Tech Questions - Drain Grommets
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- What in the world are drain grommets?
- How are drain grommets attached?
- Should I place fabric over the top of a drain grommet?
- How can I cut a piece of fabric to fit over the grommet?
- After the covering is complete how do I open the holes?
- Are seaplane grommets just for seaplanes?
- What material is used to make regular grommets?
What in the world are drain grommets?
In a fabric covered airplane we must have some method of eliminating trapped water and moisture. This is done using drain grommets. A drain grommet is a small, round piece of plastic or metal that is placed over fabric. After all chemicals coats have been applied the drain grommet it opened up to allow moisture to escape.
How are drain grommets attached?
They are attached using Poly-Tak fabric cement. Simply glue them in place on the trailing edges of wings, controls, etc. and the underneath side of a fuselage. Anywhere moisture can escape.
Should I place fabric over the top of a drain grommet?
Yes, you should cut out a small piece of fabric and place it over the drain grommet using Poly-Brush to attach it.
How can I cut a piece of fabric to fit over the grommet?
Use the inside of a roll of finishing tape as a template. Draw a circle on a smooth piece of fabric using a pencil. Cut the circle out using pinking shears.
After the covering is complete how do I open the holes?
Get a pencil soldering iron and carefully burn through the holes. This will leave a nice clean edge. Do this after the final color coat is applied.
Are seaplane grommets just for seaplanes?
No, you may put them on any airplane. They are larger grommets with a correspondingly large drain hole. If you are concerned about moisture accumulating within your airplane use seaplane grommets.
What material is used to make regular grommets?
They are made out of plastic or thin aluminum. Many people prefer the thin aluminum because it covers so easily with fabric.