Re-Roofing a Greenhouse with Corrugated Fiberglass Sheets and Panels

Fiberglass Sheet for Roofing - Patio, Greenhouse, Car Port or ?

It is Summertime and there are a lot of homeowners looking into re-roofing the house, putting on or replacing a patio roof, or maybe building a greenhouse, flat or corrugated fiberglass sheet roofing materials might be the answer to what you are looking for to meet your needs.

Fiberglass sheet roofing offers flexibility and is usually bought in sheets or panels made of synthetically produced fine glass fibers. Panels are weather-glazed, providing a waterproof seal and a tough, durable roof structure. Fiberglass sheet is very resistant to corrosion and chemicals, is shatterproof, and will not rust, rot, or mildew. It requires a low level of maintenance, is much cheaper than other types of roof paneling, and can have a life expectancy of about 20+ years. The better grades have 20 year warranties. And fiberglass sheeting is very easy to install due to its light weight. Typical sheet sizes are 26" wide (to allow for a 24" overlap) and 96" or 144" long. If you have enough need, you can get the manufacturer to run a special length for you.

Fiberglass sheets for roofing are available in a clear or white color. With orders of over 8000 sf, any color can be run to match a specification.

Special NAILS and aluminum trim are available for building a greenhouse to seal the top and sides. Even wood strips are available for securing the corrugated sheets to the cross beams and end-walls.

Corrugated fiberglass roofing can be purchased in a heavy duty form that withstands high winds, heavy snow, and extreme outdoor temperatures. With interlocking between sheets, this type provides good water run-off.


Industrial and Metal Buildings use a special wide 1/16" thick panel for their skylights called an "R-Panel" that are 37" x 144" or larger. These come in a translucent white - and a great alternative for homeowners and condo associations looking for a really high strength carport or patio roof replacement! A good amount of light will come in without the heat gain of a clear or thinner white sheet.




The designs and possibilities of use for fiberglass sheeting for roofing are improving constantly. Another very interesting application is the use of the flat fiberglass sheet for solar panel covers such as for hot water solar tanks and systems. Thanks to www.ePlastics.com for the pictures.

How Safe are Plastic Water Bottles?

Here's a hot topic. Plastic Water Bottles. Are they SAFE? Or do they pose a danger to our health?

The chemical in question is bisphenol A - known as BPA - found in polycarbonate containers.

Here is a article contributed by Britney Wilkins who write for www.onlinecolleges.net :

This has become an interesting debate in modern society, as people become more and more worried about any contaminants that may be polluting their everyday lives. This has therefore resulted in the “green” movement in which many people have opted for products that do not contain any added preservatives, flocking towards more “natural” products on all ends of the spectrum. While there is no real way to get around the plasticity of water bottles aside from simply using a stainless steel container, you can take certain precautionary measures to ensure that you are not imbibing the harmful pollutants.

Water bottles are generally safe unless you plan to use and reuse them time and again. After so many rewashes, the ingredients that make up plastic, such as polyethylene terephthalate and antimony begin to leak out due to the degrading interior. Many moms and parents are trying to teach the importance of conservation to their children and have tried to reuse these plastic containers before realizing that this could cause more harm than good. Most plastic containers are stamped with a number on the bottom to indicate how to recycle or dispose of the plastic, with most water and juice bottles labeled as No. 1, indicating their easy ability to degrade upon multiple washes. In comparison, the harder Nalgene bottles have the number 7 stamped on the bottom, although scientists maintain that this form of plastic can leak out bisphenol A, an endocrine-disrupting chemical. While this is still in debate since the amounts found were well below the Environmental Protection Agency’s standards, other scientists maintain that this type of chemical could cause behavioral and neurological problems in developing fetuses and young children.

