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Cockpit floor. StopRot I curse thee!!!

Nov 7, 2012
678
1978 Catalina 30 Wilbur-by-the-Sea
Today I started my cockpit floor restoration. I cut around the outer edge and proceeded to peal up the skin.

Everything was going well until I started in my attempt to remove the rotten core. It appears that a PO had poured a very large volume of stop rot down into the void. A majority of the plywood is now an epoxy of rotten wood that is firmly bonded to the liner fiberglass.

Attempts to pry it up have been unsuccessful as the pry bar just chips a small area off the edge or starts to dive into the glass liner.

At this point I am open to suggestions.

I guess I can cut my new end grain balsa core to fit the few open spaces but I have concerns about uneven thickness and strength of the core once I seal it up.

In addition the skin I removed has about 1/8 an inch of this stuff as adhered to the underside. I am thinking of just using all new glass and doing a kiwi grip no skip finish to hide my work.


Ugggg.
 

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Mar 20, 2012
3,983
Cal 34-III, MacGregor 25 Salem, Oregon
a grinder with a very course flap disc.... it will make reasonably short work of it, but you do need to be careful because it wont know the difference between the material you want to remove and that which you want to save....

depending on whether you have a 9", a 7", 5", Or a 4" grinder and matching flap disc, i think you could have it all removed down to where you want it within 15-20 minutes.

for quickest results use a type 29 flap disc in 36-grit. the larger grinder you can use the quicker it will remove the material.
you can use a smaller disc on a larger grinder, but dont use an oversize disc on an undersized grinder......
 
Nov 7, 2012
678
1978 Catalina 30 Wilbur-by-the-Sea
Thanks, sounds messy but I do have a 4" grinder. I will pick up the disks when I go buy all my glass mat and such. I have to flether the edges of the cutout anyway the grinder will be busy.
 
Mar 20, 2012
3,983
Cal 34-III, MacGregor 25 Salem, Oregon
Thanks, sounds messy but I do have a 4" grinder.

I will pick up the disks when I go buy all my glass mat and such.
it will be dusty...the flap wheels are self cleaning, and the 4" grinder will take a while. but you dont have any other choice other than chipping.

use a mask..:D.
 
Jan 6, 2010
1,520
Catalina 30 Mark II John's Pass Florida
Gar,

I for one do not envy you in your task. I was however never a true believer in Git-Rot solutions in large coring areas that are hidden from view.

In this scenario when injected (thru drilled holes), how far does it go, are all the unseen voids filled etc.? In your case, the topskin is removed for an all-inclusive assessment of the area & structural integrity of your coring. if you deem it to be sound, maybe some prep-work grinding & cleaning may be the way to go. You will do glass work anyhow with the new skin. I don't see where trying to grind it all out will be worth the effort. Again, it will all depend on the structural integrity you know have. I hope this will be the case.

Yours is the type of project that will require patience to finish properly. I sounds to me you are the kind of guy that does a job well, so good luck.

One suggestion, when grinding, wear a breathing mask & goggles for protection.

ps: cute little doggie.

CR
 
Jan 6, 2010
1,520
Catalina 30 Mark II John's Pass Florida
Gar,

As an addendum, I had a rotted core under my mast base. In my case, it was a 2' sq, area to be fixed. I added new coring. I had a friend "Glassman", a Russian named Vladimir do the work. What a crazy guy.

He mixed a concoction he called "MUD" as a structural component. He mixed glass with "Milled Fibers" for added tensile strength. Replaced my deck covering & it now sounds & feels like solid base.

I thought I should mention this.

CR
 
Nov 7, 2012
678
1978 Catalina 30 Wilbur-by-the-Sea
On my project it appears they drilled multiple holes in the liner an poured the stop rot down the hole for the former pedestal base.

It looks like it did a decent job of impregnating the bottom few layers of plywood an the top most layer as well. However it did not get into the middle layers. These continued to rot resulting in a rotten pulp sandwich under the entire cockpit.

I have some end grain balsa and a few gallons of polyester to recore today. This is my biggest glass project to date.

I am good with a mask and goggles, the problem is getting a mask on the dog.
 
Jan 6, 2010
1,520
Catalina 30 Mark II John's Pass Florida
Gar,

You're right, protect your doggie. Now you know why I don't like adding Git-Rot thru drilled holes unseen. Too many cavities will form in a structural sense.

If you know there are bad areas, just try to clean out the bad to get to solid fill. I know this is a pain, but if you only have to fix part of the "wheel", do that. If this works, find an etcher/cleaner chemical (a fiberglass etcher/cleaner) that could save you additional sanding/prepping. Then, the "Mud" mix should bond to the solid Git-Rot.

