Fiberglassing

[Philip R.]

Rebuilding a 25. Stripped inside down to fiberglass. Building walls and fiberglassing edges to side.
1. Correct in using pressure teated plywood? Will put weneer fininsh over that
2. Fiberlass and resin is from hardware store, coming out on wood three inches and wall three inches. Have put three layers so far. Right or wrong move?

 

[jfschena]

I would be concerned about whatever resin/hardener your using adhering to the pressure treated wood. My experience is although the stuff is rot resistant, it can leach moisture for a long time. If I were doing the job I would try and use marine ply for the bulkheads and try and follow the original design for putting it back together.

That said, I did see a guy rebuild his San jaun 21 by fiberglass taping the new bulkheads to the hull. The boat has been sailing like that for years so I guess it would work. . . .

 

[Joe11688]

I would use a good marine grade plywood. It doesn't have to be Teak if you plan on staining it a Red Mahogany color as I did on my O'Day 222.
http://forums.oday.sailboatowners.com/member.php?userid=78449&styleid=1

As for the resin. I would use a good Marine grade resin such as West System Epoxy. West System also manufactures an epoxy that can be used in an ordinary caulking gun. It's Called West System Six 10. It's easy to apply and there is no mixing involved. A good friend of mine has been using it on his O'Day 30 and he swears by it. http://www.jamestowndistributors.co...id=52008&engine=msn&keyword=west_system_six10
He's a cabinet maker and has his own shop.

 

[ChattOday]

I will chime in, since I just finished refurbing my entire exterior deck. You can look at my earlier post on it if you want to see some before and after. Since I had several bad weak spots from water intrusion, I had a ton of use of the West Systems.

As Trinkka noted, West Systems epoxy is the gold standard. I used it, all kinds, as well as Marine Tex.

Marine Tex is a great non-structural epoxy that fills gaps well and can be sanded like wood. It is great, for example, if you have to put a hole in to get to something and then want to fill it and not worried about structural support.

For actual glassing, and using an epoxy that has structural strength+ West Systems. All the way.

I used both the mixed epoxy and the caulk gun six ten. Both are great and have distinct places to use.

Difference: West Systems Mixed Epoxy - High tensile and compression strength. When used with the structural load filler (read about their system, it will make sense) the epoxy is by a factor of 2 or more stronger than the original fiberglass. This resin represents the current mode of technology. The portion of my deck rebuilt using this stuff is the strongest part of my boat.


6Ten Chaulk Resin: Easy to use, should not be used for high load structural. The ease of use comes at the cost of strength. Trade off. I used it in areas where I was patching or mating pieces, in which I needed an adhesive epoxy bond and was not relying on the epoxy alone as a structural load bearer. I re-did a chain plate and used this to add some strength. The frame of the boat was still doing most of the work. Rock solid.



As for pressure treated. No. Everywhere I read while learning about fiberglass repair echo the earlier comment. Pressure treated either a. needs to be left out to cure before you cover it or not used.

Marine grade of exterior grade plywood (non-pressure treated) is what was recommend to me. If you intend to cover and seal the wood (either in glassing it or sealing with a water barrier) exterior is fine. Marine grade is obviously the best choice, but is expensive and can be hard to get. Where I live (TN) no one sales it out the door so I would be looking at shipping it. I went with exterior grade, water sealed, coated. Will last forever.

Hope that helps. The West System stuff is AWESOME. The mixed epoxy is stinky, sticky and a PIA to deal with; but it gives results that make it worth while.

 

[cb32863]

I replaced the bulkheads on my 25 last year. Marine grade plywood, West System epoxy. No other way to go about it. As others have said, pressure treated will be "wet" for a long time. You can do it the way you are saying but, you will be doing it again. As the saying goes, do it right the first time.

EDIT: Though from your post, it sounds like you already have done it and then decided to ask if it is the right way..... Might be ripping things out anyway.

 

[Philip R.]

Thanks, will be undoing my work this weekend. Will order west systems and use exterior plywood.
Does anyone make a template for the walls?
Glad I didn't get too far along.

