TOPIC: Advice needed please.

Hello again all, I am progressing along in my restore project and I am trying to figure out what I will be needing for materials. Right now Im stripping the transom out and will be replacing it with marine ply, the transom core is only 1 inch thick so I will use 2 layers of 1/2 inch ply glued together and then glue that into the outer skin. For this I want to use epoxy adhesive and not having used this before I'm trying to figure out how much I will need. The transom is only 16" tall at the tallest point and about 5' 3" long so trying to figure out how much I will use to do that. I was looking at the transom replacement in the "restoration" section of this site and I like the way he laminated the inner skin on there before installing the new core however from what I am reading epoxy is best used only for cloth not mat? (been reading other's posts and studying the system three epoxy book). In my mind I should use epoxy to glue the ply together and glue to the old outer skin but I think I would use traditional poly resin for the inner skin and for the tabbing to the hull as there would be mat involved?? Forgive my newbie ignorance as I am trying to do it right.

With that said I will also be doing a new floor and most likely stinger repair as well but wont be cutting that out until I have the transom repair done and tabbed into the hull.

Would a quart kit of epoxy or mabye just SYS3 t-88 be sufficient to laminate my new core (ply) together and glue it in? if so mabye that would do me for epoxy and the rest would be polyester?

This stuff is a lot more expensive than the beer..

Id also go the route of just using epoxy and then adding my own fillers for adhesive and fillet's but just dont have a grasp of how far it goes yet. Thanks in advance for any wisdom..

west system has great products, information, & technical support. They sell epoxy by the pint, quart, gallon and 4 gallon along with an assortment of hardeners. West System is very easy to use and again the tech support is always there. Effectively you could use the 4 gallon system if doing any deck and hull repair along with the hull floor, stringers and transom.
Epoxies are better than poly resins but budget laws are always in effect. You need to budget for materials (resins, cloth ie; mat woven roven etc..), misc items such as spreaders, rollers, brushes, abrasive's etc...., cold beer (budget, import or micro-brew) and plenty of ice to keep the beer cold and to stop the resin from kicking off too quickly on a real hot day.
just sayin....

Boy, that is the $64 question. Better to have too much on hand that not enough. A quart might do it, but you'll get a deeper discount per unit on a gallon, and if it's kept right, it has a long shelf life. Just my 2 cents.

Frank

as far as how much plywood ,it comes in 4x8 foot sheets,so 1 sheet will give you enough to get two transoms cut out at 16 inchesx 5foot 3 inches,with about enough left over to do it one more ply,as there will be 16 inches left,but dont forget that a saw blade is aroound 1/8 inch,and you will have 2cuts if you go for 3 plys(sheets of 1/2 inch)taking away 1/4 inch out of 16 inches,john

Hm yeah the beer choice is an easy one, after years of doin concerts in the beer garden at Bell's (Kalamazoo brewing co.) and drinking for free, all other beers dont interest me anymore so its either that or rum. With that out of the way. One thing I have to be carefull of is my transom width. The wood core is only an inch thick and the outer skin is quite thick, but most importantly is that I have to be sure not to go to thick on the inner skin as the rear part of the deck has the molded splashwell which covers part of the inner transom. Infact part of the inner skin came off with the deck right there so I will have to grind that portion of the skin off of the inside/underside of the deck where it buts up against the inner skin. It seems that they actually glued it together there. So it seems I am limited to keeping the same thickness or at least not going over a certian amount, maybe a few test fits of the deck with a false core with some modeling clay stuck on it to find my clearance there to judge the inner skin thickness. The deck also caps the transom (infact it shows 1.5" right there but its not the same underneath). I suppose I could just get a gallon of epoxy and the fillers cause there will surely be more to use it on than just gluing the transom.

