If seacast is the easy way, I'd hate to try the hard way!!!

[John the landlubber]

I have just finished my second session trying to remove the ply from my transom. In total it has taken 9 hours with a chainsaw and gorilla bar and due to the length of the chainsaw I have been unable to completely remove all the old ply. There is about two inches left at the bottom in places and I don't know what to do now. I have already borrowed the biggest chainsaw I can, and where I live the hire companies no longer rent out chainsaws unless you can provide them with a forestry commision license ( on the grounds of health and safety! ). Where do I go from here??? I really dont want to cut the outer skin out so I can get the last two inches out as the point of taking this route was to eradicate the need for fibreglassing! I cannot get it with the gorilla bar as I don't have anything left to lever against once I hammer it through the ply, therefore it just leaves cuts in but does not remove the ply. Any advice will be most welcome. thanks.

 

[wire2]

Re: If seacast is the easy way, I'd hate to try the hard way!!!

What thickness is the plywood?

Get a slightly smaller spade drill bit, grind the very sharp point flat so you don't go through the fibreglass too.
Put 2 or 3 -12"drill extensions together and systematically drill lots of holes. Judge the depth by holding the bit behind the transom.

The dull tip will still go through rotten wood but will stop on the fibreglass hull.
Shop vac when debris gets in the way.

I did the above recently, have it poured now.

 

[v1_0]

Re: If seacast is the easy way, I'd hate to try the hard way!!!

Fire?

Chemicals?

 

[John the landlubber]

Re: If seacast is the easy way, I'd hate to try the hard way!!!

Fire?????????? Are you having a laugh mate? What chemicals do you think, some sort of really strong acid do you reckon mate? Lol. Machine gun or explosives might do it, eh mate, lolololol!!!!!!!

 

[pduquette]

Re: If seacast is the easy way, I'd hate to try the hard way!!!

Do you want 'ta rent my trained swarm of carpenter ants ??? They're union!

 

[redfury]

Re: If seacast is the easy way, I'd hate to try the hard way!!!

I used my 1" spade bit and bought an extension so that it could reach far enough ( you can pick up the extension at the hardware store for about 10-15 bucks )

I had tried using the wonder bar routine with a 3lb hand held sledge and beat the heck out of the transom. Once I threw the spade bit at it, it was over in no time.

Spade bit FTW. ( for the win )

 

[Willyclay]

Re: If seacast is the easy way, I'd hate to try the hard way!!!

I considered using Seacast to replace the rotten transom on my previous project boat but decided I could buy a newer boat with a good transom cheaper than what Seacast would cost. However, I recall their instructions provided the option of removing the "inner skin" of the transom for access and then fabricating a new inner skin before pouring Seacast. Good luck.

 

[60 grit sandpaper]

Re: If seacast is the easy way, I'd hate to try the hard way!!!

Great idea WIRE2.Cut that tip off.The one that went through my hull.

 

[60 grit sandpaper]

Re: If seacast is the easy way, I'd hate to try the hard way!!!

remove the bottom 1 or 2" of inner skin with a sharp wood chisel(might ruin it) cut top line first then along the bottom next to the hull second.Easy clean out then.Epoxy everything insert ply glass over the cut you made.Messy but done.I'm gona try pl premium instead of epoxy.Let us know what you end up doing.

 

[v1_0]

Re: If seacast is the easy way, I'd hate to try the hard way!!!

Fire?????????? Are you having a laugh mate? What chemicals do you think, some sort of really strong acid do you reckon mate? Lol. Machine gun or explosives might do it, eh mate, lolololol!!!!!!!

Well, sort of - but there was a point hidden in the mirth: there are other methods besides cutting/chopping/drilling/shaving, etc.

As a wild example, I might look into some solvent to weaken the glue that holds the plywood together. Shouldn't affect the aluminum - well, maybe pull any paint off of it.

But it sounds like the problem was solved.

 

[v1_0]

Re: If seacast is the easy way, I'd hate to try the hard way!!!

Or: http://forums.iboats.com/showthread.php?t=224367

 

[wire2]

Re: If seacast is the easy way, I'd hate to try the hard way!!!

As a wild example, I might look into some solvent to weaken the glue that holds the plywood together. Shouldn't affect the aluminum - well, maybe pull any paint off of it.

I believe marine plywood layers are bonded with 2 part epoxy. That's partly why it's so expensive.
Good luck finding a solvent for it after it's cured.

 

[v1_0]

Re: If seacast is the easy way, I'd hate to try the hard way!!!

Good luck finding a solvent for it after it's cured.

Methylene Chloride or dimethylformamide will 'attack' the epoxy. I have heard that some paint removers contain this, but it is very nasty stuff. ("The EPA has mandated that Methylene Chloride will mutate you, your children, your dog, the neighbors, etc. for generations to come.")

