In January, I am meeting with a potential client who will require my service, to sandblast and paint granite.
While I have sandblasted plates of granite, I have not yet had the opportunity to work with pieces I couldn't tote around with my own two hands, nor have I painted them.
I have painted several other different types of stone. No special preparation, blast & paint, with OneShot. Never had any complaints or call backs.
In my initial conversations with this client, I was told; currently, the sandblasted areas of the ganite are painted, using automotive paints. Typically a minimum of three colors per unit, then clear coated. (I am only familure with OneShot enamals.)
Any suggestions on preparation, paint and clear coating?
Also, I'm concerned about storage and moving the pieces around. I can expect to receive shipments of granite, polished on one side, sizes ranging from 2"x8"x8" to something the size of a water cooler. Quantities, in excess of 20 units/each size. I would imagine it will ship in crates, but haven't a clue.
I suppose, I need to figure the necessary preparations to ship the stuff back out, too! (direct to the end user)
Why, do I sense this potentially on-going project, isn't quite within my normal scope of work and my current pricing scheme? I suspect, there's a lot more to it, than meets the eye.
Anyone, care to elaborate on pricing projects like this?
I'm hoping, with the knowledge I receive here, I will have my ducks in a row in regard to process, product and procedues, not to mention the confidence to quote my prices at a reasonable rate, to which both my client and myself will be pleased.
I look forward to your comments and opinions...
Cher.
Posted by Laura Butler (Member # 1830) on :
Contact John Yarbourough in Mississippi. He showed us his setup when we were down there for a letterhead meet last year. 662-843-3548
Posted by Wayne Webb (Member # 1124) on :
We just painted a granite monument using Lithichrome paint. You can get it from a monument supply.
Lithichrome
Posted by John Arnott (Member # 215) on :
I was told at a letterhead meet in Niles MI. that it cost $2.00 per S.I. to blast stone. That was in the 80's. Most jobs that I have seen are painted with a spray can. Please let us know all the details that you learn when this job is done. Have fun John
Posted by David Harding (Member # 108) on :
Sandblasted Granite signs have been our main line of business for over ten years.
I use Anchor Continental #117 mask for computer cut portions, and fill in with the same grade of mask on 25" rolls for large areas to be masked. The bulk 25" is not punched and costs about half as much per square foot as the punched version. I think the product number for the bulk is #111. The #117 is a lower tack version than what would be used on raw wood. Hartco also has mask that will work, although I rarely use their brand–a personal preference, not a performance issue.
You can also tape cardboard or hardboard to the large areas to be protected using duct tape. I buy from a tape manufacturer a special duct tape that is extra thick. I get a case of 24 rolls at a time for around $170.00.
If you have a raised section of a graphic that will be painted, strip the mask and frost that raised area to give some tooth for the paint.
After blasting, I leave the mask on and prime with white shellac (about $15 per gallon at Home Depot). Once the primer is dry, I spray with automotive acrylic enamel. Spraying the automotive paint works better than brushing since the paint is much thinner than lettering enamels. The sandblasted areas have many small sharp facets that are covered better with a sprayed paint coating. I do not clear coat. If I felt a need to clear, I would use Pelucid.
Once the paint is dry, strip off the mask. The ridge of excess paint can be trimmed with a razor blade. You can also use a cuttle bone to clean any excess paint off.
I have been told that Lithichrome paint is essentially lacquer. The formulation is relatively unchanged for 60 years, so it may be true.
I have had white One Shot peel off Granite after a few years. Deka white would not stay on, however, Deka Fire Red adheres tenaciously. Spray bomb Krylon holds up very well–it probably is quite similar to Lithichrome.
If the pieces are shipped in, you might use the same crating to ship them out. Granite is best shipped on edge. If shipped flat, the pieces can get broken due to rough handling. I have had some shippers refuse to accept Granite because of potential liability for breakage, although I have never had a piece broken in transit. Testing the effects of the laws of gravity and inertia by installation gorillas is another story.
