Life Expectancy of Tamiya Plastics.

[Grumpy pants]

Curiosity really this one for me -

I get there any many factors involved, type of plastic, use, UV, temperature, environment for both driving and storage, etc, etc. 

But what is your experience of the life expectancy of the plastics used by Tamiya?

Is it 20 years for an enjoyed ORV chassis, 15 years for Blitzer wheels, that type of thing. 

I don’t run my RC much, but our LB was 2nd hand 10 years ago, so at some stage plastic parts will wear out and inevitably break.

My shelfers are now over 40 years old as well, which must mean the plastics are getting brittle as well.   

[Willy iine]

From the various restorations I did on my 30-40yr old M38's, they greatly varied in how they aged.  Some felt like new, some felt like they were going to shatter if I dropped it or disintegrate if I ran the vehicles in that state.  I kept notes on where the chassis were purchased from, but unless we were talking about condition of the box or manuals, there was really no pattern basing condition of plastic to geographical location.  It was all about how the models were kept by the previous owner(s).

My M38's are all drive worthy.. but not sure if they are at the same structural strengths as back in the 80's.  I've tumble tested them and drove over rough terrain (3/4 to one inch dips and bumps at a fast pace) and all passed these tests.    All worn parts were replaced with new or 'excellent condition' parts.  Some chassis I took the metal bits off and threw the rest out as it could not be used as a runner.. the plastics were too brittle.

My pretendRCshop's air is HVAC controlled by the central HVAC on the house.   It is on the drier side where the driest I've seen down to about 15RH on my hygrometer in the coldest days in winter (-20F outside), to less than 60RH on the most moist and cool days.  There is no direct sunlight and temp stays around 65 - 75F all year long.   I think the drier air will eventually dry out the tires if I do not treat them with either water based rubber/plastic protector like Aerospace303 or more oil based TDK if severely dry.  I am not sure about the plastic.. I think it's in a fairly ideal condition so I don't expect them to deteriorate in the next 10-20 yrs.  

I have no scientific knowledge to back this up, but I believe from my experience keeping one's models away from direct sunlight and in a cool drier place is key to longevity.  

[Kowalski86]

If you mean the ABS plastic, it varies. At this point I try to avoid anything older than the late 90's.

Somehow my Frog has had no problems with brittle plastic, despite being made up of mostly 30-40 year old original plastic. I think the cream color doesn't absorb UV light as much as the usual black.

I will say that cold weather is hard on plastic (even good plastic), that's when my Tamiyas were always more likely to break over jumps.

[Saito2]

Interesting question but one that seems nearly impossible to generate any kind of repeatable answer to I'm afraid. Cross referencing impact forces with age, type, and degradation level seem like it would be difficult. Type would be easiest to generate numbers from possibly followed by impact forces from "accident reconstruction" and then finally degradation level which would be difficult to ascertain. Perhaps some kind of "autopsy" of a given failed plastic part through someone familiar with plastic chemistry. I don't know.

I've had parts last forever on certain Tamiya cars and the same part on a different, but same type of car, fail quickly. When I see cracks, particularly around screw holes, I ask "was that due to impact forces, age or poor design (not enough supporting plastic around the screw hole)?". New built shelf queens that fail sitting still we can safely assume was down to poor design if kept out of the sun and in reasonable atmospheric conditions.. Often times durability (which can be tied to longevity in some cases) starts with design. Since Tamiya's common ABS/PC construction relies on strength through mass, the bulkier the part, usually the stranger it is. The problem is, from an economical standpoint, its best to use the least amount of plastic the do the job.