There is so much cracking in the gelcoat on the foredeck and other places on the deck that I'll probably end up having to sand thru most all of it and I guess recoat it with epoxy and sand to smoothness. Infact once I get the transom done I may put the deck back on just with a few dozen rivets to help hold the hull in shape while I do the floor/stringers and then pop it back off again and flip the hull over for bottom repairs. I have a lot of cracks in the gel right at the stern where it meets the transom on the bottom that will have to be ground down to clean glass and repaired from what I can tell and hopefully not to much more repairs. Then whatever it takes to repaint the bottom, then flip it back right again and finish the upper bits.

If I understand it correctly epoxy is not to be used with mat? and mat is used quite extensively in this process so how are people getting away with that?? I was thinking epoxy for the gluing and probably hole filling's and traditional polyresin for the laminating of cloth and tabbing ect.?? This is where I am really trying to read as much as possible to educate myself. I have no problem with the skills needed as far as actually doing it, its the knowledge I am lacking at this point. Ive done tons of woodworking anywhere from creating custom countertops (laminates) to gluing up segmented ring type bowls/vase blanks to then turn on the lathe ect. So its a learning curve on the material for now.

Thanks again for the advice.

CG,

I have attached some drawings on how I recommend building Transoms, Stringers and decks. I do NOT use epoxy in Fiberglass boats. They are made from Polyester Resin and therefore I stay with the polyester. If you use the proper methods you will have all the strength you need. The major drawback in using polyester resin is the STINK. It is NOT NASAL Friendly and if you are working inside then proper ventilation IS required. I have special made clamps I use to clamp the transom to the hull. I use MDO plywood or Regular Ext Grade Plywood for my Transoms, Stringers and Decks.I use 1.5oz Chopped Strand Mat and 1708 Biaxial Cloth. I use Cabosil and 1/4" milled fibers to make my thickened resin and mix it to the consistency of Creamy Peanut Butter. I also use PL Construction Adhesive to Bed my Stringers. I use 1/4" spacers to hold the stringers off the hull while the PL cures for 48 to 72 hours and then remove the spacers. I then use thickened resin to cove the stringers to the hull. I use a full face respirator to protect me from the fumes and dust. I wear a full cover Tyvek suit when grinding. I use a Porter Cable 4 1/2" grinder with a BackupPad and 34grit Sanding discs for quick removal of material. Sawzall, Circular Saw, Hammer, chisels, etc....

Hope this helps.


Transom

(Click the pic to enlarge)


Stringers and Deck


Transom Clamps

Nice thats what Im talking about (if I knew what I was talking about). So just a question the orange is mat and resin so when you do one like that, do you basically laminate the 2 plywoods together with mat and resin between and let that dry? I'm assuming that's right.. also let me see if I understand this from the picture, my guess would be that you would wet the csm onto the ply and then apply the thickened resin to the outer skin and clamp that in place in one move? Or do you put both of the csm layers onto the core first and let them cure (inner/outer) and then set it into the thickened resin/outer skin?

I like this idea much better using the same material the rest of the boat is made of and not needing two differnet things..

By the way I love those gigantic versions of jorgensen clamps hehe I have a bunch of those and love em.

Great info and illustrations MF, makes it much easier to understand. Thanks for sharing!

good job flamingo,i am going to have to make a set of those clamps,very clever,john

Good day, got the transom core all stripped out and it came out in about 3 big sections (albeit messy ones) but it seperated from the outer skin very easily. They had a scarf joint right in the middle of the transom (hm couldnt find a piece of ply that was 5 foot long by 16"? Reminds me of how they build mobile homes, dont waste a single scrap, but in a transom? oh well).

The floor is so rotted I can just crush it in my hand once the skin is off it. It seems my stringers are only made of solid wood about 3/4" by 1.5" looks like plain old pine. Also only the inner 2 stringers support the floor, the ply was nailed to the stringer and then covered and then the outer edge just glassed into the hull. So I'm sure I can do a better job than that.

