Need Advice on how to repair fish box hatch

[mr300z87]

My friend has a 2002 Aquasport Exporer 250 and last year he noticed that one of the rear fish box hatches was soft. Last week when the weather got good here in NJ we climbed in to remove the hatch and this is what we found after some grinding.

It seem that water got into the fastener hole and wicked up the plywood until it de-laminated and got soft. The construction is 3/32 of glass outside 1/4 in ply over the whole thing and then another layer 1/4 inch ply in the center 3/4s of the hatch and sealed up on with anoother 3/32 of glass. Wish is Took a photo before we started grinding. Since Auqasport has been out of business for a few years now finding a replacement has been tough we figured how hard can it be to fiberglass and repair it.
This is the outside of the hatch

I know we will need to grind out all the rotten plywood down to clean glass, but not sure where to go from there. My concern is how to glass up to the edge where it lay into the deck. Can anyone give me some recommendations as to how to proceed. We have some 1708 and US Composite poly resin not sure is this is the best stuff for this repair. This hatch needs to be strong as it is at the stern of the boat where a lot of fishing is done.

I have done some fiber glass work in years past although nothing like I have read about on this forum.

As always any help is greatly appreciated.

Mike

 

[GT1000000]

Re: Need Advice on how to repair fish box hatch

Carefully cut around the entire inside edge to free up the remaining plywood...
Lightly grind the inside edge of the lip and the entire surface where the wood used to be down to good solid glass...obviously trying not to break through to the outer skin and messing up the gel finish...
Cut your first sheet of 1/4" ply to fit inside the hatch but leave it about 1/4"-3/8" shy from the edges...then cut out the second piece of ply that forms the inner 3/4's of the hatch interior...
Wet both pieces of ply with "slow" [1%-1.5% MEK-P] resin on all the edges and all faces, let that get tacky...
Using the poly you have and some Cabosil/Aerosil/Fumed Silica and a handful of 1/16"-1/8" milled fibers and make up some Peanut Butter...enough to bed the first piece of plywood into the hatch and have some ooze out all around the edges...make the "Oozed" out PB into a nice smooth, cove filet...you can use a cheap metal spoon dipped in mineral spirits to create the cove...if too much oozes out just make a nice cove and discard the excess...
The next piece of plywood you can attach to the first with your choice of two layers of wet out CSM between the two pieces, OR the same PB you made before...
Another thing you can do to provide a better bond between the hatch and the sheets of plywood is to drill some random holes through the ply wood and allow the PB to ooze through those and act as sort of PB "nails" to help in locking everything together, before they kick off, use a bondo spreader to smooth them over...
Finally, as everything is starting to get tacky, lay in a layer of CSM and two layers of 1708...
Make sure they are large enough to reach all the way to the edge of the hatch and actually overhang the lip...
Be sure to do a thorough job of popping all the bubbles and get a good solid bond between all the layers...
When everything is hard, you can trim the excess from around the lip...add a couple coats of your choice of coating...gel coat [best], bilge cote [very good], or any good quality paint to finish it off...

A couple of tips...
Wet out all of your cloth/mat on top of some cardboard, then transfer the wet cloths to the piece...works best with less than 3-4 square feet of material at a time...with help, they can be a bit bigger...
Pre-cut everything and label the "face up" side of everything...and in what order everything goes..1,2,3 and so on...
Practice putting everything in its place a couple of times before the actual permanent install...gives you a good idea of what to do and eliminates surprises...a couple of good rehearsals will usually point out what you can do better and if you are missing any tools or supplies...
Have enough resin poured out in small batches with matching MEK-P next to them for quick mixing and use as needed...
You can pre-mix your PB to the consistency you want BEFORE adding any MEK-P...then if you want, you can break it up into separate batches to use and catalyze as needed...
In the end, you can salvage any NON- catalyzed resin and pour back any unused MEK-P...
Excess, pre-mixed PB won't last for more than a few days before you have to use it or discard it...
Applying the PB can be done with a 1/8"-1/4" notched trowel, to both surfaces before mating, probably be better with the 1/8"...
If you feel you need to add "clamping weight to everything, although you really shouldn't have to...have some waxed paper handy to cover the last application of 1708 and an additional piece of wood to cover the entire last piece of installed plywood and put a couple of cinder blocks or batteries on top...

