Panel with paint ready surface
In a preferred embodiment, a composite panel with a smooth outer surface, ready for painting with or without addition of primer, may be created by constructing a panel layup assembly upon a mold, the panel layup assembly including a composite panel having a core and a resin formulation, and a release film between the mold and the composite panel, where a smooth release surface of the release film is in contact with the composite panel upon construction; initiating curing of the composite panel at a first temperature within a lowermost ten percent of a curing temperature range of the resin formulation; continuing curing of the composite panel at a second temperature above the lowermost ten percent of the curing temperature range; and completing curing of the composite panel at a third temperature below the second temperature.
1. A method for curing a composite panel to produce a smooth surface, comprising:
constructing a panel layup assembly upon a mold, the panel layup assembly including the composite panel, wherein the composite panel comprises at least a core and a resin formulation, and a release film between the mold and the composite panel, wherein a smooth release surface of the release film is in contact with the composite panel upon construction;
initiating curing of the composite panel at a first temperature within a lowermost ten percent of a curing temperature range of the resin formulation;
continuing curing of the composite panel at a second temperature above the lowermost ten percent of the curing temperature range; and
completing curing of the composite panel at a third temperature below the second temperature.
2. The method of claim 1 , wherein the release film is a polypropylene release film.
3. The method of claim 2 , wherein the release film is a bi-axially oriented polypropylene release film.
4. The method of claim 1 , further comprising initiating, prior to the initiating curing of the composite panel at the first temperature, heating of the composite panel at a temperature below the first temperature.
5. The method of claim 1 , wherein the third temperature is within the lowermost ten percent of the curing temperature range.
6. The method of claim 1 , wherein the resin formulation is pre-impregnated within a fabric reinforcement.
7. The method of claim 1 , wherein the first temperature and the third temperature are less than 150° F.
8. The method of claim 7 , wherein the second temperature is approximately 200-350° F. and the composite panel is cured at the second temperature for approximately 60-90 minutes.
9. The method of claim 8 , wherein a temperature ramp up rate from the first temperature to the second temperature is less than 15° F. per minute.
10. The method of claim 9 , wherein a temperature ramp down rate from the second temperature to the third temperature is less than 15° F. per minute.
11. The method of claim 1 , wherein the smooth surface is paint-ready without need for application of a primer.