Plywood clamps

[l.clayton.parker]

I just acquired a goodly bit of 3/4" five ply birch that I would like to make clamps out of like the ones I have seen here in the forum. Can anyone tell me some measuurements for length and width of the openings? Any other clues about making them?

Lee

[JimConlin]

I've made two or three batches of 'hairpin' (or is it clothespin?) clamps over the years. They were sized to the needs of the project.
- The depth of the opening maybe 1" more than the widest plank's width.
- the width of the opening maybe 1/4" greater than the greatest thickness to be clamped. As I have used 'Tom Hill' style lapstrake planking setups, that's two plank thicknesses pus the depth of the ribband.

I used MDF for the wedges. It slides a bit more smoothly than plywood.

[TerryLL]

Here's a selection of different lapstrake clamp designs:

[l.clayton.parker]

Thanks for the info. Okay, well I just cleaned it all up and sized it into rectangles. Will stack it aside 'till I actually need it then.

Lee

[l.clayton.parker]

Here's a selection of different lapstrake clamp designs:

<Pictures deleted>

Thanks Terry, that was great. I will probably make at least a few of the "Brenne" clamps. I seem to remember seeing some of those with bolts. I think I will try it that way with quick release toggles.

I ended up with 30 pieces of 3/4" birch sized 6" x 22". So I only need about 30 more clamps.....

Lee

[James McMullen]

If you're doing glued lapstrake and painting your boat, you don't even need that many. Temporary screws driven through the lap to hold it in place until the epoxy cures is even quicker and simpler, and it will hold things in place well enough that you don't have to wait for the glue on those first strakes to cure before you start your bevels and spiling for the next set of planks cause there won't be all those clamps in the way. (This could save you many days of waiting around to start the next step on a multi-straked boat.) I only use a couple of lap clamps at a time for glued lapstrake, and I only use them temporarily until I've got it lined up enough to put in a few temporary screws.

[TerryLL]

The screw method is really the quickest and simplest for a painted hull. I use small blocks of UHMW (1" X 1") with a single hole just a bit larger than a drywall screw and predrill the outer lap about every 3 inches with the same size drill. Then as the strake goes on I can quickly run a screw through the block and outer lap into the inner plank and pull it all up snug. Epoxy doesn't stick to the UHMW so it all comes loose without any fuss.

[JimConlin]

I'm getting lots of sleazy ideas here.
I'm a big believer in temporary screws, and I was tempted to suggest it to Steven, but he's on a roll and I didn't want to do more than cheer.
The UHMW blocks are a better idea than one patch each of poly and lauan.

[l.clayton.parker]

UHMW? What is that? Some sort of slippery plastic?

I have read about the temporary screws method but wasn't really planning on going that route. I don't think wait time for curing is going to be a real issue, I will probably have other things demanding my time anyway.

But if I run short of clamps, that is always a possibility. FYI, Rockler has twin screw maple clamps on sale for $9.99 atm, online only. I use them for ordinary projects but I don't think the jaws are deep enough for lapstrake.

Lee

[TerryLL]

UHMW? What is that? Some sort of slippery plastic?

Yep. Ultra High Molecular Weight polyethylene. Very slippery stuff, easy to machine, available in sheets, rods, bar stock, blocks, etc.

A couple hundred small blocks plus a couple hundred drywall screws might set you back $20.00.

[Jlaup]

I used these:

because I wanted to keep the sanding load down in the interior of the boat. I haven't flipped the boat so I don't know how much easier it will be. But on my Pooduck, I remember that being the worst of it. The clamps are just as easy to use as screws and easier to modulate pressure. You do need a lot of them. But I got 40 out of a partial ply sheet left over from some stage construction project from my daughter's high school.

[Duncan Gibbs]

Mr Bauer has thrown together a whole host of nice clamps for his latest build.



Although I'd defer to you on almost most boat building things James, I'd have to say, unless the finish with be painted both inside and out I'd hate to see little epoxy filled screw holes on the plank edges. I'd clamp the laps.

[JimConlin]

McMaster has 1/4" x 1-1/2" x 4' HDPE for $1.08, which works out to under $.04 per pad. I'm loving this.

[Clinton B Chase]

John Brooks describes using an outside lap batten and drywall screws with pads under the heads and beveled pine blocks on the inside. I tried his system a few boats ago and haven't thought about any other the other ways since. The batten is key to fairing the lap and can be used trickily to fair low spots and push the lap into fairness if there are places that need it.

Clint

[l.clayton.parker]

Mr Bauer has thrown together a whole host of nice clamps for his latest build.

Now that is an elegant clamp design.

Lee

[Candyfloss]

For 6mm ply I use 12mmx10g pan head PK screws.



Then these 3/4" clothes pin clamps with wedges just for the sheer strake, 'cos it's varnished.



Works for me.

[Wooden Boat Fittings]

.
Nice to see a towing-eye in the right place for a change. Good for you, Candyfloss.

Mike

[Tom Robb]

I ran into someone at a years ago WB show in Mystic. They used small hex head screws that tinners use on furnace duct work. After cure and removing them, they filled the holes with round tooth picks and epoxy. They called them mini-trunn'ls (sp?). Made virtue out of necessity.
However those one-handed Breene clamps are too elegant for words. They'd be nice to have around if only to contemplate their coolness.

[Tom Robb]

Is there a trick to copy&paste-ing an entry - the Breene clamp one? I'd like to have a printout of that.

[ILikeRust]

Is there a trick to copy&paste-ing an entry - the Breene clamp one? I'd like to have a printout of that.

Right click on the picture and select "Print."

Or, right click on it and select "save as," then you'll have your own copy.

[TerryLL]

Is there a trick to copy&paste-ing an entry - the Breene clamp one? I'd like to have a printout of that.

The Brenne clamp article is from WB#29, p.67. The story was saved as a jpeg and imported just like an image file. You should be able to select the image and drag a copy off onto your desktop.

[StevenBauer]

I'm a big believer in temporary screws, and I was tempted to suggest it to Steven, but he's on a roll and I didn't want to do more than cheer.

I used screws in the laps an the last two glued lapstrake boats I built, the Elf and the Nutshell Pram. In a couple a places the screws pulled a little bit of unfairness into the lap. John Brooks' method would help avoid this but is sort of a lot of trouble. Norm's planking clamps work great, cost under buck a piece made from wood in the scrap bin. The planking in the Humblebee is narrow enough that these clamps are just perfect.







Steven

[Tom Robb]

Thanks Bill & Terry.
I'll try that.