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i have a one sided carved sign i'm working on...1.5"signfoam and i'll be using west systems epoxy to bond it to 3/4 mdo...it will be mounted between granite posts...the sign is 57"x57". my question is...can i cover the backside of the mdo with a coat of west systems b4 i paint it??? the backside of the sign gets the brunt of the sun. i'm just not sure if its a good idea because of the expansion factor. i don't want the thing to get all cracked in the back. i will be using porter paint on this sign. thanks for any advice.
-------------------- Karyn Bush Simply Not Ordinary, LLC Bartlett, NH 603-383-9955 www.snosigns.com info@snosigns.com Posts: 3516 | From: Bartlett, NH USA | Registered: Jan 2001
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-------------------- "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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Your suspicions are probably correct. But it's not the face of the MDO you really have to worry about, only the edges. Some people swear by West for sealing mdo edges but not me. I've still seen it swell and crack there. I'd be more inclined to use something like marine caulk (3M 5200).
I can definitely advise AGAINST is using West as an adhesive for large painted surfaces. Once those surfaces start moving it'll shear the paint right off at the substrate for a total failure. Glue them raw or use a different adhesive. I know that wasn't your question Karen, but worth mentioning here for anyone reading who isn't aware of it.
SONGPAINTER Original Sign Music by Sign People NOW AVAILABLE on CD and the proceeds go to Letterville's favorite charity! Click Here for Sound Clips! Posts: 1974 | From: Orleans, MA, Cape Cod, USA | Registered: Nov 1998
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I've done some experimenting with epoxy on wood. Canoes, yes, signs NO. The epoxy is peeling off the wood. I tried epoxy over paint and epoxy on the raw wood then painted. Both are peeling right off.
West System is a bonding epoxy. When used on cedar or redwood boats and canoes, they lay down fiberglass and epoxy over it. The wood is simply there to hold the shape. But all the wood is completely encased in epoxy.
In my opinion, I can't see attaching wood to HDU. The life span of the two are so far apart. I have had great success using DiBond and Alumalite as a backer. We then add two steel flats across the back. All this is done with epoxy and bolts. The Dibond is epoxied to the back, bolts are epoxied into shallow holes in the back. The bolts go through the Dibond and the steel flat. Brackets can be attached with the bolts at the ends of the flats.
I'm doing this on a sign I just blasted. I'll try to remember to take photos and post them.
-------------------- Dave Sherby "Sandman" SherWood Sign & Graphic Design Crystal Falls, MI 49920 906-875-6201 sherwoodsign@sbcglobal.net Posts: 5401 | From: Crystal Falls, MI USA | Registered: Apr 1999
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thanks guys...i won't be coating the back with west systems...however i will be bonding the two together with it...along with a few screws. i know lots of folks wouldn't dream of attaching mdo to hdu...but its in a very windy open area on a mtn top...and i need it so i can attached the brackets to the granite...i'm not a welder so this is the only way i've done it in the past. i would like to try the hard coat that coastal products put out...kellie showed us about it at my meet...but i'm already into this project so i'll have to try out in the future. hopefully what i'm doing for this will be fine!
-------------------- Karyn Bush Simply Not Ordinary, LLC Bartlett, NH 603-383-9955 www.snosigns.com info@snosigns.com Posts: 3516 | From: Bartlett, NH USA | Registered: Jan 2001
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SONGPAINTER Original Sign Music by Sign People NOW AVAILABLE on CD and the proceeds go to Letterville's favorite charity! Click Here for Sound Clips! Posts: 1974 | From: Orleans, MA, Cape Cod, USA | Registered: Nov 1998
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Hardcoat is not the answer for the back of the sign. It works great at repairing HDU though.
You don't have to weld to use my methods. I buy little angle brackets with slots from a local machine shop. Everything else is just flat steel, machine bolts and epoxy. You don't even need to drill the holes in the steel flats since your local machine can, but I do it with my drill press.
-------------------- Dave Sherby "Sandman" SherWood Sign & Graphic Design Crystal Falls, MI 49920 906-875-6201 sherwoodsign@sbcglobal.net Posts: 5401 | From: Crystal Falls, MI USA | Registered: Apr 1999
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Karyn, Why not make a frame out of 2"x4"P/T lumber and attach that to the granite in some manner. Screw your HDU sign onto the face of that. Then attach your MDO panel, or whatever, to the back for a finished look.
Simple, no glue-up, no seals to fail. Even if the sign is an odd shape, you can still place the "backer" behind the frame and it will appear as if it is one thick sign. If necessary you can add a piece of aluminum across the top to finish it off.
-------------------- Gene Golden Gettysburg Signs Gettysburg PA 17325 717-334-0200 genegolden@gettysburgsigns.com
"Art is knowing when to stop." Posts: 1578 | From: Gettysburg, PA | Registered: Jun 2003
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