Glueing and clamping hexagon

[Waka]

Need some advise on the above Peeps.

Intend to make some internal port hole surround inserts for my boat, I made some a few years ago but these have the end grain showing and with the weather differential are prone to splitting down the grain.

So my thoughts are to make a hexagon, route the outer and inner edge into a circle and then route the recess lip so that it fits comfortably into position.

The resulting thinkness of wood at all angles will be approx 1/2 inch.

First question is will end grain glueing be strong enough with using either dowels or biscuits?

Second question relates to clamping while glueing, whats the best method for this?

Your help is really needed.

 

[Guest]

Wacka, The last time I glued up a hexagon I used elastic bands to hold it together. If your portholes are too large for rubber bands find a local tyre fitters and beg a scrap inner tube and cut a ring from this.It is amply strong enough as the glue doesn't need a lot of pressure.

 

[AndyBoyd]

Waka

There is an article in this month Fine Woodworking on this, the guy make a hexagonal garden table.

From memory he clamps across the individual sections with 2 K Body clamps at each end, then another clamp to pull the K Bodies together and hence make the joint. You need strong good clamps for this (maybe with sand papaer glued to the faces?). You need 24 clamps to make this method work of course!!!!

Or one of those Bessey tape clamps things - those work quite well.

p.s I hope you not in Nigeria at the moment our people are having a rough time (work for the largest OilCo out there - you'll know who that is)

 

[George_N]

How about something like this http://www.woodcraft.com/family.aspx?FamilyID=3719

George

 

[SketchUp Guru]

A band clamp would work fine. I would do it a different way. Especially since you're planing to round them with a router afterwards.

Take a piece of MDF that is large enough to hold the hexagonal frame. Find the center for a router trammel pivot point. Layout where the frame pieces will lay and drill the MDF so you can screw the pieces in from the back. Make sure the screws don't come out the front.

Screw the pieces in place dry so you can make sure all the corners fit correctly. Then glue the corners and screw the pieces in place. After the glue has cured, run the router around the inside and outside to make your circular frame. Once the frame is rounded as desired, you can remove it from the MDF, cut the rebate in the back with a bearing guided bit, add varnish, install and go for a sail.

I'd use epoxy for these end grain joints. Coat the faying surfaces, let it soak a bit, add a little more and screw down the pieces. Epoxy doesn't need or like high clamping pressure but will give you a very strong joint.

If you need a sketch of my clamping.routing jig let me know. I'll whip something out for you.

 

[ProShop]

Second question relates to clamping while glueing, whats the best method for this?

Your help is really needed.

Do you have any of those small rachet cargo straps :?:, I use them for strapping down sheet material etc on the roof rack and they're great for clamping hexagons etc.

 

[Philly]

Waka
I reckon a single pocket hole screw on each edge will be the solution-make the hole in the middle off the piece well away from the routed edges. These will hold the thing together nicely (with plenty of a nice, modern glue) and will also solve the clamping up problem. You can glue them up two at a time, and then two and two together, etc. Should be easier than trying to site a small biscuit in the middle of the joint or dowels.
Hope this helps (and I explained myself adequately :roll: )
Keep safe
Philly

 

[les chicken]

Waka
Agree with philly on this one. Just made an octagonal table, pocket screw and a smear of gorilla glue to hold the outside together.

Solid as a rock. :lol: :lol:

Les

 

[Waka]

Thanks for all the help peep's, I'll let you know how I get on.

 

[Steve Maskery]

Waka,
Last year I made a round table (see my avatar) and I used twin biscuits and exterior PVA. It was as tight as a Scot at Hogmanay. However, just one season of sun and rain and several of them have opened up, and I'm faced with the prospect of having to remake the ring this spring . So whichever advice you take, don't do what I did!

The DAY after I made mine, I saw Norm make a round top to a gateway. He used angled wooden blocks screwed to the waste, and an ordinary clamp, to draw the two faces together. Coupled with a pair of plines across the joint (he used a dado, but you could use a meaty router in a table) and epoxy, I reckon he did a much better job than I did.

One good tip I can pass on though. Getting all the angles perfect is not easy, so I don't bother trying! Glue up you segments in threes, then shoot each half so that they mate (See my Comp entry for how I did this for my oval frame).

Best of luck,
Steve