Plastic verses metal

   / Plastic verses metal #21  
I want to test the plastic scarifier teeth, if you don't mind...

Mark
 
   / Plastic verses metal #22  
Now Mark, everyone knows that scarifier teeth are made of rubber and not plastic, you must have been thinking of the attaching bolts, your silly. Rat...
 
   / Plastic verses metal #23  
Maybe test graphite ones. Could be exciting. Different version of a power hop.
 
   / Plastic verses metal #24  
I'm waiting for a touchless system, laser or polytritium crystal influx transfuser (like the one on Star Trek) type deal. No teeth to wear or break, Rat...
 
   / Plastic verses metal #25  
They come on the plastic box blades. The only problem is you have to get plastic rocks first! /w3tcompact/icons/laugh.gif
 
   / Plastic verses metal #26  
Most plastics is far from bullet proof and particularly not plexiglas. Lexan is the material used for "bullet proof" sign protection. It is certainly a very tough material and one that I have used for high stress insulators. It is one of the few plastic materials that has good UV properties.

Plastics ARE brittle. It is the plastisizers that keep them from being brittle. Unfortunately no one has come up with a way of keeping the plastisizers from being driven from the material in UV environments and the plastic again becomes brittle.

I strongly prefer metal, because you can repair it. Start a fire under that plastic hood and see how long it lasts!

Welding plastic is simply melting it together with a rod made of the same material for a filler. You had a weak material before you welded it and you have a weak material after you welded it. Works ok on low pressure containers, but not for structural elements. The main advantage of plastic in the agricultural world it that it doesn't rust and is light. The main disadvantage of it is that it is light and isn't usable in 50 years when everything else still is. /w3tcompact/icons/smile.gif

UV deterioration has not been solved for most inexpensive plastic materials. When you think it is, patent some cable ties that don't fall off in a couple of years! /w3tcompact/icons/smile.gif
 
   / Plastic verses metal #27  
Many of the plastic parts like hoods and fenders are painted. The paint provides the UV protection for the plastic, just as it provides rust protection on steel. I wonder which would be worse off if they were both left unpainted.

There are two main classes of plastic. The thermoplastics and the thermosets. Thermoplastics such as Plexiglass (acrylic), Lexan (polycarbonate) or polyethelyne can be welded. A thermoplastic will soften and melt when heat is applied. Most often thermoset plastics are used for components like hoods and fenders. Examples of thermosets are epoxy and polyester resins (Bondo used to repair cars is a polyester resin with fillers added). They are usually combined with structural reinforcement like fiberglass or graphite fibers. They can not be welded. They do not soften or melt when heat is applied. They can be repaired with resin and fibers.

Not all materials are best at all things. For some applications plastic is better and for some applications metal is better. The best tractor would make each component out of the material that was best for the application and would contain both materials.

Bullet proof glass is actually a layer of glass, a layer of polycarbonate, and another layer of glass. The glass, in addition to providing scratch resistance, shatters on impact and dissipates the energy from the bullet over a larger area. Without the glass, some bullets would go right thru.

Andy
 
   / Plastic verses metal #28  
That was good. Thanks. Register and participate more. /w3tcompact/icons/smile.gif I saw an old BUICK that was equipped with 1 inch thick bullet proof glass and had 1/2 in steel in all of the door panels. The biggest problem they had was getting tires to hold the car up! /w3tcompact/icons/smile.gif
 
   / Plastic verses metal #29  
I don't believe it's an either or thing both metal and plastics have their good points I have plastic fenders on my atv when in the woods quarters get pretty tight, you side swipe some trees,the steel wheels look like hell/w3tcompact/icons/mad.gif the plastic fenders look like new!!! Tell me would you like to replace the soft crash absorbing dash in your car with one made of diamond plate!!!/w3tcompact/icons/smile.gif/w3tcompact/icons/laugh.gif My neighbor has a (plastic) Saturn 270,000 miles of New England (salt infested) roads, looks like the day she bought it. All the steel is under the skin, and they crash test very well, ahhh technology it's a beautiful thing./w3tcompact/icons/smile.gif/w3tcompact/icons/wink.gif
 
   / Plastic verses metal #30  
I really do understand composites and why they are superior in a lot of applications. Usually when I find something broke in my Honda or Cherokee, it was a pretty well designed part (Cherokee exepted), but it just didn't hold up as well as I would like for it to have done. No, I don't own a car, jeep, or truck with composite body panels, and probably won't as long as there is a choice. Almost every mechanical problem I can think of in them is due to the misapplication (cost savings) of composites in automobile design. Many of the problems appear to be UV related (yes, they were painted parts) or embrittlement issues.

But for tractors, all of the cracked steering wheels, knobs, switches, etc. that failed were also probably due to misapplication (cost savings) of composites. The steering wheels don't usually fall apart, because they knew they would crack and put a metal reinforcement inside them. No, I will take my tractor fenders, hoods, etc. out of metal until composites give the same serviceability. I liked the John Deere metal floorboard better than the Kubota Rubber Mat (which I saw a couple that were cracked), but after having my feet on the rubber mat all day, I now like it MUCH better. /w3tcompact/icons/smile.gif

Tractors need to be heavy for most agricultural applications. The main reason for composites is ease of manufacturing, low cost, and light weight. Seldom is the composite superior to the metal part unless light weight is of high importance as it is in airborne vehicles.

Kubota has a really nice little metal M110 Tractor Model (for $42.00). It looks really well made and I would have bought one except the wheel rims were made out of composite and really looked cheap, although I am sure it was very strong. /w3tcompact/icons/smile.gif Guess perceptions are hard to overcome.
 
 
Top