Tommorow I will grind and sand the whole deal to where it is prepped for a new core and clean it all up with the shop vac. Now I will have to find other things to do until I can get the new ply (88 bucks for a sheet of 1/2" hydrotek/meranti) and some resin/cloth/filler and tools to do the job. Suppose I can clean up the old tape where the deck met the hull and stuff like that in the meantime. Loving that multimaster tool more everytime I find a new use for it.

$88 bucks! That is a deal. I paid $130 for a 3/4" piece.
I am glad you are doing your transom simultaneously with me. Perhaps I can avoid some mistakes by watching you. I have my transom and floor area ground and sanded clean, ready for hole filling. My biggest fear is actually cutting that precious piece of ply. Gonna do it in the next couple of days. I am going to pick up the epoxy and hardener tomorrow. Say, have you seen the automatic measuring pump system West has for their products? Big pump goes into big can, and little one in the small can. One pump of large to one pump to small and I understand you have your precise formula. No more messy guessingI am going to pick that up for sure.
Andrew

C.G.,
I agree you will be able to do a better job than the manufacturer during your restoration, but be careful you don’t over strengthen the hull and form “hard points”.
Fiberglas, as used in small boat hulls is not very rigid, and it is constantly flexing while the boat is moving. The higher the speed and the rougher the water, the worse the flexing becomes. If you flex something enough times it will eventually crack and break.
The boat structure is designed to flex over large surface areas of the hull so the stress caused by flexing won’t build up in a particular area.
Hard points are created wherever the hull and rigid structures such as floor edges, stringers, seat structure, and transom edges, etc. come together. The flexing action moves across the hull until it hits a hard point and can’t go any further. Flex the hull enough times at the hard point and that is where the stress and eventual break will occur.
A good boat design avoids hard points as much as possible. Stringers are set on small spacers slightly off the floor. Sharp bends in structure are avoided, and one of the most important, any rigid structures that are attached to the hull are tabbed on by progressively wider and longer tabs.
The tabs act like the piece of rubber on entrance of the power cord into an electric tool like a saw or drill. The rubber usually starts at a small diameter farthest from the tool (usually three or four inches out) and gets progressively larger as it nears its entrance into the tool. Most people have a pretty good understanding of how the rubber piece spreads out the stress from a constantly flexing power cord and prevents the power cord from breaking right at the entrance into the tool.
To minimize cracking problems Just transfer that knowledge over to a boat hull when making modifications. The fiberglas hull is the power cord, the entrance to the tool is the hard point, and the progressive tabbing is the rubber flex absorber. If you make modifications to the structure just remember tabs, tabs, and more tabs! Yes the tabs hold the structure to the hull, but their most important job is preventing cracks.
When you’ve torn a boat apart and you look at a lot of light flexible structure you really don’t know if it’s just good design to prevent cracks or somebody skimping on material. Back then some boats were heavily engineered to resist stress and cracking, others were slammed together with only the bottom line in mind.
Finding a scarf joint in the transom of your boat suggests the bottom line was in charge and the boat will benefit from some strengthening and improvement, but keep an eye out for the infamous hard points!
One area that does seemed to be designed poorly in most fiberglas boats is water draining. If it was done correctly in your boat back then, you might not be contending with a peanut butter transom today.
There has been a lot of discussion on this board about correct floor drainage design, but it all goes back to common sense. Definitely keep an eye out for ways to improve getting the water out of the boat or keeping it away from the wood!
Good luck with your restoration!

One thing I did notice, its hard to see from my pictures but my plywood core doesnt go all the way up to the top of the outer skin. I figure this is because the transom is on an angle and since my upper deck covers the top of the transom to just run it all the way up would make the inner edge higher than the outer thus not allowing it to set down all the way flat. My core needs to be only 1 inch thick because of the way the boat is built and the splashwell/cap aspect of the deck so I'm going to laminate my 2 plys together before cutting them to size/shape. Then I will pass what will be the top edge thru a jointer set at the proper angle to compensate for the angle the transom is on (I have yet to measure it yet but wont be a big deal) this will give me the perfect angle on top to make it flat. I will still leave it just a hair below to allow a little room for thickened resin or mat or whatever I choose to do to seal that off nicely but will just be a nicer job, once I have that top angle I will use my template made from the outer skin (from the high side of my angle) to mark and cut out the actual shape. Am also considering cutting that same angle into the bottom edge (angled table on bandsaw).
The core that was in there was not marine ply it had knots and voids and only about 6 layers in an inch so 1/2 inch marine ply with 7 layers will give me 14 MUCH better.

