westpak

iTrader: (19)

Well now that the US Nismo kits are coming I am just curious to know the differerences between the two materials, it seems most people on the forums were anticipating the parts coming in Urethane but when I had my car repaired the body shop guy said to stay away from urethane. I did not get a chance to find out why so I am wondering if anyone has comments regarding the pros and cons of both.

Sup

this is a good read...from an employee of Kaminari.



"After I read a couple threads, I was moved to share some knowledge. This is not directed at any competitors or a certain company. You can do your own research and ask questions from whatever vendor you are interested in buying from.

There is nothing wrong with fiberglass if it is hand laid... almost all kits made in Japan are hand laid rather than the chopper gun method.

Chopper gun fiberglass is heavier, weaker, uneven, brittle, and can be very wavy. The only advantage of chopper gun fiberglass is the cost, and speed of the maufacturing. Thus the Taiwan and China manufacturing. It is almost impossible to find a chopper gun fiberglass component that fits well.

Hand laid fiberglass costs more but is strong, durable, LIGHTER, and is spread evenly.

When it comes to urethane there is high pressure and low pressure urethane. In short, high pressure is lighter, stronger, and will withstand a much higher temperature than the low pressure urethane. High pressure urethane costs more to produce parts, thus the price difference.

Be careful when you make your decisions on materials. It is not as simple as Urethane is better or fiberglass is better, There is MUCH more to that.

Remember, urethane will change shape at a given temperature. The question is, at what temperature will it start sagging, distorting, and falling apart? I have seen sideskirts you can fold in half.... This is NOT OEM grade material, and if you live in Texas, it's going to change shape.

Fiberglass... be VERY careful. I have seen fiberglass parts literally MELT in the heat. The resin that has cured has actually turned back into resin.

Personally I have had a fiberglass (hand laid) kit on one of my cars for over 3 years. No problem. Our Mustang has the fiberglass version of our kit, and we take it to the track regularly. No problems.

I will be more than happy to answer any questions assuming you do not ask questions about certain traded secrets I cannot discuss.

This is just a tip of the iceberg... our resin, bonding material, and other things are our own formula that cannot be bought of the shelf. It has it's own unique advantages. "

MSOsr

iTrader: (5)

It is my understanding that the Kaminari urethane is OEM grade urethane, injected at very high pressure. Same material as your front and rear bumpers from Nissan.

westpak

iTrader: (19)

Great reading.

I think that is is the reason some of have had bad experiences with the Nismo replicas, I have gone through 2 and it is just as described.

Voids that expand when baking paint causing bubbles and improperly cured fiberglass that with heat results in waviness.

ares

iTrader: (2)

from what I understand, when they say high pressure, they dont mean the pressure its injected at. urethane can be cast in a pressurized chamber, between 50 and 80PSI. normally since this isnt injection molding, the resin will have bubbles in it, first they "degas" the resin, but when its poured some bubbles are reintroduced. so they toss the whole mold into the chamber and crank up the pressure. this forces the large bubbles into suspension creating a perfect peice. lew pressure of course is just room pressure.

your body shop was probably saying that cause fiberglass tends to take paint better, easier to match colors on fiberglass vs urethane.

urethane is heavier, but its main point is its flexable. fiberglass is not. not that Ive ever seen, it just cracks.

MSOsr

iTrader: (5)

From Kaminari:

"Did you know our polyurethane is OEM grade material?
We use high pressure Reaction Injection Mold (RIM), BASF Polyurethane, which is OEM grade material. Our urethane components will retain it's shape in extreme weather conditions, and is up to two or three times stronger and lighter than anyone else's urethane. The machines that we use to inject the urethane is up 10 times more expensive than any of our competitors. Most competitor's machines could not even process the urethane that we use."

ares

iTrader: (2)

of course I dont know their setup, but BASF is just a company, not a grade. you can see it here

http://www.pu.basf.com/en/default.asp

and yes it is very high quality material, but there are lots of resins out there that will offer OEM characteristics.

westpak

iTrader: (19)

Basically it boils down to manufacturing and both methods in the high end are good.

You just have to find out if what you are looking at is on the high end from people that have invested in the equipment to do it properly.

swifty949

there is no one easy solution. however when coming down to parts for your car, you get what you pay for. Higher priced parts are more expensive to make for a reason, thus higher retail prices. For any material there are several grades on the market. It's ignorant to just say Fiberglass is bad, or Urethane is bad.

I've seen bad Urethane out there, it's terrible. Urethane will break, it's not industructible. Just it's impact resistance is better. The problem with Urethane is you cannot repair it as easily as Fiberglass, and it's heavier than fiberglass.

As far as I know, most OEM bumpers are ABS.


oh btw, people in Japan hate Urethane. They are serious about performance, so to them it's just too heavy, and unstable for high speeds.

ares

iTrader: (2)

yeah most everything OEM is ABS, cheaper to make per part when your talking about 30,000 parts a year. urethane is very very expensive actually, few hundred bucks in material alone, and the process in comparison to ABS is very slow, ABS cost maybe 20-30$ worth of plastic. I think thats probably high when you consider the bulk their using, and pouring it is a matter of minutes even for something as large as a bumper.

of course the mold for a bumper would be 50grand easy. so even considering youd make the extra profit per peice for cheaper materials, youd need to sell a whole lot of them to even break even.