ferro cement repair question

[awab]

dear readers

I don t want to start a new discussion about pro and cons of ferro cement boats.
I am aware about resale value, insurance problems etc.

I bought this boat to create a inexpensive living space. Not a world around and cape horn etc.
I cruise a wooden sailboat for 12 years and know things around wooden boats. Now with FC its a new theme and I need a new set of Ideas.

The boat ran 8 years ago in a bridge on the icw. Has a front damage and the mast is bent badly.

Over the years rain water rusted the steal fuel tanks and oel penetrated the hull.


1. need to repair the front damage.

what kind of cement
what kind of sand
ratio sand,cement and water
what bonding agent I need for bonding old and new cement

2. any ideas what to do about the oel penetration

Have contact to Darr from fer-a-lite. Very noce guy but the material would be for 10 cubic feet incl shipping 530 us. plus the cost for the resin.

The repair will be in a yard in North Carolina. I need the materials in this neighbar hood. English is not my mother language and it would be nice to have knocklage about terms of this materials. Only portland cement has many qualities.

Here are fotos from the boat and the problems I have

Flickr: awabflickr's Photostream

Are there people they know about how to repair this kind of damage.

thanks you already

peter

awab sailing charter diving,los roques,tortugas,isla margareta,caribbean dream

[TeddyDiver]

Just out my memory not sure how accurate it is.. but maybe someone will correct..

1. Portland type 2 cement, pref quartz sand. 2 to 3 parts sand 1 part cement (that is for pure 1to3mm sand) , water just to make it dirt "wet".
Not saying anything about the primer (bonding agent) but good cleaning, sand blasting or grinding (whatever)
Keep it moist a month afterwards..

2 I'd try steaming..

[awab]

thanks teddydiver

I been reading as bonding agent could be used simple white wood clue. There are also other commercial bonding solutions.
I have no idea how important this is but it make sense that there is an issue.

Hope somebody knows more about it.

Steaming sounds good and stands already on my list for a try.
Have to see what kind of tool I need to do this steaming.

Do I have to weld the new rods to the old rebar.

In the moment I have sanded away the old bottom paint. Any ideas how to treat now the bare cement.

what primer if needed
could I paint with pool paint

so many questions.
thanks
peter

[DumnMad]

Hi awab - Peter. I've used Aquron in repairing old wharves.

Use Aquron 300 in your mortar mix to reduce shrinkage and porosity.
Aquron 7000 sprayed onto your hull cement will soak in and form a gel inside and seal the ferro. No trouble to paint over and it is a rust inhibitor. They did a leaky old ferro barge here from the inside and stopped all the leaks.

The stuff looks like water so take care to follow a pattern when applyng to avoid missing an area. - Nick

[awab]

thanks a lot Nick

I been reading the specs to aquron products.
It seams they have also a good product to solve my oel penetration problem.

Will see where to get the products and how much they cost.

thanks again
peter

[minaret]

Originally Posted by awab

thanks teddydiver

I been reading as bonding agent could be used simple white wood clue. There are also other commercial bonding solutions.

Do not use wood glue as a bonding agent!

I have no idea how important this is but it make sense that there is an issue.

Very important!

Hope somebody knows more about it.

Only a little but I still know better than that!

Steaming sounds good and stands already on my list for a try.
Have to see what kind of tool I need to do this steaming.

Rent a steam cleaner for removing wallpaper at a tool rental store.

Do I have to weld the new rods to the old rebar.

Yes!

In the moment I have sanded away the old bottom paint. Any ideas how to treat now the bare cement.

what primer if needed
could I paint with pool paint

so many questions.
thanks
peter

Portland cement must be acid-etched before using a bonding agent, I don't know much about this sort of construction but I know that much! Make sure to use a bonding agent and acid etch that are compatible with each other. You might consider building an external mold for the repair on the outside of the armature, this method requires a pencil vibrator but will give you much fairer results if you don't have a master plasterer handy. Buy "Ferrocement Boatbuilding" by Jay Benford, it's a decent primer. It will at least teach you to properly slump test your mortar...


http://www.amazon.com/Practical-Ferr.../dp/0877420203

[awab]

thanks minaret

just ordered this book.
the steam cleaner for the wallpaper sounds perfect.

