I bought a new APC prop, a 10 * 4 which is grey coloured.
Someone recommended boiling the prop for 5 minutes.

Is that correct ? I thought it was only nylon props that needed boiling.

Are the APC props glass filled nylon and thus don't need boiling ?

Confused [&o]

Not sure boiling did that much for any nylon prop. But supposedly it made it less brittle. I suppose if it does, then APC would recommend to boil them, but to my knoledge they don't.

Thanks for the reply.

I thought on to do what I should have done BEFORE posting and checked online.

You are correct APC don't recommend boiling. It turns out the prop is manufactured from a composite material and APC state NOT to subject props made from composite materials to too much moisture...
I guess that rules out boiling then !

The guy was trying to help when he suggested the prop would need boiling, I guess methods of manufacture and materials used move on and the advice was based on what he new from several years ago.

Yes, water absorbtion does have an effect on nylon's properties. Look it up, if you really want to know.

There is no need to boil APC props.

Graupner does recommend boiling them.

The composition of the grapner does inead state to boil them the makeup of of the nylon of APC may be a little different, my gruapners
might have been on the shelf in the LHS for a few few years I did boil before use martin

As suggested by gkamysz I was interested enough and did indeed do some looking up of nylon and water absorption.

First - there are different types of nylon and thus the effects can be different.
Not being of a chemical bent I didn't delve into this and suspect that the type of nylon used in props may not be identified in their description - I could be wrong

As far as I can tell.... the original purpose of boiling nylon props was to relieve stresses induced in them during manufacture. These stresses would normally be relieved by ageing of the propeller, but because you don't know how old the prop is when you buy it the trend was to boil it and thus ensure the stresses were relieved.

That was OK for nylon props but now some props are made from composite materials i.e. fibreglass and nylon or carbon fibres and nylon.

For composite materials APC state that excess moisture will weaken the prop... other manufacturers I don't know about... and it was advice about an APC prop that I was querying.

I might be wrong but I will put forward an idea anyway........
Props made with composite material if subjected to excess moisture could exhibit hydroscopic behaviour whereby the fibres, either fibreglass or carbon, draw in water because thay are in effect a tube. In a normal fibreglass layup, such as used in boat hulls, this would lead to de-lamination and weakness.

I assume this is why APC state NOT to subject composite props to excess moisture.

I have had a look at Graupner's site and it is far less informative and I couldn't be bothered delving about for info that may/may not be there.So does the advice to boil Graupner props only apply to their nylon ones or the composite ones as well ?

Now... if only a leaflet was included with a new prop explaining best/safe practice how nice that would be. I haven't had such a leaflet with any prop I have bought so far [&o]

From a very quick scan around I see props made from a variety of materials, which may require different ways of treating them, and for some makes the information is not as visible as it could be.

I like mine baked...

I've never heard of that one before, and have never had any problems with any of my un-boiled props (except unplanned contact with other objects, most noteably, the earth).
Your theory of water absorbing into composites makes sense to me, but I don't really know. I would think boiling a nylon prop would make it softer, more flexible, and able to take more abuse. Just a guess on my part.

[8D]

Slope, you get a pamphlet with a lot of info on it with each Graupner prop.

Thanks for that info torque wrench.

I am going to have to buy a graupner prop I see

I have bought Master Airscrew and now an APC and never had any info with them. Some were bought at the local hobby shop and others were bought online nobody gave me any info [>:]

Being primarily a slope soarer I thought a prop was just a prop ! Playing around with some engines I now realise I may have to experiment with different types.

The learning continues......

-----------------


As Sport Pilot said, if boiling was good for them, APC would be recommending that procedure. I do not recall seeing it in any of their literature, so I have not boiled their props at all in the many years that I have used them. I've never had a failure.

The old Top Flite (and other brand) white nylon props are reputed to have benefitted from boiling. I've never had one of them fail either. With or without boiling, which I used to do once in a while. Tastes good with a little chicken boullian, celery, ochre, etc. <G>

just soaking props in water for weeks did the job for me with my pylon racer blades. Carbon blades really need it, but I don't know about anything bigger than a 5x5 prop so...

You are correct. The first nylon props I remember are the white Grish Tornado props introduced in the mid nineteen fifties. The first batch were almost unbreakable...the combat guys loved them. The next batch were brittle and broke easily. My guess is that the first ones sat long enough to relieve the stresses before the props were introduced. Someone found that boiling them would relieve the stresses; word spread rapidly.

One problem with the Tornado nylons was that the prop arc was nearly invisible so some guys injured themselves. When Top Flite introduced their Nylon series, they had red stripes at the tip so you could see the arc. Grish solved the problem by dyeing their props yellow.

I would suggest looking up each brand and type before boiling them. Some brands vary composition with a particular series.

I have no idea which should be boiled and which should not these days. I haven't boiled a prop in years.

Good luck.

George

'Nylon' or polyamide plastics is injection moulded in a brittle, dry state.
It must absorb moisture to gain or regain it's impact resistant properties.
Just time in the atmosphere will suffice, or you can speed things along by soaking in cold or warm water. Boiling is not advisable, although I have often seen it recommended.
I prepacked my props, directly off the moulding machine, in a poly. bag liner within the storage carton. I splashed a cupful of water into each liner before closing, found it was absorbed when it came to packaging for shipping and that the propellers were just fine.
Peter