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Todd McAllister Temptress Build
Inspired by Bob’s amazing (and entertaining) video series, I started my own Temptress build a few months ago on Lake Norman in Mooresville NC. I had a CNC shop cut all of the MDF jigs and the plywood pieces, and I cut the solid sapele pieces by hand (jig saw, not Shaper Origin as Bob did.). I am not the YouTube superstar that Bob is, but will make a couple of videos showing the major areas of departure from what Bob shows. I am almost exactly 1 year behind Bob in the build process. I have cut all of the pieces and have assembled frames 7,8, and 1. Shown here are Frames 1 and 8 which I built simultaneously on the construction board.
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One more background post… like Bob, I have little experience to suggest that I can do this project! The extent of my prior woodworking experience is a wooden trophy case built with two embedded fish tanks and a 300 gallon fish tank desk. Neither have flooded my study yet, so figured I was ready for something slightly more ambitious!
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Todd:
Good morning and welcome to the club. I recently began my adventure in boat building. It has been a 30-year dream of mine to build a Mahagony boat being from Michigan the home of many a boat builder. Yes, Bob has been a great inspiration. I fortunately have a large CNC Router and a full wood shop. Currently we finished our fixture table and were working on the strongback. Also building a 28-foot work bench as my knees are not what they use to be. (For building the Stringers, Keel and chines). Don't know how Bob does all his work on the floor god bless him. Please feel free to contact me we can compare notes and sources of supply. My number is 248-410-9684 I don't sleep much so I'm awake till all hours.
Best of luck and
Be weel
Greg Koukoudian
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It's soo cool to see these boats getting built all over the world! Keep the pictures coming guys!
I like the hexagon shelves Todd... before I migrated into boat building we used to make those 🙂
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Dan- I am about halfway through my frames, so starting to think about my strongback build. The MDF fiberboard that I originally started using looks pretty feeble. Saw that Bob substantially reinforced his and saw Greg built his out of 2x12 lumber. Any reason for me not to build with 2x4 legs on the frames and a 2x12 strongback on the floor? Don’t need my +/- 3mm carpentry to get any worse with a twisty strongback. On the other hand, maybe that flex will magically put everything back into alignment!
The legs could potentially be increased or reinforced as needed, I would personally form L shaped legs by fixing particle board at right angles to the original legs if more rigidity is needed.
2x4 lumber is not going to be very dimensionally stable, when juggling this whole arrangement there are a lot of things that can start moving and losing tolerance throughout the build and it can become very difficult to tie down where a dimensional error has arisen from. This is why we recommend building the strongback from particle board that will hold a very tight tolerance overall.
Bear in mind that we also recommend gluing the strongback down to the floor with large epoxy fillets. Although 18mm mdf/particle board seems feeble, once that ladder assembly is glued to your shop floor with large size fillets you've got an arrangement that is incredibly strong and dimensionally stable over it's full length.
When your setting in longitudinals and something isn't working out fair, working out where the error has arisen from can be a difficult and time consuming task. Get that strongback bang on and stable from the start and the rest will follow suit.
If you do decide to alter the material used for legs or the strongback, note what it says in the plans about this and account for the difference in material thickness in the positioning of your rungs. There are some cases where changing this dimension will alter the position of frames within the boat.
Todd:
Just to let you know that for the strongback outer frame I use LVL Beams they are laminated beams that are very stable for the uprights and dividers we are using MDF as per the plans we may right angle them as Dan recommended where needed. We are also anchoring the LVL to the floor after we laser leveled them and squared everything up. Part of the reason we used the LVL Beam was in the event that we need to move the Stoneback it would give us more stability.
Greg
All- I am nearly done with my frames and therefore about done with the setup table. A few more months before I finish with all the MDF templates. Happy to give this stuff away if there is a new builder in or around North Carolina.
So I am roughly 1 year into the build and have completed all of the frames, transome, stringers and stem. I thought I would recap a couple of lessons/differences from what Bob has done.
1. I got all of my plywood/MDF cut on the CNC. Only a few hundred dollars and done in a few days.
2. I cut my solid mahogany using a saber saw… not as accurate as the origin, but a lot faster… and accurate to within a few millimeters over the 8 foot span of the frames. That’s close enough for me!
3. This one is important! The spring back is caused almost entirely by flex in the jigs, not spring back in the wood! Once I clamped down the jigs to the table I was within roughly a quarter inch on stringers/stem. That essentially eliminated spring back.
4. I am electing to encapsulate everything before assembling on the strong back. Note also that I epoxy encapsulated the full stringer before putting on the side boards on the back of the stringer. Seems a lot easier to do all of that encapsulation when you can access freely.
I’ll post some additional photos soon, but will move to a new shop in a few months once I have encapsulated all of the frames.