Is this acid etching also good to prepare the hull after removing the old antifouling and before painting the primer.

still the question for the under water ship

which primer
which paint
is pool paint an option

thanks again to all

peter

[minaret]

Originally Posted by awab

thanks minaret

just ordered this book.
the steam cleaner for the wallpaper sounds perfect.

Is this acid etching also good to prepare the hull after removing the old antifouling and before painting the primer.

still the question for the under water ship

which primer
which paint
is pool paint an option

thanks again to all

peter

Yes you need to acid etch before coating as well. Be patient and I'm sure someone more knowledgeable about ferro will chime in, there are many here who own ferro boats. I am a boatbuilder but I haven't done much work in ferro. That book is old but so is the technology we are discussing, it is totally relevant to your problem and will probably answer many of your questions. Maybe post in one of the existing "ferro" threads as well, that way all the people with an interest in it will see your post. Link to this thread.

[SabreKai]

Awab, I had a look at the photos. You will have to rebuild the steel structure at the bow using rod. Check the way the bow fitting was mounted, there may be heavier flat plates needed as well. Once the bow steel work is done, seal it with an epoxy sealer, then you can plaster. (I'll leave the cement expertise to others)

The bow cap may be salvageable. It looks like it tore the nose off instead of deforming itself. I also had a look at the main mast. I don't think it is bent. I think the impact rolled it back and broke off the tension gear for the external furling. You may well be able to stand the mast up on its base with minimal work. The tension fitting will have to be rewelded, but perhaps the gods smiled on you. How much damage there is higher up the mast I can't tell but again, it may be minimal.

As for two, try steaming first. if that doen't work. rent a compressor and a needle scaler, and remove the top layers of cement. Then re do it. Hopefully the oil hasn't penetrated to any great depth.

[minaret]

Originally Posted by SabreKai

Once the bow steel work is done, seal it with an epoxy sealer, then you can plaster. (I'll leave the cement expertise to others)

I didn't know you could use an epoxy sealer on the armature. I was always taught that Portland Cement bonds to the rebar amazingly well, as it is designed to do just that. I was also told that slightly rusty rebar bonds better than shiny new. Is using an epoxy sealer on the armature a more recent development? Does the cement bond well to the sealer? Do you need to catch a bond if you do this? Is this a specialized sealer for ferro work? Just curious, I have never really had much chance to work with the stuff and I find it interesting...

[encore]

Would agree that you don't want to "seal" the metal work. Cement will bond to it just fine. For bonding the old cement to the new there area a couple of ways. An old product called concresive lpl (long pot life) does an excellent job. I've used it and tested it and the bond is nearly as strong as cement. It comes in two part in units to make a gallon. It's basically just an epoxy with a long pot life and can be mixed with sand if desired. I got mine from Brock White, the building people. It goes a long ways.

The other method is to use bonding agent and Elmers white woodworking glue can be used for this. (Check with Colin Brooks.) There are also bonding agents available at building stores.

For a top coating you can use swimming pool paint. It does last a long time but the problem is that it is practically impossible to remove. It's known as chlorinated rubber. My project boat had this and the only way I could get off was needle scaling, and that's a huge job. Even though sandblasting is a no no on cement boats, I tried it and the sand just bounced off, much like it does when you try to sandblast brick and run into moss-like growth. Good luck!

[minaret]

Originally Posted by encore

Would agree that you don't want to "seal" the metal work. Cement will bond to it just fine. For bonding the old cement to the new there area a couple of ways. An old product called concresive lpl (long pot life) does an excellent job. I've used it and tested it and the bond is nearly as strong as cement. It comes in two part in units to make a gallon. It's basically just an epoxy with a long pot life and can be mixed with sand if desired. I got mine from Brock White, the building people. It goes a long ways.

The other method is to use bonding agent and Elmers white woodworking glue can be used for this. (Check with Colin Brooks.) There are also bonding agents available at building stores. I'm shocked that you can actually use Elmer's! Isn't that an organic product? How does it do long term in the marine environment? Do you acid etch before applying the sealer?
Just trying to learn more in case I ever have to fix one of these. I have done a little work in the yard on them but not much, never a structural repair like this. And when I attended boat building school we built some sample planks out of Ferro and destructively tested them.

