HDU Plaque Fail When Inset in Stone

[Stormyj]

Suggestion. Please correct me if im wrong, but heres what I would do. Remove plaque, screw aluminum sheet like polymetal. Then use VHB tape to attach it to the polymetal. And perhaps a bead of silicone around the edges to prevent excess moisture getting behind it.
Any thoughts.

 

[J Hill Designs]

I would screw it in to the masonry personally

 

[Stormyj]

I would screw it in to the masonry personally

I was trying to keep away from holes and screw heads in the face. Plus with expansion, wouldn't the screws become loose with time?

 

[MikePro]

+1 glue an .090-.125 alum backer to the panel to resist curling
I use PB FastSet from Suncoast Industries, but Lord's or GorillaGlue would suffice.

you can also throw some screws through the aluminum into the HDU from the backside, as it looks like you have a nice thick perimeter to bite-into (obviously not drilling all the way-through)

doesn't matter if aluminum/HDU have different expansion rates... the aluminum simply won't curl under typical exterior conditions, and will help the HDU to resist potato-chipping.

 

[Marlene]

forgot to add that the sign is awesome looking! love the rusted metal look.

 

[Graphic Destruction]

When I do hdu I will use Lord adhesive to glue it to aluminum or dibond. For 1 ", use 3/4" screws. Once the Lord adhesive sets, back the screws out and put gorilla glue in the holes and put the screws back in. Everything is bonded together now and won't warp.

 

[SignManiac]

I've never had luck with adhesive alone. I always use both hardware (studs in this case) with adhesive... Cheap insurance.

 

[HandyManBill]

When I do hdu I will use Lord adhesive to glue it to aluminum or dibond. For 1 ", use 3/4" screws. Once the Lord adhesive sets, back the screws out and put gorilla glue in the holes and put the screws back in. Everything is bonded together now and won't warp.

I like the idea of "screwing & gluing" like belts + suspenders...one or both gotta work. That is probably the route I will go but, before that I am going to experiment with laminating of fiberglass cloth and resin to the backside of a scrap I have...leave out in the weather and see what happens. I have not even heard back from my customer yet...thought she would send me another photo or at least a good tongue lashing.

So are we all in agreement?

 

[HandyManBill]

forgot to add that the sign is awesome looking! love the rusted metal look.

Thank you Marlene!

 

[Gino]

Okay, agaIn, I'm no expert on this material, but as I was saying earlier, it's a very sloppy mortar job. Also, as mentioned..... ALL things expand and contract. Whatever rate that might be, everything does. Upon further looking at the 3 pictures and using normal deductions, it looks as if the sign itself was expanding and the rock/stone/mortar confinement is too small, thus forcing the lesser material to bend, then shoving it out. The same kinda deal when one puts aluminum or vinyl siding in and it needs enough room to expand, but not too much that it bows. Same as a electric sign face within the confines of the cabinet. Something will always give when push comes to shove and in my novice opinion, that's what happened. The hole was too small. I'll bet ya 10 to 1, the sign fit too snuggly in there and whoever installed it, never considered it.

Always..... always leave some breathing room.

 

[TimToad]

Did you prime, treat and coat the back with the same process as the front and edges? If not, I'd guess the primer and finish coating finally cured out and shrunk to the point of pulling the whole thing inward to the front.

We laminate all of our HDU signs to either 1/2" MDO or Alupanel with low foam polyurethane and then do the drill, fill with a dab of glue and screw like described earlier. Our area has temperature extremes in one day anywhere from 50 to 60 degree swings, but with very little humidity. You can't fully trust aluminum or Alupanel as a backer on anything larger than the type of size you're working with. They also will get pulled wherever the strongest force is moving towards. People constantly underestimate the power of expansion and contraction.

 

[Techman]

Did you prime, treat and coat the back with the same process as the front and edges? If not, I'd guess the primer and finish coating finally cured out and shrunk to the point of pulling the whole thing inward to the front.

^ This.. And is exactly why I asked way up above if the panel was primed both sides..

 

[James Burke]

If it were meant to be permanent, then I would have gone with cast aluminum plaque from Matthews. It would have been dang near bullet proof.


JB

 

[HandyManBill]

Did you prime, treat and coat the back with the same process as the front and edges? If not, I'd guess the primer and finish coating finally cured out and shrunk to the point of pulling the whole thing inward to the front.

We laminate all of our HDU signs to either 1/2" MDO or Alupanel with low foam polyurethane and then do the drill, fill with a dab of glue and screw like described earlier. Our area has temperature extremes in one day anywhere from 50 to 60 degree swings, but with very little humidity. You can't fully trust aluminum or Alupanel as a backer on anything larger than the type of size you're working with. They also will get pulled wherever the strongest force is moving towards. People constantly underestimate the power of expansion and contraction.

No, the sign was not primed..if I was using Precision Board or Signfoam I would definitely have to use Duratec Primer but Duna's Corafoam takes the polyester resin beautifully and it carves the same plus this is their 31lb foam which is about twice as dense as PB. Yes, the back was coated with iron, the same as the front but the front also had a coating of aluminum on the raised type.

I agree that the sign should have been backed with Aluminum or another structure especially considering the size...won't make that mistake again.

Let me ask you, if you had a two sided sign that was approx. 4' x 2' and it was going to hang from a post above the entry to a restaurant (above the sidewalk) would you worry about the expansion/contraction? and would you A) do two signs and laminate or B) a 2-3" slab of foam and carve both sides or C) something else? I ask this because most of the signs I do are more like 12" x 9" and a we bit larger but I did one for a place in NY and I hope it is doing fine..it has been about a year.