We mask, prep and finish here but I do not do the actual sandblasting. I transport it to a commercial sandblaster about 6 miles away. The cost to get a panel sandblasted is approximately 20% more than a comparable HDU or wood panel. The Granite blasts slower but there is less to cut since it is usually the lettering being carved, not the whole background.
If anyone has questions, they can call me at 972/245-1356.
Posted by Ron Percell (Member # 399) on :
Typically once the blasting is completed, use 2-4 coats of shellac, this creates a water barrier, then automotive paint & clear coat. Make sure the shellac doesn't contain any waxes that accelerate drying time, this can interfere with adhesion.
Bid your job by Material cost doubled(mask, aggregate), Labor(prep,paint,delivery), & then add 10% profit, if you desire more, increase your profit to say 20%
Good Luck
Posted by Cheryl Lucas (Member # 1656) on :
quote: Once the primer is dry, I spray with automotive acrylic enamel.
I swear, everytime I enter an automotive paint store, I am totally out of my element and I am never looking for something to paint an automobile. If I go in there asking for automotive acrylic enamel, do ya recon they'll give me exactly what I need or will they start spouting off questions? The first that comes to mind is; what kind of automotive acrylic enamel? lol, it happens everytime... Is there a particular name for this product? Is it two part? What products do you use for clean up?
For the life of me, I can't remember what a cuttle bone is. (?)
I share space with an industrial sandblaster, so I won't be toting the pieces far, just figuring out where and how to store 'em and how many times I'll be moving 'em around is the issue, for now.
David, when you are required to spray multi colors, what material do you use to mask, to prevent overspray from getting on the other colors? Mine, will be as close as 1/8" apart. How long does it take automotive acrylic enamel to dry? Does it cover the primer well enough with a single coat?
Thank you all, this has been very informative...
Cher.
Posted by David Harding (Member # 108) on :
The automotive acrylic enamels I use are one component, air dry products. They were used predominantly 30 years ago and are actually considered obsolete by today’s standards. Since most current paints are basecoat/clearcoat multi stage products, I sometimes have to press the store a bit to give me the correct paint.
Acrylic enamels usually cost me $30-$40 per quart. The store will have a reducer to use as well. The reducers are considered fast, medium and slow, depending on the temperature when you spray. The fast reducers are for lower temps. I have also reduced with straight toluene with no bad results. You can clean your equipment with lacquer thinner.
Most automotive paint stores have books by make and year in which you can choose colors. Usually, they will also have a book which is more of a pallette of colors, often for trucks. That is the one I choose from. It is often too hard to find your color match by going through all the manufacturers and their models. The stores will also be able to mix most colors in pints.
Also available are spray cans with touch up automotive paint. I have even seen those at WalMart. That should do the trick as well, although that is probably the most expensive way to buy the paint.
Acrylic enamals dry to the touch in a matter of minutes and dry quite hard in a few hours. They will often cover with one coat but since they dry so quickly, I usually do two or three thin coats a few minutes apart.
If you wait overnight to recoat, the fresh paint may lift the older paint since the recoat window is usually less than two hours or past several days. They should have a tech sheet that gives paint/reducer mixes and time between coats. If not, you can usually download the info from the manufacturer’s web site.
If painting different areas an alternate color, you can mask with tape or even premask. You can also cut vinyl and stick it on the face. Masking is often fairly easy since the graphics are recessed. We usually use premask over previously sprayed areas and finish any tight masking with vinyl or blue 3M masking tape. Since we leave the sandblast mask on until the painting is finished, masking is not a big job.
Cuttlebone is the white, chalky internal shell of a cuttlefish. A cuttlefish is related to squids and octopi. The cuttlebones will be available in the pet section of WalMart or at any pet store. They cost about a dollar each and are used in bird cages to give birds the calcium they need. Cuttlebones are soft and will not scratch the Granite but grind excess paint off very well. I rub one in a circular fashion around the edges of the painted areas to help clean up any overspray or paint bleeding under the mask. The cuttlebone is large enough to span across most graphics and lettering, enabling easy cleaning of the perimeter.
