TDB 14 Classic - "Easy" Fix

Noah Shaver said:
SJ, I have purchased pretty much all the materials needed to do the rebuild. I have all of the resin and fiberglass sitting here in the garage ready to go. I have the sheet of Coosa staring at me too. I've also been chipping away at rebuilding the trailer. The bunks were trash and anything not galvanized was rusted to oblivion. I have pretty much planned my duck hunting adventures this season around this boat being ready, so I've got to get to work!

Eric, Carl, or any others, any insight on how to repair this patch? Try to grind down/scarf and then reglass? Or just say heck with it and glass the whole bottom of the boat?
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Glad to hear you're not throwing in the towel.

I wouldn't trust that patch. Remove the patch and glass the repaired bottom, carried over and around the transom patch area at a minimum. If you glass the entire bottom you need to sand that gel coat for good adhesion, but it also might be worth it in the long run to avoid finding another surprise. You'll want some heavy cloth in that corner surrounding the Coosa, or mat if there's room. It doesn't need to be pretty on the inside. It wants to be robust as it is subject to deformation when under power. I like the Coosa, my only experience was with a small piece but it's great stuff when properly installed. Anything but wood in a transom.
 
Noah,
You seem very talented so my suggestion shouldn't be that difficult. If it were me I would be inclined to sand all remaining gel coat off the bottom and sides of the hull and epoxy a couple layers of 10 oz boat cloth or maybe a single layer of epoxy compatible 1708 cloth. At this point I would trust nothing, so significant reinforcement is warranted. Maybe it is throwing good money after bad but the water is cold in late season and I would be asking myself at this point if the boat is safe. RM
 
noah, this boat wasnt in lewes delaware was it? I took a look at one that seemed to good to be true but when i saw some floor patches i decided to pass. I hate to see this when someone puts there hard earned money out there but you will learn quite a bit and those lessons are never free.
 
Noah Shaver said:
SJ, I have purchased pretty much all the materials needed to do the rebuild. I have all of the resin and fiberglass sitting here in the garage ready to go. I have the sheet of Coosa staring at me too. I've also been chipping away at rebuilding the trailer. The bunks were trash and anything not galvanized was rusted to oblivion. I have pretty much planned my duck hunting adventures this season around this boat being ready, so I've got to get to work!

Eric, Carl, or any others, any insight on how to repair this patch? Try to grind down/scarf and then reglass? Or just say heck with it and glass the whole bottom of the boat?
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Since you already have the area close to fair. Once you're finished your repair I would just re-glass the entire bottom of the boat to tie everything together. And peace of mind
 
Noah Shaver said:
Got an update........the lid on the can of worms continues to be peeled back further.

Saturday afternoon I finished the transom demo, which I thought would be the end of demo on this project. As I chipped out around the edges, I went to pry back on the last section and the fiberglass cracked and a good sized chunk busted off.

I've got a pretty good feel for the strength of this lamination of fiberglass with how much I have demo'ed, and the force I applied was nowhere near what should have caused a crack, so I started investigating with my angle grinder.

I had previously noticed that the bottom of the hull on the port side near the transom was a bit out of level. I just attributed this to rough manufacturing and figured I would fix it when I was fairing the hull after I completed the patch.

The more I looked at it, the more suspicious it became, so I put on a 40 grit flap disc and went to work.

What I uncovered appears to be an old patch job in the bottom of the hull. What's strange is that I spoke with the previous owner, who bought the boat new, and he never did any work in this area.

The patch had no fiberglass over it, only epoxy. I sanded it to "close to fair" and doing so got me into the balsa used for the patch. The top of the core material (balsa) is fair with the fiberglass of the hull. Any fiberglass applied here would cause a hump and a hook in the aft end of the hull.

The more I work on this old TDB the more I realize that there could have been much better specimens for my efforts. This old boat continues to throw curveballs that require quite a bit of time, effort, and money to fix. The way I see it I've got three options to correct this old patch area:

1) Continue to grind down the area, build back up with fiberglass.
2) Demo the entire patch area to remove the old balsa core. Replace core and reglass.
3) Grind to perfectly fair. Finish center hull patch and transom, Reglass entire bottom of hull to tie everything together.

The last piece of transom plywood removed:

View attachment 67713

The patched area in the hull:

View attachment 67714
View attachment 67715
View attachment 67716

Overall current status:

View attachment 67717
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Good morning, Noah~

I am in the "continue as planned" camp. Your Option 2 makes sense to me. I would certainly dig out the repaired balsa core unless you are certain that is is dry, sound and well-adhered. In any even, grind it "below grade" and build back up to fair with 1708 and epoxy - however many layers you need.

I would 'glass the bottom, but only an area below a waterline - that I would strike maybe an inch above where she actually floats at rest. No sense adding more weight than necessary for peace-of-mind. If all of your currently exposed bottom is finished with 1708, a layer of 10-ounce cloth set in epoxy should tie all together. Mask the waterline with packing tape or the like - something more rugged than the typical masking tape - to get a nice crisp waterline.

re RM's suggestion: I do not see the need to sand/grind through the gelcoat. If intact, it does provide its primary intended purpose - to keep moisture away from the original polyester-resin impregnated 'glass matrix. Sanding with 80 or 60-grit should give enough "clean" surface to bond chemically with the epoxy and enough "tooth" to bond physically/mechanically. (Of course, I welcome further insights from RM!)

