Posts Tagged ‘Redwood Plastics and Rubber’

Part of the trick of figuring out your plastic application and finding which type of plastic to use. This is because 1.) engineering plastics are not widely known to most people and 2.) several of the plastics may work in an application. The trick is to find out which plastic is ideal in a given application, but how do you do that? Well, first you need to figure out what your priorities are either regarding properties: do you need a plastic with excellent impact-resistance? Or perhaps slickness? How about the ability to hold tight tolerances when machined?

After you pick your top couple priorities the next step is find a plastic that best matches your needs. Redwood Plastics and Rubber offers a handy webpage with some information here. However, we’ll also copy and paste the contents of that page below:

SLICKNESS (Most to Least)

Redco PTFE (Teflon®)

Redco UHMW

Redco Tuffkast

Redco Polyurethane (Redco 750SXL)

Redco Nylon

Redco Polyurethane (Redco 750)

Redco Phenolic

 

 

MAXIMUM TEMPERATURE (500+ F) (260+ C)

Redco PTFE (Teflon®) (500 – 600°F)

Redco Phenolic (400 – 500°F)

Redco Nylon (240 – 275°F)

Redco Tuffkast (220 – 240°F)

Redco Polyurethane (200 – 240°F)

Redco UHMW (160 – 180°F)

 

 

HARDNESS

Redco Phenolic

Redco Nylon

Redco Tuffkast

Redco Polyurethane (Redco 750 & Redco 750SXL)

 

 

GLAZING

Breakage Resistant Windows

(Redco Acrylic/ Redco Polycarbonate)

Security Windows

(Redco Acrylic / Redco Polycarbonate)

 

 

LOAD STRENGTH (P.S.I)

Redco Phenolic (10000)

Redco Nylon (4000)

Redco Tuffkast (3800)

Redco Polyurethane (3000)

Redco UHMW (500 – 800)

 

 

IMPACT STRENGTH

Redco Polyurethane

Redco Tuffkast

Redco Phenolic

Redco UHMW

Redco Nylon

 

 

SHOCK & VIBRATION

Redco SVI PADS

 

 

(KRAFT MILL) PULP SAFE

Redco Synsteel (Redco UHMW)

Redco SPS-2000 (Redco POLYURETHANE)

 

 

LOW WATER ABSORPTION

Redco Acetal

Redco UHMW

 

 

Sheet Rubber For DIY Applications

Posted: October 3, 2018 in Uncategorized
Tags: , ,

Rubber is a topic we haven’t covered much on this blog so this is overdue! The main thing we hear is that people don’t really understand what types of rubber are out there or what they need for an application. Often people will ask for “neoprene” since it’s the only name they know. Neoprene has obtained a good reputation because it’s similar to a multi-tool: it does many things good, but it also isn’t optimal in many applications and a discussion with a rubber expert can lead you to a much better rubber choice.

Several other types of rubber including EPDM, natural gum, butyl, Viton, silicone, and SBR exist. In addition, each of those types of rubber exist in various strata of quality – general purpose, commercial grade, and premium grade. For example, natural gum rubber while being ‘natural’ is actually a premium grade product. We know of cases where people get quotes on natural rubber, primarily because it comes in some colors, and are shocked at the price. We’ve said this before and we’ll say it again: with plastics (and rubber) you will pay a premium for color with almost every product. When it comes to applications if at all possible it is best to take the default color it comes in.

Rubber varies widely in properties. For example, “neoprene” is not resistant to some common chemicals and is poor with extreme temperatures. But if you’re unsure of your applications requirements you may use it in a place it will fail. Likewise, Safeguard gum rubber, while expensive, has exceptional UV-resistance and functions well over a wide temperature range. Other rubbers have severe limitations with UV and mechanical properties. Again, you wouldn’t know if you didn’t ask!

Redwood Plastics and Rubber has an excellent line card breaking down many types of rubber to various categories and giving their strengths and weaknesses. Click on the link in the previous sentence to view a downloadable copy.

For members of the public PTFE (polytetraflouroethylene) and UHMW (ultra-high molecular weight polyethylene) seem to be very similar materials. They’re both white, soft, food-safe, and widely available from plastic companies. But are they that different? Oh yes they are! The first thing you would notice is the price. PTFE is literally in another category of plastics called the “high performance” plastics. This means the cost is going to be much higher than UHMW. So when do you need PTFE?

It would be an application where slickness is important above all other factors. UHMW, while less expensive, will outwear, outbear, and outperform PTFE in tough mechanical applications like homemade bushings, cutting board, etc. PTFE is very soft, so soft in fact it suffers from something called “cold flow”. This means that PTFE slowly creeps like a semi-solid liquid almost just sitting at rest in room temperature doing nothing. What PTFE does have in addition to outstanding slickness (low coefficient of friction) is that it takes very high temperatures up to 500 degrees Fahrenheit. UHMW does poorly in high temperatures and cannot handle more than 180 degrees Fahrenheit.

To be honest, in most DIY applications that call for a white plastic with balanced properties UHMW is going to be your go to. It’s too available, too cheap, and too balanced to go with PTFE. But in certain situations where very low friction is required (telescope mounts for example) or high heat will be encountered – PTFE may be your only choice.

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