Mold Fair? & Upper/Lower Center Line - Bob’s Special

[EvanstonBay]

Good morning,

I am a first time builder and I’ve come across two points I cannot seem to address on my own after reading/watching videos. The first question is coming to test whether the molds are fair after setting up all the stations and batten down the keel. Each resource says that the batten “should touch the edge of each mold.” Is simply touching the edge of the mold enough? I’m just worried that there is not enough mold hitting the plank so as a staple will not nicely attach when needed.

Second, I’ve hit a point where when I get all the molds nicely set up under the top center line, they are not nicely set up on the lower center line (some are on, some are maybe 1/8” or 1/16” off). If I align them on the lower center line, same thing with the top line. I am not sure why this has happened. Some center lines on the molds where done with a fine point pen while others with a dull pencil so the cut at the tops could be off for that reason (by just a smudge) and my stern also was bowed so getting the lower center line was difficult. That said, Mold Station 0 and Mold Stations 6 are all center on upper and lower center line. I suppose the question is which is more key, having them aligned on the upper line or lower line?

Thank you in advance,
Ryan

[Cruiser]

Hi Ryan,

When checking for fair, the batten will likely only ever hit flat on the middle mold, on all the rest the batten is going to be curving to the bow/stern, so it should only hit the corner of each mold, nearest the end it is going to. Those mold edges run parallel with the the strongback, while the batten is curving to the last mold.

Mold alignment is crucial and they all need to be reasonably aligned. If I understand your question, it sounds a lot like you are saying that the mold center line is not vertical, so when aligned to the bottom strongback centerline, the top centerline is not aligned along the bow/stern top centerline. When I place my mold, I first lightly clamp it it in place aligning the lower center lines, then I check the upper, if they are off, I loosen a clamp and add a small shim to rock the top alignment while holding the bottom aligned (for shims I find thin cardboard works well). Recheck and repeat till the alignment is good.

You can take a look at that portion of my last my last build and maybe get a few ideas, it's posted here https://www.canoetripping.net/threads/l ... ost-105619

All of the molds need to be well aligned, don't get in a hurry and just ignore this, the entire shape of the build is being aligned in this step. If you have a "bowed" bow/stern mold, straighten and if you can't redo it. Without any pics or mention of materials used, you limit the advice that can be offered.

Keep posting and asking as you move forward.

Brian

[EvanstonBay]

Thank you Brian. Really appreciate your advice. I feel good about the molds being fair but adding as photo for one where I was concerned.

I'm trying to figure out how to add photos. I've read the FAQ and it appears I should use Photobucket so trying that but if it does not work, let me know.

Fair Mold

https://hosting.photobucket.com/images/ ... fit=bounds

Center- Lower & Upper Lines

Center Line

https://hosting.photobucket.com/images/ ... fit=bounds

Off Lower Line

https://hosting.photobucket.com/images/ ... fit=bounds

At first, I did clamp the molds to place when I had the lower center aligned to the mold and then, the center line was not aligned with the string. My question is how would I use shims to fix that? It seems like moving them left or right would then move it under the string but then of course, the mold center line is not aligned to the strongback line. I took the approach that I wanted my mold center lines to be aligned with the string and to make the strongback center line aligned the best I can.

[Cruiser]

I can get at the Photos, but I would recommend you avoid PB at all costs

Suggestions
1) if you don't have a copy of CanoeCraft, think about getting one, there is a whole step by step section on setting up the molds
2) the Strongback has to be marked with a center line and the station line locations
3) the stations molds go on specific sides of the station lines (not all on same side)

I can't see any station cleats in your photos, but you place cleats (i.e. 2 x 2 pieces) at each station location and the stations are attached to those (look at the pics in the link I gave you).
To place a station,
- align the center line of the station bottom to the strongback centerline and clamp lightly
- check the alignment at the top, if it is out, shim one side of the station bottom, while keeping the bottom marks aligned, this tilts the top a bit, you won't need much
- once align, clamp firmly and drive in screws to hold it (you could leave the clamps, but they get in the way later)

There is a whole process to square and level the strongback, which I hope you have also done, if not get the book and read that section. Even though the strongback is mostly stiff, it can still twist if it isn't sitting square.

The basic steps to setting up the strongback are:
- mark in SB centerline
- mark in all station locations with side to side line. Allow for station material thickness, you want the station line to pass through the middle of the station.
- move the SB to a location where you have good access to all sides
- check and level the SB end to end with shims as required
- check side to side at bow, middle and stern to make sure it is level side to side
- now that it is straight and level, do not move it until after you finish to the external glassing step
- attach the station cleats

At this point you are ready to attach the station molds

Hopefully this helps some ... keep asking if it's not clear


Brian

[EvanstonBay]

Thank you. I have read CanoeCraft once through and watched the Nick Offerman videos. I'm going back through CanoeCraft as I work on each section. I do have cleats and thanks for the head's up on PB.

I'm going to back and try this again. My SB is level, I spent a long time doing, and redoing, that part to ensure. Cleats are affixed to the garage floor with epoxy as well. Overall, I feel confident on my SB center line, I spent a long time on that as well doing and redoing it, so I'll give this a third try and keep going at it until all lines are properly aligned.

[Cruiser]

Please ask as required, we can keep thrashing this about till it gets where it needs to be. I just hope the idea that you can basically lift that form a bit in the corner to adjust the top alignment without losing the bottom alignment, is clear. Even on the most carefully aligned SBs, this can be required.

Also, when you get it all setup, attach a batten and look down that, as a final check. Making sure everything flows nicely, after all the mechanical adjusting, the eye is still better as the final check that everything flows nicely.

Good luck, keep us posted, we love seeing builds progress.


Brian

[EvanstonBay]

I will and thank you, it's hard to get through this as a first-timer without a little bit of guidance. I took most of my week off of work to get a jump start and get ready for the planks. I just milled and bent the wood for the sterns today.

https://hosting.photobucket.com/images/ ... fit=bounds

I think where I got caught up on center/upper/lower line deal was my false impression that the bottom of the mold had to be flat against the SB which is why I was having a hard time conceiving the idea of shims but now I got it. Going to try to correct it all tomorrow. If you do recommend a different site to upload photos to for the purposes of posting them here, please let me know. Thanks again

[Cruiser]

I use Google Photos, free and works fine and it doesn't have the bad history that PB does.

If you go to the beginning of that thread I linked you, it is a detailed build, start to finish, posted specifically for newer builders, showing build techniques. Other experienced builders also chime in with thoughts and ideas ... may be a worthwhile read for you, although there is a section in there about lofting a boat shape which you should likely just scroll through.


Brian