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ichthos
04-10-2006, 11:55 AM
Hello,
I have my cooling system dismantled at the moment. I figured as long as it is apart, I would try to repair the two quarter size chunks out two of the blades. Does anyone know if it is possible? Most places that have plastic repair need to know what kind of plastic it is - I have no clue.
Thanks, Kevin

Alan_Myers
04-10-2006, 01:05 PM
Hi,

I dunno what kind of plastic it is, either. Maybe TRF could tell you, since they have replacement fans manufactured.

But, I'd strongly recommend replacing the entire fan.

Centrifugal force on it is quite strong when the engine is revving and blades of a damaged fan are far too likely to break some more, which can lead to much more serious problems (such as if a broken blade goes through the radiator, which happened to two out of three TR3s entered in LeMans back in the mid-50s!)

Even if the damage to the blades is just out at the tip of the blade, that imbalances it and probably sets up vibrations that will eventually weaken other areas of the fan.

Considering the cost of a new one is modest, I'd just replace it.

/ubbthreads/images/graemlins/cheers.gif

bobh
04-10-2006, 01:13 PM
Kevin,
I'm not sure of the type of plastic. It may be some type of polypropylene. Unless you can insure that the repair material will make a strong bond I would not recommend trying to repair the damage. Most slick plastics will not accept any glue. If the adhesive does not hold, the patch material will be thrown off when the blade turns. If this happens when the hood is closed the damage will be limited to the items under the hood. If it happens when the hood is open and you are nearby. You could be injured by the patch.
What part of the blade is damaged? Is it near the tip? If it is not near the tip, as a precautionary measure, you should replace the fan. Like the patch you don't want the rest of the blade breaking loose and flying out.
The other issue is balance. A repair that does not match the weight if the missing material will cause the fan to be out of balance. The fan is already out of balance due to the missing material. If the chunks are missing at the tip of a blade. You may consider cutting the tip of the blade so that it is square with the length of the blade. Then cutting each blade to remove the same amount of material. This would eliminate the danger of a patch coming loose and get the fan closer to a dynamically balanced condition.
Whatever you decide keep in mind the speed of the fan when the engine is turning 1000, 2000...4000+ RPM.

ichthos
04-10-2006, 02:35 PM
Thanks - I'm convinced. I'll fork out for another fan.
Kevin