Embedments in Solid Plexiglas Acrylic
Lucite® is a high quality acrylic product. The versatility of Lucite® allows it to be custom designed into a variety of shapes and sizes, incorporating many different types of embedded elements. However, due to chemical reactions during the process, not everything can be embedded. Here's the top of a champagne bottle (removed with a sword) cast into Plexiglass by a factory.
The process starts with two basic ingredients, an acrylic resin powder and monomer, a crystal clear liquid. The powder and monomer are mixed together in specific proportions. The result is a thick, opaque liquid. The mixture is hand poured into molds and allowed to partially harden. Objects to be embedded are then hand placed into the Lucite® layer. Another layer is poured over the embedded object and the Lucite® is again allowed to harden. Heat and pressure are applied to the parts to remove any air bubbles and completely harden the part. Parts are then sanded to size then buffed by hand to a bright crystal-like finish.
Sounds simple? You need an AUTOCLAVE to actually cast the Lucite or Plexiglass materials. Unfortunately, these chemicals are not available in a DIY shop or to the general public. Then again, not many of us have autoclaves in the kitchen. No, a toaster oven duct-taped shut won't work.
So - a lot of us turn to polyester resins - clear casting resins that emulate this process of clear casting of plastics - and embedding in plastic.
I have successfully cast certain bugs that decided to enter my office or my garage - but I probably "cooked" even more by putting too much catalyst in the resin mix. The problem with casting "organic" items in resin is that they contain water and when they warm up as the plastic is turning to a solid - they expand.
Putting catalyst into polyester casting resin activates the molecules to form a solid. A pretty neat trick. But to do that, the temperature must be raised. Trust me, this can get out of control and you can start a fire with too much catalyst. But when you put something organic - like paper, flowers, crickets and the like, the water in them will go gaseous and muck up your casting.
Pennies, rings, teeth are more stable and you have more successes. The shapes you see in these pictures are cast ACRYLIC shapes that are standard - and that can be used for embedding items into by a factory - not DIY stuff (sorry).
Remember, always try this FIRST on something similar. Write down the ambient temperature, and the amounts of resin and catalysts. When casting in layers, let the layer beneath cool before adding another layer...until you are skilled and learn to adjust the catalyst downwards for the next layer.
Casting resins are not UV stable so make sure you don't put your cool new casting in the sunlight.
Thursday, May 21, 2009
Embedments in Solid Plexiglas Acrylic
Wednesday, May 6, 2009
- ACRYLITE GP sheet is more capable of withstanding continuous loads than continuously manufactured or extruded sheet.
- ACRYLITE GP sheet maintains a high level of mechanical strength after water absorption has reached equilibrium.
|T - thickness of sheet|
H - height of tank
L - length of tank
|Required Thickness T (in)=|
H = 15 in.
L/H = 2.4 therefore: b = 0.866 (taken from the chart for L/H = 3.0)
q = (0.0361 lbs/in3) x (15 in) = 0.542 lbs/in2
Download the XLS from Evonik - Calculate Aquarium Thickness
Tuesday, May 5, 2009
Check out the picture above.
First, from the left, fiberglass in the form of continuous roving filaments, or fiber bundles, is drawn though the liquid resin, which saturates the glass reinforcement. Next, this combination of resin and glass is then pulled through a special die using a continuous pulling device (hence the name pultrusion for pulling through, rather than extrusion which is pushed through).
The resulting high-strength profile is cut to length -- ready for use when it leaves the pultrusion machine.
Pultruded products provide manufacturers and designers with the benefits of high strength-to-weight ratios, corrosion resistance, heat resistance, dielectric properties, dimensional stability and weatherability. In the end, pultruded products are a cost effective and versatile alternative to traditional materials.
Here is 48" wide sheet being pultruded...
The fiberglass material is typically produced in 3 grades:
1. Standard with isopthalic polyester resin and various layers of fiberglass roving and mat.
2. Fire Retardant and UV resistant chemicals added to the Standard Grade
3. Vinyl Ester Resin, FR and UV additives - for extreme chemical resistance.
Standard colors are Green, Gray, and Beige respectively. Any color can be run if the quantity is high enough.
A short list of pultruded products in the marketplace: Tool handles, ladder sides, skateboard decks, fiberglass stairs and platform systems, fiberglass grating, fiberglass decking, u-channel, I-Beams, structural profiles of all sorts. Photos: (courtesy of Liberty Pultrusions)
Saturday, May 2, 2009
Chrysalis and Ridout Plastics will be at the NEOCON show June 15-17, 2009 to show off all of the patterns available and some interesting fabrications at BOOTH 8-3130C. For you technical types, the material has a CLASS 1 FIRE RATING, is GREENGUARD & LEEDS COMPLIANT, is BACTERIOSTATIC and GRAFFITI RESISTANT. You can use as a DRY ERASE board OFF THE SHELF - no special coatings and Chrysalis HD resin panels are 40x MORE IMPACT RESISTANT THAN GLASS. That said, it is more expensive than Plexiglass or Lexan - but then again, there is nothing like it!
Friday, May 1, 2009
Glastron boats, as well as many other OLDER outboard motor boats, have thermoformed plexiglass acrylic windshields. After a few years, usually 30-40 years, owners want to spiff up their motor craft and put a new windshield in. Problem is, Glastron doesn't make them anymore.
Here's Bryan with a recent windshield sent in to the shop for a replacement. We don't have a mold either, so I thought I would share a few pix from the process....
The boat windshield starts out as a FLAT sheet. A rectangle that fits the outline of the finished windshield if you could lay it out flat. Now, when the plexiglas is heated up to forming temperature, about 350F, the material will SHRINK about 2%. But according to the laws of expansion and contraction, the material will also EXPAND when heated. So a fabricator has to be a bit of an artist to attempt this particular job.
But wait - there is no mold. Or is there? Our man Bryan has decided to use the OLD windshield as a mold. It's not a perfect mold - if you lay the heated plexiglass OVER the old windshield, the new one will be slightly bigger. Using the inside as a mold will result in a windshield that is smaller. We decided to use the outside as a mold and then use a heat gun to wrap the sides after the windshield has cooled - a secondary operation.
The end result? A perfect match - new for old - and the new windshield is masked to protect it on its journey back to its owner.
This is something that everyone at Ridout Plastics (ePlastics.com) is proud of. The United States Small Business Administration decided to create a special award for Family Owned businesses across the country in 1995. In each major metropolitan region, they hand selected a short list of contenders. You could not apply to be considered. You had to be nominated by a qualified local organization and these organizations could only nominate one company. The San Diego Chamber of Commerce chose Ridout Plastics as their nominee and we underwent a grueling series of tests and reference checks.
After about 6 months of interviews and checks, their were 5 contenders vying to be the first recipient of this prestigious award in San Diego. We won this based on our years of contributions to the local community, a successful transition from one generation to the next, and our excellence in customer service. Basically, for being good guys. There is an article in Entrepreneur Magazine from back then.
It might have been 14 years ago, but we remind ourselves every day why we earned this recognition and strive to exceed customer expectations each and every day.