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I have made two attempts at these projects, one of them several years back, before I was in signs. The first one as I remember, we used white silica sand by the bag, and 3-m hand cut gravestone stencil. The sign cut very quickly and deep. Today I went to a similar company which was blasting with the black beauty. It is much grainier and I was afraid that it would cut even much faster, but even with 120 lbs of pot pressure and a firehose size nozzel it took quite a bit of blasting to get the depth even respectible. I really didn't have the other problems, with it sticking in the grains, but it did leave dent impressions through the resist, and when I took the resist off it pulled my redwood grain and primer off in several spots. It appears that the pressure of the larger black beauty didn't cut as well, but the pressure was to much on the resist. The redwood was sealed with Sign Life - First Step redwood primer. Is this just a problem with the wrong materials. I am able to salvage everything with sandpaper and elbow grease this time, but...... Are these common problems? One other question, Do some of you paint to your finish coat before you blast and then just touch up the copy?
------------------ Jack Davis 1410 Main St Joplin, MO 64801 www.imagemakerart.com bronzeo@prodigy.net http://www.imagemakerart.com
Posts: 1549 | From: Joplin, MO | Registered: Mar 2000
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Jack, I have known West Jenkins (that used to work for Anchor Continental) to swear by applying the finish paint before applying the sandblast resist. I have NEVER had any luck doing this. Now, I just use the Anchor #117 High Tack stencil applied directly to raw wood and sand with a 6" random orbit sander after blasting. I just don't need the aggravations of grain and paint pull up. And, recently, I have come to LOVE the #116 med. tack when it comes to blasting prepainted SignFoam! Now, THAT works!!! Just find what works for you . . .. and, keep on keeping on !!
------------------ John Smith Kings Bay Signs Kingsland, GA
Purveyor of fine signage and Innovator of good things yet to be
www.finewoodsigns.com
WoodCarver on mIRC chat
Posts: 817 | From: Central Florida - The Sunshine State | Registered: Jan 2000
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Jack,everyone has their own ideas about what to do...here's mine, keep in mind I just did two today and it worked perfectly.
I never try to pre-coat a redwood sign,too much can go wrong!
After my slab is ready(cut to size and shape), I belt sand the slab making the surface as smooth as possible and then I finish the edges of the slab with the router blade of choice (round over,ogie,bevel,etc.)This gives me a "roadmap" for adding borders and tells me exactly where copy goes.Next I coat the entire face of the slab with Lacquer sanding sealer,this penetrates the wood and makes the surface stable so you don't rip out pieces of the face with the sandblast mask (when removing it).after the sealer has set up, (usually about and hour) apply your sandblast stencil(only on the flat face)I use 2 layers of duct tape around the edges and try not to blast it any more than necessary (more than adequate).Roll down the mask with a printers brayer (I made one out of a 3' roller handle covered with a piece of pvc)use a "pica rule"(one with the hook on the top)and measure in from edges and mark the stencil with a ballpoint then draw on your borders, if you make any mistakes lacquer thinner will erase the ballpoint markings (it will not hurt the stencil)After you apply pattern and cut your stencil,roll down the stencil one m,ore time.This next part is crucial,use only "fine grade"brown sand, the grit number is 20/50 .It cuts better than anything else I've ever used and leaves no residue embedded in the wood.
When you blast stay well back and move around the entire surface until you identify ther soft spots and hard spots,then blast as you see fit until you reach a depth of 3/8 to 1/2 deep over the entire surface. If your mask turns brown as you blast you are staying too long in one spot (you are burning the stencil)back off.Blast straight on (angles under cut the wood and blows off stencil. After removing the stencil once again belt sand the entire surface (first with 50 grit then with 80)This removes the leftover adhesive andsmooths out any areas the stencil may hve pulled,the reroute the edges (slightly deeper) next sand with a vibrating sander.
