I'm a new member. I'm an embroiderer who started doing vinyl signage as a complement to my embroidery and screen printing biz.
I would like to try sandblasting signs on large rocks/boulders. However, I am a complete novice at sandblasting and I have a couple questions.
- what type of sandblast material is recommended for rock (sandstone is the most common rock here in my area of PA) - what type of paint is best on rock - also, what type of sandblast material works best on wood (cedar)
Thanks, Rege George
-------------------- Rege George Swiss Mountain Design Pittsburgh, PA rege@swissmountaindesign.com Posts: 2 | From: Pittsburgh, PA | Registered: Aug 2003
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I do quite a bit of this type of work. Currently, I have two orders in house, for which I can explain my process and the materials I use.
I use Intertape Anchor #116 high tack sandblast stencil for most all applications. (wood too)
1) Sandstone Boulder: The surface of this stone is a bit worn and not clean. I'm going to give it a light scrub (no soap) and a rinse, then allow it to dry in the sun. Before I apply the sandblast stencil, I'll give it a wipe with laquer thinner then blow it off. Giving it some air time before I apply the stencil. The surface isn't totally smooth, so basically, I massage the stencil to mold it into the uneven surfaces. Voids and air pockets will cause the stencil to lift during the blasting process. I allow a good 8" of stencil, bordering the area to be blasted. We blast using 30/45 sand. Pressure no more than 80-90 lbs and less, depending on the stone.
If stencil begins to lift, during blasting, I use 3M77 spray adhesive to re-attach the stencil to the stone.
The blasted areas of this stone will be painted, using OneShot Lettering Enamels. Depending on the job, I may or may not remove the stencil before I paint. I have never used a primer. Thinning the paint, will create a stained look. I've used an airbrush too. Sometimes, paint isn't necessary at all, it will depend on the look you wish to achieve.
Some glue may remain when removing stencil. Sometimes, the adhesive on the stencil will pull it away, with a dabbing motion. On more difficult or excessive adhesive left behind, I usually use sand and a putty knife to work it and scrape it away.
I give everything a final rinse before turning it over to the customer. Take a picture, when it's wet, the colors are awesome!
***One note about boulders; a forklift will come in handy and in my case a necessity!***
2) 12"x12" (man-made) patio stones: These are for a memory walk and require names and numbers to be blasted into the surface.
The minimum height of letters I will blast is .75". Any less and the insides of P, A, R, etc. will blow away. I choose fonts with large 'insides' to avoid fallout. I may also cut the points off W, V, N, etc. because the surface area/adhesive is so small, these areas of the letters tend lift and lose definition.
When blasting small letters, spacing can also be an issue. Straight strokes, side by side with little adhesive/surface area can become a potential hazzard and lift.
These patio stones will be painted and I am leaving the stencil intact. I'll paint them, using Rust-Oleum Satin Black spray paint. Before I paint, I hit the surface with a blast of air. This will show me any areas that are not adheared properly and will produce bleeding edges. I tack lifting areas with 3M77 Spray Ahesive. I spray them, lying flat, with 4 light coats, each from a different direction for good coverage.
I remove the stencil after the paint is completely dry. I use a putty knife/scraper to remove the insides of letters.
I touch up bleeding edges with carefully mixed OneShot paints.
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I don't know your set up or if you intend to do your own blasting. I am fortunate to work in the same building, with a sandblasting company. Sandblasting is a mess and a health hazzard.
Working with these products (stone, bricks, pavers, patio stones, etc.) requires a lot of baby sitting, on my part. Sand, (stone, etc.) isn't the easiest substrate to work with and I can usually expect some fallout, here and there. I am always available during the blasting process, something usually goes wrong and needs fixing, right then and there.
Bricks, are a pain in the butt, because the letters are so small. People want to put their life story on them, within the constraints of 4"x8". I do my best to discourage this, but no one pays attention and they all want to get their money's worth...lol
Pavers, have a smooth surface, but blasting eats into it and reveals an agrigate. The agrigate and sand blasts unevenly and most times, the color is skewed, and is undesirable in appearance, IMO. These look best when sealed with a clear coat. I don't clear coat them, I leave that up to the company doing the installation. Clear coating, is a maintenance issue.
Glass & mirror, is another interesting substrate you did not mention. Lots of potential here too.
These products do not come cheap. Not everyone is set up to provide them and it's something rather out of the ordinary. ($$$)
Hope this helps!
Cher.
-------------------- Co-Host: SANDCASTLE Panel Jam 'a Dixie Letterhead Reunion' Fort Myers, Florida
Cheryl Lucas a/k/a "Shag" on mIRC Vital Signs & Graphics, Etc. Cape Coral, Florida 239-574-4713 VSignsNgraphics@aol.com Posts: 987 | From: Cape Coral, FL USA | Registered: Aug 2000
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I thoroughly enjoy making sandblasted signs, but I feel I must be honest & say that the actual sandblasting part is akin to the hardest industrial labor I've done in my life. Of course, the right set up can make it a relative breeze.
I've worked with HDU, redwood, spanish cedar, cypress, marble and granite.
When we blast, we rent an industrial compressor that is towed behind a truck like a trailer. It's huge, and is the same type of machine the industrial sandblasters use. Our 6lb pot & hose setup is the same too. We basically use as much output as that setup can deliver & I can't imagine being able to get anywhere with anything less. When your sandblasting you wan't to get it knocked down, make it pretty, & go take a shower. We are fortunate to have a rural outdoor invironment to work in. The sand basically goes in the low spots.
When we blast granite it usually has a smooth finish, so we use a lower tack stencil that doesn't leave as much residue behind.
Lots of local sign companies use a sandblasting company to blast their signs.
It's great to have ultimate control over the entire process though.
Oh yea, we use #4 fine sand for everything.
-------------------- Glenn S. Harris
....back in the sign trade full time. Posts: 293 | From: Baton Rouge, LA, USA | Registered: Jul 2001
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I always like to be trying new things and learning. I have never sandblasted and was anxious to try it. Now I wonder how sane I am :-) Never the less, I'm always willing to tread where only the fools go.
I was looking at ultimately doing boulders that can't be taken to a shop. So, it would be on-site work. I had already assumed that clean-up wouldn't be that much of an issue. (Glenn's approach of filling the low spots.)
Is it safe to assume that you both use regular silica sand rather than aluminum oxide or silicon carbide?
Again, thanks for all the help!
-------------------- Rege George Swiss Mountain Design Pittsburgh, PA rege@swissmountaindesign.com Posts: 2 | From: Pittsburgh, PA | Registered: Aug 2003
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posted
I guess its in the eye of the beholder. For me sandblasting IS fun. I love carving away layers of rock, wood, HDU, glass, what ever.
I am allergic to cedar so I don't work with it. But before I knew I was, I didn't like cedar. I don't like the way it blasts, feels, cuts, paints, stains. HDU is my favorite followed by redwood.
I use silica sand outdoors and aluminum oxide indoors for signs, silicon carbide for glass. Silica is very hazardous. Use a pressurized hood with proper filters when using silica sand.
Cheryl, unless you have a polished rock, why not stand back and give it a light blast after the stencil is removed? Ta da... new rock. I've done this several times. Just a quick dusting gets rid of all the nasties and doesn't do anything noticeaple to the letters. Of course only unpainted or painting after stencil removal.
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