Flying fish , thanks for the comments. I have read some thing about just what you were saying about the hard points.. even saw a video of some guys putting in foamcored stringers that had a soft layer on the bottom for just that reason, makes good sense. I like the strain relief of a cord analogy. For many years I was a concert audio engineer and have done thousands of shows with all sorts of gear as well as being a musician myself and if there is one thing that is a constant in that world is "CORDS" hehe.. it is a proven fact that almost all failures in electrical cords/cables occur within a few inches of the end/jack/plug.

One other thing I was thinking of was adding some floatation foam in between those stringers either hard board or a waterproof marine type foam of some kind.. as to the water drainage well that was a fault of this boat.. I have cut it out now but where the drain hole is there was a sort of fiberglass "pan" that served as a low point for any water above the floor to drain into and then out.. only problem was that there was also some holes on either side drilled into the under area of the floor but they were high enough up to where it would never really drain it out so that was kinda funky.. Im still considering what I will do there..

The PL Adhesive Remains Flexible for Life thus aleviating Hard Spots. I always make a pattern for my transom from cardboard and then make the transom outside the boat. I first coat the wood with resin and let it dry paying close attention to the edges. I then coat mating edges and lay a layer of 1.5oz mat and then clamp em up. I Wrap the edges with the mat and use Stick pins to help hold the mat down. I then drill several 1/2" holes in the transom in various locations to allow air to escape during the clamping process and the thickened resin will fill these holes. If you want to add floatation foam you might consider using the blue or ping slab foam sheets from Lowe's. It is 100% closed cell, easy to cut to shape. I would recommend creating a bilge area and drilling weep holes to allow drainage. You can use resin to glue 1" pvc pipe into the holes in the stringers to seal them up and then use standard drain plugs.

Man this has turned into a great thread, very informative and easy for inexperienced folks to understand. Don't mean to be redundant, but thanks again MyFlamingo and FlyingFish for taking the time to explain your procedures in detail!

Question: For the 1/4" spacers under the stringers - Could you use dowel rod (wrapped in cellophane or somethingto ease their removal)? Once removed, would you then shoot more PL adhesive into the void left where the spacers were? I'm thinking placing these under the cross-braces (where there is no tabbing) would be the best location?

Speaking of the cross-braces, do you screw them to the stringers, or just use the PL adhesive to secure those as well? And I guess the same thought process carries on the securing the floor, really don't want to run screws into all this glass work, right!?

I think I'm finally feeling enough confidence to tackle this project, sorry to jump in the middle of your thread Clark.

MarkS wrote:

Man this has turned into a great thread, very informative and easy for inexperienced folks to understand. Don't mean to be redundant, but thanks again MyFlamingo and FlyingFish for taking the time to explain your procedures in detail!

Question: For the 1/4" spacers under the stringers - Could you use dowel rod (wrapped in cellophane or somethingto ease their removal)? Once removed, would you then shoot more PL adhesive into the void left where the spacers were? I'm thinking placing these under the cross-braces (where there is no tabbing) would be the best location?

Speaking of the cross-braces, do you screw them to the stringers, or just use the PL adhesive to secure those as well? And I guess the same thought process carries on the securing the floor, really don't want to run screws into all this glass work, right!?

I think I'm finally feeling enough confidence to tackle this project, sorry to jump in the middle of your thread Clark.

Yep, Dowels would work great. I'd coat em with vaseline

Use PL and Screws to secure your Bulkheads.