This poses many worries about the proper way to drink water: can we no longer use typical plastic water bottles? These findings are not meant to scare us off from our regular water bottle usage, but simply to remind us not to continuously wash and reuse the same water bottles. Once we start to overanalyze every form of plastic and the type of containers we use on a daily basis, we realize that there are contaminants in nearly everything, which makes it almost not worth it to worry about. While many of these findings have brought on increased amounts of worry within parents, the bottom line is to remember to only reuse plastic bottles a handful of times before you throw them out. If you want a container that has staying power, resort to the stainless steel bottles, although plastic still remains the best alternative and is much easier to tote around. (She welcomes your feedback at BritneyWilkins81@yahoo.com)

OK - interesting take on the BPA worries.

Here's some information just in from "Plastic News" July 20th 2009 issue:

The 6 major manufacturers of baby bottles have agreed NOT to make bottles containing BPA. Health Canada said it would draft regulations banning the import and sale of baby bottles containing BPA. Health Canada issued three separate reports 7/9/09 affirming the safety of bottled water, powdered infant formula and baby foods in glass jars with metal lids - all of which contain BPA.

Health Canada added that BPA levels in bottled water is negligible for the general population and that an adult would have to drink 264 gallons of water every day to approach the safe intake limit for BPA recently established in Canada.

Closer to home, in California, on 7/15/09 the California Developmental and Reproductive Toxicant Identification Committee voted 7-0 not to include BPA on the state list of toxic chemcials regulated by Prop 65.

Well - it is safe to say that the wheels are turning in North America - BPA is on the way out and the levels are very very low in current production containers. There is no level of BPA acceptable for infants - that seems clear.

What about the bottles you ARE drinking from right now? They are safe.

What about re-using a water bottle over and over? They are safe - but the reality is that I would worry more about what is in the refilled WATER than leaching out of the plastic container. After a few re-uses there is bound to be some amount of bacterial contamination in the water that is far more bothersome than a fractional amount of BPA. That bacteria comes from the air, your mouth, the food you eat and the air getting in the bottle when it's sitting around waiting for a refill.

So... I am only refilling my bottles ONCE - and toss the old ones in the recycle bin for cash.

Plexiglass at Home Depot or Lowes

I love Home Depot. I love Lowes. I go there when I need hardware, lumber or a new BBQ. But I don't go there when I need a sheet of Plexiglass acrylic sheet. It's not because I have a plastic company, but because I know the difference between what is being offered for sale there vs a plastic distributor's shop.

For MOST consumers, you are looking for the best value for your money. Something that will last and do the job correctly. Sometimes we just need an inexpensive sheet of clear plastic right now. When the second reason is the case, by all means, go to the big box store (Lowes or Home Depot). The rest of the time, visit your friendly plastic distributor, explain your application, and they will set you up with the correct material - Plexiglas, Acrylite, Optix, Lucite are typical brand names. It's printed on the paper masking. It's on a label under the film masking. No label? Ask for proof it's domestically made (North America).

The material you find at Home Depot and Lowes is an inexpensive "extruded" sheet of acrylic with a typical film masking. Usually it is made here in the USA. But what I don't like about the big sheets is that they are too thin. But - they sell some small sheets too! If you're looking for some small 8x10 or 24x24 sheets of THIN clear Plexiglass - then they are a great source. Most plastic supply companies do NOT want to sell just an 8x10. But at Home Depot you can. Even self checkout!

Should you want to cut the Plexiglass - they usually sell a small Plexiglass scribing tool that allows you to put a groove across the sheet, and then snap it in half right along the groove!

Embedments in Plexiglass Acrylic

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.

Calculate Aquarium Thickness - How THICK must the Plexiglas be?

AQUARIUM THICKNESS CALCULATION

To determine the proper thickness for an aquarium made of ACRYLITE® GP acrylic sheet...

OK - this is for all you Einsteins out there - even if it's high school physics and math... please don't ask me the calculate this.. :-) - check out the Cyro Tech-Knowlogy site for a spreadsheet to help. You have to login in - but it is a killer info site.

