Measuring material thickness of huge dome 1

[gsb]

There's a sealed (apart from a doorway) fibre glass dome with an internal radius 20ft . I need to measure the dome material thickness in various places. Any measuring instruments or ideas would be helpful.

 

[butelja]

Try looking into ultrasonic thickness measurement methods. They are very common for metallic materials, but I'm not sure about using it for FRP. Alternatively, drill a hole through the dome and use a micrometer, but this is probably not what you are after.

 

[gdodd]

Talk to a NDT (non destructive testing) supplier in your area. There are a number of different instruments available that can measure thickness of metalic and non-metalic parts using ultrasonics.

Good luck

 

[D2]

There are magnetic measuring systems for FG parts. I dont know what thickness range you are looking for. It requires a steel plug to be held on one side while the probe is held on the other. Check with Mitutoyo, they make some of these devices.

D^2

 

[dgallagher]

Nova 200D Ultrasonic Thickness Gage permits digital thickness measurements from only one side of most materials including steel, iron, glass, plastics, ceramics - any material that conducts ultrasound. It can be found at:

http://www.reliabilitydirect.com/ultrasoundproducts/nova200d.htm

 

[jamesxi]

At various points on the outside of the fiberglass, glue a few neodymium magnets to the structure. Then, use a gausse meter to measure the strength at various possible depths. Then, use the gausee to measure the magnetic reading from the inside. It might end up being just as expensive as the ultrasonic equipment though(I don't know how they compare).