Sandblasting Precision Board HDU: Tips from SignCraft Readers

Sandblasting Precision Board HDU can allow for many more interesting and subtle textures than a wood sign.  In addition to sandblasting much faster than wood, it allows the sandblaster to move much closer to the surface.  Because of the low blasting pressure, the detail and shapes can be much more subtle.  Dave Showalter of David Design and Danny Dean of Dynamic Signs Design recently wrote into SignCraft Magazine with their tips for sandblasting HDU.  They also sent us photos of some of their signs, fabricated from Precision Board high-density urethane foam, manufactured by Coastal Enterprises.

Danny Dean, Dynamic Signs Design, Rice Lake, Wisconsin:

Sandblasted effects on HDU
“I like to mix textures when sandblasting a high density urethane sign. I may blast the background through the Grain-Fraim [] to get a wood grain effect, then blast the border or a panel directly to get a stucco or stone effect.
I like the contrast of the stucco finish against the woodgrain.
I sometimes make a template with a slot in it that lets me blast faux mortar joints for a brick or stone look. You can create a stone effect that way by monkeying around with the sandblast to get an irregular surface.”

David Showalter, David Design, Bryan, Ohio:

Make sandblasted HDU woodgrain look even more realistic
“I often sandblast high-density urethane through the Grain-Fraim to simulate sandblasted woodgrain backgrounds. Over the years, I’ve found that a couple of tweaks during the blasting process that make the effect look even more realistic.
First, my sandblaster does an initial blast through the Grain Fraim. Next, he moves the Grain Fraim about an eighth of an inch up or down and continues blasting. This really creates a great look.
Finally, we remove the Grain-Fraim and continue blasting. It deepens everything. It just adds to the effect and makes it look more realistic.”


Both of these gentlemen used Precision Board HDU in their sandblasting tips for SignCraft Magazine.  You can check out our SignCraft Magazine page on the website HERE to see all the articles where Precision Board and Companion Products (adhesives, primers & fillers, textures & coatings) from Coastal Enterprises are mentioned.

We offer more detailed tips on sandblasting Precision Board high-density urethane HERE as well as in this blog post from Kendal Signs in Florida who not only replaced several cedar signs with Precision Board HDU, but also sandblasted them and let us in on their process.

Not sandblasting, but still want to get that wood grain effect on Precision Board?  Coastal Enterprises’ TSF-45 Texture Coating is perfect for adding grain to HDU.  Call us for samples!

Coastal Enterprises manufactures Precision Board HDU, a versatile, cost-effective and eco-friendly urethane sign material that is particularly effective for making professional-looking indoor and outdoor dimensional signs.  It is a closed-cell rigid substrate that does not rot, warp or crack.  You can request free samplesget a quote or sign up for periodic newsletters packed with helpful information.

How To Make A Sandblasted Precision Board HDU Sign

Sandblasting HDU can allow for many more interesting and subtle textures than a wood sign. In addition to sandblasting much quicker than wood, it allows the sandblaster to move much closer to the surface. Because of the low blasting pressure, the detail and shapes can be much more subtle.

This sign was sandblasted and finished by Insignia, a full service sign shop based in Anaheim, CA. Having sandblasted signs for over 20 years, they are sandblasting experts!

Step 1: Masking the Precision Board

Sandblasting HDU is done by applying a vinyl mask weeded from digital coordinates that are input into a plotter, or weeded by hand. All parts of the sign that will be sandblasted are cut from the mask, protecting any smooth surfaces you wish to keep.

Several different types of sandblast mask are available, from low, medium and high tack. Use a medium tack mask for pre-primed HDU, and a high-tack mask for unprimed HDU.

Step 2: Sandblasting Precision Board

Sandblasting Precision Board is just like sandblasting a lightweight wood. Recommended blasting pressure must be approximately 60 psi max. at the pot. This will allow for the unique textures only available with HDU.

