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Is Bondo suitable to use when I start fairing uneven areas on DeNada's deck?

The deck will be plywood covered with fiberglass and polyester resin.

The uneven area that I am concerned about are areas where the glass overlaps....

I want to apply Gel-Coat as the final wear surface

Harry,

Polyester resin is not an adhesive and will de-bond from plywood rather easily. And Bondo has a place in my heart on the same level as chrome plated potmetal by Perko.

If you're going to make your deck from plywood, you really need to glass it with epoxy.

Br,

Patrick

Well....Its not to late to change to Epoxy.....

So what is a good Fairing media?????....I am guessing Epoxy and Cabosil????

Chrome plated Potmetal! ! Ha Ha.....I know how we all feel about that decompsing stuff

Harry

The last 31 I did had a plywood deck glassed over with polyester and mat.

I stood at the transom and ripped up sheets of the stuf to uncover the hold down screws to remove and replace the deck.

Are you fastening the deck from below so you are able to remove it?

Harry,

I wouldn't do a deck in plywood to begin with. Far too many things need to be screwed down, too much chance of water intrusion, and by the time your through you'll spent close to the same money as using Coosa board instead of plywood. One cost saving aspect of Coosa board is that you use polyester resin.

Sounds like you've already made a commentment on ply, so epoxy prime the areas needing to be faired and build up with thickened epoxy. If the fairing is directly on the ply, to be benieth the glass, you can actually use saw dust as your main filler, together with a bit of Cabosil.

After the glass is down and you reach final faring you can use your own blends of epoxy, microbaloons, cabosil, or a premixed fairing compound like Awlfair.

Br,

Patrick

Bruce, I did not construct the deck so that it is removable. I pretty much copied the original Bertram deck construction.

Pat
I'm quite confused about the use of Epoxy and Polyester. I have used Epoxy for everything else that I have done up until now. The reason that I started using Polyester for the deck is that I understood other materials, such as Polyester Gel-Coat does not bond well to the Epoxy.....and my intentions are to apply Gel-Coat for the final wear surface.

I actually thought that it is necessary to use Epoxy when bonding to old glass but for new construction the Polyester would be a good choice.....

Harry

Polyester, both gelcoat and resins, really doesn't bond very well to anything other than itself. Polyester & vinylester gelcoat can be applied over epoxy, but it's necessary to include a tie coat between the two. The best tie coat is Duratec surfacing primer by Hawkeye Industries. It's a polyester primer that will bond tenaciously to epoxy, and most other materials, and perfect for gelcoat adhesion.

As I've mentioned in several other posts, where Duratec was recommended, the material has a very short shelf life, short pot life, and needs to be used as soon as possible after purchase. Make sure that the supplier verifies that the Duratec has not reached it's shelf life before sending it to you.

See: Duratec Surfacing Primer and Other Duratec Products

It sounds like you already glassed your wood, but you have some uneven spots you want to even out.
As long as these areas are lets say less then 1/4" you can use a polyester fairing. We have been doing this longer then I have been alive, the system works and works well be it a new transom, deck, dash repairs, structrual repairs- thousands of boats.

But lets get back to the wood- what type of wood did you use, and did you grind the wood?
We have done extensive in house testing and the only way to get a good bond to any kind of plywood is to grind the wood and use either marine ply or at the least exterior AC fir.

People can usually take a glass edge and pull it right off because the initial repair was not good enough, so once again its not the materials that fail, its the application of the materials.

Harry: I did mine out of plywood built in 7 years ago. Use epoxy on all six sides!! I had my deck painted with Awlgrip nonskid and love it! I also did built in drains around 5 foor long hatches. Call me if you have any questions. (804) 7761-0892. Rawleigh

...its not the materials that fail, its the application of the materials.

Quite right you are, Robbie!

I tend to lay off the problem of polyester to wood bonding by just blaming the compatibility of materials because, for the novice, it's better to steer them into a materials choice that is less prone to fail, even when they don't use the best techniques... However, and I think you'll agree, a polyester bond on wood will fail before an epoxy bond on the same piece of wood, regardless of surface prep.

