I haven't really wished the transom height was taller in all the time I've had this boat, so I decided to stay with 20" transom, to avoid making a motor project out of my transom repair. Also went with polyester resin, after talking to a few more guys I know that have done this. I'll let you know later if I regret it!

Anyway, I know this will fall short of the works of art I've learned so much from on this forum, but I'm itching to get the boat back in the water. Here's what I got done so far.

I made a cardboard template from an old freezer box.

Bought 2 shts of 3/4" AB marine grade plywood from SPS in Jensen Beach (thanks, fdheld34), cut to size, dry fit, and laminated them together.

Also against the advise of many on this forum, I got advice from others I know and I decided to use polyester resin. I can feel the spears already!

Coated the surface of the core to be laminated to the transom with resin, layed a layer of 1 1/2 mat on transom skin, troweled some thickened resin on the transom skin with a tile trowel, and clamped the core to the transom. I didn't have enough thickener to make a bed all around the core, so I had to add that later. I would have liked to have had more putty on the transom, too. I miscalculated on the short side.


After loading up on cabosil and glass balloons, I made some more putty and stuffed it in the gaps around the core, and dragged a fillet in it for the inner skin glass to lay down nicely. I was kinda surprised how much cabosil was needed to get a decent putty consistency. I used about 1 1/2 cup cabosil and 1 cup glass bubbles to 16 oz of resin to get a good thickness.


Did some grinding/sanding to prep for laminating inner transom skin. Was going to lay the glass today, but it looks like the weather is no cooperating. There's always Sunday:)

My plan for laminating inner skin is a 1 1/2 oz mat, 1708, 1708. Should I did a layer of 1 1/2 oz mat between the two 1708 layers to build thickness?

Any recommendations for what to paint to use in the bilge?

Lookin good! Far as the layers or glass, I would use another layer of 1708 if you got it to build thickness due to you will get much more strength out of it. I sometimes use matt to build up thickness but only on non-structural items due to it being cheaper than the high dollar 1708. The matt will add much more weight and lot less strength to the lay up per same thickness. The resin to cloth ratio is better with the 1708 by having more cloth and stronger cloth at that. The matt dose well up aginst the ply wood due to it holds a lot of resin for a good bond plus it fills any voids to the wood but that is the only place it is needed.

FF- Thanks.

Got any advice on bilge paint?

Just noticed this post, I used epoxy only for the bond to the old glass skin. I thickened it with cabosil and troweled it on with a notched spreader and bonded it in place. Quantity used was less than a gallon for that part. The core had 2 layers of Matt applied to it on the bench to fully sill it up before I bonded it to the hull. I also laid strips of matt at the base of the core to bed it in to the bottom of the hull. In between the plys I used 2 layers of Matt then 2 layers of thick roven with Matt stitched to the rear. (Simular to 1708) then 2 more layers of Matt. I used the roven due to It was free gIven to me, 1708 would be slightly stronger but I wanted to use the roven/Matt up. The Matt holds a lot of resin to fill voids and for the wood to soak up. Make sure the wood is pre coated with resin a few times before the layup. I use thin vocosiy resin so standard resin you might want to thin it so it will soak into the wood better. On the outter layers I would start with the Matt then several layers of 1708 after that. Also I filled any voids around the edges and bottom with a thickened paste to avoid air pockets before I started on the outter layers. I added lots of extra tabbing to the hull sides with each one slightly larger overlapping the last. I would say but not sure it took around 3 to 4 gallons maybe close to 5 time I filled the stringers back in.

Maybe this will help you out, I know you have got passed most of these points. Sorry to be late on the reply.

http://www.fibreglast.com/product/du...-coat-additive

Mix it with white gel coat. Roll it on.

strick

I have been using interlux products and will be coating mine with their "bilgekote" product. A lot of people use this and love it and it will help prevent gas and chemical damage. Also I coated mine with vinylester resin to seal the polyester, water proof it better and smooth out the surfaces then will spray the bilgekote over this. If you use epoxy you must use epoxy barrier kote product first to make sure the bilgekote will bond well.