 

[jfschena]

Go to the west system website. Lots of free down loads. Free fiberglass boat repair manual and even a boat building manual. Lots of good info right there, all for free and they wrote the book on epoxy use.

 

[jfschena]

http://www.westsystem.com/ss/assets/HowTo-Publications/Fiberglass-Boat-Repair-and-Maintenance.pdf


Here is the repair manual.

http://www.westsystem.com/ss/use-guides/

West system guides

 

[Ritdog]

I concur with the others- PT is not the way to go- I used exterior when I did my 25s bulkheads, and it worked well, tabbed in like you are doing. I used the old piece for a template. Buy / rent a Sawzall with the LONG demo blade, insert that parallel to the hull and just saw the whole thing out, pressing the blade against the hull to follow the profile. The long blade allows it to bend nicely. Take out the screws top and bottom, and there you go.
The port side is tricky to install if the mast post is in- you have to bring the top of the bulkhead into the hatch area, and it will JUST go in - it's tight....We covered the bulkhead with beige Volkswagon convertible roof material - nice surface, and it looks great.

 

[Philip R.]

All the wood was rotted when I started. Got it pretty close to start with. Second time should right. Thought about making a template from cardboard.

 

[Brian S]

Types of plywood

When we talk about "marine" plywood, we have to be very careful, because there are limited standards in the plywood industry.

Some lumberyards would call exterior/immersion rated fir plywood "marine" ply. IMO, you don't want that, except for structural use. Fir plywood is pretty ugly, and it is prone to checking, no matter if it's encased in epoxy or not. Further to this, although building grade "marine" fir plywood is made from waterproof glue, there tend to be fewer and thicker plies.

If you want better marine grade plywood, especially for visible wood surfaces, you'll want to source BS1088 grade plywood. BS1088 is a British designation, and it is tested for waterproofness, has no voids in interior plies, and is comprised of more plies than other plywood.

BS1088 is commonly available in okoume or sapele wood. Okoume is a fairly light wood, with benign grain pattern, while sapele gets a more rich color and extravagantly swirly grain patterns - definitely better for brightwork surfaces. However, sapele is more expensive than okoume.

Hope this helps,
Brian

 

[Golden Road]

I concur with plywood opinions, marine grade is best. Pressure treated is toxic anyway, and you don't want it in a cabin! If you are tabbing bulkhead to hull (I didn't think any O'Days did that...) I would not use epoxy. It is expensive and difficult to work with. It can't be covered with anything but certain paints, and not polyester resin. Read System 3's epoxy manual. Quite frankly, if the bulkhead is really structural, you'll want to through bolt the fiberglass tab on the bulkhead at say 10" intervals as eventually the tab will delam under stress. If you're working on a fiberglass boat, get good with polyester resins, and get the right kind. You want laminating resin that is air inhibited on drying, that way you never have to sand between laminations or corrective builds. Then you top it with a nice finishing coat of resin which you can blend into whatever. I am fortunate to have LBI supply near me, check out their catologue (lbifiberglass.com ). I HIGHLY recommend their Vinylester polyester resin which is as strong as epoxy esp when bonding to an existing glass hull, easier to work with, much cheaper.

 

[Philip R.]

Thanks for all the advice. Has helped a lot.
I have a 6" X 10 " cut in my deck (not the fiberglass) where the chain stay came thru when the previous owner hit a bridge. The original hole was about 2" around but the wood was wet pretty far back. Do I use marine plywood and fiberglass the whole thing or what?

 

[Golden Road]

The "wood" is/was balsa coring which you can get from Defender or LBI. It is squares of balsa glued to a flexible fabric backing so it will drape around surface irregularities. It soaks up lots of resin and won't delam. Use the right stuff!

 

[Philip R.]

T

mo
he "wood" is/was balsa coring which you can get from Defender or LBI. It is squares of balsa glued to a flexible fabric backing so it will drape around surface irregularities. It soaks up lots of resin and won't delam. Use the right stuff!

Will order balsa wood today.

 

[Philip R.]

Will order balsa wood today. Thanks

 

[Steps]

any recommendations for minor gellcoat cracking on the topside? is there a way to match colors with the epoxy for an off-white surface? We have learned that one should always cover the boat in the winter...