For a top coating you can use swimming pool paint. It does last a long time but the problem is that it is practically impossible to remove. It's known as chlorinated rubber. My project boat had this and the only way I could get off was needle scaling, and that's a huge job. Even though sandblasting is a no no on cement boats, I tried it and the sand just bounced off, much like it does when you try to sandblast brick and run into moss-like growth. Good luck!

Aaah, now I understand. Sabre wasn't suggesting epoxy sealing the armature, but epoxy sealing the cement edge to get a bond to the new plaster. Do you chemical bond the fresh plaster to the epoxy sealer? I would assume that's why it has a long open time...

[awab]

hello friends

thanks SabreKai, I also think the bow section could be saved. Will hammer the cement away and see what s under.

The mast has a bend above the spreader. In oct when I start the project the yard will take the mast down and I will see more. Perhaps I can cut before the bend and after and make a sleeve between. The mast has a roller furling system for the main sail. This means there is no track. This makes it much easier.

the oel penetration.

The penetration should go in this case through complete. The diesel comes from inside. I can either take all the cement off and replaster or find a solution to eliminate the diesel. There are so many products out there its confusing. I have to try some.
The penetrated hull section sounds still good to me. Used a hammer and the cement feels hard.

about the sand
one is proposing basalt sand
other talking about quarz sand.

which one is better

about the pool paint.

I dont see a problem if the paint is difficult to remove. I would be happy if it never would go away. Could be also a solution for the deck to paint.
Any more knowlage about it. It would be relativly inexpensive.

all the best
peter

[awab]

hello friends
By building the new armature was the question to weld the new rebar to to old one.

minaret means YES to welding.

now I found this side.

The Home Machinist! • View topic - Welding Rebar
and
Fluxcore & rebar? [Archive] - WeldingWeb™ - Welding forum for pros and enthusiasts

The welding of rebar does not seams that easy.


In my case I dont even know the rebar used is weldible. I can imagine also the heat to the existing cement is not really good.

It seams now it is better to build the armature without welding.


What is the word on this by the group.

Another idea to repair the mast:

After stepping down the mast I could cut it before the bend and after. The bend lets say is about approx. 6 feet. This 6 feet get replaced with a new piece and spliced together like done with a lot of masts. This should make a straight mast again.

Bending back would be much more difficult if not impossible.
Buying a used one has a lot of other very expensive problems.
Buying a new one is would cost more then the boat.

It was clear to me to face a lot of challenges. Its getting very interesting to find solution.
thanks
peter

Hope there are more ideas out there.

[hellosailor]

Peter-
"I been reading as bonding agent could be used simple white wood clue. "
White glue, which in the US is generally called "Elmer's Glue" after the milk company that makes the biggest brand name, is made from a milk product called casein. It is infamous for NOT being waterproof and I would suggest anyone using it for a binder is a poor source of information. There are "latex" based primers and additives that are used to help bond cement products to each other and that is something locally available all over the US.

But the company you contactred apparently mentioned "resin" and resin-reinforced concrete is very different from plain concrete or cement. The use of resins as additives can add great strength and adhesion, but that is more of a specialty market. You are relying on the reputation of the seller. Is $500 too much to pay for materials, when you are relying on that for the strength of the boat? If you try to find some random product locally, and your repair falls off, what will that cost you?

I would suggest that you want to buy materials that are professional made and sold for this purpose, from trsuted companies, if you can't find better information than using white glue.

Oil (oel) penetration of the hull is something you will have to live with. Concrete/cement is porous and there is no way to get out whatever has soaked in, aside from massive attempts to vchase it out with solvent. By all means, use solvents on the hull and expect to take out SOME of the oil, but most of it is there forever now, or at least until it goes down further and possibly exits. Ironworkers routinely used to pour used motor oil around fenceposts that were set in concrete pads, so the concrete would absorb the oil and prevent water from rusting out the iron that was set in it.

Splicing the mast is about as simple as you think. Cut, splice, if the work is done carefully it will be as strong as new, although of course you will have a shorter mast and need to adjust everything else to match.

I've heard that some folks have bought surplus aluminum street light poles to use as masts, that's another option available all over the country.