I have noticed you use a lot of Duratec products and was looking in to their Vinyl-ester primers. I was wondering if you use their fairing primers before and how did you like them? I was thinking about getting a gallon of the VE primer to coat my hull with for block sanding and fairing. I would like to get something that I can spray on thick that will cover those pesky little pin holes. Also I think it would be good far as keeping all the chemicals VE based. I been using the 3m VE underwater line type puddy and been coating with a epoxy primer. My thoughts are that the more similar chemical make up I can keep the better. The epoxy primer might do better for water proofing but the duratec VE primer should do about as good as what Im using now. Also dose the duratec sand well and what do they recommend for thinning it?

I have used their both their VE primer and polyester primer. It sands very easily and I usually thin with acetone after catalyzing it. Although they have a special thinner I have not used it. Duratec needs to be thinned as it is very viscous and hard to spray. I have sprayed awlgrip over it with good results. It has a fast cure rate so you cant let it sit like awlgrip primer. I mostly use duratec as the first layer on a new part in a mold. You can roll it on inside the mold. Let it cure and then start laying glass. So instead of gel coat I like duratec so I can then sand the part and spray with paint. It will cover pin holes easily.

strick

Thanks for the bilge paint info. Got the stringers tabbed in, and getting close to putting the cap back on.


While it's all opened up, does anyone have advice on whether the thru hull drain features should be reinforced? If so, how?

Looking good, I am at the point of re-installing my cap as well on the sceptre. Not sure how I am going to do my deck drains and tru-hulls yet but I will be using the ball type sculpers to prevent wash from coming back in.

Your glass work is very clean looking!

I am of the opinion that there is no such thing as too much tabbing. Great looking transoms and stringers don't work so well if the connection isn't robust. Those "tabs" help keep the transom from moving so much by tying them to the stringers. Outboards spend their whole time trying to tear the transom off the back of the boat, so more strength where you can hide it in the bilge is good.

I was taught to use smaller strips on inner layers, and wider on outer layers. As if you were using 2,4,6,8, 10 and 12 inch wide tapes. And I wouldn't be afraid to use mat on compound curves or between layers if you use it to better spread the load across the compound curvature at the intersection of the tops and sides of the stringer to the transom. The alternative is very generous curvature at the intersection so you can get fabric to drape. (Think of using a bowling ball to make your cabosil fillets)

That's just an opinion based on memories in composites class at university almost 20 years ago. So take it with a grain of salt.

By the way, if you have a sandblaster, that is way faster than sanding between layups, but you have to be good with a vacuum for cleanup.

x2 on what fishstrecher said, I sometimes use matt to make my fillets instead of thickened resin. I will use several 1/2" strips then several 1" strips then several 1 1/2" strips to make the fillets. This way it makes the fillet a bit stronger and also uses up all of the scrap laying around. After the fillet is in place I do like FS states start out with 4" to 5" to 6" and so on. the transom on my sceptre has a ton of tabbing. One thing I also do to add strength is to cut the transom cloth layers larger on the sides and bottom (8" wider overall and 4" taller) and use the last 4" on either side and the bottom for tabbing. This makes a strong lambent and ties the sides in with one piece. There is no seem to give way and it makes the transom and hull sides one continuous layer without any week points. Then I add the extra tabbing over this. Also take the time to roll over the lambent and get all the air pockets out from between the layers. This will help make it a lot stronger also. I'm not an expert either but this is just how I learned to do it and it works well for me. Like FS said take it with a grain of salt.

Thanks FS. Good camera angles hide a lot :) I had some trouble rolling out all the air pockets before resin kicked over, especially on edges with 1708. I read about FF's adding a chamfered edge where the sheet rolled over the top. I routed a round edge, but it could have been bigger. The large sheets were harder than the small stuff. But it wasn't too bad. I'm learning what my capabilities are (more like aren't). But so far I have managed not to make a cat's ass out of it.

Great advice on tabbing. I wish I learned all of that earlier. I did not lay as much tabbing as you all mentioned. Do you all recommend following up what I've done so far with additional tabbing? Does it help strengthen the joint if I were to go over what's been glassed with the tab schedule you mentioned, or is it better to always have the outer layer overlap the previous one? I plan to come back with 1708 final inner transom layer like FF did on his, and that should tie the added tabbing in?