It's ok to use the PL to secure your Deck but I also use stainless screws, but... I predrill all my holes and then squirt 3M 4200 sealant in the holes and coat the screws with it when installing. This quarantees that no water can penetrate the wood.

One thing I had to add, maybe someone will confirm this but I have read where stainless will corrode if it is sealed off from the air. It may have been in some of my reading about building wooden boats as they are encapsulated in epoxy and a lot of times people ask about using stainless instead of silicon bronze or galvanized fasteners, eventually someone brings up that point about stainless wanting to be exposed to air. I know that in the newer forms of pressure treated woods that stainless is about the only one that holds up for long periods compared to other fasteners with various coatings (decks, ect). So just something to chew on.

This only applys to Saltwater not Freshwater.

Stainless Steel Corrosion

Update: I found some 1/4" dia rubber o-rings to use as the spacers, so I won't have to worry about pulling them out after the stringers are bedded in. Hope to get this phase done in the next week or so, got some time off work coming up.

Does the same "hard spot" rule apply when putting the floor in? (Where it would contact the hull on the sides.)

Nope, just fill the gap with thickened resin. Use a large plastic spoon dipped in mineral spirits to create a nice cove joint.


Heres a drawing on how I do my decks.

(click to pic to enlarge)

Flying Fish wrote:

C.G.,
I agree you will be able to do a better job than the manufacturer during your restoration, but be careful you don’t over strengthen the hull and form “hard points”.
Fiberglas, as used in small boat hulls is not very rigid, and it is constantly flexing while the boat is moving. The higher the speed and the rougher the water, the worse the flexing becomes. If you flex something enough times it will eventually crack and break.
The boat structure is designed to flex over large surface areas of the hull so the stress caused by flexing won’t build up in a particular area.
Hard points are created wherever the hull and rigid structures such as floor edges, stringers, seat structure, and transom edges, etc. come together. The flexing action moves across the hull until it hits a hard point and can’t go any further. Flex the hull enough times at the hard point and that is where the stress and eventual break will occur.
A good boat design avoids hard points as much as possible. Stringers are set on small spacers slightly off the floor. Sharp bends in structure are avoided, and one of the most important, any rigid structures that are attached to the hull are tabbed on by progressively wider and longer tabs.
The tabs act like the piece of rubber on entrance of the power cord into an electric tool like a saw or drill. The rubber usually starts at a small diameter farthest from the tool (usually three or four inches out) and gets progressively larger as it nears its entrance into the tool. Most people have a pretty good understanding of how the rubber piece spreads out the stress from a constantly flexing power cord and prevents the power cord from breaking right at the entrance into the tool.
To minimize cracking problems Just transfer that knowledge over to a boat hull when making modifications. The fiberglas hull is the power cord, the entrance to the tool is the hard point, and the progressive tabbing is the rubber flex absorber. If you make modifications to the structure just remember tabs, tabs, and more tabs! Yes the tabs hold the structure to the hull, but their most important job is preventing cracks.
When you’ve torn a boat apart and you look at a lot of light flexible structure you really don’t know if it’s just good design to prevent cracks or somebody skimping on material. Back then some boats were heavily engineered to resist stress and cracking, others were slammed together with only the bottom line in mind.
Finding a scarf joint in the transom of your boat suggests the bottom line was in charge and the boat will benefit from some strengthening and improvement, but keep an eye out for the infamous hard points!
One area that does seemed to be designed poorly in most fiberglas boats is water draining. If it was done correctly in your boat back then, you might not be contending with a peanut butter transom today.
There has been a lot of discussion on this board about correct floor drainage design, but it all goes back to common sense. Definitely keep an eye out for ways to improve getting the water out of the boat or keeping it away from the wood!
Good luck with your restoration!

I glued my spars to the Hull with thickened Poxy then Filleted them ..They are Suppose to be Louse ?? Am I gonna have hard points and cause Cracks ??