Just don't get frustrated man, this is the type of project that demands, "Do it right the first time, do it once".

Let us know....Remember, it's only a boat, it's not a Swiss watch. Structural integrity is what you are really after.

CR
 
Sep 30, 2013
3,042
1988 Catalina 22 central Florida
Garbone, may I join you?? I'm getting ready to tackle a very similar project!

Question: will your old skin get re-used somehow, or will the floor be all new? I'm unsure if I should just open up a part of the floor, or just cut out the whole durn thing the way you did yours?

This crack only runs from the transom to the forward end of the lazarette. It doesn't sound or feel rotten, but I know it must be, at least somewhat. It belched out that brown fluid after an overnight freeze. The PO owned it for a couple years and never fixed it, and the PO before him tried and failed to fix it (notice the smooth areas around the crack).




 
Jan 6, 2010
1,520
Catalina 30 Mark II John's Pass Florida
Dixie,

Seeing the pics, I would have to assume the core rot extends from both sides of the crack.
Unfortunately, the only way to asses the damage, is it to remove all top glass back until you hit good coring. How far is this, I cannot say.

Look at an earlier post from Gar on using Kiwi-Grip as a top replacement, I would check this out. Or, it may be wise to find & talk to a good glass man for ways to fix.

Until you dig, you will not know the extent of damage or, how best to proceed.

CR
 
Nov 7, 2012
678
1978 Catalina 30 Wilbur-by-the-Sea
Got up this morning at 9am, pretty late for me. Had a head ache but decided to power thru it. After a light bfast I dawned my nasty grinding cloths, mask and goggles and started at it. By 11:15 I had removed most of the rotten wood and feathered the edge of the opening as best I could. Oh my, what a awful dusty mess.

I hosed myself off and using my shop vac cleaned up.

After attempting to remove the stop rot at the forward end of the cockpit I have decided a new plan is in order.

Now I have order some more balsa from defender, 3/8 I am thinking. This I can put on top of the stop rot plywood areas to build it up. The 3/4 I already have I will use to fill the clear sections.

I may need a third gallon of polyester for this. It is a lot of area. I do have a quart of gel coat.

After all this work and looking at the removed piece of glass I will not reuse it. Rather a smooth surface and Kiwi Grip. We already have done the rest of the boat in kiwi grip, the cockpit is the last of the exterior to get painted/ redone.
 

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Nov 7, 2012
678
1978 Catalina 30 Wilbur-by-the-Sea
Dixie,

On mine the entire floor was spongy and made a squish sound as well as extruded a similar brown water sludge from the pedestal hole.

On mine I want it fixed properly and with an ok appearance. Some suggested going in from the bottom (quarter berth) but I prefer to have gravity be my friend. This will end up a 2 or 3 weekend project.

I had hoped to open it, clean and dry It Saturday. Laying in the new core and reglass today but things happen.
 
Sep 30, 2013
3,042
1988 Catalina 22 central Florida
Thanks Garbone, keep up with the pics, you're an inspiration! I've been reluctant to fire up the grinder and open the floor up, not knowing what I was doing. Like you, I'm okay with an OK appearance as long as it's structurally sound. I'll be following your progress!!
 
Nov 7, 2012
678
1978 Catalina 30 Wilbur-by-the-Sea
Here is a basic balsa core question. Is it better to take the squares off the backing allowing resin between or to leave them tightly
packed? Judgement tells me leave them on the backing for ease of handling and to save resin. Maybe I am over thinking this.
 
Jan 6, 2010
1,520
Catalina 30 Mark II John's Pass Florida
Gar,

I left my balsa on the backing, it will promote better structural strength as the remain tight against one another (friction). Besides, I thought the resin soaks in alot as the grain runs top to bottom.

CR
 
Nov 7, 2012
678
1978 Catalina 30 Wilbur-by-the-Sea
Started patching it this weekend. Put down two different thicknesses of balsa. Matt, cloth. Still want to put a few more layers of cloth but am out of time for now.

Thing I discovered.

Not all resin is equal. Better resin is easier to work, stinks less and sets up better quicker

Not all cloth is the equal.

An orbital sander can not completely make up for an uneven substrate.
 

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Nov 7, 2012
678
1978 Catalina 30 Wilbur-by-the-Sea
The first type of Polyester resin I used was a gallon of Boaters Choice.
Resin with balsa


This stuff was horrible. Although it works it had a lot of odor and always seemed to have a slight tacky feel after setting up. The bottles the hardener it came with were hard to measure from and messy to handle.
The second gallon I have been using is Boatyard, it seems a lot better in all aspects than the cheaper Boaters choice. I imagine West Systems is better yet but have yet to try it.


More info on my blog... ;)
 
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