Laminating an outer stem

[imported_maguro]

Hi All,
I am building a 15' v- hull skiff.
I was wondering what the best way is to laminate an outer keel around the bow with 1/4" mahogany laminations. I am just not sure of the proper way to hold the first piece flush around the bow while the second piece is glued up flush and parallel o the first piece and so on. I'd really rather not put a million holes in the boat and the keel to do this. I have to build it up to 1 1/2" thickness so that is 6 separate laminations. Is it commonly done all at once?
Thanks for any advice. smile.gif
Chris

[Mad McGee]

Is the inner stem already made and attached to the boat?

I have made my inner and outer stems together on the same mold before the backbone is made up.

ARM

[Mad McGee]

Thought about it some more. If the inner stem is already made and attached I would do the following:

From the plans or if necessary by tracing the bow of the boat, make a mold out of plywood of the shape of the inner edge of the OUTER stem. Cut holes in the plywood mold for clamps to be inserted. Then bend and laminate normally. Make the bend a bit greater then the actual curve because there is always springback.

ARM

[imported_maguro]

Thanks MM. I thought about that plywood method but I'd really like to use the hull as a form so I can get it perfect. I think I will resort to the former method as a last resort. Yes the hull is already constructed so inner stem is already installed. I thought about screwin and gluingone layer at a time but that means lots of holes and lots of worries.

[Paul Scheuer]

This is the skiff from the "test picture" thread, right ?

I can appreciate your not wanting to put in a lot of holes for laminations. If you can locate where (if) you want a bow eye, you could get the laminating pressure from a single piece of plywood cut to the approximate curve and anchored in the bow eye hole, with starategic wedges along the length of the arch. You might be able to get some help at the bottom (keel) end with a temporary cross piece under the gunnel and some lashing. I'd use small brass tacks to locate the laminations. My experience is that my best plans for keeping the parts in place with strategic clamping go out the window when the parts are buttered up with epoxy.

If a single hole is out of the question, you might try a large plywood "C clamp" reaching around the planking to the inner stem.

Of course, you know what you should have done, right ?

[Walcheren]

You know, I can not remember how I did it except I steamed all the pieces. I do not know whether you can steam mahogany. Anyway. You might make the first one an inch too wide on each side. Steam or just put in place and use a few screws nicely embedded in something, whatever you use. Then you have on both sides an ledge you can use to clamp the other five on at your leisure. And again I probably would use a few more screws with each pair or so. Each layer I presume is epoxied to the next one. Let us know what you end up doing.

[GROOVY]

1 1/2" ? I made a 3/4" outer stem of white oak,
after trying steam (faiures at sharpest bend), then cold laminating to a jig(pieces sprung back too far or not far enough), soaking before steaming (pieces cupped)... I laminated directly to inner stem with wider than needed pieces bedded first piece with colored boat life caulk used few small counter sunk screws and clamps where I could, epoxied and clamped the rest to the lip of the first. Then planed/sanded to shape.

[WFK]

Maguro
Here's a shot of a lamination that I did for some knees. I used the same approach for doing an outer stem for the skiff I did. As mentioned above I made a patteren off of the existing stem, used a slight overbend and it came out close to perfect, with only little changes needed. When gluing up this many pieces, it's best to start in the middle and work your way out to the ends. Another neat trick is to lay a piece of thin metal against your outside piece which will prevent cracking or splitting. you can have perfect dimensions by either (if you feel comfortable) running them on the table saw (not an osha approved procedure)or through a thickness planer.
Bill http://www.imagestation.com/picture/sraid56/p8f13c0df1546c0f1b4ee756414ff49a9/fc782612.jpg