posted
I need to make a 4' by 4' sandblasted sign using HDU. (double sided)I know a sign of that size need reinforcement, what's the best method to attach the HDU to MDO? Gorilla glue? The sign will be mounted between 2 granite posts.
Just double checking here....I am planning on a couple of coats of Jay Cookes primer before adhering the HDU to the MDO, right?
Thanks!
-------------------- Mike Berry New England Posts: 534 | From: New England | Registered: Jan 2002
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posted
If you want to shorten the potential life of an HDU sign, go ahead and attach wood which can rot. With all the talk on this board about how lousy MDO has gotten, I'm surprised anyone would want to use it.
Here's what I did on a 5' x 8' 2 sided sign. I used 2" thick HDU becuse it was going to be carved fairly deep. For a 4x4, 1 1/2 inch HDU would be fine using an average blast depth.
I then routed a 2" wide and just a hair deeper than 1/4 inch channel, or dado from one edge to the other, one a little ways down from the top, the other the same distance from the bottom.
I got some 2" by 1/4" thick steel flats and had a square flat flange with holes near the corners welded on. Some precision is necessary here as you want both brackets to be the same length.
Mix some epoxy and thoroughly wet the bottom of the channel and one side of the steel (the center 4' in your case) and set the steel into the channels. Square them up good and let them set up. The next day, epoxy the second sheet to the first.
The steel will stiffen up the sign plenty and give you nice flanges to mount the sign to the columns. My 5' x 8' made this way just survived a major storm with tornados that shredded signs all around it and there is nothing on the sign that can rot.
posted
Dave, we do very much the same thing with steel, building brackets on each side of the sign and having two pieces of flat steel (1&1/2 x 1/4) recessed and sandwiched between two sheets of foam. I use gorilla glue and do the glue-up all in one step - for large signs (we did a 5' x 8' recently) we glue them on the floor, using sandbags for "clamping". One trick about glueing like this - glue is likely to ooze out of the edges and effectivly glue the sign to the table or floor! We use ordinary wax paper under the sign around the edges; glue won't stick to it and cleaning up is easier.
Don't prime HDU before gluing. You want the glue to penetrate all the tiny cell pores to make a solid bond.
-------------------- "A wise man concerns himself with the truth, not with what people believe." - Aristotle
Cam Bortz Finest Kind Signs Pondside Iron works 256 S. Broad St. Pawcatuck, Ct. 06379 "Award winning Signs since 1988" Posts: 3051 | From: Pawcatuck,Connecticut USA | Registered: Nov 1998
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