Since the blasting pressure is low, the grit moves slower and takes out small pieces of the background instead of pulverizing the surface. This also means that a smaller compressor can be used, allowing almost anyone to make their own sandblasted sign.

Popular types of sandblast grit include clay sand and aluminum oxide. The density of the grit depends on which type of texture you desire. A larger grit will allow for a rougher texture, and finer grit allows for a smoother texture. Joseph Westbrook, owner of Insignia, specified that this sign was sandblasted using a 60/90 blend of Red Ruby Garnet, which is a great media to blast with because it is sharp, cuts nicely and is uniform in size. Background texture largely depends on the size of the medium.

Step 3: Priming the Precision Board:

Since not all paints adhere to raw HDU for the long term, it is necessary to prime Precision Board prior to painting. Coastal Enterprises manufactures FSC-88WB, a single component water based primer/filler. Any primer that is made for HDU will also work. FSC-88WB is a high build primer, able to be used on materials other than HDU and can be sprayed, brushed or rolled. We also have an excellent step-by-step video on priming Precision Board.

Step 4: Finishing the Precision Board

Any type of paint can be used on Precision Board once it is primed with FSC-88WB. Many of our customers use 1-Shot Paints. Coastal Enterprises also offers a complete line of applicable textures and coatings that allow the priming step to be skipped.

This is an example of a sandblasted Precision Board HDU sign:

Step 5: Send Us Photos Of Your Project!

If you send us pictures of your Precision Board project, we would love to feature your company in a blog or a newsletter! You can submit your work here.

Additional Tips:

  • Practice on test sheets. Request a free sample here.
  • Move the nozzle as evenly as possible.
  • Re-using old sandblast media can allow for better control and more detail
These are all Precision Board HDU sandblasted signs by the experts at Insignia:

Ten Tips For Working With Precision Board Plus HDU

1. Carbide cutters are not mandatory when cutting Precision Board Plus. Because it is non-abrasive, Precision Board Plus can be cut with anything that cuts wood, but much easier.


2. To maximize CNC efficiency and cutting time, and to minimize dust and increase chips, the Onsrud Router Bit Selector Guide provides guidelines for proper router bits, speeds and feeds.

3. After you have primed Precision Board Plus using FSC-88WB Primer/Filler, it is best to dry using a large shop fan. Do not place in the sun, as this will cause it to dry too fast resulting in blisters. The FSC-88WB Primer/Filler training video can be seen here.


4. Be sure to prime and paint all sides of your Precision Board Plus sign. Because it does not have grain, it has no beam strength and can be pulled in the direction of the drying paint.


5. When sandblasting Precision Board Plus, use a larger grit for larger texture. Similarly, a finer grit allows for finer texture. Aluminum oxide is used most often.


6. If something happens to your sign during the build process, it is possible to fix the damaged surface. FSC-360WB Crack Filling & Repair Putty dries quickly and sands easily, and can really save the day in the event of a mistake.


7. Optimize your Precision Board Plus purchase by bonding and laminating the excess using PB Fast Set or PB Bond-240 adhesive.


8. PB Resin can provide an eye-catching, ultra-smooth protective finish to your sign. Be sure to only add enough lettering enamel to the clear PB Resin that will hide text on a printed page.

9. If you do not have time to route in wood grain, or to sandblast, TSF-45 or PB Hardcoat are excellent time saving alternatives for simulating wood grain. Apply both directly to raw Precision Board Plus, eliminating the priming step.


10. If you have a question, call us! We offer free technical support and are happy to assist in any way we can.

Precision Board Plus FAQ’s

Have you ever had questions about painting, CNC machining, or laminating Precision Board Plus? Our FAQ page on our website has answers for the signage, tooling and boat building industries and is designed to make your job easier. It covers everything from standard sizes, the tools used to cut Precision Board Plus, proper oven and autoclave ramping procedures, to tips on priming and painting the best HDU on the market.

Check it out here:  //