BTW: For such sanding, I would probably begin with my belt sander (80 or 60-grit) - keeping it moving and using a "light touch". The concept is similar to using a long board for hand sanding. I always wield it at an angle to the run of the hull - and reverse positions frequently.

All the best,

SJS
 
Thanks for all the advice!

I will plan on grinding the rest of the epoxy off the patched area to assess the soundness of the balsa core. From what I can see right now it appears to actually look really good, but we'll see. If it's soft I will plan to remove, if not I will glass over with 1708 until fair.

Either way, I think at this point I'm going to commit to glassing the entire bottom of the hull.

I will have to build some fillets in the channels so the glass will take to those inside corners, but other than that it should be fairly straightforward.

I have a good bit of 1708 on hand, is there any disadvantage to using that as the final layer of glass on the bottom as opposed to the 10oz cloth? I've never worked with the 10oz cloth; if it's easier to work with I will gladly pick some up!
 
Noah Shaver said:
Thanks for all the advice!

I will plan on grinding the rest of the epoxy off the patched area to assess the soundness of the balsa core. From what I can see right now it appears to actually look really good, but we'll see. If it's soft I will plan to remove, if not I will glass over with 1708 until fair.

Either way, I think at this point I'm going to commit to glassing the entire bottom of the hull.

I will have to build some fillets in the channels so the glass will take to those inside corners, but other than that it should be fairly straightforward.

I have a good bit of 1708 on hand, is there any disadvantage to using that as the final layer of glass on the bottom as opposed to the 10oz cloth? I've never worked with the 10oz cloth; if it's easier to work with I will gladly pick some up!
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Noah~

1708 is great stuff - both strength from the biaxial rovings and great adhesion and waterproofing from the mat. There are 2 downsides/considerations for your sheathing application. First is the added weight. It is thicker and needs more epoxy than cloth. On the other hand, I met a guy at Tuckerton last year who put 2 layers of 1708 over his classic Barnegat Bay Sneakbox cedar hull. The second consideration is the finish. It leaves a more open weave - which you could fill will more epoxy. I usually go over 1708 with a cloth to achieve a smoother finish. You could use a light cloth (7.5 ounce?) for that purpose.

Regarding the fillets along your strakes/channels - you might consider a twill weave in the cloth. I have been using it recently and like the way it finishes - as well as conforming to tight inside curves.

All the best!

SJS
 
Steve Sanford said:
re RM's suggestion: I do not see the need to sand/grind through the gelcoat. If intact, it does provide its primary intended purpose - to keep moisture away from the original polyester-resin impregnated 'glass matrix. Sanding with 80 or 60-grit should give enough "clean" surface to bond chemically with the epoxy and enough "tooth" to bond physically/mechanically. (Of course, I welcome further insights from RM!)
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Yes, Steve is correct. Epoxy should bond to gel coat just as easily as the substrate polyester resin. I'm glad you haven't thrown in the towel as it is fun to watch these wonderful old vessels brought back to life. Once you have it sheathed in 1708 and boat cloth, I highly recommend Wetlander below the waterline for additional water resistance. While it is much too shiny and slippery for the topside, Wetlander also makes an industrial primer you could knock down with steel wool to eliminate the shine. RM
 
sean kane said:
noah, this boat wasnt in lewes delaware was it? I took a look at one that seemed to good to be true but when i saw some floor patches i decided to pass. I hate to see this when someone puts there hard earned money out there but you will learn quite a bit and those lessons are never free.
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No sir, I bought it out of North Central PA. The seller was completely honest about the work it needed, albeit we didn't expect it to be this severe. The price I paid was very low for what I got, which is why I've been willing to pump time and money into it to get it right
 
RM Anderson said:
Yes, Steve is correct. Epoxy should bond to gel coat just as easily as the substrate polyester resin. I'm glad you haven't thrown in the towel as it is fun to watch these wonderful old vessels brought back to life. Once you have it sheathed in 1708 and boat cloth, I highly recommend Wetlander below the waterline for additional water resistance. While it is much too shiny and slippery for the topside, Wetlander also makes an industrial primer you could knock down with steel wool to eliminate the shine. RM
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I had planned on using Wetlander, I think it will be perfect to fill in the weave of whatever fiberglass I use on my final layer of the lamination.

I am curious on bonding to the gel coat. When I sand the gel coat with 60 grit sheets on my orbital sander, it doesn't do much in the way of "roughing up" the surface. I don't have a belt sander, unfortunately. Would I be better off to sand this by hand for maximum adhesion, or maybe go to a more coarse sandpaper on my orbital?
 
Noah Shaver said:
I had planned on using Wetlander, I think it will be perfect to fill in the weave of whatever fiberglass I use on my final layer of the lamination.

