S-11N 973

[goyousalukis]

Hello Everyone,

So I just got my plans for Spindrift hull 973 it is an 11N. I was hoping for the magic number 1000, but that's ok. I've been combing through the archives reading all of your great posts. I am a fairly accomplished woodworker, but this will be my first boat. I helped my uncle build some boats back in high school, but that was 20 years ago.

I have a question: I've decided to use Raka for the epoxy. I believe at least one poster said that the odor was not too bad for this brand, and it is on the recommended list of products.

On their website you have a coice of three viscosities: Thin, Medium and Thick. Which would you recommend? They also have slow, medium and fast for the hardener. I live in El Paso, TX, so it is pretty hot, but I will be mostly be working outside in the evenings and we are approaching fall. I was thinking medium would be best. Any opinions?

Lastly, does anyone have any specific recommendations for sources of plywood that ship to Texas relatively cheaply?

I'm sure I'll have more questions as I go.

Thanks for your help,

Justin

[Howard]

I'd stick with their basic 127 marine epoxy and a mix of fast (610) and slow (606) hardeners. The fast and slow rates are the extremes, but you can mix them as needed (still in the proper 2:1 ratio) to get the speed you want. If I bought 3 gallons of hardener, at least 2 of them would be the slow.

The other epoxies you found are more for specialty uses and you won't want them.

You can also get your glass, glass tape and any additives, such as Cabosil, sawdust or microballons from them. When I have ordered from them, it usually shipped the same day.

Can't help you with a local supply for the plywood, except to suggest it is probably available near the gulf coast if you want to drive some. If not, there are a number of online shippers..........some more reputable than others.

[brerrabbit]

Hi

I am a bit concerned with your plan to work outside. That makes things tougher on many fronts

1. Temperature issues with epoxy
   
2. Security
   
3. Tools getting rusty
   
4. Cleanliness of the work
   

it is do-able but, having been there, I have a boat shop for my Lapwing #15. I live in Miami where it rains every afternoon during summer

Good luck

[goyousalukis]

Howard,

Thanks for the info. I'll check those specific products out.

Donald,

The situation dictates an outdoor build, but at least I have a nice covered patio. I had to downsize my shop to a one car garage. I have a tablesaw, jointer, planer, cnc machine, large workbench, drill press and various other tools, so the garage is packed.

Thanks guys,

Justin

[makenmend]

To the bast of my knowledge the nearest supplier of marine ply to you would be,

Austin fine Lumber and plywood

9407 brown lane,

Austin, Tx 78754

512 836 8990

As far as epoxy I always use US Composites and primarily use the slow harder, but do have a bottle of the fast for the few days its cool enough to use, very rare this year.

I should have prefaced this by saying I'm In the Tx hill country, so similar conditions.

MM

[ilnadi]

You can try http://www.woodfinder.com/

I've had very good luck searching for "marine plywood" around my zip code

[hokeyhydro]

You can try http://www.woodfinder.com/

I've had very good luck searching for "marine plywood" around my zip code

You must be search lucky. I did "marine plywood" and my zip and closest hit was 150+ miles. The woodfinder site totally missed World Panel in Windsor, NC (80 mi) and AV Mill Outlet in Beaufort, NC. (40 mi)

[goyousalukis]

Thanks MM,

I'll give them a call and see how much shipping would be. I did try the woodfinder site, but there is nothing even relatively nearby. I'll follow yours and Howard's advice and get mostly slow hardener with a smaller amount of fast. Here's a dumb question: Raka sells a mixture of hardener that is 50% fast and 50% slow mixed together. Wouldn't that be the same(approximatley) as a medium speed mixture? What's the advantage of slow and hard mixed together?

Justin

[John Burritt]

Mixing the slow & fast hardeners lets you mix different amounts of each to adjust the reaction speed to more closely meet your needs & the temp.

