PDA

View Full Version : Extira...living and learning



jshoes51
04-19-2009, 11:51 PM
I volunteered to make new signs for the local village library. Since they exist entirely on donations, and always struggle for hand-outs to pay for maintenance etc, I decided to give Extira a try instead of HDU for the 6'x4' oval signs they asked for. I got two sheets of 1" as they'll get mounted on each side of posts already spaced about 3' apart.

I did a search about Extira beforehand as I had read about its painting issues. I washed both blanks down with soap, water and scrub brush, let them dry overnight, then primed with Sherwin Williams Prep-rite quickseal, an oil-based primer/sealer. I lightly sanded that, then followed with three coats of Ben Moore Aura acrylic latex paint. I brought them in the house and put them near the woodstove for four days before masking and carving.

I used Gerber sign mask, and when I gingerly pulled it off, enough of the paint came with it to wreck the job. It didn't come off with the mask, but it did pull up in little blister type areas that I could easily pull off with my fingers.

I'm a pretty patient person so instead of getting out the sledge hammer, I thought about it overnight. The next day I got out my 6" fein sander and stripped all the paint and primer off the sign, which left me with nice, gold painted carved letters surrounded by bare Extira. This time i went to Extira's web site and bought the Zinsser oil base cover stain primer recommended. I lightly rolled on a primer coat so hardly ant paint went down into the letters. I followed with a couple very light coats of topcoat rolled on.

Now I have an idea which may be may be sheer folly or may be worth a try, so I thought I'd mention it to see if anyone has tried anything like this or has any advice to save me hours of handpainting. I'm thinking I might be able to fill all the carved letters with water and then spray on the final top coat with my HVLP sprayer. That would keep the top coat out of the carved gold letters, and when it dried, I could just drain the water out. If the HVLP air stream is too strong and blows the water out of the letters, maybe I could thicken it with something? Has anyone ever tried anything like this? The worst thing that could happen is having to sand all the paint off again and start over.

joe
04-20-2009, 12:15 AM
Jim,

Thanks for posting your experience with Extira.

I've posted on the topic several times. One of my most successful techniques has been to coat with a epoxy wash. This is regular epoxy thinned down about 20% with lacquer thinner. This will soak right in and give your the surface stregnth needed. Two coats are best. At this point you can prime with most any primer since the oily surface is isolated.

I use soap and water on most panels but when using any mask it's best to go the extra distance with epoxy.

If this was my job, I would have used good old MDO or HDO. I've gotten away from the 1" Extira due to the weight. Installation is also a problem with extira. It has soft edges which should be sealed up well. They are proned to flaking and this material will warp without cleates.

Keep us informed.

Joe Crumley
www.normansignco.com (http://www.normansignco.com)

zeykr
04-20-2009, 09:17 AM
Interesting idea Jim, don't know if it will work or not, but please let us know the results. I wonder if you could add gelatin to thicken?

dakers
04-20-2009, 09:42 AM
Jim,
I am a sign painter so i would probably just roll the top with a thin foam roller like pro tiz with light pressure. and touch up letters later with the gold paint. since the letters are routed it is easier to touch up with small brush. The worst case scenario is that i would have more time in it than i wanted to have but i would be done with it.
I have experienced these learning curves.
There are alot of solutions for preventitive problem solving depending on each substrate/situaion/deadline/expectation/

rb99
04-20-2009, 10:11 AM
Don't try the water.

RB

ndupuis
04-20-2009, 12:20 PM
Hi all
First, Excuse my format text
I use extira for my sign, and I dont have a problem.
Here my method
First: I wash the extira with tps www.recochem.com/.../tsp_trisodium_phosphate (http://www.recochem.com/.../tsp_trisodium_phosphate)
Second: I apply the cheap varnish to fix the grain of extira
third: little sanding + two coat of alkid primer
fourth: litlle sanding and two coat of alkid paint
5: litlle sand and apply clear coat (Impotant: without reducer)
6; I apply the paint mask avery before carving
7; carving
8: paint or apply gold leaf
9: remove paint mask
the result is very good
Norbert Dupuis
www.vectorclip3d.com (http://www.vectorclip3d.com)

5640

jshoes51
04-20-2009, 12:53 PM
I'm going to do what Dick said...roll on another light coat and touch up the letters. But I an going to experiment on some scrap with the gelatin idea. My wife said to use unsweetened gelatine or the birds and bees would be all over that sign. I'll post results.

joewino
04-20-2009, 02:41 PM
This is just my opinion, but it seems that you have to go to a lot of time and trouble to get Extira to work correctly. I would rather just use HDU.

knight_toolworks
04-20-2009, 03:30 PM
I ne3ver tried this mate3rial but if it is a bit oily i would think epoxy would have issues. what about shellac? it will stick to anything. or shellac based primer.

joe
04-21-2009, 09:04 PM
WOW,

Now we know what a lot of experts think!

ndupuis
04-22-2009, 08:34 AM
Steve
I'm tried several products including shellac, and it did not work,
when I tried to peel the paintmask, the paint come off with the mask, since I use varnish, nothing takes off and remains strong, because most varnishes can a phenolic resin component and extira also has a phenolic resin as a component , so by putting a light coat of varnish, the extira becomes saturated and the extira grain are fixed.