Redwood Plastics and Rubber, the sponsor of this blog, offers many resources on their website to help their customers work with plastic. Some of these charts and information are ‘overkill’ for what the DIY community really needs, however. In this case, more basic information is best. The good news is their website actually has a page that links to several sub-pages that give general information on fabrication and care for plastics. These guides include some of the most common plastics used by the DIY community: UHMW, acrylic, polycarbonate, and acetal.

You can find the guide and the link to the sub-pages here: https://www.redwoodplastics.com/tools-data/fabrication-machining-guidlines/

 

 

“So do you have any of that neoprene?”
From the DIY community that is what most plastics and rubber companies hear from a customer. You can’t really blame them, they don’t know about the different types of rubber and what they need for their application. In addition, people don’t want to sound “dumb” – they want to act like they know what they’re talking about and often “neoprene” is all they know. The best thing to do is phone your trusted plastics and rubber specialists, let them know about your application, and they’ll help you find the best material. Here is a primer of the commonly available rubber types:

Natural:

Just because it’s the “natural” grade of rubber does not imply poor performance! Natural rubber, in fact, has outstanding wear resistance and “Redco Safeguard” natural rubbers has excellent UV-resistance.

EPDM:
Commercial and premium grades have excellent weather resistance including UV-resistance. All Redco EPDM has excellent temperature resistance 220-250 F (depending on grade). Functions well as a gasket or seal, especially outdoors, but is weak to oil, gasoline, and other hydrocarbons.
NBR:
It is an economy grade rubber and has the advantage of price. This comes at the disadvantage of mechanical properties and chemical properties.
SBR:
An economy grade rubber that does in fact have good mechanical properties as well as wear/abrasion resistance; however, this comes at the cost of poor UV/weather resistance and resistance to oils, gas, and other hydrocarbons.
Neoprene:
Name recognition combined with a wide variety of “good” properties. However, it has limited performance in the cold, doesn’t excel at any one property, and depending on your application you may be needless paying for a higher grade neoprene that you do not need!
Other grades are available. If you want to get in touch with a rubber expert, please contact Redwood Plastics and Rubber.

One new DIY application that’s started popping up on the internet in the past few years is what’s called a “water table”. This a play table where water is sprayed from the top and drains through small openings on the base of the tray(s). The table allows kids to splash around or use toys in it yet is constantly replaced by new, clean, water. This project is indicative of the types of fun and simple-to-make projects you can do with PVC pipe and fittings. While we don’t have any designs to offer you, we do have a couple videos that will provide tips and inspiration!

 

 

One of the most requested acrylic fabrication techniques requested of plastic companies is bonding (or more correctly, “solvent bonding). This is a process that most people would consider “gluing” acrylic together but it really is a different process chemically. In the case of a glue, two separate pieces of plastic would be held together by the solidified glue itself. However, acrylic solvent bonding goes a step beyond. The solvent actually dissolves part of the acrylic turning it liquid at the point the bond occurs. When the acrylic re-solidifies it is now truly one piece. This solvent bonding, while obvious a better bond then glue, has different requirements but the good news is it can be done at home.

The video below is a great approximately 5-1/2 minute overview of solvent bonding and how to solvent bond acrylic. The video is detailed and we recommend you take a look as there is no reason this bonding cannot be done by the home hobbyist.

Industrial plastics can be quite expensive and this is compounded by the fact that for certain applications you may have your hands tied to use a material that is costly because it’s whats required to work. However, there are some tips you can use to minimize the costs to yourself and make sure you don’t waste your money! Without further adieu, here are some tips for saving money with your industrial plastic purchases.

1.) Don’t be picky about color

This is a surprisingly big deal and why we’re leading off with this suggestion. Members of the DIY community at times seem to want to prioritize a certain color of the plastic to fit in with their application. However, in the world of industrial products color is often not changeable without high costs or custom orders. In most cases, plastics have a standard color and if you insist or request certain colors you will pay dearly for it. Accept that color is just that – color – and for the right functional material go with the standard color the material happens to come in.

2.) Hunt for offcuts

Most plastics distributors with fabrication capabilities get left with offcuts from larger fabrication jobs. These pieces of sheet may be in odd shapes that are difficult to use or sell so they sit in a rack collecting dust. If you need just a portion of sheet material, ask your distributor if they have an off cut close in size they could cut you a deal on. Many will! But don’t make the mistake of then asking them to take that offcut and cut it to size for you. This will incur costs and essentially rob the distributor of the convenience you’re offering by taking an “as-is” piece of plastic they don’t need to do any work to.