Got any tips on how thick I should get? My transom laminate currently is, from outer skin inward:
- Original outer skin
- 1 1/2 oz mat
- thickened resin (applied with grooved trowel), squeezed by core to bed it to outer skin
- double 3/4 plywood core, with 1 1/2 oz mat in between
- 1 1/2 oz mat over the core
- 1708
- 1 1/2 oz mat
-1708

I'm using polyester resin, so maybe err on the thick side?

One last thing- while I have the cap off and have access to the deck drains that feed to the bottom of the hull, any reinforcing that you would advise adding to these? If so, how?

Thanks for all the help.

Those scuppers go thru a wood block between inner liner and hull; the flared part of the brass scupper tubes will eventually corrode and start to leak, which then rots the wood block. You can do a search for a post I did several years ago on how to replace the rotted wood with thickened epoxy. Now would be a good time to either replace the scupper tubes or reroute them to run out the transom, where you can install the Raybud ping pong ball check valves. (Those check valves MUST be above the waterline or the scuppers won't drain!)

The original boat was polyester. It doesn't bond as well as epoxy to wood, but it did hold up for quite a while.

There are two schools of though on the layering of tabbing- the way I mention and the reverse. ( I was taught that way to better avoid peel failure). We aren't building airplanes, here, we are fixing recreational boats, so it isn't as critical. But in either case the joints use fabrics/tapes of different widths to taper the joint and spread it over an area.

If you mimicked the thickness of the original transom, you are probably fine there. If the tabbing looks similar, you might be fine. My gut feel is that you only get this opportunity once, so I think if it were my boat, I would use more tabbing, and use different cloth widths to taper the thickness and stiffness.

They get into this stuff at boatdesign.net and there are crusty naval architect types there- and I am not one.

This thread there is good: (is a link to another forum ok?) http://www.boatdesign.net/forums/fib...ion-45735.html


The attached PDF (first image for a non cored hull) and images in that thread are interesting. There they discuss bulkheads, but a transom is sort of a bulkhead, just one sided. It at least talks about tapering cloths and some of the concepts.

On mine the brass tubes are corroded on the top where the flanges roll back. Instead of replacing them I will be running them out the back of the transom. With the 465lb motor I am using I think the original ones will be too low. The way most people repair them or beef them up that I have seen on this site is with thickened resin. They apply it around the blocks thick and use strips of 1708 wrapped around it to keep the resin in place till it hardens. I am filling mine in with scrap cloth cut to fit in the tube holes and filling with resin. I will use tape to close off the hole under the bottom of the boat and then added the cut up cloth and resin while packing it in and getting all the air out so it fills the tunnels left from the removed tubes full solid. Once that is done, I will add the thickend resin and wrap around the blocks between the hull and deck with the strips of 1708.

Been out of commission for a few weeks, and I'm getting back around to finishing this repair. I added more tabbing to the stringers, and laid a final full sheet of 1708 to finish off the inner laminate. Now I've ground back the butt joints about 3" on each side of the joint, preparing to butt join the cap back on. The picture shows where I plan to place butt blocks. After taking the picture I decided I would use a long 68" x 6" wide block along the bottom, 21"x6" along each side, and the two a block under each rail at the top. I plan to resin coat the wood, and add a layer of matt to seal it in the bilge area. Anyone see flaws in this plan, or got advice on the best way to get the cap back on?

Looking good. I didn't grind my edges back far enough the first time around. Members up here corrected me on that. 3 inches both side is what I was told. That would be enough but nothing less. I clamped mine in place with wood blocks then glassed what I could then moved the blocks then did the rest under it. I would think the blocks of wood would work for lining it up but once I got the front glassed I would remove them then glass the back side. I defiantly would not leave the wood blocks in the boat. It will be hard and messy to do the back side but that is where I built up most of my thickness. I got the liner twice as thick on the back side. I will try to post some up dates on my sceptre rebuild thread.

FF- Thanks for the quick reply. Great idea to build up on the back side. It'll be a pain initially, but it will be strong, and no fairing!

Some progress pictures:

- Fixed some corner cracks on rear hatches
- Glued the vent boxes in with cabosil thickened resin
- Primed with Interlux InterProtect 2000e and topped with Bilgekote
- Glued on cap back sheets to transom with thickened resin
- Added tabbing

Looking ahead at the fairing and sanding job, anyone have any tips for how to best sand the fillets, especially where three corners come together? Is there a sanding tool with a ball tip?

