posted
I am making a double sided 8' sandblasted sign out of HDU...in the past I have not been pleased with the strength a panel this big after blasting...I am thinking of sandwiching PVC or MDO board between 2 pieces of 3/4" foam board and gluing them together with gorilla glue...how does this sound...any suggestions?
posted
MDO would be the better choice than the PVC, IMO. Don't forget to drill some holes in you MDO panel for the glue.
-------------------- Bruce Bowers
DrCAS Custom Lettering and Design Saint Cloud, Minnesota
"Things work out best for the people who make the best of the way things work out." - Art Linkletter Posts: 6451 | From: Saint Cloud, Minnesota | Registered: Jun 1999
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posted
Well I have a different approach to this. I have never been ok with the idea of strengthening a product that doesn't rot with one that does.
MDO does work and seems to be popular, although what I have been doing is sandwiching a steel frame into channels routed into the back, then sealed and bonded with west systems epoxy. The steel is enclosed. The neat thing is you can design your mounting brackets as part of the frame as well
[ December 10, 2008, 08:23 AM: Message edited by: Bob Rochon ]
-------------------- Bob Rochon Creative Signworks Millbury, MA 508-865-7330
"Life is Like an Echo, what you put out, comes back to you." Posts: 5149 | From: Millbury, Mass. U.S. | Registered: Nov 1998
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Right now we're finishing up a double sided HDU sign. I routed two half inch deep channels for 1 inch square steel tube to fit. We'll epoxy the two sign faces with the tube enclosed within the sign. This one is going between brick columns so I bought some 3/4 inch round steel rod. I'm going to weld a 6 inch steel flat to the end of the rods. The rod will slide into the square tube. Slide them out a tad to meet the columns. Instant adjustable brackets.
-------------------- Dave Sherby "Sandman" SherWood Sign & Graphic Design Crystal Falls, MI 49920 906-875-6201 sherwoodsign@sbcglobal.net Posts: 5397 | From: Crystal Falls, MI USA | Registered: Apr 1999
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posted
I've used any number of things for strengthening HDU panels, and I taught Bob Rochon my technique for using internal steel frames. I've never used tubing though, just flat stock, usually 1/4 x 1 1/2". I have a DF 4x8 HDU sign, suspended between posts, that's been in place at least five years now without problems.
-------------------- "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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DrCAS Custom Lettering and Design Saint Cloud, Minnesota
"Things work out best for the people who make the best of the way things work out." - Art Linkletter Posts: 6451 | From: Saint Cloud, Minnesota | Registered: Jun 1999
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I agree with Bob, Dave and Cam and think you'd be going in the right direction with that type of process. MDO is used a lot but I am in the same opinion as Bob; why use a product that will last forever along with one that won't? The only other thing that I will add to this, when you do adhere two unlike products together, is to remember that everything expands and contracts at different rates. This means that when laminating 2 different substrates, do not do a full face bond. Put a bead of glue around the perimeter and every 8" or so (depends on size of panel) vertically. This allows for movement and if a stress point is started, it shouldn't crack the HDU. It's also best to use a rigid adhesive when laminating and not a flexible one. I've been pretty general in my answer, so if you have any additional questions please ask or call our technical department. Thank you, Kellie
-------------------- Kellie Miller Customer Service Mgr. Coastal Enterprises Company Mfg. of Precision Board (800) 845-0745 www.precisionboard.com hdu@precisionboard.com Posts: 118 | From: Orange, CA | Registered: Feb 2002
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posted
Each of these two panels has two 1"x2" rectangular aluminum extrusions embedded in a dado and extending through the sign into mortises in the posts. It's two sided and it's 3" thick (two 1.5" HDU panels). Monte Jumper showed me this technique. It's very strong, doesn't flex, and I wouldn't do a sign any other way.
-------------------- Wayne Webb Webb Signworks Chipley, FL 850.638.9329 wayne@webbsignworks.com Posts: 7404 | From: Chipley,Florida,United States | Registered: Oct 1999
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quote:Originally posted by Bob Rochon: Well I have a different approach to this. I have never been ok with the idea of strengthening a product that doesn't rot with one that does.
MDO does work and seems to be popular, although what I have been doing is sandwiching a steel frame into channels routed into the back, then sealed and bonded with west systems epoxy. The steel is enclosed. The neat thing is you can design your mounting brackets as part of the frame as well
+1 This is what we do as well. This sign is 4'x10' HDU and has a welded steel interior frame with stubs set in the masonry foundation on each end.
posted
Thanks for all the advice...it's very gratifying to find such people that are willing to share their experience and expertise to help out a fellow craftsman...I do appreciate it and in the future hope to have something of value to add that might help someone else...though I must admit that seems a bit unlikely right now as I feel more the student than the teacher...I really like Wayne's optometry sign (3" thick)...but I only figured in $330 for the substrate in the pricing and can't see doubling that cost and coming out very well...I think I know the best way to go on future signs but this time I'm still thinking how to do this and stay under $350.
posted
Why would MDO rot if it's sealed off from moisture?
Just askin'.
