HELP! Molding HIC volvo panels

So about 6 months ago I managed to get my hands on a Volvo panel and I've finally had a chance to start tackling the project of making a silicone mold of it. I decided that I wanted to seal all the openings with 1/16" pieces of a plastic "no trespassing" sign so that it'll be nice and flat when I pour silicone since most of them will be solid pieces and only the hero panel will need the openings (right?).



Anyhow, I'm curious to know from those who have made their own molds, what would you have done differently? Do you have any tips for someone making their first big two part mold? Anything I should keep and eye out for during the process?

Thanks!

Since over 100 people have viewed but no one commented, I figured I'd give an update.

I set the panel into some sulfur free clay, cleaned up the edges, added registration, put it in a mold box and poured the first half.


Once that cured, I flipped it over, removed the clay and cleaned it up a bit before pouring the second half.



Once that cured, I was able to separate the two halves and remove the original panel. What I didn't expect was to find that I hadn't fully sealed the openings in the panel. So silicone crept underneath the plastic inserts I added to all the openings (to some degree or another). Some spots were filled to the point that when I dislodged the volvo panel, I tore the silicone. Sadly, that spot was in one of the triangle areas at the bottom of the panel. There were some other spots where there's definite seepage of silicone that shows up in the casting, but generally speaking it's ok. Most, if not all can be cleaned up with an xacto or dremel. Also, as you can see by the pictures, it's not a great mold but not worth starting over again.



TAKEAWAYS:

1. Make sure that all the areas where you don't want rubber to go are COMPLETELY sealed up.
2. Be gentle when demolding.
3. Take your time and be patient. (see point 1)
4. Aim for the best, but plan for the worst. (This is a totally useable mold. I don't need it to be 100% screen accurate)
5. Understand your materials before you begin (a silicone with higher viscosity may not have found all the openings in the part and may have produced a better result. Additionally, a silicone with a higher tear strength may not have torn when removing the panel)

Hopefully this will be useful to anyone doing something similar.