Sanding Plugs: Foam, Bondo, Duratec

Table of contents

Teams that do this

Baja, FSAE, CUAir, CU Sail, CEV, CU Solar Boat, Hyperloop

Chemicals involved & MSDS for each (should also be included in confluence SDS) 

Safety Gear

• White masks / particle protective respirator

Step by step

1. Dry sanding foam:
   Once the foam parts are assembled, the plugs are sanded to remove the machining marks from the CNC. To ensure flat surfaces on the plugs remain flat, it is easiest to begin with a sanding block, which is less likely to create small divots or waves in the plug. We start sanding at 100 grit, then move up to 200, and finally 300, before spraying Duratec.
   
   
   
   
2. Applying Bondo & Dolphin Glaze as needed:
   Bondo & Dolphin glaze are body fillers that can be used to fill holes, cracks or bumps in the plugs. Mix the Bondo with a small amount of cream hardener in a cup and then apply to the divot. Smooth the top of the Bondo flat using a spreader.
   
   
   
   
3. Dry sanding duratec:
   After the Duratec is sprayed and cured (see next section), the surface will seem relatively rough and bumpy, like coral. Therefore, Duratec sanding starts as low as 200/220 grit. At 400 grit, change to wet sanding. 
   
   
   
   
   
   
   
4. Wet sanding duratec:
   Duratec is wet sanded from 400, 600, 800, 1000, to 2000. Dunk a piece of sandpaper in water then continue sanding. Remove excess sand by periodically dunking the sandpaper in water.