...
- 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 of the sample, and calculated/recorded used this to calculate/record 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)
...
Below is a table showing the results of the thermal tests. Consult the test matrix above to see what each "series" corresponds to (for example, "Series 1" means 1/4" phenolic sheet). All samples measured 2" x 2" in area. For a more detailed spreadsheet, consult the attached Excel spreadsheet. (ATTACH SPREADSHEET) In the table below, since some samples have multiple layers of ablative coating, a key is used to denote the mass/thickness of each layer, followed by the total mass/thickness.
F = fiberglass
P = phenolic sheet
PM = phenolic microballoons
H = high-temperature paint
*Mass of sample measured after hole drilled (to attach sample to test stand) and after all ablative coatings have been added, which is why there is a discrepancy between the total mass and the sum of the masses of each layer. In some cases, the mass measures zero for the high-temperature paint because the scale was not accurate enough and the layer was thin.
| Series 1 | Series 2 | Series 3 | Series 4 | Series 5 | Series 6 | Series 7 | Series 8 | Series 9 | |||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Initial mass (plain sample) | |||||||||||||||||||||||||||||||||||
| Initial average thickness | |||||||||||||||||||||||||||||||||||
| Trial | 1 | 2 | 3 | 1 | 2 | 3 | 1 | 2 | 3 | 1 | 2 | 3 | 1 | 2 | 3 | 1 | 2 | 3 | 1 | 2 | 3 | 1 | 2 | 3 | 1 | 2 | 3 | ||||||||
| Initial mass* [oz] | P: 0.780 | P: 0.780 | P: 0.780 | F: 0.135 | F: 0.135 | F: 0.145 | F: 0.290 | F: 0.295 | F: 0.280 | F: 0.140 PM: 0.050 Total: 0.200 | F: 0.150 PM: 0.065 Total: 0.220 | F: 0.160 PM: 0.060 Total: 0.220 | F: 0.305 PM: 0.075 Total: 0.365 | F: 0.300 PM: 0.055 Total: 0.355 | F: 0.305 PM: 0.050 Total: 0.355 | F: 0.150 H: 0.000 Total: 0.145 | F: 0.130 H: 0.005 Total: 0.135 | F: 0.135 H: 0.000 Total: 0.140 | F: 0.295 H: 0.000 Total: 0.290 | F: 0.280 H: 0.000 Total: 0.280 | F: 0.305 H: 0.000 Total: 0.305 | F: 0.140 PM: 0.04 H: 0.000 Total: 0.180 | F: 0.140 PM: 0.045 H: 0.000 Total: 0.185 | F: 0.140 PM: 0.045 H: 0.000 Total: 0.185 | F: 0.270 PM: 0.035 H: 0.000 Total: 0.305 | F: 0.270 PM: 0.035 H: 0.000 Total: 0.310 | F: 0.285 PM: 0.035 H: 0.005 Total: 0.320 | ||||||||
| Initial average thickness [mm] | P: 6.20 | P: 6.15 | P: 6.13 | F: 1.02 | F: 1.01 | F: 1.04 | F: 2.05 | F: 2.00 | F: 1.95 | F: 0.99 PM: 0.7 Total: 1.69 | F: 0.96 PM: 0.76 Total: 1.72 | F: 1.08 PM: 0.62 Total: 1.70 | F: 2.13 PM: 0.70 Total: 2.83 | F: 2.13 PM: 0.54 Total: 2.67 | F: 2.05 PM: 0.56 Total: 2.61 | F: 1.09 H: 0.04 Total: 1.13 | F: 0.94 H: 0.08 Total: 1.02 | F: 0.91 H: 0.06 Total: 0.97 | F: 1.94 H: 0.10 Total: 2.03 | F: 1.84 H: 0.18 Total: 2.02 | F: 1.89 H: 0.19 Total: 2.08 | F: 0.85 PM: 0.42 H: 0.28 Total: 1.55 | F: 0.84 PM: 0.59 H: 0.31 Total: 1.75 | F: 0.80 PM: 0.53 H: 0.35 Total: 1.68 | F: 1.75 PM: 0.55 H: 0.25 Total: 2.55 | F: 1.75 PM: 0.53 H: 0.33 Total: 2.61 | F: 1.75 PM: 0.52 H: 0.35 Total: 2.62 | ||||||||
| Final mass [oz] | 0.785 | 0.115 | 0.285 | ||||||||||||||||||||||||||||||||
| Final average thickness [mm] | |||||||||||||||||||||||||||||||||||
Useful links:
https://tfaws.nasa.gov/TFAWS12/Proceedings/Aerothermodynamics%20Course.pdf