How2 make Custom molded GPS Lid Mounts

Guys, I know I am in the deep end of the pool here, but this thread got me to thinking...
http://forum.notebookreview.com/showthread.php?t=430183&page=4

As Toughbook pointed out what we really need is a custom molded part that would replace the factory corner piece and yet provide enough space to mount and protect the GPS antenna.

So armed only with a small and dangerous amount of experience in the matter I started thinking about us making our own parts using Urethane Casting Resins. All we would need to do to make the part is to start with an OEM corner piece, perhaps even a WWAN model, and then using clay make the bump out for the antenna housing large enough to hold our chosen antenna, perhaps with a carbon fiber or other rigid plastic tube to actually hold the antenna. These would be a lot cheaper then paying someone to tool-up to make them in the thousands and should be fairly easy.

I spoke to an engineer with Alumilite Corporation and he took the time to look at a picture of the CF-29 on the Internet. He told me that their Flex 80 might be the product to use as it has hardness "similar to a roller blade wheel or hockey puck." When cast at under 1/8" this material will break if bent to much, but that does not seem like a problem in this application, as the part would be mostly supported by the lid.

The exothermic reaction will generate heat of about 160F degrees during the casting procedure and the resistance of the antenna to this heat, along with other factors, might determine if you would actually want to try and cast the antenna in place. I think that an internal support/mounting tube would be the answer here and put the antenna in after casting.

The material can be dyed different colors, and these folks are very helpful when it comes mold making, calculating material per part, usage, etc.

So what do you think? The Flex 80 costs $36.00 for the small 20 .oz kit to try and it should be way more then enough material to do quite few to try out the idea.

Using the provided formula I calculated that with the rough dimensions of the part being 2.5" by 1.5” at .33” thick it would take 1.2375 cubic inches of material to make each part, which would mean about 0.68142 fluid ounces of casting resin needed, per unit. So we are talking about 32 parts per kit, the price would go down of course buying the material by the gallon.

The mold would need to be made from a kit as well, but and as I have said a vacuum pump would be the ideal to control bubbles in the mix. This is mostly an aesthetics issue. But the engineer and the site both said that they could be controlled well enough for testing by mixing slowly. 32 parts at $15 each would quickly pay for the experiment, acknowledging some waste in trial and error.

Here are some links to look at:

Alumilite Corporation: http://www.alumilite.com/index.cfm

Here is a “How To” example of Tail Light Molding w/o Equipment: http://www.alumilite.com/HowTos/TailLightMoldingNoEquipment.cfm

A competitor: http://www.smooth-on.com/Urethane-Plastic-a/c5_1120_1159/index.html

I found this short video found on a competitor's site showing how it works.

http://www.youtube.com/v/dcRv__zNxYE&autoplay=1

If I knew that I had the time, I would give this a shot! I can see making 200 over a week or so of piddling. As a wild guess I think that amount would be easy to sell to the TB Community? It would not be hard to make molds for the CF-18/19/28/30 as well.

The whole Mold Box thing in the video and the sealing with hot glue could be streamlined out of the process by using a ready made container for the molds, like a waxed milk carton bottom.

So, what do you guys think?

 

Reuseable molds are pretty easy to construct from either silicone rtv or common epoxy resin and cloth. I've used both to fab custom rubber for pedals, bootheels and motorcycle handgrips. There are a number of rubber concoctions available for use as molding material; I've used Dippity-Goo and other RTV rubber products with varying success. As long as you use a medium-hard duramer resin, you should be good.

Mnem
Rubber duckie, you're the one...

 

FYI... Jim D Gray offers this as well... But of course his would be professionally done. I spoke with Tom Lambe about it today and we agreed it wouldn't justify the expense of doing it.

 

If I could find someone local to take the project over if I had to go, I would give it a shot myself. I even have a small vacuum pump but do not know how to use it offhand with the crude molds that are discussed here.

I can understand why a large company would not want to mess with it for less then 1000 parts! As Steve Martin once said in The Jerk, "..it's a profit scam!"

 

Yeah... It's obviously all in the mold making.... Tom said anywhere from $500 to $5000 depending... This would be a pretty cool thing to do if someone would make a mold and then pass it around for the "one-offs... If that is what you want to do.

I really don't think there would be a market for it to be able to make any money...

 

Yeah, I never anticipated making money on the idea. I do think that it has the potential for the perpetrator to break even, unless you had to buy a pressure pot to get a good part.

Making a Gypsy Mold does have its merits, but I can not see where you could save much money that way, everyone would to but their own resin kits.

I would have a hard time making the mold, I have never seen the antenna or did the mod, yet...