Plywood core in hatches

[FELLOW-SHIP]

HA SCOTT
IN FOR A DIME IN FOR A DOLLAR I TRIED USING POLYESTER RESIN PUT ONE COAT ON THE DECK PLATE THAT FITS ABOVE THE GAS TANK AND THAT WAS IT FOR ME. I HAVE USED WEST EPOXY FOR THE ENTIRE JOB. IT DOES COST MUCH MORE BUT FOR ALL THE EFFORT AND TIME SPENT TO RE DO YOUR DREAM BOAT I DECIDED TO GO WITH THE BEST. I GUESS IT IS LIKE RAPPING RODS YOU WANT TO DO IT RIGHT. NOW IF I WAS TRYING TO MAKE MONEY BY FIXING UP BOATS FOR A LIVING I WOULD GO THE CHEEP ROUT. NO ONE WOULD PAY ME ENOUGH TO BUY THE RODS I MAKE OR THIS BOAT I AM DOING. AS FOR THE HATCHES I USED ½ MARINE PLYWOOD ONE PIECE AND EPOXY GLASSED IT INTO PLACE. I ALSO RE ATTACHED THAT BIGGER HATCH AND REMOVED THE HINGE IN THE CENTER. I AM GOING TO USE THAT HATCH FOR 400’ OF ROPE, ANCHOR, CAST NET, AND A SEA ANCHOR. SINCE I REMOVED THAT SEAT TYPE THING ON THE DOOR OF THE CENTER CONSOL PUTTING THAT HATCH BACK TOGETHER MAID A LOT OF SENSE TO ME. I WILL PUT HINGES ON ONE SIDE AND A FLUSH MOUNTED OPENING DEVICE ON THE OTHER SIDE PLUS A GIANT SPRING TYPE HATCH STAY OPEN DEVICE ON THE SIDE.
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[FELLOW-SHIP]

OH SCOTT
I ALSO THOUGHT THAT PLYWOOD WAS ½ X 6 X 6 BUT I THINK IT REALLY IS 3/8 OR 7/16 THICK. THE REASON WHY I SAY THAT IS I REPLACED THE OLD DECK WITH NEW AND USED ½ THICK MARINE PLYWOOD. IT RAISED THE DECK SOME AND I NEEDED TO BUILD UP WITH FAIRING COMPOUND TO GET IT RIGHT.
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[Billybob]

FWIW, I used 1/2" BC or maybe even CDX plywood(don't remember) for my hatches and then Epoxy.I figured you don't need marine ply because it isn't going to get wet, and I didn't even know where to get it.Epoxy was recommended over polyester, because it soaks in better.My original coring was like a 2" x 4" sliced like bread and all the pieces laid side by side, presumably cause the end grain would suck up the resin better.Mine looked just like your pictures do, man that outer skin is pretty thin huh.I soaked the ply real good, let it set.Then I flowed it on to the back side of the skin, put the skin on a flat concrete floor,put in the ply, and then put a lot of weight on it so that the hatch would be perfectly flat, then I glassed the backside.I was concerned that the thin skin might set up a little twisted (or unflat) without the weight on it - they came out plenty strong and flat.I personally would go with epoxy - but I'm far from an expert.

[Scott]

Thanks guys
I too pushed for the epoxy and they would have sold it to me but they really feel (and who am I too question a shop thats been doing this for 25 years)that this is the way to go

I thought I would get that response about the Vinylester as I too felt that way... but they assured me that it will come out to my liking .... I hope soooo....Guess I'll be the "sacrificial lamb" for now!!! [img]images/icons/confused.gif[/img]

Billybob ... when you say alot of weight .. how many cinderblocks to keep it flat??? I'm more concerned about the big deck (53" X 31"). I was told to drill a bunch of holes (to let the bonding material seep through) in the plywood to ensure that the whole face is bonding to the skin...I was also told how to thin the resin to help soak into and wet out the plywood.

Your not kidding about the thickness of those skins....had to be real careful esp. with the big deck ... surprised that didnt fold in half on me!!

This should be an interesting adventure !!!! [img]images/icons/wink.gif[/img] I'll keep you guys informed of the progress....

[hermco]

Scott,
The plywood is cut into squares so that you can insure you do not create air pockets between the outer skin and the core material.I am not a big fan of epoxy it is difficult to use and if the mixing ratio is not just right you can have problems.The boat is made of polyester and I would use it for any repairs.I would use a polyester or vinyl ester resin and saturate a 1 1/2 oz. mat then place the squares down making sure they "seat" well.After this kicks I use a cabosil/micro baloon putty to fill any voids,sand flat then add your bottom laminate.

d.h.

[ April 16, 2002, 07:24 PM: Message edited by: HermCo ]

[Scott]

Guys
What are you using for core material in the deck and hatch rebuilds?????.....

I'm rebuilding the fuel hatch and the hatch forward of the console. I will use the old skins to put the new core in. The old core material was 6”x6”x1/2” squares of plywood ….. I’m not doing that but will replace with a solid sheet of some kind of plywood.

DH .... any insight into why they built the deck like this....or if anyone else knows...

Right now I’m going with marine grade plywood……but I have heard that plain old regular sheathing would work fine….but I've also heard that the resin may not adhere as well to this?? Any hints on what type/grade of plywood I should get???

I dont want to have to do this again....

Was also advised and have purchased Vinylester resin, mat and Biaxial cloth to do the job as I was informed this resin will bind better with the mat and form a stronger stiffer hatch…..

I originally wanted to go with epoxy but two separate individuals that work with the stuff said the epoxy would work (and cost buckets more) but they both independently said this would be a good route (we'll see about that esp after seeing Trayder's issues). They both sell epoxy and steered me away from it….at least for this application. One of the shops told that they have rebuilt many transoms using this method with great , lasting results

[Scott]

DH thanks for the answer on the squares... that makes sense now.....

Do you think that by drilling 1/4" or larger holes in a grid pattern throughout the plywood laminate would facilitate a decent bond....do you know the original thickness of the plywood used as per Fellow-Ships discovery...3/8 or 7/16

Right now I'm going with 1.5 oz mat on the original fiberglass skin... then a thin cabosil putty to bed/lay the plywood in... then mat on top and glass to finish.

[FELLOW-SHIP]

HA SCOTT
IF YOU TAKE ONE OF THOSE SQUARES AND PUT IT NEXT TO A PIECE OF ½ PLYWOOD YOU WILL SEE THE DIFFERENCE NOT ONLY IN THICKNESS BUT COUNT THE LAYERS OF THE WOOD LAMINATION OF BOTH PIECES IF I CAN REMEMBER CORRECTLY THERE IS ONE ADDITIONAL LAYER OF WOOD LAMINATION IN THE ½ PLYWOOD I DIDN’T MIND BUILDING UP THE DECK A LITTLE I WANTED A BULLET PROOF BOAT AND ½ “ DOES NOT GIVE EVEN WITH 2 OR 3 BEER DRINKING GUYS ALL STANDING SIDE BY SIDE.
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[hermco]

Scott,
I don't know the original thickness but it probably would not apply with todays measurements.Use what will work the best for the job at hand.I would use AC ply and the drilled hole trick will work fine as long as you weight the wood down good.Using a notched trowel to apply the putty will help also.

[Scott]

Thanks guys

I'll keep you informed of the result....