How to: Duplicating a radio bezel. - Page 4

killerfishes · 01-10-2005, 01:12 AM

to bad this costs a lot. I wonder if RTV gasket sealer will work

what is the cost of the plastic? if its cheap i may need to try that.

Giuliano · 01-10-2005, 06:36 AM

Quote: Originally Posted by killerfishes

to bad this costs a lot. I wonder if RTV gasket sealer will work

what is the cost of the plastic? if its cheap i may need to try that.

I don't know about RTV sealer.. might work if it's silicone, but you'd need a lot of sealer to cover.

There are also brush-on rubbers that can do the same thing, but you need to build a support structure for it.

The plastic, in this case Poly 15-3, is $35 for a 5 pounder, $80 for a 20 pounder, including shipping. I could probably get away with a 5 pounder, but I may get a 20.. I can always use more.

The rubber actually cost me about $86 instead of $116, due to the new customer free-shipping deal.

integramodder · 01-10-2005, 01:03 PM

good thread...

I've done a 2 cast aluminum mold with sand, that was interesting. This seems like a very interesting project....cant wait to see the end result.

Giuliano · 01-10-2005, 01:06 PM

Quote: Originally Posted by integramodder

good thread...
I've done a 2 cast aluminum mold with sand, that was interesting. This seems like a very interesting project....cant wait to see the end result.

Yeah, I did a 2-part aluminum mold with sand ages ago in high school, where you compacted this black sand down hard into the shape of the master part.

I still have the large aluminum boat tie-down that I made, too.

The other thing you might find interesting is that they have resins that are filled with aluminum, for heat-resistant parts.. they're also machinable, though you can do that with normal resin too.

nzKAOSnz · 01-10-2005, 01:39 PM

How flexable is the rubber mold? Would you ever need some sort of stiffening material in it?
Good Job!

Giuliano · 01-10-2005, 01:50 PM

Quote: Originally Posted by nzKAOSnz

How flexable is the rubber mold? Would you ever need some sort of stiffening material in it?
Good Job!

The rubber is very flexable, not very stiff at all, and although you can get mold rubbers that are stiffer, the softer rubbers capture more detail.

The box that I poured the rubber into also will act as a support container when pouring the resin, because the rubber by itself would compress when stood on end.

The half that I poured literally weighs 6 pounds.

To give strength to molds, you can lay down some fiberglass mesh cloth during the pour, and that will help prevent the rubber from stretching too much or tearing.

So the rubber usually can't support itself for larger pieces, and you have to use some kind of a box or a shell to support the mold.

I have done smaller molds that didn't require support, but they were less than 6" cubed..

I poured one in a Lego(tm) box, and the plastic nubs on the Lego pieces actually formed the locating keys on each half of the mold, keeping the two halves aligned together. I still have the mold downstairs..

Grey · 01-11-2005, 08:10 AM

ack!!! going on almost 18 hours of no update. I can't handle this stress!

looking absolutely amazing. I am loving this technique Giuliano

Giuliano · 01-11-2005, 08:34 AM

Quote: Originally Posted by Grey

ack!!! going on almost 18 hours of no update. I can't handle this stress!

looking absolutely amazing. I am loving this technique Giuliano

Hey, I got to wait for the rubber to air out and finish its cure before I can continue..

And even then, I still have to order resin...

Giuliano · 01-14-2005, 10:52 PM

I took the pieces from the original mold pour box that I had cut apart, and re-used them to re-construct the box for the 2nd pour of rubber.

This time, I flipped the base over so as to provide a flat surface for the existing rubber, and taped the sides to act as hinges.

Presto, a box that I can fold together, and will seal together with masking tape.

The inside of the box and the flat surfaces of the mold rubber will be sprayed with a lacquer-based primer paint, which will act as a seperator between the two mold halves.

With a layer of lacquer paint on top of the existing rubber, the newly poured rubber won't stick to the first half.

The lacquer paint won't harm the silicone rubber, but I'll have to lay it on in thin coats for the posterboard, because the solvents in the paint can eat away at the foam inside the boards.

The posterboard base also acts as a sturdy support for the rubber while I spray it with the lacquer primer, because if the rubber flexes, the primer will crack off - it doesn't stick to the rubber.

Giuliano · 01-15-2005, 11:05 AM

I used up the rest of the rubber that I had left (~2 pounds) and poured the 2nd half of the mold.

I probably could have used a 3rd or 4th pound to thicken the back side up some, but this should be just enough.

It covers the entire mold, but in some places it's only 1/4" thick or less.

Some of the parts stick out of the rubber, but that's OK.. those are on the back side, and I'm not going to need to mold those.

Giuliano · 01-15-2005, 08:37 PM

About 9 hours later, and the rubber for the 2nd pour has cured enough for me to de-mold the part.

I'm glad I sprayed a few coats of the lacquer primer all over the box, because even in the small spots that the primer didn't land, the rubber stuck together.

However, the rubber peeled apart with not too much effort, though I did have to slice apart a few small sections.

Part of the top of the bezel opening did start to tear apart where the piece had poked through, but I won't need some of that section, so I can mix a few ounces of rubber and fill in the gaps.

The "back" section of the mold isn't very thick, and it doesn't have to be - it just has to reproduce the back side of the part, and I don't care about the detail on that side.

In any case, chances are that after I've modified the duplicate part, I'll cut the front-side part of the mold to fit the new part, and re-pour the back-side.

I can even re-use the old rubber as filler when I pour the new back side again.

The gray sections in the picture is the dried primer - it will be flaked off and the mold will be cleaned up.

Grey · 01-15-2005, 09:41 PM

beautiful

Supermike · 01-15-2005, 11:29 PM

Have you seen this:

http://www.mp3car.com/vbulletin/classified-archive/29910-fs-lilliput-lcd-bezel.html
http://www.tmz.com/wrx/bezel.html
http://www.tmz.com/wrx/build3.htm

It may be just the thing to mount the LCD in, once you have a mod'ed bezel.

Giuliano · 01-15-2005, 11:40 PM

Quote: Originally Posted by Supermike

Have you seen this:

http://www.mp3car.com/vbulletin/showthread.php?t=29910
http://www.tmz.com/wrx/bezel.html
http://www.tmz.com/wrx/build3.htm

It may be just the thing to mount the LCD in, once you have a mod'ed bezel.

Oh yes, I'm very familiar with the work on his WRX, but I'm working on something rather different.

I'm putting an 8.4" LCD panel in the dash, and that necessitates modifying the bezel to fit the 4:3 aspect ratio screen.

The computer itself won't be behind the LCD, but up in the center console, in a 1-din housing on top of the dash.

I have another thread here on the details of that:
http://www.mp3car.com/vbulletin/lcd-display/39131-8-4-lcd-wrx-dash.html

The heavy modificiations are why I'm making a duplicate of the bezel instead of working on the original - it's easier to make modifications to a duplicate, being softer plastic.

I'm also going to airbrush the finished product to match the color of my WRX, using touch-up paint from Subaru.

Giuliano · 01-16-2005, 02:02 AM

I cleaned up the back-side half of the mold, and mixed up a little bit of rubber to fill in the various holes that were in the back.

I filled in the spots for the mounting posts, a few holes, and the section around the opening.

It was a bit messy, but that's OK, because this is for the back-side of the part, where a perfect impression isn't necessary.

The original mounting posts will be replaced with something else, either some kind of a metal spring-clip, or velcro, or similar.