[Howard]

The rate or speed that epoxy sets up and cures is directly related to ambient temperature you are working in and the hardener used. If you have a small part that you want to setup quick, use a fast hardener, even at higher temps. If you are making a mix for fillets, and want to extend your working time, you need to slow it down so you might want a slow hardener. Since both Raka hardeners....fast and slow.... can be mixed together (still maintaining the 2:1 ratio), you can get various rates of cure from slow to fast, and keep in mind, this always varies directly with ambient temps. Even the slow stuff might kick pretty fast at temps in excess of 90 degrees, but could take days, if at all, at temps as low as 50. So mixing your hardeners to get the rate of cure you want for the job at hand becomes an intuitive thing after a while. The cure process itself also gives off heat (exothermic) so if you leave it in a mixing pot too long, heat from the chemical reaction is trapped and that batch may go into runaway mode, kicking in front of your eyes and getting hot enough to melt the mixing pot in the process. So the same mix, if left in a pot, might go off in a matter of minutes vs. several hours if you poured it onto a large panel and spread it out. Again, all part of the learning curve of working with the stuff.

There are two methods used to measure your epoxy mixes. One way is to use calibrated pumps, so it's always one pump of epoxy and one pump of hardener. The epoxy pump delivers twice as much as the hardener pump does, so it's exactly 2:1. If you are only mixing one pump (about 30 ml), you pick hard or slow.....two speeds. With a batch size of two pumps, you can do one or both of the same hardener, or mix them.......fast, slow or medium.......three speeds. With three pumps, you move up to five speeds, but by then are also mixing 135 ml of epoxy (90 plus 45).

So the second way is to use graduated mixing cups that you pour your epoxy resin and hardener in. This way you can mix small batches, which also allows you a variable speed mix. You have to carefully measure them and keep track of what you are doing, but if you do it right, it works the same way. So there is really no need to have a separate jug of medium hardener, unless you find that is what you are constantly using and would like to have it around for convenience.

As for your marine plywood (again, assuming you don't want to drive to the gulf coast or Houston), here are some online sources that will ship directly to you:

http://marine-plywood.us/

http://www.noahsmarine.com/items.asp?Cc=33

http://www.edensaw.com/application/MainSite/Store1/Store/CategoryHome/373

Others may have additional recommended sources.

Whatever the source, if this is to be anything but a disposable boat, it is suggested to go with the BS1088 Okoume, and a reliable brand to look for is Joubert. Okoume is about the only plywood that will take the tortured bends the build requires and once you coat it with epoxy, the "durability" issue most sources of Okoume plywood talk about goes away. Okoume is strong enough and is lighter than all the rest. There are places for Meranti (hydrotek or aquatek) and marine fir, but this isn't it.

[Steve W]

After spending all the time building my 11N, the decision to buy good plywood seams like a no brainer. As for the epoxy, I bought mine from B & B and other than the fact it chrystaled on me it was very good, and the price was right. If it gets lumpy, just put the whole jug in a pot of boiling water and heat it slowly to make it like new again.

One thing was that I bought slow and fast hardener. The fast was slow, and the slow was slower. I think since I made my boat in my basement, where the temp was about 62 degrees, was the factor in the slow cure. Once you get past the first few steps, there seems to be rarely a time where you can't glue and then move on to some other activity, so the cure speed just didn't matter as much as I thought it would. As a newbe to eboxy/taped seems, I was happy it stayed fluid longer.

On the advice of B & B, I used silica/epoxy for the jonts were stregth was an issue, but for anything else I used west system 407. the boat came out pretty light.

Take Care

Steve

[goyousalukis]

Thanks for all the advice guys. I bit the bullet and just ordered the Okume plywood. The cheapest I could find was around $525 shipped for 5 sheets, so around $105 apiece. I used epoxy quite a bit, but always in small batches, so I appreciate all the expertise you have shared on the forum...

[cprinos]

For the time and effort put into the boat, I don't think you will regret spending a bit extra for good ply when she is ready to launch. Keep us posted on how your build goes!

