When a project calls for sanding, one must confirm the correct materials are being used. Reason being is due to the different sizing, backing and grit of the sandpaper. But, how can we identify what type of sandpaper is best? Subjected to the work needed for your project, grit size will come into play. Thus, we must make note that sandpaper is measured by its grit size while others are measured by both the grit and grade of the backing. When buying your sandpaper, check the item to confirm it states the pressure sensitive adhesive (PSA) or the grit and size number. This will help when deciding which one is best for the project at hand.
Sandpaper Grit Sizing: If you are looking to remove a previous material such as gelcoat; begin sanding your surface with a 150 grit or lower. A low grit number determines the coarseness of the sandpaper which will give you the ability to remove materials and coatings. Sandpaper with a grit number in the 200’s and higher would be great for finishes such as buffing, polishing or the removal of small scratches. A high grit number is equivalent to how small the grains are which will allow you to smooth the surface.
Sandpaper Weight Grade: One may see grade letters ranging from A-E which represents the durability of the sandpaper, where E is the strongest. For example, (based on the figure above) the red Mirka Royal 40 grit disc would be ranked as the most durable, next the Mirka Bulldog 120 grit Gold, followed by the gray Mirka Bulldog 400 grit Gold .
Here is a great tip!
If you are looking to conduct a wet or dry sanding, the sandpaper coating must be waterproof. An abrasive that is waterproof will last you longer with end results you’re aiming for in a wet/dry process.
The University of FGCI partnered with Composites Consulting Group (CCG) and Diab to introduce the fundamentals of infusion. To begin the seminar, the definition of infusion; a specific technique that uses vacuum pressure to pervade or direct resin into laminate, was discussed.
As we highlighted key points in the infusion theory, we visited the sandwich concept; which consist of two layers, a top and bottom with a thick core. This learning material soon tied in with Darcy’s Law in correlation to the 5 variables of control fill time.
At Fiberglass Coatings, we have all the tools, materials and knowledge to help you with your job, whether it being a large commercial job, or just doing a project around the house. With that in mind, we are spotlighting a product we have had around for a long time, but not everyone knows about; 
At Fiberglass Coatings, we try to provide the best products at the best price, along with the best knowledge for all your fiberglass and resin projects. Now, we are making it even easier with several spots in the state of Florida having daily deliveries, so it’s even quicker and easier to get the products you need when you need them!