Heating may also cause the expoxy to gel, but I'm not sure how hot it has to be (?200 F? ).

-V

 

[John the landlubber]

Re: If seacast is the easy way, I'd hate to try the hard way!!!

I ****ing give up with this seacast method. Now i'm really annoyed. I cut the top off the transom. Bought a cheap electric chainsaw from homebase (electric), with the knowledge that it would not reach right the way to the bottom. Reason I did this was to minimise time spent with my dad's very noisy but longer petrol chainsaw. I'm doing the job on my driveway in my lovely quiet neighbourhood. So I spent nearly 12 hours in total, with 2 chainsaws, a drill with two extension pieces with wood hole cutter with point ground off, crowbar, chisels etc. After 12 hours+ I'm still finding areas I can't get to due to the varying width of the transom and the fact that as I get deeper into the transom with the chainsaw the exhaust gases go between the skins an blow upwards into my face and nearly kill me!In addition the fibreglass skin is very thin at the top of the transom and very thick at the bottom, (i imagine for structural reasons) so the width of the cavit varies to such an extent that I can't fit the drill bit in as I get further down. Some of you might say "USE EVER DECREASING SIZED DRILL BITS" but it's taking hours with the bigger one and only removes the wood intermittenly as after having removed the sharp point you cannot drill precicesely, you need a flat starting point. So, despite the fact that I really wanted the seacast transom for longevity ( I realise this is a scientifically unproven statement but it looks good in theory on paper !!! LOL) I lost my rag as i felt I was no longer able to progress and I only had 2 hours left of light so I drove to diy shop and bought a cheap grinder and "MULLERED" the outer skin, to enable complete removal of very rotten timber.
I know, I know, some of you old hands out there will be saying "avoid removing the outer skin at all costs" but on my boat the ply extends past the ends of the inner skin, plus there is a splashwell, plus the outer skin already looked a bag of (not sweets!) because of some poorly filled self draining holes.

So I'm gonna have to go back to the traditional method, and that leaves me with some questions.

1. How do I replace plywood when lower transom is narrower than upper transom?

2. On outer skin, how far widthways past the ply should I cut my vertical lines and do I need to somehow "step" the cut depth for each layer of matt?

3. Pressure treated ply or marine ply, what is the difference? Exterior ply???

4. I live in England so I would prefer to use Epoxy as the temperature only gets up to 70 degrees her in july and august and I ain't plannong any more delays cos it's nearly 2 years and the fish are gonna die of OLD AGE!!!!!!, lol. Is there anything else I need to consider???

5. Do I need to "rough up" the inside of the inner skin with a wire brush or something before I start with the resin and matt?

6. I have damaged the gel-coat on the top of the inner skin in places where I have been levering with my pry bar. Do - simply fill this with gel-coat filler and paint?

 

[Old Salt Oz]

Re: If seacast is the easy way, I'd hate to try the hard way!!!

G'day John,

<<<1. How do I replace plywood when lower transom is narrower than upper transom?>>>

If the difference is not great you can fill the void with resin and micro fibres (not micro balloons as they may get crushed).

<<<2. On outer skin, how far widthways past the ply should I cut my vertical lines and do I need to somehow "step" the cut depth for each layer of matt?>>>

Run a 4 inch angle grinder along to form a dish shape and place the largest patch on first out to the edge then add progressively smaller patches to build up to the required level less a couple of mm to allow for filling and fairing or gel coat.

<<<3. Pressure treated ply or marine ply, what is the difference? Exterior ply???>>>

Marine ply has no voids in the layup, construction ply used by builders is as waterproof but has small voids and is OK for a transom. I would recommend that the ply be coated with an epoxy resin before you install it. Also remember to drill out any required holes oversize and backfill with Micro fibres and epoxy resin to avoid another transom replacement later.

<<<4. I live in England so I would prefer to use Epoxy as the temperature only gets up to 70 degrees her in july and august and I ain't plannong any more delays cos it's nearly 2 years and the fish are gonna die of OLD AGE!!!!!!, lol. Is there anything else I need to consider???>>>

Just add heat, a fan heater will be fine.

<<<5. Do I need to "rough up" the inside of the inner skin with a wire brush or something before I start with the resin and matt?>>>

No, your transom will encapsulate the ply, you do need to clean it though, a wash with Acetone should be enough.

<<<6. I have damaged the gel-coat on the top of the inner skin in places where I have been levering with my pry bar. Do - simply fill this with gel-coat filler and paint?>>>

If you plan it just fill and fair with Micro balloons, if you are not painting then gel coat it.


I hope this helps.

Avagoodweekend......