MP3Car.com - View Single Post

Giuliano · 01-09-2005, 10:35 AM

The first half of the mold is complete, and I've taken it out of the box to air out.

The silicone RTV produces alcohol while it cures, so you should let it air out for 24 hours before using it.

There's a lot of pictures here, and they're all hosted from my cable connection, so please bear with the load times.

First, I modified the box some more to reduce the amount of rubber I would need to pour. The fact that it isn't a square anymore doesn't matter.

In order to measure out the rubber, the mixing bowl was placed on the scale, and the scale was re-set to 0, to ensure an accurate measurement.

I measured out 3 pounds of rubber to start, and measured 0.3 pounds of catalyst on the digital scale on the left.
Actually, I used Google to convert 0.3 pounds to grams, and measured it out in grams, as it's a bit more accurate that way.

Here's what the base materials look like:

And mixed:

As you can see, 3 pounds wasn't quite enough to cover the piece. Not a problem, as I had 60 minutes to work with, so I mixed another 1 pound.. then another.. and finally another, making 6 pounds total to cover.

About 8 hours later, and the rubber has cured enough to de-mold the part.

But first I have to get it out of the box - and the easiest way to do that is to cut the box apart at the seams.
Easy enough to do, and the box can be glued back together for the second pour, or a new box constructed.

Some of the excess rubber was trimmed off the edges, and the mold peeled right off of the posterboard.

The blanks on the back of the bezel were popped off, and the part was re-inserted into the mold face down. I also sliced the modeling clay venting channels off the posterboard, and re-inserted them back into the rubber.

All of the blue sections you see above will be later sprayed with a lacquer-based primer (without the part installed), the box will be reassembled with the mold face down (as shown), and the second half of the mold will be poured.

The lacquer primer will prevent the two halves of the mold from sticking together, and is called a barrier coat.

I don't have too much rubber left in the bucket, but I won't need that much, as the rubber doesn't need to cover too much of the back side of the mold.

01-09-2005, 10:35 AM	#44
Giuliano Maximum Bitrate Join Date: Feb 2004 Posts: 749	First half complete.. The first half of the mold is complete, and I've taken it out of the box to air out. The silicone RTV produces alcohol while it cures, so you should let it air out for 24 hours before using it. There's a lot of pictures here, and they're all hosted from my cable connection, so please bear with the load times. First, I modified the box some more to reduce the amount of rubber I would need to pour. The fact that it isn't a square anymore doesn't matter. In order to measure out the rubber, the mixing bowl was placed on the scale, and the scale was re-set to 0, to ensure an accurate measurement. I measured out 3 pounds of rubber to start, and measured 0.3 pounds of catalyst on the digital scale on the left. Actually, I used Google to convert 0.3 pounds to grams, and measured it out in grams, as it's a bit more accurate that way. Here's what the base materials look like: And mixed: As you can see, 3 pounds wasn't quite enough to cover the piece. Not a problem, as I had 60 minutes to work with, so I mixed another 1 pound.. then another.. and finally another, making 6 pounds total to cover. About 8 hours later, and the rubber has cured enough to de-mold the part. But first I have to get it out of the box - and the easiest way to do that is to cut the box apart at the seams. Easy enough to do, and the box can be glued back together for the second pour, or a new box constructed. Some of the excess rubber was trimmed off the edges, and the mold peeled right off of the posterboard. The blanks on the back of the bezel were popped off, and the part was re-inserted into the mold face down. I also sliced the modeling clay venting channels off the posterboard, and re-inserted them back into the rubber. All of the blue sections you see above will be later sprayed with a lacquer-based primer (without the part installed), the box will be reassembled with the mold face down (as shown), and the second half of the mold will be poured. The lacquer primer will prevent the two halves of the mold from sticking together, and is called a barrier coat. I don't have too much rubber left in the bucket, but I won't need that much, as the rubber doesn't need to cover too much of the back side of the mold.