New to HDU for exterior signs

purpletang

New Member
Quick version: My dad wants me to make him a double sided, routed, painted, hanging sign for the end of his laneway. It will be oval and about 30" max length and It needs to survive year round in Southern Ontario.

I was told to use HDU. I'm ok giving that a shot even though it's pretty pricey material.

My previous experience with my small CNC machine is primarily smaller interior signs etc.

I talked to a guy at the supplier and he said I should laminate 2, 1.5", 15# boards together around a metal frame so the sign can handle winds without disintegrating itself against the post it will be hung from.

Does this all make sense?

Thanks, Scott
 
Your main concern is prepping and painting the HDU after t's been carved Those steps are critical in the longevity of that kind of sign. The aluminum frame inside is a good idea.
 

Gino

Premium Subscriber
Don't do many HDU signs, but the Jay Cooke primer is really good. Most of the time, we'll use two coats of primer with a light sanding in between. This way you really are sure you got all the crevices. I almost always use an oil-based top coat with at least two coats or even a third for good measure. Are you spraying, rolling or brushing ??
 
You can route a channel in the back of the HDU to fit a frame for an "invisible" look. Or attach the backs to an ACM panel for a sandwich look. Jay Cook's is a good quality high-build primer that is easy to sand. It's what I use. Top coat with acrylic polyurethane, and if you don't have that capability high quality acrylic latex works fine. No need to top coat (I do not recommend not top-coating latex; it will fail before the paint will).
 

purpletang

New Member
Don't do many HDU signs, but the Jay Cooke primer is really good. Most of the time, we'll use two coats of primer with a light sanding in between. This way you really are sure you got all the crevices. I almost always use an oil-based top coat with at least two coats or even a third for good measure. Are you spraying, rolling or brushing ??
I plan on brushing and rolling - there are some detail spots that would be a tough go without a lot of masking and are likely easier to brush in.
 
Top