We are installing large vinyl backed murals onto 1/2" foam core. Large as in 7 feet by as low as 7 feet side by as long as 13' wide.
The foam core is preassembled with tape on the back and thickened epoxy at the seam. The core has low shear, so the epoxy is supported by the tape and eventually the mural itself.
We tested various adhesives and all wallpaper adhesives failed to bond well. We also realized we needed to seal the foam core and are using Roman 999. The glue we are using is actually flooring adhesive. The flooring adhesive passed our test which was to have a shear failure in the core. All other adhesives failed to bond well to the mural.
The only issue is the adhesive application is with 1/16th or 1/32 trowels and we are getting quite a bit of air pocketing. Due to the size of the mural; they are rolled onto a pvc tube and rolled off onto the glued surface carefully to help stay square to the core.
The resultant parts looks good, but I am wondering if anyone can advise a way to improve.
Some ideas....
Use a wide glue roller and roll the glue on flat and without the lines which are air, or after troweling; roll the glue flatter. This sounds ez, but a little daunting to end up line free.
Use a weighted roll off tube. Our roller is a piece of 3" pvc. We could put some sand in it and cap it on the ends. The table is designed specifically for the mural height.
Use a different glue? I don't see this is an answer, although a spray adhesive might have less air pocketing; the murals are too heavy to slip sheet and we would need to wear respirators and build a spray chamber and we might still get some bubbling.
Thank you for allowing me to post. I can add some pictures later.
The foam core is preassembled with tape on the back and thickened epoxy at the seam. The core has low shear, so the epoxy is supported by the tape and eventually the mural itself.
We tested various adhesives and all wallpaper adhesives failed to bond well. We also realized we needed to seal the foam core and are using Roman 999. The glue we are using is actually flooring adhesive. The flooring adhesive passed our test which was to have a shear failure in the core. All other adhesives failed to bond well to the mural.
The only issue is the adhesive application is with 1/16th or 1/32 trowels and we are getting quite a bit of air pocketing. Due to the size of the mural; they are rolled onto a pvc tube and rolled off onto the glued surface carefully to help stay square to the core.
The resultant parts looks good, but I am wondering if anyone can advise a way to improve.
Some ideas....
Use a wide glue roller and roll the glue on flat and without the lines which are air, or after troweling; roll the glue flatter. This sounds ez, but a little daunting to end up line free.
Use a weighted roll off tube. Our roller is a piece of 3" pvc. We could put some sand in it and cap it on the ends. The table is designed specifically for the mural height.
Use a different glue? I don't see this is an answer, although a spray adhesive might have less air pocketing; the murals are too heavy to slip sheet and we would need to wear respirators and build a spray chamber and we might still get some bubbling.
Thank you for allowing me to post. I can add some pictures later.