...
- 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 containing all of the results, 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
**This is the sample after all the coatings (if relevant) have been applied, after the hole was drilled in the sample (hole needed 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 | |||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 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 (plain sample) * [oz] | P: 0.785780 | P: 0.780 | P: 0.780 | F: 0.135 | F: 0.130135 | F: 0.150145 | 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. 305060 Total: 0. 300220 | F: 0.305 PM: 0. | 150075 Total: 0. | 130365 | F: 0. | 135300 PM: 0. | 295055 Total: 0. | 280355 | F: 0.305 PM: 0. 140050 Total: 0. 140355 | F: 0. 140150 H: 0. 270000 Total: 0. 270145 | F: 0. 285 | |||||||||||||
| Initial average thickness [mm] | |||||||||||||||||||||||||||||||||||
| Initial mass (sample + paint/PM*) [oz] | |||||||||||||||||||||||||||||||||||
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] | |||||||||||||||||||||||||||||||||||
| Initial mass (sample + PM + paint) [oz] | |||||||||||||||||||||||||||||||||||
| Initial average thickness [mm] | |||||||||||||||||||||||||||||||||||
| Initial mass (prepared sample)** [oz] | |||||||||||||||||||||||||||||||||||
| 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 mass of sample [oz] | |||||||||||||||||||||||||||||||
| Final average thickness of sample [mm] | |||||||||||||||||||||||||||||||||||
Useful links:
https://tfaws.nasa.gov/TFAWS12/Proceedings/Aerothermodynamics%20Course.pdf