seacast

[wca_tim]

Re: seacast

I was actually thinking the same thing after reading this last night.

 

[jonesg]

Re: seacast

After gutting most of the transom out today it doesn't look like theres enough room to get a plywood core down there so I might end up just using the resin.

 

[jonesg]

Re: seacast

Either way, cleaning out the original hole is critical. Any wood clinging to the fiberglass sides or bottom will cause the new lamination to eventually fail at that point for lack of adhesion. From what I've heard, SeaCast is less forgiving in that area, and many fail because of the preparation shortcoming.

Here's a link to the bass boat orthoscopic transom project. It's a whole different boat now, even had to relearn how to drive it.

http://forums.screamandfly.com/forums/showthread.php?t=159482&highlight=wet+transom

hope it helps
John

I can't find a single example of seacast failure, except on their own website. Interesting reading here about it, guy says the same thing.
Some guy tried to make a jackplate with it, it could have worked if he knew a bit about how things need to go together.

Screamandfly is for guys who can afford epoxy.



http://www.boatdesign.net/forums/showthread.php?t=16263&page=2

 

[j_martin]

Re: seacast

Screamandfly is for guys who can afford epoxy.

Screamandfly is for guys that care enough about high performance and safety to do it right.

Good luck with your project.

John

 

[jonesg]

Re: seacast

ok, heres couple of pics tackling the transom removal.
And the tools we mostly used.

What we found is the inner transom wall, below the splashwell is all done, I ripped it out with my hand.
Then I cut the splashwell out so we could see better.
So it looks like everything will have to come out, as far fwd as is necessary Mr Pullings.
Next is remove the center console and cut across the deck, then down both sides leaving 3 inches of deck on both sides to the transom and take a looksee.

I figured this was what we'd find so its no shock.
The general consensus being , if the transom is rotted the rest of it will be too, holds true.

I probably don't need the seacast now, too late.

 

[reelfishin]

Re: seacast

Hi Jonesg,

From Seacast:

Q: Do I have to have an inner skin
and cap on my transom when I
am using Seacast??
A: Yes. Seacast??s strength is
dependent on being sandwiched in
fiberglass skin. It is a core material.​

Alan

Not to get off subject but I think this answers a former question on using Seacast on an aluminum boat, most aluminum boats have exposed wood transoms and no room for an inner skin.

As far as the question at hand, Seacast is meant to be a wood free replacement, I don't think I'd want to introduce a material which may rot in the future or jeopardize a $600 investment trying to do something that's not recommended.

I think Seacast is a great choice for larger boats in which it would be very difficult to either remove the upper cap or on those where the hull is bonded together. On smaller boats, where the cap can be easily lifted off and the transom can be easily accessed, I don't see Seacast as a choice due to cost.

In most cases, one the average smaller boat, its far cheaper to laminate at transom from plywood or even other synthetic materials vs. the $600 cost of Seacast. If I had to spend $600 to repair every rotted transom, I'd have to pass on a lot of boats.

I also think the cured Seacast product is much denser than wood, you could have clamping issues created by the softer wood core.

If your only looking to use the Seacast as a filler, wouldn't it be cheaper to just use epoxy with some filler or short chopped fibers to do the same thing?

Filling the cavity leaks into the bilge can be done by hand laying some glass over those openings, that way the glass will bond to the Seacast or other resin fillers. If your deck is out in that area, this can be done from outside of the transom cavity as well. You will need to make the entire transom cavity leak proof before pouring the Seacast.

 

[jonesg]

Re: seacast

"I also think the cured Seacast product is much denser than wood, you could have clamping issues created by the softer wood core. "

Good thoughts..
Exactly what I was wondering about,
the ply core could compress and crack the seacast....
or if the core got wet and expanded , it would crack again.

The plan now is to build a new inner skin and pour the seacast.
I don't need it but I've already got it and its paid for.

We cut the splashwell top off, both sides of the bilge are rotted, soft.
I mean from the bilge sidewalls to the hull sides, theres substructure in there thats shot. Boat is over 6 feet wide, bilge is just 20 inches wide.

I played with different mixtures yrs ago,
the best was kevlar pulp in resin ,
I think it was poly resin, so hard it was difficult to drill.

 

[jonesg]

Re: seacast

I'm updating this, seacast is just about finished, I ended up installing a 1/2" plywood back wall , slipped inside the transom slot. The bilge area in the center was completely rotted out so I had to put something there.
I used 10oz cloth , both sides of the ply , braced it in the transom slot with blocks and poured the seacast in. I used a LOT less resin than planned.
The seacast is still almost 2 inches thick and solid as rock.
As someone else said, the actual mixing and pour is a non event, true enuf.
I ordered 2 buckets of seacast, and still have the second one unopened but need a bit more to do the cap and sides.
I'm certain that this stuff can be made with resin, thickener , chop'd fibre and BPO catalyst, the cabosil iws needed to prevent the resin from draining to the bottom, it keeps the fibre suspended. BPO is available from the company that makes it (itsw not widely qavailable), but in the end theres not much of a savings, might as well just let seacast do it.


Now I'm moving on to the 2 main stringers, they're rotted.
I started ripping them out,
Photo #1 cut the deck off to get at them, foam seems ok too.
Photo#2 looking fwd from stern, wood is bad...slightly.
Photo#3 Wood gone. I'll glue new stringer to foam and glass to hull.

Question...
Can seacast be used to bed the stringers or is it too hard?
It would greatly simplify installing the stringers.

My plan is to cut stringers from 3/4 ply, glass both sides, seal edges, pour seacast into the slot left by the old stringer and brace it in place, then run glass tape to seal the bottom joint. Finish with coat of white bilge gelcoat resin.