OK, that should give you a basic rundown of what's ahead...
I may have missed a trick or three, but you should be good to go...
Good Luck and be sure to let us know how it all works out...

 

[jbcurt00]

Re: Need Advice on how to repair fish box hatch

tips...
Wet out all of your cloth/mat on top of some WAXPAPER or SARAN WRAP covered cardboard.........

Little edit ^^^ otherwise, yep

 

[zool]

Re: Need Advice on how to repair fish box hatch

You shouldn't have too much trouble doing that repair Mr300, GT has you all set up. Just grind off enough of the lip edge to accept the cloth lams, then fair it a little thicker, and sand it back to width....I had to do the same on my engine hatch repair.

 

[Yacht Dr.]

Re: Need Advice on how to repair fish box hatch

GT1M has you covered

Although..In an instance like this I typically make my core 1-2 inches shy from the edge. This way I have more bonding surface for my glass when I wrap the ply. But if you bond your ply to the part correctly..then its probably not going anywhere. Its just how I prefer to do hatch cores

Good luck.

 

[mr300z87]

Re: Need Advice on how to repair fish box hatch

Thanks everyone for the quick responses. GT that is a great explanation on the procedures and we will follow your advice. I was also thinking of leaving some space from the edge of the ply to the lip of the hatch to make it easier to re finish the lip. What do you recommend grinding with the owner has a harbor freight 4 in grinder and is use a metal cutting wheel to cut the glass but not sure what kind of wheel to use for clean up. Here is a pic 99% of the wood gone.


Tomorrow we plan to get whatever we need for the clean up grinding and the ingredients for PB which I hope we can find locally. Not sure how much progress we are going to make this weekend, sat we are supposed to help another friend get his boat ready for the water. This would be the friend who is going to let me keep my boat the dock behind his house this summer and then Sunday is holiday. I will keep posting our progress.

Zool, I was very impressed with you hatch repair and look forward to watching your boat building, spray booth and LBI house projects. In your spare time your more than welcome to come down to Jackson and help out. I am sure Don would buy the adult beverages.

Have a great weekend

Mike

 

[GT1000000]

Re: Need Advice on how to repair fish box hatch

The hatch itself looks good and ready for some put back, nice job!
For any additional grinding you can get some sanding discs with a backing plate in the 36-60 grit variety for some serious material removal, or you can get some flap discs in the same grits...
Obviously for finer finishes you start moving up the grit chain...80-120-220-320-400-600, etc...
If you need to get into tight spots a small rotary tool [Dremel] with a carbide burr or sanding drums will work...
Actually, if you do a fairly good job of applying the layers of cloth, you should have almost no clean up required, except for maybe a few nubs or hairs sticking up and grinding off the excess that overhangs the lip...a final prep sanding after all the glass work cures with some 80-120 grit before applying your finish coats of paint or gel should give you excellent results...

 

[mr300z87]

Re: Need Advice on how to repair fish box hatch

Today we picked up sanding discs and 1/4 in ACX plywood which was expensive. When time permits we will get to sanding prep and cutting out the plywood pieces in order to get this back together, as the weather is starting to get better here in NJ and we can't fish without a deck. We still need to get the Cabosil/Aerosil/Fumed Silica to make up PB although I was thinking of using PL premium to glue the 2 plywood cores to the hatch. I have a tube laying around. Other than having to wait 48 hours before glassing do you see any problems with that.

All have a great weekend

Mike

 

[GT1000000]

Re: Need Advice on how to repair fish box hatch

It would probably work OK, but I am not a huge fan of PL...and be sure to read the label, I believe it can take as long as 72 + hours to fully cure...
Here is an alternate method if you can't get hold of some Cabosil...you could use CSM sheets to glue the pieces of wood to the hatch and to each other, instead of having to make up PB...
Then finish everything off with a couple of layers of 1708...
Here is a rough sketch of what I mean...

 

[Yacht Dr.]

