I have fallen in love with Extira !
You can get it up to 1 1/4 " thick. It machines like HDU (slower feeds) It accepts paint finshes much better than HDU !
The big seller for customers is that it has a really good "green" attribute. It isn't made from the wood of old growth forest . It isn made from farmed wood combined with recycled wood.
It is rot proof,termite proof, and much stiffer than HDU.
I made several 8ftx4ft HDU signs . I had to use 2 sheets of 11/2" HDU and put a sheet of PVC between them to add some rigidity. That made the substrate overhead over $700.00.
The last 8ft x4ft I made was with 1 1/4" Extira.
The sign was double sided . But the Extira is much more rigid and heavy. So it was even stiffer than the 3" of HDU and PVC !
I used 1 sheet of Extira and half the time to paint it, because it doesn't take 2 days oof primer,sanding,primer,sanding to get ready for paint.
I just picked up 20 sheets of this stuff in various thicknesses!
Best of all ..........the Extira was $118.00 for a 4x8 sheet for the last sign !
The down side is that it takes 2 men to load a sheet on the Bot, and I can load a sheet of 11/2 HDU by myself. It's heavy!