Another question I am often asked when we talk routing is "Why do I recommend and always use 30 pound Precision Board brand HDU as a minimum standard?"
The answer is simple. Back when I first looked at High Density Urethane my concern was that it was fragile. The 15, 18 and 20 pound boards were easy to work. The material just evaporated under my tools, there was no grain to contend with, it held paint well and the material was stable. But there was a downside too. It was FRAGILE! Handled incorrectly a sign that I had labored over was easily and instantly damaged.
About eight years ago (before I discovered CNC routers) at a Letterhead meet in Minnesota I met Kellie Miller from Coastal Enterprises. I expressed my concerns to her about the fragility of HDU to her. She just smiled at me and dug under the display table and pulled out a sample of 30 lb Precision Board. As soon as it hit my hands I was SOLD. Coastal Enterprises was the only company to offer it and it is the lightest weight HDU in our inventory.
Later Kellie sent me some small samples of the various weights of the HDU's they make and sell. Precision Board is rated by the weight per cubic foot and ranges from 4 pound up to an amazing 90 pounds. I keep those samples handy and they are a great selling tool. When we are discussing signs and materials with a customer I pull out my sample of 18 or 20 pound Precision Board. I run my fingernail into it, breaking off a sizable hunk. I explain that is is the material most sign shops would use for their sign. I then whip out my sample of 30 pound board and hand it to my customer. They can't leave a mark. I ask them if they would be willing to pay a little more for that kind of quality. I always get a yes. The 18 pound board in the picture below bears witness to my abusing it for the sake of a sale. The 30 pound under it is still perfect.
The 30 pound (and forty pound too) still route at the same speeds as lighter weights. Gluing the pieces, and working them changes little. If I'm carving by hand I like to use a die grinder as it is easier and quicker than doing things with manual tools.
We are planning a new house, hopefully to be started soon. We plan on going crazy with our CNC router on that project. We'll be doing some projects that will call on even heavier weights of Precision Board. High wear locations like dimensional doors and such will get even higher densities. Will the raw material be more expensive? Undoubtably. But factor in the wear and tear they will be subjected to. I only want to do them once.
In our work, the last thing I want to do is skimp on materials. Quality materials and tools are critical to do a job right. In the end my labor and expertise are (or should be) worth far more than any other component of a project. Skimping on materials would only damage my long term reputation.
I simply can't afford anything less than the very best.