3.) Don’t request a higher grade of plastic than you need

For many DIY applications a top-level grade of plastic isn’t required for success. An example we commonly see is people requesting cast acrylic or “Plexiglass”. This product is about 30% more expensive than the more common, and more available, extruded acrylic. For a modest boost in physical properties and optical clarity you may be paying a lot extra. People tend to look at websites, see something “cool” that happens to be a premium grade product and request a quote whereas an economy grade will work just fine.

4.) Ask for help with your application

This one is pretty simple but effective. Simply tell your local plastics distributor what you’re doing with the application and ask for the most economical plastic for that purpose. They’ll likely have questions for you such as what tolerances your part needs to be held to (if any), impact, chemical exposure, etc. However, as long as you’re able to answer those questions, they will have the knowledge to point you to the least expensive material that will still work.

5.) Do the fabrication yourself

This might be a surprise to see on a blog devoted to people who “do it themselves” but surprisingly members of the DIY community often provide sketches of the simple parts they need and request that the distributor quote completed parts instead of material. This should go without saying, but you are adding massive cost to your project as shop labor is sold to you within the price to make your pieces. If at all possible, BE the “Do-It-Yourselfer” and make the parts yourself buying only the raw sheet/rod/tube.

For assistance with your plastic application, please contact Redwood Plastics and Rubber.

There are a lot of outdoor enthusiasts who are interested in food-grade plastic cutting boards. But it for an outdoor kitchen to something exotic like a fish cleaning station on a boat. The applications might seem different; however, the same family of plastic, polyethylene, is almost always used. But which plastic to use? What concerns are there?

Both UHMW (ultra high molecular weight) polyethylene and HDPE (high density polyethylene) in their “white” or more correctly, “natural” grades are FDA and CFIA approved for direct contact with food. HDPE, even though it’s less expensive, is preferable because unlike UHMW, it will not dull knives over time. If you have UHMW lying around it’s certainly a good option though and is probably worth the trade-off vs. buying a whole new sheet of HDPE. UHMW is commonly available in 4′ x 10′ sheets but many plastic companies will send you a partial piece of that sheet (with a nominal cutting fee included). HDPE is commonly available in 4′ x 8′ sheets though many companies also stock it in 4′ x 10’s.

Cutting the plastic to size is easy: household power tools such as drills and saws will easily cut it. Having a 40 grit sandpaper on hand would be good to deburr the cut edges. The plastics glue very poorly so if you’re installing a blacksplash, for example, attached to the cleaning station or cutting board you will need to screw it in. 3/16″ or 1/4″ self-tapping screws 6-12″ apart should be fine. The plastics are soft enough that your drill will countersink the heads slightly.

The problem with these natural grade plastics is that they are not UV-stable. You should expect some cracking of your cleaning station if exposed to the sun in about two years depending on exposure. The board surface should be seen as a “sacrificial” surface which will need replacement every few years – just part of the gig. The surface will become brittle and crack which isn’t good because it allows bacteria to hide in the crevices but otherwise this degradation does NOT make the plastic toxic.

If you need assistance or a quote on either of these food-safe plastics, please contact Redwood Plastics and Rubber.

 

SDS Documents

Posted: March 21, 2019 in Uncategorized

Commonly requested from plastic companies by industry and government are “SDS” or ‘Safety Data Sheets’ (sometimes also referred to as MSDS). These sheets give a range of information on potential hazards of plastics and are legally mandated for plastic producers to produce and regularly update. Where these sheets intersect with the DIY community is that home machinists and fabricators should be aware of any hazards with the materials they’re working with too. The sheets will cover what to do if the plastic shavings or dust touch you or enter your eyes or lungs, for example. The good news is in most cases these plastics are simply irritants and won’t cause harms but others, such as phenolic industrial laminates, can cause more issues.

Due to changes in U.S. Federal law plastics distributors can no longer rebrand and pass off SDS data as their own. Instead, distributors such as Redwood Plastics and Rubber need to supply SDS documents straight from the manufacturer. So this means the documents are somewhat harder to come by these days. However, for the home fabricator the most recent SDS isn’t required and Redwood still keeps some old SDS documents on their site. You can access them here: https://www.redwoodplastics.com/tools-data/msds/