[goyousalukis]

My epoxy arrived yesterday, and the plywood comes tomorrow so I'm almost ready to begin(if I can find some time!). A couple of quick questions if you don't mind:

Is redwood acceptable for the solid wood parts? They have it here at the local bolx stores. I built an outdoor table covered in spar urethane, and it is doing good over a year later.

I think the part I am most worried about are the gunwales. I understand they need to be clamped to the boat at the same time to avoid distorting the shape. Once I have them dry fit with the forward part mitered properly, how do I glue them up? Do I unclamp the forward part(both sides), glue the laminations, then reclamp that section and move down the boat to the rear? It doesn't seem possible to wet the laminations on both sides, and get the whole thing clamped up before the epoxy sets. Thanks for your help?

Justin

[Hirilonde]

Redwood is very soft, I can't think of any particularly good applications for a Spindrift. You could make the removable seat sections and maybe the boom, it would certainly keep the weight down. But it would not be my first choice for either.

Actually, you do wet out all the layers for both gunwales and clamp them up in one shot. If you use slow catalyst and spread the epoxy quickly so as to not let is start to kick in the pot it really isn't that hard. It is a bit tedious and I recommend a few practice runs clamping dry (no epoxy). It is also messy, you will likely end up wearing some epoxy, so plan accordingly. I glued mine on long at the bow and stern, later butted the bow and stern trim to fit and trimmed them flush with a hand saw. I hate miters. I never use them except for mouldings that need that joint to carry the detail. You could also trim the gunwales a little long and fit a half lap to them if you feel the need for a fancier joint.

The building can be as enjoyable as the sailing, have fun.

[goyousalukis]

Thanks for the reply,

Ok, redwood is out. I will go to the local hardwood store and see if they have spruce or fir, but I doubt it. I have a nice stock of hard maple, but don't look forward to trying to bend it. It is also quite heavy. Would walnut be ok? I have a nice 8/4 12' piece.

Looking back at the plans, I see now that the gunwales do not form a sharp point at the bow as I had envisioned, but instead are trimed perpendicular to the boat's centerline. I've done a complicated glue up on the carcass of a philidelphia lowboy, so I know what its like to have to work fast. Ill just do a few dry runs first.

I know what you mean about the building being as enjoyable as sailing. My wife thinks I'm nuts for building a boat in El Paso, but the building process is what I look forward to the most. Hopefully I'll get to take the kids out a couple of times a year at least.

Regards,

Justin

[Howard]

On the gunwale laminations, the issue with them is once they are buttered up and ready to install, they are like wrestling a sack of eels. They are slippery and like to crawl all over the place. The best way to tame them, if working alone, is use a series of clamping aides. The 4 inch PVC clamps work well for this. Aside from providing the right amount of clamping pressure, the "ring" shape of the clamp will corral the three lamination strips in close proximity to their final resting place. Thread the buttered up strips through a few of these rings clamped to the top of your sides and there they will stay until you get to them.

You start at the bow and when you get the bow ends where they need to be, you run a drywall screw through the laminations to lock the bow end in place. You then start aft, working side to side, keeping each side even working aft to the stern. You work side to side evenly. If you did one complete side first, there is enough spring tension in the lamination to rack the boat out of it's fair alignment.

There is some serious twist in the bow sections near the forward bulkhead. Enough clamping pressure to pull them together caused mine to slid apart rather than more together. I found it helpful to clamp a series of small blocks under where I wanted the laminations. When the clamping pressure goes up, the laminations slide down to the block and then rest evenly upon it. Once you get past the halfway point and out of the bow section, most of that problem goes away. Make sure the epoxy for the laminations is fully cured and setup before you take the clamps off. If still on the green side, there is enough spring tension in the laminations to pull them apart. Again, since you will likely be using a slow hardener to buy working time, this is going to be temperature sensitive. If you did this below 60 degree temps with slow hardener, it might not be cured enough to hold together after several days.

