Speaking of fans...

[Susanne]

2 days ago I got to witness a 10 year old plastic fan grenade itself while in use. Further inspection of the remnants showed it had hardened with age (and perhaps heat) and lost all semblance of flexability... an old, frayed belt tipped it's fray into the fray, and ping pop gone.

I know the latest rage is to retrofit plastic fans on the front of our engines, and of course you can do as you wish, I'm just not sure that plastic is so fantastic.... My 2¢, YMMV and all that other internet stuff....

[Professor Fate]

Currently there is no way to set the model A plastic six blade fan dead center and indexed on the modern roller bearing pulley. Being off balance and off center is detrimental to blade life and personal safety.
My recent foray into the plastic fan world has fallen short of success.... for now.
Maybe someone will 3D print an update on the plastic fan that allows for indexed accurate placement on the pulley hub.
We'll see I guess....

[Mark Nunn]

Maybe someone will 3D print an update on the plastic fan that allows for indexed accurate placement on the pulley hub.

I have used 3-D printed plastics to build prototypes for over 25 years. I would NEVER trust a 3-D printed fan behind my new Brassworks radiator.

[Kaiser]

Ah the exploding plastic fan, the idea that plastics were forever was planted in the '50s, plastics are not forever as we now know, and some plastic deteriorates faster than others.
The main reason plastics (or more accurately polymers) lose their strength and flexibility is not so much the aging of the polymers themselves, but the loss of plasticizers through time because of heat or/and UV light
For instance the most widely used plastic, PVC (poly vinyl chloride) is a rather hard and brittle plastic, but add some phthalate esthers and wahoo! You have a very durable, pliant polymer that can be easily formed, stays flexible and is sturdy, and is almost impervious to chemicals.
However, through time the plasticizer weeps out and the PVC becomes brittle, first effects of this vary, but most pvc products show signs of this after 10 to 15 years.
Voilá the deeper source of the exploding fan fenomenon.
I'm NOT a Geek

[Paradise Garage]

I got a fan of a chev 1/2 ton from a junkyard and it only lasted a few days before blowing apart. The truck I got the fan off had no front clip on it and I believe the sun rotted the plastic away. It had only sat with no front clip for about a year. I don’t see any plastic fan lasting any amount of time compared to a steel one

[M.Sinclair]

3D printed fans in their current state should NEVER be considered unless you have access to the new shiny multi thousand dollar industrial printers. Standard hobbyist printers leave plastic layer lines like sedimentary rock where the plastic will quickly shear off if it’s put under any extreme stress like for example being at the front of an engine spinning

[BobD]

Besides being of plastic construction, IMHO Those modern 6 bladed plastic Model A fans look horribly out of place either on a Model T or A.

[Wayne Sheldon]

At the risk of stepping on my tongue as I put my foot in my mouth? I just really don't get this whole "plastic fan" business.
In the first place, any obviously anachronistic alteration of an antique vehicle, to me, lessens the value, and the effect, and in turn my interest, in said vehicle. Whether in a photo or a car show, an open hood showing modern alternators, modern oil filters, and modern plastic fans, along with silly accent color painting, freakish color wiring etc etc etc, ruins the historic effect and feeling for the vehicle. Not only do such things ruin the look, they ruin the feel, they do not in any significant way improve the ride or reliability to the driving of said vehicle.
Secondly, at the speeds a model T (or almost any prewar era car?) engine turns, good steel blade fans that have not been somehow damaged by mishandling, collision, rust corrosion, or extensive vibration, have been fine for three quarters of a century or more! Yes, they do need to be carefully inspected during restoration, and occasionally during routine service to avoid a nasty future failure. However, if they look good? They should be good for another quarter century or more.

How many people (here? anywhere?) actually know what the word "plastic" means? What is its origin? In a "universal" sense, "physics" is the scientific study of matter and energy in the universe that surrounds us. Most people "know" of the three stages of matter; "gaseous", "liquid", and "solid". However, there are a few others. Two that we hear about more than most people realize, are "plasma" (an extremely active supper-heated gas), and "plastic". "Plastic" is a middle-ground. It lies between when a material mass is a solid or a liquid. Different materials have differing "plastic" stages (that condition where it is neither truly solid or really liquid). Some materials have very narrow ranges of temperature between liquid and solid (ever try to weld brass?). Other materials like steel have wider plastic stages (and are much easier to weld!). Some materials have almost no plastic stage. Wood for instance does not have even a liquid stage, let alone a plastic stage. It goes almost straight from solid to gas (or in the absence of oxygen, dust). Sugar can be a solid or a liquid, however the molecular structure falls apart if heated too much, so there is no "gaseous" state.

"Plastics" in the modern sense, are artificial materials that have a not quite solidness about them. They are in our normal environment, never quite solid. That means that they continue to flow, no matter how slowly, well after they have been manufactured into some product. Most plastics of the past three quarters of a century also literally evaporate. Again, very slowly. Heat, chemical contaminants, and UV or other external energies can speed up the material flow and evaporation of plastic materials.
Plasticity, flexibility, and bending, while similar, are not exactly the same things. Plastics tend to be more flexible, while solids may be bendable. Defining that whole thing would be quite a dissertation.

It seems to me that a plastic fan on a model T is a short-term fix for a long term problem.
I think I will stick with the original fans.

