Boiling plastic bits?

[vrooom]

I seen references of boiling the plastic bits on the internet to make them more flexible and stronger by soften them and remove the "casting freeze".

Is this true or a complete myth?

And boiling front shock tower a bad idea?

[kaszal]

I've done this with 20 year old Schumacher Procat wishbones and I think it helps. I've read it has something to do with absorbing moisture and/or relieving residual stresses from the injection moulding process.

[Pacman]

When nylon is fresh out of the mould it will be naturally brittle as it is in a dry state. However Nylon absorbs typically 2-3% moisture from the atmosphere within days. Some manufacturers will immerse items in water to temporarily absorb 6-8% moisture content to accelerate the process. The moisture content improves the strength of nylon, but this can not be artificially improved, unless you choose to run your car in deep puddles!

Adding heat to plastics and letting it cool slowly (aka annealing, e.g. boiling) will stress relieve the plastic but there will be a risk of dimensional instability. Therefore be careful as your part may not fit when finished.

http://www.annealingplastics.com/

Ageing of plastics is irreversible. There may be a temporary effect when boiling due to low conductivity and therefore whilst the part retains the heat it will be softer/less brittle in the short term.

[crtpromachine]

You would be suprised how many racers actually boil there plastic parts especially for nito outdoor racing through our lovely U/K whether conditions through the winter

I certainly have done it on more than 1 occassion 4 lower arms on a truggy is no fun in 1 day

[dicky14]

boiling plastic parts used to save me a fortune on my old PB Maxima, wishbones were made from glass they were that brittle, but dont let the pan boil dry as i found to my expense LOL