Re: Need Advice on how to repair fish box hatch

Might I make one suggestion..Do NOT put wood where your Hinges or Lifting rod thingy is. Instead use all glass or putty covered in glass. Just so you dont have any problems in the future.

Personally..I would use the cabosil/resin mix. Also..when you do your glassing watch and wait for it to cure just enough that you can take a utility knife and cut the over hanging glass. You have to catch it at the right time or your back to your grinder

Good luck.

 

[mr300z87]

Re: Need Advice on how to repair fish box hatch

Gt and yacht dr thanks for the input. I am sure we will get it figured out. A little web surfing had found Don a new replacement hatch however we still plan to repair the original. So now total failure is less of a issue now. Lol However we are still going to attempt to repair the original as a learning process. I will keep posting updates as we proceed.

Mike

 

[mr300z87]

Re: Need Advice on how to repair fish box hatch

We have not had much time to work on the hatch, but earlier this week Don cut out the first piece of plywood. I know it not much but progress is progress. Here is pic to prove it.



Have a great rest of the weekend. Maybe boat work tomorrow the weather is getting nicer.

 

[mr300z87]

Re: Need Advice on how to repair fish box hatch

Yesterday we made up some PB and filleted all the sharp 90 degree corners. It seems to have set up nicely. This morning before the kids soccer game and mothers day festivities we are going to give is a quick clean up sanding and make an attempt to lay down some 1708. Question which side of the 1708 goes down? The csm side? Also we will be gel coating as a finish coat, do we add wax to the resin and sand before gel coat? Or do we just add the was to the gel coat? Remember the gel finish will be on the underside of the hatch so it will not be seen. As always advise is always appreciated. Pics will be forthcoming as I know, no pics and it didn't happen.


Have a great Sunday

 

[GT1000000]

Re: Need Advice on how to repair fish box hatch

CSM side down on the 1708...
Only add wax to the very last coat of gel...
Hope the kids win their soccer match, mom has a great day and you guys have fun!

 

[mr300z87]

Re: Need Advice on how to repair fish box hatch

Thanks for the info. We just finished cam side down 2 layers of 1708. Unfortunately I added the wax? Can I just sand and wipe with acetone before gel coating? Or just leave it unfinished? It is the underside you know. Pic later when I get to the computer

Mike

 

[mr300z87]

Re: Need Advice on how to repair fish box hatch

As promised here are some pictures of what I think was a successful fiberglass job. First with the wood substrate glued in



next with PB fillets.



and finally 2 layers of 1708 and it seams very strong. I guess time will tell.

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That stuff is the easiest fiber glass I ever used. I Fooled around some with fiberglass when I was a kid back in the 80s With little success, technology like 1708 biax and forums like this make for good results.

One question as I mentioned in my previous post ^^^^^ we did this early this morning before I read GT's post and I had added wax to the resin. We plan to attempt a gel coat finish, how do I now prep the waxed fiberglass for gel coat?

back to the grind tomorrow. One of these day I will work on my boat.

Mike

 

[GT1000000]

Re: Need Advice on how to repair fish box hatch

Looks like an excellent job from here!
All you gotta do is sand the 1708 until when you wipe it down with some acetone it becomes kind of tacky/sticky...
The sand paper is probably going to gum up pretty fast due to the wax...you can clean it up some, to extend its useful life a bit by using a stiff wire brush to get rid of some of the gummy-ness...but you might need a couple of sheets of sandpaper...you could start with 60-80 grit on a D/A, and knock it out pretty quick...

 

[mr300z87]

Re: Need Advice on how to repair fish box hatch

Don was very proud of our work so he shot this video with the iphone. i don't know how to post it as a video but her is the link.

https://www.youtube.com/watch?v=hB268Lar1vA

 

[mr300z87]

Well now that the forum has stabilized I figured I would post the final results of our repair. We gel coated the under side before installation.


Then we drilled new holes for the hinges and the pull, here it is installed and ready for the water. It acutally seem stronger that the original next to it.



Happy boating all. Today in NJ it is a perfect boating day however I have been battling a cold so I am home laying on the couch instead.