For rough sanding, a set of cartridge rolls in a die grinder might work. (try grainger) Either an air or electric powered die grinder.

http://www.3m.com/product/informatio...dge-Rolls.html

I used to port cylinder heads with one. Once a finer grit roll breaks in and softens up, I bet it would do a rolling ball fillet in a corner pretty well.

Sheet sandpaper (or the sticky backed discs, which I like) and tough fingers.
If they're not tough when you start, they will be when you're done.
:D

You'll need to stay away from the ladies stockings/pantyhose though.
Lest you get scolded for ruining them.
:rolleyes:

Cap is glassed in, with two layers of 1708 on the backside, and one layer on the exposed side. Started to putty fairing work, and took some time off for Christmas. Getting close.

It may be too late now, but does anyone suggest doing anything to stiffen underneath the motor fasteners? I recently read how some repairs drill large holes in the transom wood prior to laying the fiberglass, fill with thickened resin, then glass over the top to create a stiff cylinder for the bolts to squeeze. I could still do something like this from the outside...

I spread the load on the motor fasteners with aluminum C channel. You could at least make 6" square washers out of aluminum. You can have a sawdust transom, and this will work.

http://www.classicseacraft.com/commu...ad.php?t=24398
http://www.classicseacraft.com/commu...5&postcount=11

That is a good idea. It helps beef up the bolt holes and keeps the wood from crushing down. It also gives the wood a thicker barrier to help keep water out of the wood. I was going to drill my 1/2" holes to 7/8 then refill with thickens epoxy so they could be re drilled to 1/2". That would stiffen the holes up and seal them well. I saw a post here showing some one doing this but can't find it now. I didn't do this but probably should have. I just coated the slightly larger holes with epoxy and redrilled. I did add a piece of 3/8" thick by 4" wide aluminum flat bar down the entire length of the bracket mounting lip on the inside of the tramsom. That helps a ton. I had a 17' skiff with a rotten transom that ran a year with a piece of 4" channel across the back threw bolting the motor. It was the only thing holding the motor on. Once I pulled it to replace the transom you could grab the motor and move it 4-6" in and out flexing the rotten transom. With the channel it was much stiffer. The things I Don as a kid to be able to fish.....The outside skin had two cracks a foot long either side of the 1980 70 hp from the flexing. It's amazing that motor didn't end up on the bottom of the sound.

Finally finished the putty /sanding. Day job has been getting in the way.

I've bought Interlux epoxy primer and perfection topside paint. Anyone have an opinion on whether to drill motor mount holes and thru hull drain holes prior to painting? I was thinking I'd prime and paint inside the holes for a little extra protection against water intrusion. If the edges are rounded, I figure the paint will hold.

I would drill them now. Most people will take resin or better yet thinned resin and apply it in the holes and let it soak into the wood grain. Paint won't protect nearly as well as the resin will. Some will even over drill holes to 3/4" or 7/8" then back fill them with thickens resin then re drill the mount holes. This gives you a 1/8" or more of barrier to protect the wood. It also beefs up the holes where the bolts will not crush the wood in if over tightened.

This is may be too late and I'm not sure if it would work for you but here is my plan - I am getting some 1" diameter fiberglass rod from McMaster-Carr and am cutting it to match the thickness of my transom core (I'm using 1.5" Coosa). I am putting those short pieces of rod everywhere in the core where a bolt goes through (tab attachments, platform bolts, etc.) before I glass it in and redrilling afterwards - these make compression columns so that the core does not get crushed and they seal the core off from water. Where my sterndrive goes through there will be a 12"x24" solid fiberglass plate in the core before it gets glassed in - for the same reasons. At first I was only going to use the rod on the bolts there too but I want the extra stiffness around the drive hole.

The compression columns need to be much smaller than the washer inside the hull. Otherwise the outboard is only held in by the shear strength of the secondary bond from the column to core. I would suggest having fibers run transverse to the bolt axis. Or put in a load spreader like c channel. At which point, the pressure drops to the point of not needing compression columns. I think?

