Laminating stem problem

[S B]

Last year I got it in my head to build a punt, looks similar in size and shape to Haven12 1/2 without centerboard. It was intended as a traditional build plank over natural crook frames.
plan A; cut timber in fall ,build boat in winter. Problem; snow showed up before a suitable stem was found.
plan B; wait for snow to melt and start building late spring.;problem; 1 1/2' of snow fell on Tuesday , starting to look like plan A. patience wearing thin.
plan C; cheat a little and laminate stem. The stem isn't a big stick, 5 1/2' long and sided 2",Iwas going to prebend 3/4 larch strips and use recorcinol as stem will not be sealed with epoxy. problem; I don't have the hundred clamps it will take to apply enough and even pressure. The project doesn't warrant their purchase and borrowing is usually a more expensive route. Here is where I would appreciate comment, what are the chances of a good joint if i wrap the lamintions with tightly stretched rubber, in the form of 2" ribbons cut from inner tube, overlapped and probablytwo ply.

[paladin]

Lay it out flat and use wedges......the rubber bands work well if you have lots of them...use old auto inner tubes and bicycle inner tubes. If you make a bunch of wooden wedges, then nail small cleats an inch or so from the stem outline, then you can tap the wedges in place to make the laminations tight enough to use resorcinol....

[S B]

Lay it out flat and use wedges......the rubber bands work well if you have lots of them...use old auto inner tubes and bicycle inner tubes. If you make a bunch of wooden wedges, then nail small cleats an inch or so from the stem outline, then you can tap the wedges in place to make the laminations tight enough to use resorcinol....
Slightly confused inside the rubber bands or outside ontop of the bands.

[paladin]

if you use wedges, you don't need the rubber bands.....I'll try to scan a sketch tomorrow and post it for you......

[Mrleft8]

Let me see if I can clarify a little... Make a "male" mold of the stem (IE: the inside of the stem), take a 3" block of wood about an inch square, and scribe a line on the floor (or work board) 3" from the male mold. Now screw "L" shaped plywood cleats, about 3"x4" with the 4" leg on the floor along the scribed line. Use round head screws, and washers, and pre-drill the holes. Line the male mold with wax paper, put your plys in, put another sheet of wax paper along the final ply, then add another sacrificial ply. Now put a pair of wedges in between the sacrificial ply and your "L" cleats and tap them snug. I usually space the cleats about evey 3 or so inches apart, so you'll need a pile of them. This method works amazingly well.

[JimConlin]

Buy at least a dozen clamps. You'll need them for many other steps.

[Thorne]

I don't think I'd try using recorcinol unless I could be absolutely sure of meeting both temperature and clamping pressure requirements -- otherwise it could fail. Do a search on this forum and see what the experts say.

Sure seems like thickened epoxy would be more forgiving...

Harbor Freight has cheap 4" clamps for $2 US (plus shipping) -- might be worth ordering up a bunch.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=37848

[Mrleft8]

I don't think I'd try using recorcinol unless I could be absolutely sure of meeting both temperature and clamping pressure requirements -- otherwise it could fail. Do a search on this forum and see what the experts say.

Sure seems like thickened epoxy would be more forgiving...

Harbor Freight has cheap 4" clamps for $2 US (plus shipping) -- might be worth ordering up a bunch.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=37848 The power of the inclined plane is ledgendary. In fact, the threads on screw clamps are nothing more than inclined planes wrapped around a pole. While the purchase of a dozen or so screw clamps would be a wise investment, you can still glue up your stem while you wait for your clamps to arrive.

[neilm]

If you were to go with a Natural Crook you would need to season the wood 1-2 years. Also, wood won't dry in the Winter. If you bring it indoors it will dry too quickly and check.

Another option to consider is a 2 or 3 piece sawn stem. I like the 3 piece stem best reinforced with carriage bolts or large copper rivets. A stem doesn't have to be super strong. Some Stitch & Glue boats don't even have a stem. I think the primary purpose of a stem to something to sink a screw into. I could be wrong.

Neil

[Bob Smalser]

The stem isn't a big stick, 5 1/2' long and sided 2",Iwas going to prebend 3/4 larch strips and use recorcinol as stem will not be sealed with epoxy. problem; I don't have the hundred clamps it will take to apply enough and even pressure. The project doesn't warrant their purchase and borrowing is usually a more expensive route. Here is where I would appreciate comment, what are the chances of a good joint if i wrap the lamintions with tightly stretched rubber, in the form of 2" ribbons cut from inner tube, overlapped and probablytwo ply.

Resorcinol is an excellent choice but needs lots of clamping pressure and heat. The wedges will work, but you can also buy some C-Clamps from Harbor freight for a couple bucks each and use both.

http://www.harborfreight.com/cpi/ctaf/Category.taf?categoryid=221&pricetype=S&categoryname=C-CLAMPS

I''d toss a heat blanket over the glueup to insure it remains as warm as you can get it overnight.

[S B]

Thank you, people, for the info. The wedge thing looks like it will work. I do have a handful of clamps, the heat isn't a problem and I should have added that the stem is molded 4". If I have any luck I will post the results if anyone is interested.
In regards to force drying natural crooks, we cut the stick to rough dimensions as soon as possible, to reduce strain. Then the ends are sealed and the timber wrapped in cloth or covered in sawdust to prevent the surface from getting ahead of the center. This doesn't always work, but the percentage is acceptable.