I am curious on bonding to the gel coat. When I sand the gel coat with 60 grit sheets on my orbital sander, it doesn't do much in the way of "roughing up" the surface. I don't have a belt sander, unfortunately. Would I be better off to sand this by hand for maximum adhesion, or maybe go to a more coarse sandpaper on my orbital?
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Gelcoat is not made to bond to anything unless you cut corners and use marine-tex lol. You will need to get an air-sander if possible with some rough 40- 60-grit at a minimum. Sand down to the bare glass for adhesion. This is a crucial step as if this doesn't bond correctly it will de-laminate and water will enter. When you re-spray the gelcoat that's another fun project in itself ensure the temperature is correct. I just re-sprayed an entire boat with gelcoat call me if you have any questions Noah
 
Anthony Babich said:
Gelcoat is not made to bond to anything unless you cut corners and use marine-tex lol. You will need to get an air-sander if possible with some rough 40- 60-grit at a minimum. Sand down to the bare glass for adhesion. This is a crucial step as if this doesn't bond correctly it will de-laminate and water will enter. When you re-spray the gelcoat that's another fun project in itself ensure the temperature is correct. I just re-sprayed an entire boat with gelcoat call me if you have any questions Noah
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Noah & Anthony~
I defer to Anthony on this topic. I, too, was thinking of an air sander. The guy who owned my old boatyard used one all the time - including a flat "long-board" type. You need a big compressor for such tools, however.
Your angle-grinder with the 40-grit flapper wheel will get through the gel coat (which, as you have seen, is lots harder than plain 'glass) but it is difficult to avoid dishing with that tool.

Also, orbital sanders are designed primarily for the finishing/surfacing tasks. I also use a 5-inch disc sander that cuts much more quickly than an orbital. It' a good tool to have in your arsensal.

https://www.homedepot.com/pep/DEWAL...__98LjmqnsU39mSxl_o5h9QvUU412yjEaArGNEALw_wcB

All the best,

SJS
 
Noah

I like my Makita sander polisher with the 3M soft backing pad for such tasks but a 6" random orbital will get it done too, just longer. The pad gives you very good control of the sanding disc and pretty much eliminates gouging and grooving the stock hard rubber pads are notorious for.

My experience with gel coat is different than Anthony's. I've had no problems bonding fiberglass to gel coat as long as the gel coat wasn't flaking or otherwise compromised and I was wetting with epoxy. Just like the resin used in the glass it covers it is polyester. Epoxy will bond to gelcoat, but not the other way around. I've always sanded with 80 grit taking it down until it looks good and frosty. No gleam or sheen left. You are working with a very large surface area for the epoxy to adhere to. It bonds to polyester when properly prepared. I wipe down with VMP Naphtha or acetone to remove and oil on the surface. If the boat had a two stroke there is always chance for oil residue. Wipe it down and eliminate that chance. If the gelcoat has cracks everywhere or is blistering then I'd sand all of it way.

3M Stikit Disc Pad 05568
 
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I will add that Anthony's method does remove any possibility of the gelcoat separating from the original glass beneath it. Depending on how the hull was laid up that bond may or may not be tenacious. It is a lot of work to take all the gelcoat off. I think it were me if I saw any signs of gelcoat failure I'd take it all off as well. If it is in good shape I'd be comfortable roughing it up and bonding to it.
 
Thanks for all of the tips guys. I'm going to do a little test run and see how accurate I can be with the angle grinder and 40 grit flap discs removing the gel coat. I know it's not a precision tool, but let's face it, I'm going to be fairing the entire bottom of this hull, it doesn't have to be perfect. If I do leave a gouge or two I can fix it.

We've had rain every day for two weeks straight, so it makes it difficult to make progress. I'll attach today's humidity forecast below; it's the wrong time of the year to attempt fiberglass work!

IMG_5872.PNG
 
Noah

You think now is bad, try winter. I always like working epoxy in Aug because it shortens cure time and you can start sanding sooner. Are you working outside? Rain will certainly get in the way if you are.
 
I am working outside during this phase of demo and sanding. Once I have all of the sanding prep complete I will bring it in the garage and do the core replacement/fiberglass work inside. I don't want to do all of this sanding indoors, I made quite a mess this past weekend just taking that patch area down with the angle grinder.
 
Eric Patterson said:
I will add that Anthony's method does remove any possibility of the gelcoat separating from the original glass beneath it. Depending on how the hull was laid up that bond may or may not be tenacious. It is a lot of work to take all the gelcoat off. I think it were me if I saw any signs of gelcoat failure I'd take it all off as well. If it is in good shape I'd be comfortable roughing it up and bonding to it.
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So the epoxy will bond yes but far too many times we've seen situations where the bond separates and eventually delimitates from gelcoat. The location of this fix is far too critical for a bond on gelcoat. We had a guy locally put MarineTex over his gelcoat underwater on a southbay boat didn't last too long lol. Noah- Be careful with that angle grinder don’t make her a "see-thru" hull! :LOL:
 
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