Sounds like you are getting on well Todd. Good to know that this can be done a more manual way and not all CNC. How have you found the construction board for sawn frames, does everything still assemble nicely?
I too clamped down the stem lamination jig and spring back seemed minimal. I think I'll do the same when I get to the stringers.
Looking forward to seeing some progress pics.
Great update Todd. I would love to see some pictures.
I 100% agree with you that the flex of the jigs is the primary cause of stem spring back.
I also agree that the Shaper Origin is too slow for building this large boat.
but all of this is behind me now…
Best of luck.
Epoxy Encapsulation Questions:
OK, so I am getting a little ahead of myself, but on a wide range of other projects, I have never managed to get the glass-like surface that the pros get in either urethane or epoxy. I thought I'd use my frames/stringers/stem as practice so that when i get to the planking I am getting the results that I want. Obersvations so far:
I have been using a foam roller to apply thin coats of epoxy to the frames and bulkheads. This has the advantage of going on quickly, but I am left with a heavy orange peel finish... especially for the coats i apply toward the end of the batch as the epoxy is starting to set up a bit... I've been mixing small quantities such that I roll it out within 15 minutes, but even in that short time I see differences in the viscosity/flow of the epoxy.
For the sides of the stringers I experimented with thick coats with a brush, and ultra thin coats with the scraper. Thick coats look amazing and glassy, but hard to keep level... plenty of sags and deep spots which doesn't look great. Also not feasible on the curving surfaces of the planking, so won't pursue that route anymore.
I have practiced sanding and polishing going from 220-400-600-800-1500 and then polishing compound. This works pretty well and goes surprisingly quickly, but two problems: (1) I am afraid i will burn through the epoxy as i sand through the orange peel, and (2) i end up with a nice, smooth finish, but not glassy. I'll post a few pictures, but hard to really appreciate the successes and failures in a picture.
So while I have some beautiful frames that will never be visible on the boat (will make me feel good to look at them while I am building in the shop!), I am definitely not up to the quality I will need for the visible surfaces and the planking. So Dan, some questions for you:
- Did you ever make the video you referenced a few months ago about epoxy finishing?
- What do you recommend for applying the epoxy... brush or roller? Thich coat or thin?
- Is the ultimate solution in elbow grease and sanding?
I'm not sure I have the attention span for a full course, but would sure love a 20 minute video to help jump start my efforts. I've finished Frames 1 and 2 and the transome, but going to pause until I get a smarter approach for the others... will leave the intermediate frames around the cockpit and the engine until last as I want those to look amazing. I plan to install glass in the engine access doors so that the engine will be visible... not quite sure how I will engineer that, but want to make sure my finish quality is decent. Appreciate any thoughts from the community.
Here are my completed stringers... will be a shame to start fairing them and ruin the nice finish. But they look great in the garage now!
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Here is what I mean by the orange peel finish… even after a decent amount of sanding and polishing, I still have some pitting… that might not be waterproof. Anyway, they look good from far, but… far from good.
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Hi – I took Dan’s online course on varnishing. It explains til he process for epoxy coating as well. You can just watch the sections most important to you.
I deleted/edited my response after reading Dan’s. I don’t want to cause confusion. I did get some white blush.
Epoxy is a difficult one to get a good finish with, however, a good finish is not usually the aim with that product. It should be seen as a base coat and protective layer, like a solid primer for varnish/clear coat work.
The finish you are getting is very common, I almost always get the same. It's a thick product (don't under any circumstances thin it) and so finishes will always be textured. Regarding application and everything that you should consider, it's not something I can explain thoroughly here which is one of the reasons I made a course on the subject. There are a lot of factors to consider and understand in knowing how to get the best results in your particular set of circumstances.
Understandable that not everyone want's to go to the extent of a full course though. As some basic pointers I would recommend the following:
Don't try and get the surface flat in the epoxy stages. You'll end up sanding too much of it away and you wont keep your vapour barrier there. Do this work in the varnish stages that follow.
I certainly wouldn't recommend polishing it, you still have a lot of bonding processes to follow on with those stringers and you don't want to risk introducing potential contamination issues at this stage that will bite you later on down the line in the build.
You will need to build varnish on top of these later. Preferably a two part clear system that will give additional UV protection which you will need some of even in areas of the boat that aren't directly on show.
I did make a video on the process that will give you a basic overview of the process: How To Varnish Wood Quickly | Fast Epoxy Clear Coating Method - YouTube
For a more in depth learning of the process this is of course covered in more detail in the varnishing course.
Hope that helps... Stringers are looking good by the way!
I wouldn’t bother with being too perfect on these parts, they’re buried in the hull and nobody but you will ever see them. Waterproof everything with epoxy and get it done while they’re still loose parts. Anything that sees sunlight will need a UV barrier over the epoxy, spend your efforts, money and time there.