Absolutely right if the columns get put in after the core is laid up - if you put columns in after the core gets laid up then you need to make sure not to drill through the exterior skin and also make them smaller in OD than your washers on the inside. If you are going down that route you can also use fiberglass washers or plate glassed in on the inside (if there is enough room) and still keep larger diameter columns. You would still need the metal washers though.

I think you are right about embedded columns of fiberglas/garolite, although the transition from column oriented fibers to in plane might be interesting to think about. I am a fan of a channel as a washer to spread the load under the less stiff glass and core.

I'm a big fan of using aluminum channel or flat bar to spread load too. I usually use 2 pieces of 4"×3/8" anodised flat bar between 12-20" long across top 2 and bottom 2 bolts.

All good ideas. Thanks

Drilled motor mount holes and drain holes in the transom, and treated the holes with thinned resin. Rolled on some Interlux Interprotect primer, sanded down, applied some more on the remainder. This stuff works pretty well at filling in some of the smaller pits that remained in the fairing.

Just tried to roll and tip first coat of Interlux epoxy primer, and made a cat's ass out of it. It seems like the paint did not flow at all, and dried way too quickly. I thinned it about 25%, which is what data sheets recommended as a minimum thinning.

Anyone familiar with this paint application method, and got any tips? Does it sound like the paint was not thinned enough?

Primers usually have a fast drying time and are very thick . Better off spraying primer.

Did you use epoxy resin or polyester resin? if you used regular polyester I would put a coat of epoxy over that as it seals the wood better then the former....

Love my little sceptre and yours is coming along nicely!

strick

I use a lot of interlux products, It is what my local marine supplier stocks plus I really like their products. I know I usually spray my primer as well but you could roll and tip it. You need to make sure you use the right reducer. If using interlux reducers with their products they have fast drying for spraying and slow for rolling and then they have a type for roll and tip applications.

I would try the the 333 or 433 if compatable for one part paints. If you are using a two part paint you need the 2333n or 2316n reducers. It says on can what type to use.

From their site:

216 Special Thinner is a fast evaporating solvent which, when added to specified paint coatings, improves drying in cold climates and facilitates spray application. Also recommended for removing sanding residue from hull bottoms, wiping down bare aluminum clean and for the general clean-up of paint equipment.



333 Brushing Liquid is a slow drying solvent to ease brushing and facilitate the flow of specified paint coatings. Extends drying in hot weather.
Also recommended in various topside systems for removing sanding residue from fiberglass and wood surfaces.



Brush-Ease 433 is a slow drying solvent to ease brushing and rolling and to improve flow.
Interlux Brush-Ease 433 should only be used in products where it is specified in the directions, mostly antifouling paints, it is not an all purpose solvent.



Reducing Solvent 2316N is a fast evaporating solvent to be used in specific two-part polyurethane and epoxy products when spraying and is a fast drying reducer. Refer to the specific product directions for the amount of Interlux Reducing Solvent 2316N to be used.

Reducing Solvent 2333N is a slow evaporating solvent to be sued in specific two-part polyurethane and epoxy products when brushing and slow drying reducer. Refer to the specific product directions for the amount of Special Solvent Reducer to add.

Strick, FF- Thanks for the tips. I did not have epoxy resin on hand so I used the polyester to coat the wood in the drilled holes. I painted some Interprotect in them also, so hopefully that'll help. I know, not optimal, but it's done. I sprayed the last time I worked on this boat, and thought I'd try the brush method for kicks.

FF- I used the 2333N reducer that the data sheet specs out for brushing. Lots of contradicting advice out there. The data sheet says to thin 25% minimum. Yachtpaint videos on youtube say to thin no more than 10%. Anyway, I think I thinned the first coat too much.

I sanded most of the brush strokes out with 120 grit. Thinned the second coat to ~10% and rolled on second coat with a glasscoater roller. Tried to tip again, but was having similar results, so I just rolled it. I cut in the fillets with a brush this time (last time I rolled in the fillets using a small foam roller). I thought brushing in the hatch channels and fillets would be a pain, but that worked really well! The roller left some stipple, and the brushed areas smoothed out well and needed very little sanding. I sanded most of it down today with 220 grit. Plan is to finish sanding and roll/tip the topcoat tomorrow. I hope the top coat paint is more self-leveling. I will be using Perfection two-part urethane.