For this type of lamination work, I have found it helpful to put some type of "grit" in my epoxy. The grit I use is either 30:100 sieve walnut shells or a the plastic granules System 3 used to sell as a non-skid for their paint. This acts as both a spacer, to keep you from squeezing all the epoxy out of your lamination......with epoxy, a dry, epoxy starved bond is a weak bond............and it also helps lock the lamination in place, preventing the pieces from sliding around while clamping. Both the walnut shell and plastic granules can be machined and worked with wood tools, vs. something like silica sand, which would damage wood tools on contact.

The main concern with the wood choice for laminations is rot prevention, and that mainly comes from if you are intending to nail or screw a protective bumper of some type to it. The rot starts at the nail holes. So woods like ash and oak are out. The material list from a few years back suggested CCA treated yellow pine for laminations, but that is no longer available unless you can find a stash of the older stuff somewhere. Rip them from flat sawn stock so that your lamination pieces come out as if quarter sawn. I used southern cypress and have had no problems, but I epoxy coated and varnished mine and have not nailed anything into them. I used 5/4's black locust for the breast hook and knees and that is bomb proof. I used western red cedar for all my cleat stock. Light, rot resistent and glues up well, and strong enough for cleats.

I've never thought of walnut as being good for this type of use, but I've heard from two independent sources that it is one of the more rot resistent woods out there. And I think it glues well. A lamination of walnut, ash and walnut might look nice if you are going to leave it bright and not nail into it.

[Steve W]

I made my gunneles out of white oak and spanish cedar. I wanted both impact resistance and light weight. there is an old tale about white oak being closed cell and not real good for gluing, but I think its a bunch of nonsense and used it after testing its joint strength. I did leave the glue surfaces rough. Being closed cell, if you gash through the epoxy barrier, it will still be somewhat weather resistant. I also used it for the keel, so if you find one nice piece long enough for the gunnels and keel, it's not that expensive. The spanish cedar was used because its a good choice for the breasthooks, and so I bought a nice piece. I did have a butt joint in the center cedar section, but its hard to see. I could have scarfed it, but one thing you'll find out after building is that every little belmish you see building goes away in the completed project.

I did a three part lamination, but if I had to do it again I'd make it two parts, because it would be easier. Carefully cutting that nice trapezoid shape from three pieces was interesting. It probably could have been shaped with a rabbit plane, but my confidence wasn't that high, so I presahped them on my tablesaw. I also presahped radiouses with my router on the outer piece of oak before I glued everything, but I wouldn't have doe that either. It's so easy to sand a fair radius that it was just extra work.

I was working alone, so I did clamp it all up and then I drilled and countersunk a brass screw at the bow. After removing the gunnels, coating with glue and putting the screw at the bow back in, I carefully picked them all up and wrapped them around the stern and set them on a block of wood I'd clamped to temporarily support them. I had coated all my pieces on the glue sides with silica thickened epoxy so it didn't run. Working from the bow I clamped all the way back, being carefull to get everytihng lined up. It was a bit messy, but the thickened epoxy helped a lot.

I worried that gluing one side at a time would make the boat unfair, so as a precaution I temporarily clamped the cedar piece to the other gunnel, but as far as I can tell it made no difference. I'd do it again, because I would still worry, but doing the two gunnels seperately was less stressful, and I would have had to get more clamps! when I was done clamping everything, I put another brass screw in through the stern to the breasthooks, although it was probably not neccesary.

Upon further review, this picture is just a dry run with the strips. I believe the bow piece and breasthooks were glued in first.

Take Care,

Steve

[goyousalukis]

Thanks guys,

Steve, I've gone through your photos several times. Very helpful, thanks.

Unfortunately, I'll have some more time to stew on the wood choice. My plywood arrived today. It was damaged in shipment. All five sheets were broken in a corner. I could see the problem through a rip in the carton. The only option they gave me was to accept or refuse the shipment, so I refused it. I called the supplier, and they said I should have accepted it and marked it as damaged. I am pretty sure I could have worked around the damaged spots, but without taking the carton apart, I don't know for sure. The supplier said they would call me Monday, so I guess I'll find out what's next then. Bummer.