The aqaurium in the picture is 12ft long, 4ft high and about 3ft wide in the middle. It was constructed of 2" thick acrylic sheet, the outer walls were thermoformed into convex sheets, and please note the "top cap" made of 1" thick plexiglas sheet, then routed out for access holes. This top cap also creates a structural member that keeps the outer walls from bulging under pressure. This aquarium is now doing service in upstate Michigan.

CYRO recommends that all acrylic water vessels, including aquariums, should be constructed with cell cast ACRYLITE GP sheet. This requirement exists for two reasons:

1. ACRYLITE GP sheet is more capable of withstanding continuous loads than continuously manufactured or extruded sheet.
2. ACRYLITE GP sheet maintains a high level of mechanical strength after water absorption has reached equilibrium.

Cemented joints must withstand the effects of the continuous hydraulic pressure and the high level of water absorption for many years. Two-part polymerizable cements are recommended for this to meet this requirement. See Weld-On #40 information in the blog. Solvent cements are NOT recommended.

To determine what thickness acrylic sheet should be used, the calculation below can be used assuming the base is uniformly supported.

T - thickness of sheet H - height of tank L - length of tank

Required Thickness T (in)=

q = maximum water pressure (lbs/in.²) = (0.0361 lbs water/in³)* H (inches)
H = aquarium height (inches)
α = maximum permissible stress for ACRYLITE GP in an aquarium (750 psi)
β = coefficient from L/H relationship as follows:

L/H	0.25	0.50	0.75	1.00	1.50	2.00	3.00	4.00
β	0.037	0.120	0.212	0.321	0.523	0.677	0.866	0.940

Note: For L/H ratios not shown, use the β value for the next higher ratio.

Example:

L = 36 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

T (in) =

=

= 0.375 inches

If a top is cemented on (this would have 2 cutouts to prevent bowing), the recommended thickness in 0.375 inches. With an open top use a safety factor of 1.5, bringing the recommended thickness to 0.563 inches to be used in this size tank. Since a thickness of 0.563 is not made, simply increase this to 0.740" (3/4") which is stock.

OK - did I blow your mind? WWPGD? If you want to build an aquarium, and the edges are hidden by framework, or the mounting in a wall, etc. then use 1/2" CAST ACRYLIC SHEET for aquariums that are 15" high x 20" wide x 36" long. Make sure there is a top cap to keep sides from bulging. 24" x 24" x 48" - use 3/4" sheet and 30"x30"x48" use 1" sheet. Always use a top cap sheet to hold side together!

If you are not skilled with gluing Plexiglas, search out a local plexiglass fabricator in your area. Typically under the Yellow Page heading of Plastics - Fabricators. If the edges are showing, make sure the fabricator defines how bubble-free their bonds will be and the quality of the edge polishing. Expect to place a 50% deposit on the order and the balance when complete to your satisfaction. To save money, identify what edges do NOT need to be polished - that saves time and your money!

Fiberglass FRP Pultrusion process and shapes

Fiberglass Reinforced Plastics (FRP) can be manufactured several ways. Let's explore the pultrusion process of making fiberglass sheet, shapes, and profiles. The pultrusion process allows production of continuous lengths of fiber-reinforced polymer profiled pultruded shapes, angles, rod, beams, and tubes.

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 die is made of metal, with a highly polished interior to allow the rather corrosive fiberglass and resin mixture to pass through easily. The mass of materials conforms to the shape of the die and is heat-set into a permanent, structurally reinforced shape. Fully cured when exiting the end of the heated metal die.

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)

SHOJI Chrysalis Resin Panel fabrication

Plastic Fabrication using Chrysalis HD resin panels is pretty cool. I can't do this with 3-Form or Lumicor panels. That is really SHOJI (shogi) paper inside the sheet. Duraglas, the maker of Chrysalis HD, uses a patented process to manufacture these panels. The base sheet is PETG (same stuff as soda bottles) and is thermoformable. The surface is unique in that it is "self healing" - small scratches (yes, scratches) can be removed with a small heat gun such as a cooking torch or industrial hot air gun. A few short passes will heal the surface.

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!