Transom soaked - Plan of attack - Splashed

[TrybalRage]

We actually did make some cuts with the saw across the exposed wood - unfortunately visibility is so bad we could tell that the wood thickness 'stepped' but we couldn't tell how thick it was. So initially we were able to break it out in squares, but alot is just getting busted up. We also have a small oscillating saw we've been using to cut here or there when it gets tougher.

 

[Woodonglass]

You might investigate this tool. Works pretty well for a Recip Saw...http://www.homedepot.com/p/Milwaukee-5-in-Scraper-Reciprocating-Saw-Blade-49-00-5455/204453966

 

[ezmobee]

Looks like the splashwell drain tubes being poorly sealed was the culprit. You can see the staining fanning out from them on both sides.

 

[TrybalRage]

We have everything off except the sandwiched ply layer all around the edge. This will be interesting...

 

[Woodonglass]

Make sure and save the Glass that you cut out. It'll be handy on the go back!!!

 

[TrybalRage]

Yep, we saved the outside skin to graft back on again when we're done.

Got the bulk of it out, still working on those edges.

You can clearly see the stepped inside glass where the second ply was embedded. We'll have to repair some of that.. things happen during demolition. One nice thing - we measured the sizes of the wood and we can get both pieces from a single 3/4" piece of 4X8 ply! Money saved

One tool for getting down in that groove was a mini chainsaw attachment for my angle grinder. Unfortunately at 4" diameter, didnt dig too deep. But fun to use nonetheless.

 

[sphelps]

Carefully use the chainsaw is how I would do it ... But that would only work on the port side ... Unless your chainsaw can run upside down ...
An electric chainsaw would work both sides ..

 

[Woodonglass]

Yup Electric Chainsaw would be my tool of Choice!!!

 

[ahmincha]

Question would there be a advantage of using seacast? Graft skin back on drill some holes and fill it up ?

 

[TrybalRage]

I'm afraid Seacast might be hard to get in and fill all the voids with this shape, especially with the cap still on. Plus I'm not sold on the poured-in transom.

On another note, I'm still looking at materials to buy. Seems like a lot of people go through a crazy amount of epoxy on transom repairs, but if you use the calculators on the different sites (like West Systems) the math works out to about a gallon for me. Now, I think a gallon sounds a little light so I'm looking at a 3 gallon kit - found a good price on Boat Builder Central with their MarinEpoxy brand.

I already have a little 1708, so I was going to get more. Seems like a simple, strong, and commonly used fabric. One place I'm not sure of, however, is against the existing glass on the inside. Some of it is damaged from our excavation, some is just very, very thin. I wanted to put a fresh layer of something against it, before putting the new wood panels in. Not sure something like 1708 is right for this - I could almost see a CSM layer between it and the wood, but using epoxy most CSM wont work properly. If I just use 1708, the mat side would only be against one or the other - the wood or the existing glass.

Any suggestions?

EDIT: West System does say that you can use Epoxy to wet out CSM, just that the binder doesn't dissolve and it doesn't get as flexible as it could using poly/vinyl resin. http://www.westsystem.com/ss/chopped-strand-mat-epoxy/

 

[ahmincha]

Csm is useless with epoxy waste of material. Same with 1708 all you need is 17 oz no mat the csm will just absorb epoxy and add no strength.
As far as damage dependent on size you can grind in a flare type pattern from center out start glass small and larger pcs until correct thickness is achieved.
On the smaller ones you can just add extra pb in the small dips and that will level out the imperfections.

 

[Woodonglass]

This ^^^ is exactly how I'd recommend doing it. All sound advice.!!!:eagerness:

 

[TrybalRage]

Csm is useless with epoxy waste of material. Same with 1708 all you need is 17 oz no mat the csm will just absorb epoxy and add no strength.
As far as damage dependent on size you can grind in a flare type pattern from center out start glass small and larger pcs until correct thickness is achieved.
On the smaller ones you can just add extra pb in the small dips and that will level out the imperfections.

Thanks - but I have a few reasons I want to justify the use of 1708 (as long as it won't cause issues with the repair).

1. I already ordered some So, yeah. There's that.

2. The damage I speak of is on a layer of glass that is quite literally eggshell thin. "Grinding" isn't an option... maybe a light sanding but otherwise it will just rip bigger holes in it. So I'm hoping to not only repair but 'bulk up' the interior layer in the thin areas.

3. The original transom material was a layer of glass (CSM?) between the two pieces of plywood. Since I'm using epoxy, I was not going to do this but instead epoxy wood-to-wood. I'm hoping that the interior layer mentioned above will help account for the additional thickness that I may be missing out on since I don't have this layer.

I don't plan on using all that much glass. Currently I only want to use it to thicken/reinforce that interior layer before I install the plywood (1 layer 1708) and then cut into strips to help reattach/blend the old exterior skin back into the hull (approx 3/8"-1/4" thick). Number of strips is dependent on what it takes to build up that thickness.

Everything else will be thickened epoxy. I bought some System Three silica (5qt tub - Amazon) for thickening the structural repairs (bedding and adhering the plywood to the existing skin, etc). I also bought System Three microspheres (1qt) for blending (fairing?) the repair on the exterior skin. Supposedly easier sanding? Hopefully this is enough material.

I also ordered a notched spreader, a dozen mixing cups, roller for bubbles, and some syringes for filling any smaller holes with epoxy.

So while 1708 may not be preferred or necessary due to using epoxy, is there anything wrong with using it as above since I've already ordered it? Or should I maybe look into just cloth around that weight, especially for reattaching the old skin?

 

[ahmincha]

When you boat was built it was using poly so they had to use csm without it poly is worthless. so the layer you are speaking of between wood and skin is mute with epoxy.
as far as grinding in a flare pattern sounds like that has been done during skin cleanup put a strait edge across the areas and you can see how much you need to fill in. Same as i described above start small over lap each pc a little till close to thickness. little variances will be filled with thickened epoxy.
with the way you have to put the wood together in your transom I would soak all wood with epoxy a layer of 17 oz on all flats,
Then I would pb them in place using enough pb to ooze out between seems of plywood to protect the wood. Even pb the edges as you put together

 

[Rick Stephens]

It surprised the hell out of me how much PB I used doing a transom. Lots more than I thought it would.

 

[ahmincha]

I agree I think formulas are in a perfect world. Also as a beginner I am sure i Wasted alot always used to much error on to much then to little.

 

[DeepBlue2010]

Never mind then. Ondarvr answered below

 

[ondarvr]

The CSM on 1708 is stitched, so the binder isn't normally an issue.

​What you run into is the CSM sucks up a bunch of epoxy, which is expensive, so you end up using more epoxy with little too no benefit. It's not going to make it weaker in this application.

 

[DeepBlue2010]

Ondarvr, just for my own understanding. The CSM layer as a whole is stitched to the 17oz fabric, I get that. But, the csm layer itself - still being a chopped stands - is it not fabricated with styrene soluble binder? and if so, there are no adherence issues if this binder is not dissolved?

 

[ondarvr]

Normally the CSM is chopped onto the surface right before it's stitched, so no binder is needed, but there are other methods. The binder doesn't dissolve in epoxy, but not all binders are the same, and the amount applied can be different, some CSM can be stiff, others can be very fluffy, so the results with epoxy can vary.

​Stiff CSM can be hard to work with when using epoxy, the fluffy stuff isn't really a problem.