The Letterville BullBoard: Backer for HDU

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Posted by Wayne Webb (Member # 1124) on :

Would a 10'x7'single sided sandblasted HDU sign need some type of backer? The sign is to be mounted against a wall of pylons. Seems like someone here mentioned laminating a piece of alumalite or something onto the back? I believe that the SignFoam How-To Book says to face-screw it and fill the holes. This doesn't seem strong enough for a sign of this size.

Thanks for the help.

------------------
"autograph your work with excellence"

Wayne Webb
Webb Sign Studio
Chipley, FL
850.638.9329
webbsignstudio@digitalexp.com

Posted by Pierre St.Marie (Member # 1462) on :

Wayne, what's the thickness and weight?

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& Makin' Tracks Sound Studio
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Posted by Wayne Webb (Member # 1124) on :

Sorry Pierre, I'll be using 15lb density so the sign in 1.5'' HDU will weigh approx. 100.39 lbs.(45.54 kilograms)
and a 2'' one will weigh approx. 137.5 lbs. (62.37 kilograms)

The sign is elliptical in shape.

Come to think of it, that's not a lot of weight. But, being that large, it could get a little flimsy. What do you think?

Thanks

------------------
"autograph your work with excellence"

Wayne Webb
Webb Sign Studio
Chipley, FL
850.638.9329
webbsignstudio@digitalexp.com

Posted by Dave Draper (Member # 102) on :

Wayne,

Not sure you stated how far the pylons were apart, which could make a difference.

We used treated 2 x 12's for backing on the last sign we did.

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Draper The Signmaker
Bloomington Illinois USA
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Posted by Wayne Webb (Member # 1124) on :

Hey Dave,
There is no space between the pylons because it's like a solid wall of them. I don't know how far apart their tangents will be but I assume the posts are either 6'' or 8'' diameter. I have alot of trouble with PT wood warpage down here in Florida.

------------------
"autograph your work with excellence"

Wayne Webb
Webb Sign Studio
Chipley, FL
850.638.9329
webbsignstudio@digitalexp.com

[This message has been edited by Wayne Webb (edited April 10, 2001).]

Posted by Pierre St.Marie (Member # 1462) on :

Definitely need backing. 1/2" MDO is ok, but I'd use 5/8" or 3/4" anyway. Just make sure you make your backing joints in opposition to the HDU joints. Use a good HDU adhesive like PB240 or Gorilla Snot or whatever you call it. (Gorilla Snot is what we use in the recording studio for guitarists and drummers)

If you use something like PB240 you won't need screws at all. Do NOT prime or paint the two sides to be joined by the adhesive. Leave it raw wood and HDU. Make sure the MDO is single sided and turn the raw wood part to the inside against the HDU. Let me know if I can help any further. HDU is our "thing".

[This message has been edited by pierre (edited April 10, 2001).]

Posted by Dave Draper (Member # 102) on :

Wyane,

If the Signfoam is bolted down to a solid wall, I can't see where you would need any backing. Just bolt it up and go home.

I have Signfoam on brick walls with no backing, they are dong fine. I have 2 with just 1 2x4 running horizontaly on the back side of the sign (sign between posts) to keep it from flexing in the wind.

If Signfoam can start flexing in the wind, then it will crack down the middle. If it is up against a wall, then there is no wind problem and no need for a stiff back board as your pylons should provide that.

Posted by Pierre St.Marie (Member # 1462) on :

Not to be arguementative, but 1.5" in that size is simply not strong enough. Suppose it takes any kind of a hit or good push between the 2x4s? It's only 15# material. Why roll the dice on something that large and shallow?

Posted by Wayne Webb (Member # 1124) on :

Thanks Dave,
I don't see why directly attaching the sign to the pylons wouldn't be sufficient. Do you just countersink screws into the face to attach?

Will there be alot of expansion/contraction in relation to the wood on a sign of this size?

Thanks Pierre, would the 2'' 15# that I mentioned be thick enough or should I go with something thicker with 18# density?

------------------
"autograph your work with excellence"

Wayne Webb
Webb Sign Studio
Chipley, FL
850.638.9329
webbsignstudio@digitalexp.com

Posted by Pierre St.Marie (Member # 1462) on :

If it's without backing, I'd use the 18#.

Posted by Wayne Webb (Member # 1124) on :

Thanks Pierre.

------------------
"autograph your work with excellence"

Wayne Webb
Webb Sign Studio
Chipley, FL
850.638.9329
webbsignstudio@digitalexp.com

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