I would like to know from other sign carvers and sandblasters what they think about Extira? I've carved it and sandblasted it, but am somewhat concerned with it's longevity. Except for occasional vandalism, I have been well pleased with high density urethane for it's longevity. I like the heft and density of Extira and feel that many of my clients would be happier with that also.
Posted by Cam Bortz (Member # 55) on :
I personally prefer higher-density HDU (18lb or more). The only drawback with HDU is the lack of structural strength; I solve that by either laminating another material to the back, or with internal steel support between matching faces for DF signs. Also, HDU has great paint adherence, something that I've heard can be an issue with Extira.
Posted by Jonathan Harvey (Member # 6580) on :
I just did my first extira sign about a month ago. I loved using it. It cuts good, sands easily, You can basically do the same or even better with it than MDO no holes to fills. Except for the fact if you have concrete floors, with the dust extira gives off you are liable to break your neck(the floors get super slick). I painted it with one shot black and overlaid with colored sticky stuff. No problems so far.
Posted by Richard Heller (Member # 2443) on :
Robert, I am working in the Cleveland area as well, and I have worked for a couple of local shops that have used Extira with no problems. Some of the keys are to ease the sharp edges, and the manufacturer recommends water based paints, which might be the issue Cam refers to if people have been using 1-Shot. We have used Porter, TJ Ronan Aqua Cote and other house acrylic paints with Jay Cooke's primer and the projects have held up for years.
I agree with Cam on HDU being the best product especially with all the heavier densities available today.
Posted by Joe Crumley (Member # 2307) on :
It has a place in our shop. Gotta be choosey though. As Jonathan mentioned the dust left behind is very oily. It sticks to equipment and is slick on the floor.
We had some paint adhesion problems at first. Since it's made with water replant oils, water based primers aren't a good idea. If you must, a quick wash off with soap and water will help.
Our standard coat out process is a light epoxy wash. It's Epoxy diluted with 30% lacquer thinner.
I've found HDU much better for deatail work on the CNC.
But both are floppy at legnth. Neither have fibers that allow for good screw holding power.
Just a thought are two.
Posted by Robert Malkamaki (Member # 4817) on :
Thank you all for your input.
Posted by Doug Bernhardt (Member # 1568) on :
I also have used it with some reservations. I finished with oil paints and the usual 1-shots and gold leaf decoration. That was 4 years ago and I go by it several times a month....no probs so far!! The reservations are sharp edges and would sand them slightly.
Posted by Joe Crumley (Member # 2307) on :
I agree with Doug.
Because the material is a little soft, it's prudent to ease edges over a little. For that reason we've used the thinned down epoxy as a stiffner
I've found Extira carves like butter but healthy stop cuts are necessary.
It's also great for fluted post covers over treated 4"X4"s.
