Both molds are done and ready for a production run:
I finally figured out what was causing my pock mark issue......dust! The kind of dust you can only see when the sun is shining in the window. Acrylic is really prone to static buildup, and the 18% humidity in my garage was only making it worse. No matter what I tried I couldn't stop the acrylic from acting like a giant dust magnet. I got the humidity up to 35% and even put a pan of water in the oven but nothing would stop the dust. After a dozen tries I finally found something that worked.......Plasti-Dip. There is a product out there specifically designed to protect acrylic throughout the thermoforming process, but it's not cheap, so I thought I'd try Plasti-Dip a substitute. It works quite well and eliminates 99% of the dust divots.
Just the plastic. Every pull of acrylic I leave half wrapped
If you don't have an ir heater and have to remove the sheets, just use acrylic cleaner. It removes the static. And Don't blow with air as this creates static.
BTW, why are you using such a large sheet? For something so shallow, you can get away with less than an inch of trim. Get some half inch square tubing and remake your clamping frame. You'll save a ton of product
[This message has been edited by Slammed (edited 01-25-2016).]
Time for an update. Progress on the Formula lens covers has been a little slow but things are happening. Due to the long shallow area on the bumper I have decided to drape form the acrylic instead of vacuum forming it. This means the piece of acrylic will be cut prior to heating, after heating it is laid in the form and the other half is set on top to form it to shape.
To make the molds, I used a Formula bumper set flat on some saw horses. After filling the opening with ultracal30, I formed a plug to the compound curve of the bumper opening. Once that was set, I applied a release agent and covered the area with another layer of ultracal30 to pull a negative mold. I left that to dry for a few days and then applied 4 coats of wax as a release agent. Tonight I filled the negative mold full of ultracal30 to form the positive half. This will need to dry for a few days before I can run a sample lens to check fitment. If all goes well, I will repeat these steps 3 more times to make molds for the other lenses.
Here are a few pics, note the compound curves, these follow the bumper contours exactly. As a side benefit the curves should also add some rigidity to the long narrow lens. Stay tuned.......
[This message has been edited by seajai (edited 02-18-2016).]
So here we go. I used the plug I made as a guide to make an MDF template for cutting the acrylic blanks.
With the acrylic cut to approximate size, I attach it to the MDF with tape and run it through a spiral flush trim router bit to trim it to the exact size needed. Next I used a round over bit to to radius the edges of the acrylic so it fits the rounded sides of the opening. I did a few test runs experimenting with oven temp and time to get the best results and this is the finished prototype.
It fits nicely in the opening and is recessed only slightly from the surface to the bumper. Here are a couple profile pics of the finished cover showing the compound curves.
The benefit of using an MDF template and a router to cut my acrylic is that I just need to flip the template over to cut the opposite side. So now with a successful prototype made I just need to cast the forming molds for the right front and both rears and make a router template for the rear covers and I'll have them ready to sell. (Oh yeah, and figure out how to mount them). Stay tuned
I won't be making covers for the bumper pad cars or the rear GT reflectors, I just don't have the R&D time right now. I already have enough projects stacked up to keep me going til next summer. I may at some point but not right now. If someone wanted to make a mold and send it to me, I will form up covers for you.
Follow my sale thread in the mall for info and updates.
[This message has been edited by seajai (edited 10-11-2016).]