Now you are ready for paint... I use Ace brand 7 Star exterior flat for all exterior work...(2 to 3 coats always)then all lettering is 2 coats of paint(I prefer Chromatic some like 1 Shot)Sometimes I coat the flat surfaces with enamel and the apply vinyl(works great).
Well I gave you more than you wanted but "it werks fer me and it'll werk fer you"
If you have any other questions e-mail me at <jumpers@telepath.com> Also you may want to check this site out for a couple of my older signs (not much there,but it's a free look) http://members.tripod.com/~JumpersSIGNLanguage/index-3.html
------------------ Monte Jumper SIGNLanguage/Norman.Okla.
[This message has been edited by Monte Jumper (edited April 26, 2000).]
[This message has been edited by Monte Jumper (edited April 26, 2000).]
posted
The depth and blast time always vary, depending on how soft the wood is. I have had some boards that blast in seconds, and others which were harder that seem to take forever to get an acceptable depth.
I have blasted over 300 redwood signs in the last few years. I always used First Step and prepainted all my graphics & letters with One Shot and masked with Anchor medium tack rubber. The only time I ever had a problem was when we tried blasting with black beauty or blackjack. It just doesn't come fine enough and it will break the paint bond at the edges of the rubber. Use a fine silica sand. It should have the consistancy of sugar. It used to be called "sugar sand" years ago. The high pressure also did the damage away from the edges. 90 psi should be max. I've had occasional redwood boards that just took longer to blast. Density of wood varies greatly.
In my experience the prepainted method is much faster and I've always had crisp clean edges.
------------------ Dave Sherby "Sandman" SherWood Sign & Graphic Design Crystal Falls, MI 49920 906-875-6201 ICQ: 21604027 sherwood@up.net
Posts: 5397 | From: Crystal Falls, MI USA | Registered: Apr 1999
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Bronzeo, I agree with everything Dave Sherby says on this. In addition to this, we've found that the longer that we alow the topcoat to cure before applying the stencil and blasting, the better. We allow our painted blanks to cure for about a week before blasting. We too use Anchor medium tack stencil and keep the pressure at no more than 90 psi. As someone posted above, keep the nozzle moving. Sweep back and forth parallel to the grain and try to sweep it fast enough accross the sign that the tan colored stencil doesn't "burn" or darken at all. If you've ever blasted at night or late in the evening, you'll see that the point of impact of the sand with the wood gives off fairly bright light and heat.
------------------ Wayne Webb Webb Sign Studio,Inc. Blastin' "woodesigns" in The Sunshine State "autograph your work with excellence" webbsignstudio@digitalexp.com
Posts: 7404 | From: Chipley,Florida,United States | Registered: Oct 1999
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Wayne, I'm going to blast some redwood at night just so I can see that. Cool!
I agree with you 100% as to letting the paint cure completely and keeping the nozzle moving.
Don't you just love it (NOT!) when you get one of those boards where the wood between the growth rings just keeps blasting deeper but the growth ring itself just won't blast away at all?
------------------ Dave Sherby "Sandman" SherWood Sign & Graphic Design Crystal Falls, MI 49920 906-875-6201 ICQ: 21604027 sherwood@up.net
Posts: 5397 | From: Crystal Falls, MI USA | Registered: Apr 1999
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Yea Dave, ain't that frustrating? Sometimes you can blast two boards that have identical looking growth rings and one will blast evenly and the other does what you mentioned above. I haven't completely figured that one out yet. I think sometimes using a little coarser sand and/or a "richer" sand/air mix in the blast might help. Thankfully it doesn't happen too often but I have stopped blasting to rub the growth rings off, being careful not to damage the graphics, and then blast over it again. If they're left on the finished sign, they have a tendency to crack, split, and come loose leaving strips of bare redwood showing. PS If ya blast at night, don't stay up too late!
------------------ Wayne Webb Webb Sign Studio,Inc. Blastin' "woodesigns" in The Sunshine State "autograph your work with excellence" webbsignstudio@digitalexp.com
Posts: 7404 | From: Chipley,Florida,United States | Registered: Oct 1999
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