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- Fiberglass
- West Systems 105 epoxy (resin + hardener)
- Phenolic microballoons
- POR 15 High-temp Heat Resistant Paint
- 400-grit sandpaper
- Small popsicle sticks
- Mixing boat for epoxy
- Dremel
- Worthington propane blowtorch (14.1oz)
- Arduino Uno
Thermocouple Amplifier MAX31855 breakout board (MAX6675 upgrade): https://www.adafruit.com/product/269
K-type thermocouple: https://www.adafruit.com/product/270
Jumper wires
- Breadboard
- Test stand
- Calipers
- Mini scale
- PPE: Gloves, respirators, safety goggles
Safety Notes:
- Use a respirator when working with phenolic microballoons because the tiny particles will get into your lungs otherwise. Make sure you have the proper canisters for your respirators as well (contact EHS for details)
- Use gloves whenever you are working with fiberglass because the fibers are very splintery. Additionally, the samples will have sharp edges before they are cut and sanded.
- Use safety goggles when using the Dremel (sanding or cutting) so your eyes don't get irritated by the dust or so small pieces don't fly into your eyes when cutting the samples!
- Make sure to use a respirator with proper canisters when doing the blowtorch testing because off-gassing will occur when the samples are heated.
Below is the matrix for samples used in this thermal test. All samples measured ~2" x 2" (with thickness depending on the sample), and there are three samples for each combination (for three trials).
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- Used West Systems epoxy to make 4 of 8" x 8" sheets of fiberglass (2 x 5 layers, 2 x 10 layers), making sure to put Mylar beneath to keep the samples from sticking.
- Let the samples cure for at least 24 hours.
- Sanded with a Dremel, then with 400-grit sandpaper. Make sure to sand the shiny side as well.
- Mark and cut into 1.5" x 1.5" squares .using a Dremel
- Recorded dry mass of each sample (series 1-9)
- Took three measurements of thickness on three different sides, and calculated/recorded average thickness (series 1-9)
- Wearing respirators, mixed 50 g. West Systems resin + 9 g West Systems hardener (100:18 ratio for West Systems, but this depends on the epoxy you choose to use)
- Mixed in phenolic microballoons using a popsicle stick until a consistency slightly thinner than peanut butter (like melted ice cream) was reached.
- Applied an even but thin layer of phenolic mixture to samples (series 4, 5, 8, 9) using popsicle sticks
- Let samples cure for 36 hours.
- Wipe samples with acetone to remove any dust or debris.
- Recorded average thickness of samples with phenolic coating (series 4, 5, 8, 9)
- Sanded with 400-grit sandpaper then recorded mass (and wiped with acetone)
- Applied high-temp paint to fiberglass samples (series 6,7) and fiberglass + phenolic samples (series 8,9)
- Let paint dry for at least 24 hours (depending on what paint you use)
- Wipe samples with acetone to remove any dust or debris.
- Record mass of each sample (series 6, 7, 8, 9)
- Record average thickness of each sample (series 6, 7, 8, 9)
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Setting up thermocouples
Samples
Test Procedure:
Testing in blast chamber
Heat for approximately 12 seconds
Improvements for Next Tests:
- When preparing the samples (fiberglass layup), use a flatter surface so that the average thickness is more consistent
- If testing high-temp paint, use more than one coat so that there is enough paint to show results
- Find some way of remote-triggering the blow torch for added safety
- Use a more accurate scale so that initial and final mass is more accurate
- When measuring thickness (for average thickness calculation), be consistent when choosing points to measure on the sample, and take more than three measurements for a more accurate estimate
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- Use thermocouple with thinner tip for more accuracy