There are times that I know that I can get away faster and less expensively, and with a 95% assurance of long term bonding success using polyester directly over wood. But almost always, the peace of mind gained by going ahead and using epoxy has out weighed the time and expense forfeited. I classify it as a "Do it Once and be Done" type thing.

the wood will probably rot out before you would see the difference, people drill holes, dont seal them, that is where the problem lies.
Water entering the core, even if its composite, will still result in delamination and in northern climates freeze/thaw cycles and cracking.

You can cut into a poly/plywood boat from the 60s and come out with a nicely bonded dry sample, but take a sample from a deck hatch that had a latch and a hinge not sealed and it wont last no matter what the resin used is.

Doing it yourself you have the choice of materials and your time to consider, give a customer the choice and they dont want to pay for different cores and more expensive epoxy resin/filler systems. Sad reality is its hard enough to recoup the cost of doing business in this wonderfull state let alone expecting people to pay the premium.

Interesting test was done in Boatbuilder's last issue on bonding to wood, should check it out if you get the chance, pretty much the same tests we have done over the years.

Just to sum up where I am and post the entire story on DeNada's deck.....

I used plywood to make the new deck. This deck has 5 hatches and 2 fish boxes (to be completed later)

I painted the underside of the plywood with a good 2 part of epoxy paint, 3 coats...it covered very well and built up thick enough to seal. After cutting out the hatch openings I radiused the edges then sealed the edges with Polyester resin. I sanded and coated the upper surface of the plywood with Poly resin.

Next I sanded the underside back to wood about 2" around each hatch and on the edges. At this point I mixed up Epoxy resin and thickened it like peanut butter and used it as a sealer/glue to attach the plywood to the stringers.....making sure that Epoxy squeezed out and sealed around all of the hatch openings and on the edges. I used SS deck screws to fasten the plywood back to the framing.

My next step is to sand the top of the plywoood to remove the glaze and use Poly resin and mat/cloth to cover the deck surface and seal hatch openings.

Win.....lose or draw that's where I am right now. I really wanted to purchase the fiberglass deck kit that we all talk about....but....I was not willing to bear that much more expense.....I am thinking that I can do that in the future if I so desire.

Right now I am really sick of this project.....I am sure that everything "Under the hood" was done correctly and substantially.....but at this point I just want to get back in the water and take my grandchildren Spanish fishing along the Gulf Beach.

Thanks guys

Harry

if im reading right you first sanded or ground the wood and coated it with resin, then sanded it and applied fiberglass matting with resin.

You have achieved the text book procedure for your purpose, the only way it could have improved was to laminate the wood while the first coat was still green, but you did fine. Hopefully you were using laminating resin with no wax in it.

Use a polyester filler- you will be fine, then you can go with gelcoat right over it, no tie coats with no sanding tie coats.

Harry: Are you adding gutters? I have a fairly easy way to do that if you want to try it. I screwed and epoxied 1 x 4 fir around the inside of the opening to form a lip that the hatch sets on 2 1/2" wide. I used a bowl cutting bit in a router to rout a 1" wide trough in the wood using a top bearing on the router bit that ran along the opening. It made a nice flat bottomed trough with a radiused edge that followed the hatch dripline perfectly. I then drilled the aft corners of each hatch to accept PVC pipe fittings for the drain. All of it was coated with epoxy and painted. The only thing I would change is making the lip thicker so that i could make the trough deeper.

http://www.toolstoday.com/p-4946-bowl-t ... guide.aspx

Robbie....that is exactly what I have done.....The only reason I coated the plywood with resin was to protect it from moisture (ie:rain) until I can get the mat overlay on it.....DeNada is outside the only protection is a tarp...which is at best a false sense of security.

I sand the deck with a DA sander using 40 grit paper....

I will try to post a pic or 2 tonight

Rawleigh....gimme your tele number one more time....to many digits in the post above...

Harry

(804) 761-0892.

sorry for the call. I have been all around the world except the US and seeing your phone number I dial just to get in touch with one of the team of Bertram. sorry just for the fun but if you came to Portugal , Lisbon ring me and I must be available no matter what. And this offer is also for all that are together on this instructional site. greetings and best regards and sorry again for the call.