 

[Marlene]

No, the sign was not primed..if I was using Precision Board or Signfoam I would definitely have to use Duratec Primer but Duna's Corafoam takes the polyester resin beautifully and it carves the same plus this is their 31lb foam which is about twice as dense as PB. Yes, the back was coated with iron, the same as the front but the front also had a coating of aluminum on the raised type.

I agree that the sign should have been backed with Aluminum or another structure especially considering the size...won't make that mistake again.

Let me ask you, if you had a two sided sign that was approx. 4' x 2' and it was going to hang from a post above the entry to a restaurant (above the sidewalk) would you worry about the expansion/contraction? and would you A) do two signs and laminate or B) a 2-3" slab of foam and carve both sides or C) something else? I ask this because most of the signs I do are more like 12" x 9" and a we bit larger but I did one for a place in NY and I hope it is doing fine..it has been about a year.

I wouldn't use 1" thick or a 2' x 4' double sided. hanging from the top of the sign, I would run flat bar on the top and bottom of a 1.5" thick or thicker mounted between posts or just one post, I'd run flat bar on the both sides

 

[TimToad]

No, the sign was not primed..if I was using Precision Board or Signfoam I would definitely have to use Duratec Primer but Duna's Corafoam takes the polyester resin beautifully and it carves the same plus this is their 31lb foam which is about twice as dense as PB. Yes, the back was coated with iron, the same as the front but the front also had a coating of aluminum on the raised type.

I agree that the sign should have been backed with Aluminum or another structure especially considering the size...won't make that mistake again.

Let me ask you, if you had a two sided sign that was approx. 4' x 2' and it was going to hang from a post above the entry to a restaurant (above the sidewalk) would you worry about the expansion/contraction? and would you A) do two signs and laminate or B) a 2-3" slab of foam and carve both sides or C) something else? I ask this because most of the signs I do are more like 12" x 9" and a we bit larger but I did one for a place in NY and I hope it is doing fine..it has been about a year.

If I put myself in the shoes of an innocent passerby as I always do when considering how to construct something from a liability standpoint, I always use some kind of rigid core and laminate my pieces to each side of it. We have to be able to bolt, screw, etc. into something that both passes our own liability considerations and our local sign codes.

Wind, exposure, vandalism (picture some punk jumping up and giving your HDU only sign a high five!), etc. also contribute to the loosening or failure of hanging hardware. A couple years ago I came up on a sign bracket to replace the blade sign that looked perfectly normal but the slight vibrating action of the wind over the years had literally worked the inferior plastic shields that were used loose and the only the sign gods know what was holding that whole thing up. We all gripe about the fly by nighters and inferior quality signmakers out there we have to compete against, the sign installer world is equally filled with hacks.

IMO, the best signmakers are the ones who both design and build the best signs, but also are the ones who also install their signs with the appropriate and sufficient hardware to insure safety and durability.

 

[Marlene]

If I put myself in the shoes of an innocent passerby as I always do when considering how to construct something from a liability standpoint, I always use some kind of rigid core and laminate my pieces to each side of it. We have to be able to bolt, screw, etc. into something that both passes our own liability considerations and our local sign codes.

Wind, exposure, vandalism (picture some punk jumping up and giving your HDU only sign a high five!), etc. also contribute to the loosening or failure of hanging hardware. A couple years ago I came up on a sign bracket to replace the blade sign that looked perfectly normal but the slight vibrating action of the wind over the years had literally worked the inferior plastic shields that were used loose and the only the sign gods know what was holding that whole thing up. We all gripe about the fly by nighters and inferior quality signmakers out there we have to compete against, the sign installer world is equally filled with hacks.

IMO, the best signmakers are the ones who both design and build the best signs, but also are the ones who also install their signs with the appropriate and sufficient hardware to insure safety and durability.

I couldn't agree wth you more.

 

[player]

I have seen hanging signs where the heavy chain has been almost worn through from years of swaying back and forth.

I started welding the chain so the sign looks like it can swing, but it is actually in a fixed position.

 

[Techman]

HDU is guaranteed not to warp.

I would contact the manufacturer and get some input from them.
Duna board is good stuff. Having to back that stuff when it is guaranteed not to warp seems to be an unreasonable expense. A closed cell product repels moisture and has no reason to curl or act like wood. It would be time to find a real expert to get an answer.

There are posts around different sites that show HDU failing like this. One common detail is that the panel was not painted the same on all the sides. To me that makes more sense as an explanation than anything else.

 

[Techman]

this is from another website written nearly 8 yrs ago.
I tend to agree..

One MAJOR Factor when first painting primer on HDU is to quicky paint BOTH sides of the panel ASAP....If only one side is painted, such will cause the HDU panel to bow or warp substantially...I think this has to do with surface tension that the drying paint film exerts on the HDU panel....I have certainly seen it happen....

here is another.

I'm guessing the face is the concave side. Yes priming one side especially with the auto primer will warp it. We do routing for a shop that uses the polyester primers and their panels are warped alot of the time and that's priming 2 sides. I think they put it on too heavy.

and more

The same number of coats of paint need to be put on the back as are on the front. Also, the area blasted or routed away creates tension on the face because that area is thinner than the rest of the sign.

and another

Precision Board Plus FAQS

Should I prime and paint all sides of my sign since Precision Board Plus does not absorb moisture?
Yes, Precision Board Plus does not have grain and therefore does not have the beam strength that comes with grain. This means Precision Board Plus can be pulled in the direction of the drying paint. All paints shrink as they dry which causes tension across the surface of the sign. The higher quality of paint the more strength this shrinkage has. Painting both sides of the sign with equal thickness of paint provides equal tension and will keep one side from drawing the other. This is especially true of dark colored, heat absorbing paints. See our Paint Tension Data Sheet.