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James1586 · 09-14-2010, 09:51 PM

The engine cover on my 4500 has cracked. At sometime, something fell on it causing the original crack, that was promptly ignored. It shouldn't have as now it extends from the fuel fill to almost the front corner.
I'm sure that some sort of epoxy might repair it, but was hoping that someone had done some trial and error experiments that I might benefit from.
Does anyone know what type of plastic JD uses on the body?
Thanks, James

**tractor beam** · 09-18-2010, 10:30 AM

My 84 is fiberglass. No cracks in mine, but I would use JB weld and try to cover as much surface on the underside for a better bond. Trim the top surface with a utility knife as it begins to cure, to minimize sanding. Because of my sheet metal background, I fabbed a hood for my 2005 990 that had the cheapist piece of crap hood. Never looked back. Some of the JD hoods are destined to fail by design, as the constant vibration and flexing due to opening and closing, causes the corners to crack on the newer designs. You might also try fiberglass and resin too. Good luck and hows about some pictures?

MFreund · 09-20-2010, 09:25 AM

I found this on another tractor site for the same question.

It's a soybean / corn ethanol polymer made for Deere by Ashland Composite Polymers division of Ashland Oil. The trade name is ENVIREZ. The problem is that Deere went to Ashland about 10-12 years ago with the idea of making an organic based polymer sheet molded product to use for Deere products (the soybean polymer is from research done at a number of universities). Based on Deere's annual usage, Ashland agreed to start making the material and they keep improving the product so it can change from year-to-year.

Basically, it is an organic polyester resin, and most of what Deere uses is a slab compression molded (SCM) version of the material as opposed to a sprayed / molded.

If you treat it as a polyester resin composite, you should be okay.

If you need to read all the thread send me a msg and I will forward you the thread.

Mickey · 09-20-2010, 10:16 AM

Just did some reading on the material. from the little I read this is a thermal set polyester resin. Applied heat is used to cure the resin and subsequent heat will not melt it. Have not heard of SCM but from what I've read the material is used in the form of SMC (sheet molding compound) and compression molded into its final form.

The hood on my JD 318 was compression molded. I don't pay much attention to JD products today but I'm sure I've seen hoods that were injection molded on some of their lower cost machines. Injection molding requires the use of thermal plastic. Heat will soften/melt the material every time heat is applied.

Chipmaker · 09-20-2010, 11:29 AM

Its called Zenalloy (fancy name for a plastic. It does respond well with the typical plexiglass glue. Specifically Weldon 3, or Craftics Plastic Acrylic Solvent Cement. Its a water thin clean liquid and is used in a hypodermic syringe and wicked into the cracks. Use tape on the back side to hold pieces in place and then on the fron slowly trace the joints and cracks with the syringe and slowly wick the solvent into the cracks. You may get a bit of white residue where the solvent lays on the surface but that can be polished off later. Be sure to stop drill the cracks. (Drill a tiny hole at the ends of any crack that goes into a piece of plastic that does not go to the end. This relieves stress and prevcents crack from spreading further. ABout a 1/16" dia hole is fine.
Make sure parts are good and clean before useing the solvent. I wipe them with alchohol.
The main ingredient is methylene chloride and its commonly used in construction of plexiglass items so any place that sells acrylic plastic will have it, as well as some craft stores like Michaels etc. YOu can abreade the backside and reinfoce it with a layer of fine count fiberglass or carbon fiber cloth and poly resin if desired. My front plastic bumper on my John Deere GX335 hsa been held together with this Weldon 3 solvent cement for over 4 years now and its still good.

Mickey · 09-20-2010, 06:11 PM

Never heard of Zenalloy but I've been out of the plastic business for some yrs. Did a search and found nothing. There is a Xenoy material that has been around for quite a few yrs. It is a blend of Polyester and polycarbonate. It is a thermoplastic that is used in injection molding.

Seems to recall some yrs back JD was using Xenoy for some body parts in their LT and GT machines.

**tractor beam** · 09-20-2010, 06:54 PM

Still no subsitute for good ole' steel in my opinion!

Chipmaker · 09-21-2010, 04:53 PM

Sorry I had the name in my mind but did not get it out right.it is xenoy. Thats what happens when you rely on an old mind too much. Its repaired though as I previously posted. Thew big problem with it, is heat and sunlight seems to suck out the goodie in it and makes it very fragile. I broke my bumper by leaning on it when I had the hood off doing something to the carb. I merely pushed on it with my hand. That is not saying much for the material, but if its kept inside under a roof out of direct sunlight its supposedly supposed to last a long time and be as durable as fiberglass or steel. Mine got fragile as its a very hot area from the muffler and exhaust port there on the front. The hood itself is tough as nails and its been bumped into many times with no obvious damage

John R · 10-02-2010, 03:38 PM

Go to the hardware store and get ABS pipe cement, it works great.
It's balck so be careful.
Don't use PVC, it won't hold, and it will ruin your chances of using the ABS stuff.

James1586 · 10-07-2010, 12:08 AM

Thanks for the replies, information and education. I almost hate to admit it to this crowd, but I view the tractor as a functional piece of equipment, with the fashion or style coming in a distant second.

That being said, I won't resort to attaching a plate of galvanized with some screws...yet.

For the benefit of knowledge, I will attempt repairs with the 2 easier suggestions, Weldon 3 and regular ABS cement. I've used the ABS cement before (on completely different projects) and know it well. I feel that I know the properties of Weldon, and expect the results to have similar results for the short term. The ABS will be cheaper, but long term results will justify the better choice. I will of course document and post the progress and results for reference.

And if all else fails, I'll get that sheet of steel and crudely scratch "Tractor Beam" upon it...

Chipmaker · 10-07-2010, 03:38 PM

Well the twop ends and the center section of what John Deere calls a bumper and bumper ends on thre GX335 L & G tractor was broke on mine. The bolt hole ears on the end caps were broke ff, and the center section I put my hand through when I had the hood off and leaned on it. IOt eviodently does dry our or dry rot for lack of a better term, when exposed to sunlight and UV rays or heat such sa is in that area fromthe muffler. I pirced it out at JD and just did not feel like paying that kind of money out.

I rep[aired my bumber caps with Weldon 3 and reattached the broken bolt hole tabs, and also glued on a thinner piece of clear poplycarbonate plastic as a reinforcement. Its underneath and out of sight. I wicked in Weldon 3 into the busted nto about 6 or so pieces of the center section which merely snaps into place between the two end caps. It looks great, and the joints where it broke are barely visible, since I buffed away the white residue the weldon 3 left due to humidity. I merely used a handcloth and rubbing compound and about 2 minutes it was gone. I cut grass and also got into the brush with it, and everyhting has held up just fine since I repaired it. If I say on the grass and out of the tall stuff there is no doubt in my mind it will last probbaly forever sa weldon melts the base material and when it evaporates the solvent out it becomes practically all one piece again. I can not say about ABS cement, as all I ever used it for is the black ABS drain type pipe.
I may unsnap the center section and heat up a thin section '0.083" thick of polycarbonate sheet and form it to fit inside and then use Weldon #16 (thicker glue in a tube) or melt some polycarbonate in Weldon #3 to make it thicker and use that and attach that clear formed p[iece under the center section just for insurance. Give me something to do once it starts raining around here which is usually in the winter months.

Lots of luck and let us know how it comes out.

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