Making a large two sided sign.

[genek]

I think I have come up with a way to do large thick two sided signs that would be easy to mount. First carve both side of the sign. Next cut mdo 1//32 smaller than the hdu sides. Mount mdo to hdu, mount the sides to a 4 x 4 post now take thin aluminum flashing and nail or screw to the mdo on the back side of the sign, if you use primed aluminum you can paint to any color needed. you can also do a inset on the mdo and make it look 3d..

[RossMosh]

I'd hardly consider myself an expert on the subject, but this is what I'd do.

The HDU is "resting" on the posts. The cross beam keeps the posts from growing apart. Fasteners can and should be used to assist rather than support. If you can get the cross beam right under the sign, which may not work for aesthetic reasons, you'll be even better off. Higher density HDU is also another way to protect yourself against failure. 15lb Duna vs 20lb Duna from my supplier is about $40.00 difference in a 1in sheet. It may be worth the overkill and throw a piece of 3mm "DiBond" in between the two panels to just stiffen up the sign against wind.

With my limited experience, I'd probably pick PVC over HDU for signs mounted on posts. PVC may expand in the heat but it's overall a far more durable material. Expect routing times to increase if you use it though.

One thing I forgot to mention, there are two high stress points in the way I suggested mounting. They are at the corners in the notch. Rounding that off instead of using a hard 90 degree angle will help. You can also make two notches into the 4x4 which will give you double the stress points, which is probably how I should have drawn it in the first place. See v2 to see what I mean.

[joe]

Going back in time:

Back in 2006 I posted on this topic under "New Project". That was a long "Step by Step" series done in real time. Each day I'd take photo's and post the progress. However for this posting if you scroll down to page 5 there are photo's showing the method of locking sign and posts together.

This is the fastest and easiest technique I've found.

Keep in mind, the tines can be attached to either the posts on be included in the sign panel. All my double sides signs now have the tines attached to the post as per the photo's in "New Project"