No problem Luis! It was fun talking to Portugal! Call me again if I can help you in anyway. Rawleigh

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here is a slight variation to capt patrick method. after changing the deck support beams i put a 3/8" notch in the last 3" of the beam at the trasom.that notch plus 3/4" is dead level with the bottom of the scupper.next built a 2" high scupper box by 3' wide with front open. install cockpit trasom panel with 3m 4200 on face of box . now you have a seal and i made a 3" wide piece shape to the contour of the trasom .next install this completly sealed on all sides against scupper box and sides.after you install deck this entire piece will be 3/8" recess from cockpiy deck height with the very,very important aspect of a "toe hold " for the wireman and the same for the tailrope man on the opposite side.harry no faring at all the extreme port and starboard also has a 3" strip recess from bulkhead to trasom . because of the cockpit taper from center to sides all water goes in channel and leds to scupper box. i have bury the trasom and put a wave right over backing down and although scarry the water flow out the scuppers. i have gemlux brand scuppers that far exceed stock .here is a photo

Harry,
What's your plan for liner panels. Are you putting them back in, glassing/instant fairing the sides and transom? I didn't notice a gutter around the edge but was curious about the transom.
For what its worth I do like having the toe kick all around the pit (always seems you end up in the corner pulling on something and its nice to have your toes ahead of your knees)

Looks like your moving along pretty well.

Your gran kids and you watch Finding Nemo? Remember the line Just keep swimming!!! That's you pal, just keep swimming through it.

jp by any chance did you go over the transom like me?and that was a tuna!!

Lookin' good Harry!

harry i will see you at port judith we will go over the whole cockpit.plenty of options and you can see 9 differant ways each of us solve the problem.

Bob,
Only been off the back of a boat on purpose (first blue one, did it before I was forced to). Started practicing dumping wraps when I was 11 years old leaning against a piling wrapping and dumping. Pulled on quite a few big things (mostly stubborn tunas) and always liked having my toes ahead of my knees. This way even if you get bent over you can still lock in with the top of your thighs on the gunnel.

The trick has always been pulling with a straight back and keeping the weight on your quads. Once you get bent over- your bent over.

Its a good design plan regardless if you plan to fish or not. Stern lines always seem to need a little tweak now and then, and of course it makes answering natures call off of the stern a little safer (how many guys do they find a year dead with their flies down?) Better safe than sorry.

JP......You know for sure that I will keep swimming....in fact when I get fed up with a project I usually dig in even deeper just to get finished....or in this case back in the water......I really want to know how the engines are gonna perform.

As far as side panels.....I still have the original panels....I have never really liked them for reasons like you explained....

I am thinking of not using side panels at all. I am kicking around an idea of using thin wood horizonal strips to dress up the inside walls of the cockpit. I really don't know what I am gonna do quiet yet. Who knows I may see something at the Pt Judith Rendezvous that I really like. I talked to Rawleigh yesterday....he had good ideas of making storage space behind the side panels.....not a bad idea.

I did not plan far enough ahead to put gutters on the port and starboard sides of the deck. The deck that I built is pretty much exactly like the original Bertram deck...except for the hatches.

I have decided that if I catch a fish that complains about the way I construced the hatches I'll just throw his ass back in the ocean...

Harry

on a stock configuration boat it is actually a fair amount of work to get rid of all the cockpit panels.

I have a 31 at the shop now and with the deck and panels removed there is quite a bit to address.

When custom vents and intakes are on the menu that solves alot of the issues right there, but there is still the fill and vent hose, etc.

Harry: I'll take pictures for you this weekend.

Harry, Looks good.....You've been busy...Looking forward to Pt Judtih to get a few Ideas of my own.....see you soon...BH

Well guys I have to tell you......I don't know the pay scale for Fiberglass Fabricators but whatever it is.....It AIN'T enough! ! ! !

I have put down more glass in the last 2 days that I have ever done at one time before in my life.....(if this don't make sense its because of the fumes)

I say give you Fiberglass/Paint guys a big raise.....the work you do requires great skill...............