock up a cardboard template and get a good fit. I'm assuming ill need to also grid any surface that the core will touch so that's there's fresh glass for the epoxy to mate up with. Probably a good idea to rough up the Coosa surface a bit too.

Once I cut the core to shape, I'm assuming all that needs to be done is trowel on a good, even layer of thickened epoxy and clamp it evenly to the transom skin. Wipe any access that oozes out and allow to cure.

[RickK]

Good to see you still at it.  You're going to have to lightly grind all the new glass with 80 grit to get it ready to get a bite on the core. I did not work with composite coring in the transom so I'll leave that up to someone else to fill you in. I did use small pieces here and there and always added 3/4oz CSM for the pieces to have something to grip.
Remember to round the edges of the core where it'll meet the hull sides and bottom. When you lay in another fillet make sure you use a good roulded applicator to mate with that rounded edge.
The sides and hull bottom will need to be ground clean to prep it for the next 3 layers of 1708.

[AquasportEd]

Rickk, so your saying I shouldn't mate up the core directly to the 3 layers of glass i originally laid, and instead, i should be adding an additional layer of glass?

After ive cut the core to fit is it best to:  cut a piece of glass a matching size, wet it out on the back of the core, then clamp the whole thing to my transom skin

[RickK]

Your glass is 1708 correct? One side of the 1708 has 3/4oz CSM on it. Did you lam the outside of the transom glass with it or the inside? I always add 3/4oz CSM to give whatever I'm laminating something to grip. Here is a good video on laminating Coosa - around 6 mins he shows adding CSM. https://www.bing.com/videos/search?q=instructions+for+coosa+composite&&view=detail&mid=3F61B3FF8058B8A4FD123F61B3FF8058B8A4FD12&&FORM=VDRVRV

Hopefully TB Mike or mshugg will offer their experience on this.