-------------------- Brian Oliver Paxton Signs Fort Collins, CO paxton@peakpeak.com www.paxtonsignsofcolorado.com Posts: 237 | From: ft. collins, colorado,usa | Registered: Mar 2001
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posted
Brian...super nice work on your site...I only wished when I clicked on a sample to enlarge that they came up bigger...enlargements didn't seem large enough.
posted
Thanks for the kind words, Rusty. I'll look into making those enlargements bigger.
-------------------- Brian Oliver Paxton Signs Fort Collins, CO paxton@peakpeak.com www.paxtonsignsofcolorado.com Posts: 237 | From: ft. collins, colorado,usa | Registered: Mar 2001
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posted
The MDO won't rot if moisture stays out of it. The problem is keeping moisture out over the long term, and what "long term" means to each project and each customer's expectations. If I can put out an MDO sign, using standard sealing proceedures, and confidently expect it to last ten years, then I can certainly expect at least that long from an HDU sign with an MDO core. And thats not an idle claim; I have such signs going on twelve years, with no obvious indications of decay.
I'm not really trying to contradict myself; I like internal steel frames, and use them regularly. But I think it also depends on what's appropriate for each project; one is not necessarily always better than the other. I don't share what in the sign trade has become a loss of confidence in wood and wood products - hell, there are wooden houses round here still standing after 300 years. If an MDO core makes more sense for a particular project, use it - but do it right. I'm convinced, after all these years, that the vast majority of material failures can be traced to incompetence and carelessness, rather than some inherent flaw in the material itself.
-------------------- "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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posted
What if you....... 1. Lay one full 96x48 sheet of HDU down flat. 2. Spread epoxy on it. 3. Lay a cut-down sheet of plywood (92"x44") on it and center it. 4. Now your plywood (or MDO) is inset 2" all the way around. 5. Lay strips of HDU 2" wide and the same thickness of the plywood in the inset. The plywood is now surrounded by 2" of HDU. 6. Spread epoxy on all of this. 7. Lay your other sheet of HDU on top. Weigh it all down with clamps and sandbags.
If you make sure every laminated piece of HDU and wood is completly coated with epoxy, there should be no reason why the plywood wouldnt' be completely encapsulated in epoxy and HDU. and protected from moisture. But the thing is, different materials have different rates of expansion/contraction and if a breach occurs, the plywood will absorb moisture. So I'm still a firm believer in the internal aluminum frame method.
-------------------- Wayne Webb Webb Signworks Chipley, FL 850.638.9329 wayne@webbsignworks.com Posts: 7404 | From: Chipley,Florida,United States | Registered: Oct 1999
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posted
Wayne...I like that idea...but I have one question about the plywood...MDO has smooth surfaces...much smoother than regular plywood...that makes it great for gluing...but do you think regular plywood's surfaces are good enough for gluing...I would like to try your suggested method with a regular plywood instead of MDO...what do you think?
posted
Rusty, I was only suggesting ext grade plywood because, since it has no smooth overlayment, it can allow the epoxy to soak in and have more "bite" than smooth MDO would. But like Dave said, it could be more prone to warp. I've never tried this method and was only suggesting how it could be properly done. But I don't recommend MDO or plywood at all. Like I said, I use aluminum extrusions in my signs.
[ December 12, 2008, 09:38 AM: Message edited by: Wayne Webb ]
-------------------- Wayne Webb Webb Signworks Chipley, FL 850.638.9329 wayne@webbsignworks.com Posts: 7404 | From: Chipley,Florida,United States | Registered: Oct 1999
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quote:why use a product that will last forever along with one that won't?
a procedure that we have used with much success is the flat bar alluminum with a routed space for it to rest on the edges or part of the suport structure as other have said....But what i use is Stucco mesh and the gorilla glue or the product that Pression Baord recomends (PB Bond-240) and when you glue the 2 peices together you cannot break it...i tried!!!
i have a Step By step in this website if you want to check it out. it works and it will expand right along with the HDU No Failure!!!
Could you elaborate on your experience with West's epoxy popping off of MDO? You just sent chills up my spine as I've used these materials together assuming that I was fabricating a bulletproof panel.
You can just email the details to me if you like, though if you post them here I think a lot of people could benefit from your story.
Thanks.
-------------------- Brian Oliver Paxton Signs Fort Collins, CO paxton@peakpeak.com www.paxtonsignsofcolorado.com Posts: 237 | From: ft. collins, colorado,usa | Registered: Mar 2001
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I had a job that was decided to make out of MDO but 1.5" thick. So I epoxied 2) 3/4" MDO sheets together using West systems epoxy. I did sand he faces with 220 before adhering together. After the sheets were epoxied together I cut the shape and that's were I found the problem. One of the "drops" hit the floor and the 2 sheets popped apart leaving a smooth and clean break from the epoxy and the MDO. Now we are talking about a wooden floor not a concrete floor.
-------------------- Bob Rochon Creative Signworks Millbury, MA 508-865-7330
"Life is Like an Echo, what you put out, comes back to you." Posts: 5149 | From: Millbury, Mass. U.S. | Registered: Nov 1998
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