[Oldav8tor]

Rich Eagle graciously allowed our club to use one of his drawings on a club T-shirt. The idea was because we were coming across so many unusually mechanical conditions when we worked on member's cars....coining the motto "Never saw that before!" The cartoon shows a fan blade exiting thru the hood of a Model T - fortunately we haven't seen that but have seen some metal fans requiring replacement. Personally, I would never go with a plastic fan for a number of reasons. I did, however, replace my original 1917 fan with four riveted blades for one consisting of two double blades, one crossed over the other. After smoking a fan belt due to a stuck fan pulley I also installed a ball bearing unit which has been trouble free.

[Allan]

So, replacing a 100 year old metal fan with an ugly 10 year old plastic one is an upgrade? No thanks.

Allan from down under.

[ModelTWoods]

At the risk of stepping on my tongue as I put my foot in my mouth? I just really don't get this whole "plastic fan" business.
In the first place, any obviously anachronistic alteration of an antique vehicle, to me, lessens the value, and the effect, and in turn my interest, in said vehicle. Whether in a photo or a car show, an open hood showing modern alternators, modern oil filters, and modern plastic fans, along with silly accent color painting, freakish color wiring etc etc etc, ruins the historic effect and feeling for the vehicle. Not only do such things ruin the look, they ruin the feel, they do not in any significant way improve the ride or reliability to the driving of said vehicle.
Secondly, at the speeds a model T (or almost any prewar era car?) engine turns, good steel blade fans that have not been somehow damaged by mishandling, collision, rust corrosion, or extensive vibration, have been fine for three quarters of a century or more! Yes, they do need to be carefully inspected during restoration, and occasionally during routine service to avoid a nasty future failure. However, if they look good? They should be good for another quarter century or more.

How many people (here? anywhere?) actually know what the word "plastic" means? What is its origin? In a "universal" sense, "physics" is the scientific study of matter and energy in the universe that surrounds us. Most people "know" of the three stages of matter; "gaseous", "liquid", and "solid". However, there are a few others. Two that we hear about more than most people realize, are "plasma" (an extremely active supper-heated gas), and "plastic". "Plastic" is a middle-ground. It lies between when a material mass is a solid or a liquid. Different materials have differing "plastic" stages (that condition where it is neither truly solid or really liquid). Some materials have very narrow ranges of temperature between liquid and solid (ever try to weld brass?). Other materials like steel have wider plastic stages (and are much easier to weld!). Some materials have almost no plastic stage. Wood for instance does not have even a liquid stage, let alone a plastic stage. It goes almost straight from solid to gas (or in the absence of oxygen, dust). Sugar can be a solid or a liquid, however the molecular structure falls apart if heated too much, so there is no "gaseous" state.

"Plastics" in the modern sense, are artificial materials that have a not quite solidness about them. They are in our normal environment, never quite solid. That means that they continue to flow, no matter how slowly, well after they have been manufactured into some product. Most plastics of the past three quarters of a century also literally evaporate. Again, very slowly. Heat, chemical contaminants, and UV or other external energies can speed up the material flow and evaporation of plastic materials.
Plasticity, flexibility, and bending, while similar, are not exactly the same things. Plastics tend to be more flexible, while solids may be bendable. Defining that whole thing would be quite a dissertation.

It seems to me that a plastic fan on a model T is a short-term fix for a long term problem.
I think I will stick with the original fans.

WAYNE, The recent post on this Forum advocating the use of a plastic fan, did so because the poster was advocating that a plastic fan (if it came apart) would be gentler and kinder to a new expensive radiator, and/or car or truck hood, than a comparable steel fan would be (if it came apart). I am not an advocate of a plastic fan. I am just saying what I believe the original poster was trying to point out. Obviously, any owner who who use a plastic fan isn't concerned with originality.

[Wayne Sheldon]

Terry W, That might be a valid point? I generally avoid threads that titles indicate certain modernization upgrades. I prefer to not read most of those, and prefer to avoid arguments in them. The title on this one caught my curiosity, and when I read about a plastic fan breaking, I thought a little background into the nature of plastics was in order.
If I find a few minutes to do so, I may come back here and tell another tale of engineers and bad plastic designs. Caused us a bunch of hurt in the communications contracting business thirty years ago. Not all engineers are smart engineers. I had planned to tell the tale, but got interrupted before I got to it.
And thank you for the clarification!

[Dan Hatch]

Plastic fan easily on radiator? Why not just fix the metal fan so it doesn’t kill your radiator?

[TXGOAT2]

A four blade steel repro fan is probably the safest bet. It would be a good idea to check it for straightness, balance, concentricity, and tight rivits befor using it. Blade pitch needs to be uniform. The fan hub needs to be in good condition to minimize wobble and vibration.

Old fans need to be checked the same way, with special attention being paid to any evidence of cracks, welds, old repairs, loose rivits, rust, etc.

Any fan ought to be balanced and have uniform blade pitch.

Any fan needs good bearings and the older style fan support needs to be in good shape.

A spliced, damaged, or ragged belt that does not run smoothly should be replaced.

[Professor Fate]

Maybe someone will 3D print an update on the plastic fan that allows for indexed accurate placement on the pulley hub.

Mark N. wrote....
I have used 3-D printed plastics to build prototypes for over 25 years. I would NEVER trust a 3-D printed fan behind my new Brassworks radiator.

To clarify, I meant that maybe someone would find a way to create an adapter so as to be able to index/center the 6 blade plastic fan, sold by vendors, on the hub.