Bubble Tech Passenger Handle

[muibubbles]

First off, I'm studying Industrial Design @ NJIT college. As I'm nearing the end of my Jr year, I'm trying to gather my portfolio together. In addition, I'm trying to improve my prototyping skills. So, I thought I would attempt the passenger side door handle as it could be useful to others.

My main objective is to create and improved door handle from the OEM version for prototyping practice and portfolio use. If the quality comes out to my standards I will look into selling them as well. With that said, production/sale is not my primary goal.

When I first bought the car my handle was actually broken. To remedy this issue, I just fiberglassed it solid to the trim piece. So to begin Prototyping an improved piece, I had to order a new one. I went cheap and bought one that was broken. So the first step was to repair the handle. The clear part is the added "cast" I did to fix the "missing/broken tab."

http://i426.photobucket.com/albums/pp342/muibenjamin/bubble%20tech/DSC_1015.jpg

http://i426.photobucket.com/albums/pp342/muibenjamin/bubble%20tech/DSC_1026.jpg

Next step I stripped the cheap tacky "vinyl?" handle cover and prepped the handle to cast the mold. A little body filler and some sanding did the trick. The first modification I did was fill in the voids under the tabs with body filler. In the new piece, this will translate to a stiffer and more robust tab support. This also gets rid of 2 undercuts to ease the casting process.

(Forgot to take pics)

After I had a " rough sketch model" plug, I began to cast the mold. Even though there were a few imperfections and known adjustments, this was simply a test to see if I could successfully cast a new piece due to its complexity and undercuts) To compensate for some of the under cuts, I ended up going with a 3 piece mold

http://i426.photobucket.com/albums/pp342/muibenjamin/bubble%20tech/DSC_1153.jpg

http://i426.photobucket.com/albums/pp342/muibenjamin/bubble%20tech/DSC_1154.jpg

http://i426.photobucket.com/albums/pp342/muibenjamin/bubble%20tech/DSC_1156.jpg

opposite view
http://i426.photobucket.com/albums/pp342/muibenjamin/bubble%20tech/DSC_1157.jpg

I made a few cast and shortly found out some flaws. I had found some trapped air bubbles and errors in the mold itself. I drilled an hole for one air bubble to vent and the other one was solves by angling the mold when I poured the cast. some pics of the first revision with flaws.

Also im using a Clear resin that is suppose to be for artistic purposes so the next step is looking for a more durable resin. (The black color is from a pigment dye)
http://i426.photobucket.com/albums/pp342/muibenjamin/bubble%20tech/DSC_1149.jpg

http://i426.photobucket.com/albums/pp342/muibenjamin/bubble%20tech/DSC_1150.jpg

http://i426.photobucket.com/albums/pp342/muibenjamin/bubble%20tech/DSC_1151.jpg

http://i426.photobucket.com/albums/pp342/muibenjamin/bubble%20tech/DSC_1152.jpg

Feel free to post comments, interests and concerns!
:party:

[vex]

Always wanted to get into injection molding.

[Garfinkles Motor Works]

There are many people with talent on this forum. I for one find all of the information and skills shown to be the best reason to read this forum .So much good work that is done by so many very smart people .

[muibubbles]

Vex- although the i believe the OEM piece is injected molded, my method is simply a resin cast.

Garfinkle, you're definitely correct, these forums are filled with so much intelligence and inspiration, you are one of them. Its awesome to be able to be part of a community that stimulates creativity!

[muibubbles]

Might as well post and update-

Problem: As you can see in the last picture, the corner by the big tab is missing. This is because of the mold and the pouring point. This creates an air pocket and doesnt allow the resin to flow into that area.

Solution: I drilled a small hole through the mold to create a air pocket, this should allow the air to escape and the resin to flow in.

Problem: As seen in the last picture is one of the thin wall tabs towards the top of the handle. Indeed another air pocket.

Solution: Shake/have mold angled when initially pouring resin. This will cause the resin to settle in the corner while letting air bubbles out. Once I feel its shaken/leveled, continue to pour. (this has been tested and worked successfully)

Problem: There are little tiny bumps on the handle itself. This is caused by air bubbles in the mold because of the way i made the casting.

Solution: Although it wasn't intentional, I may leave it. Because the handle will be treated with a leather wrap, it will give the leather more to grab on and adhere to. If I do decide to get rid of them, it is a simple fix by reconfiguring the casting order/pattern.

Problem: The thin wall at the top of the handle has an obvious cast line.

Solution: Reconfigure the Casting line.

Problem: Tabs still have some flexibility. This could be a possible problem, but more testing will need to be done.

Solution: I still want to add more material to eliminate uneccessary undercuts as well as strengthen the tabs base. This will make a stronger post for the mounting tabs, make it easier to cast, and more rigid (not sure if thats a pro or con yet) In addition, different types of resin still need to be tested to find the right properties, shore hardness, tensile strength etc, etc, etc!

[bbade]

Bubbles, you may want to consider placing the part in a pressure vessel to cure. In the past I have made a "pressure vessel" out of the tank from a large paint sprayer. Use of the pressure vessel makes a noticeable difference in reducing the size of the air bubbles.

[muibubbles]

bbade! thanks for the suggestion, I was actually looking into a pressure pot a few weeks back. I'm looking to buy a vacuum pump from my classmate and a DIY pot. They're fairly cheap and easy to make but as I'm crammed with a bunch of school projects, I don't have the time to invest on parts or working on this project at the moment... Thanks for the suggestion! I'm definitely going to do it further on! any pictures of yours?