Needing advice with an HDU project

[UKSigns]

I've been assigned a very unfortunate job by someone extremely high up at the place where I work. The assignment, a 42" x 84" shadow box from 20# HDU. I've designed all internal elements to be attached to the wall separately, so the HDU frame will only be supporting a piece of .25" acrylic that weighs roughly 40 lbs., plus the weight of the HDU frame. I'm going to reinforce the frame with 3mm ACM from the rear, and then it will be primed, painted, clear coated, and wrapped in 3M DI-NOC vinyl. My questions are as follows:
• Once the ACM is glued to the HDU, will that be strong enough to support the 40 lbs. of acrylic and roughly 30 lbs. of HDU that makes up the frame?
• Can I mount French cleats to the ACM after the finishing work is complete?
• I'm assuming a point setter won't work in HDU, so is there anything else I can easily use to secure the acrylic in the HDU frame?
This frame needs to be easily removed from the wall to service the internal LED lighting in the HDU frame, as well as updating the printed map that will be behind the acrylic. TIA

 

[John_Smith]

Do you have any sketches, drawings, or sample photos yet?
WHY HDU vs plywood or ACM ?

 

[UKSigns]

 

[UKSigns]

 

[UKSigns]

Do you have any sketches, drawings, or sample photos yet?
WHY HDU vs plywood or ACM ?

HDU was chosen because of immediate avaialbility and need to wrap the finished product. We're a sign shop for a major University and don't do any in-house wood working. Most of our work is anything and everything printed, as well as ADA compliant signage galore. This is just a very special demand from a VIP with no direction, no contact, and a very short timeline for completion.

 

[UKSigns]

HDU was chosen because of immediate avaialbility and need to wrap the finished product. We're a sign shop for a major University and don't do any in-house wood working. Most of our work is anything and everything printed, as well as ADA compliant signage galore. This is just a very special demand from a VIP with no direction, no contact, and a very short timeline for completion.

Since this shadow box needed to have a pull-out drawer on either side, I made a frame and drawers of 6mm PVC sandwiched between two layers of .030 impact styrene. There will be Teflon tape to help with any friction on the drawers and the top layer of styrene will be held to the PVC frame with magnetic materials. On top of those 3 pieces will be will be a shape routed from 3mm ACM held in place with anchored stand-offs. The frame fits over everything else and just needs to support the weight of the clear acrylic face and minimal weight of the LED lighting.

The drawers and the routed shape will have prints that will change with time. Why they chose this direction instead of an interactive display is beyond me.

 

[Ryze Signs]

I would have built the whole thing out of Aluminum or aluminium as you would say over there. They make all kinds of different extrusions that are similar to the shapes you are trying to achieve. If you don't have the capability to fabricate then find someone that does and sub it out. I don't think I'd ever use sign foam (HDU) for anything structural like that. Wood, PVC, acrylic are all good options but aluminum can be cut bent, welded, painted,wrapped, etc.

Wood would be my second material choice. I know you said you don't do woodworking in house, but all you need is a router to cut what you need. If you put a decent finish on the wood it could easily be wrapped.

 

[John_Smith]

Agree with Ryze - you are not applying the wrap directly to the bare HDU are you???? Assuming you will be priming and painting everything appropriately, you would have to do the same process for aluminum and wood.
How long will this project be expected to last? Is it a temporary display or will it have to last a decade?

 

[UKSigns]

I didn't have time for anything else. It was very difficult to find anyone that could CNC what I needed in short order. Aluminum couldn't happen because there's not enough support in the wall to handle the weight, I don't order aluminum extrusions on any kind of regular basis, and the powers that be didn't want to add the bracing in the wall. Wood at this size would have been unrealistic and expensive as this person would not accept plywood. It would have had to been of hardwood that I have no sourcing for.

Yes, it's getting sanded, surface primed, sanded, epoxy primed, painted, wet sanded, painted, clear coated all in Matthews paint before it's wrapped in 3M DI-NOC arch vinyl.

 

[jfiscus]

It is looking nice so far, pop back in and post up some completion photos if you don't mind!
If you ever have a project needing complex woodworking, we have a master carpenter on staff here who would love to help you with any wooden projects you have.