Dave (SOD),
I appreciate and understand what you are saying, but…
I have two of the 10W heaters fitted to the underneath of the bed of my lathe. In fact they are running at 19W each which is within the specification that I saw when I first fitted them. In terms of temperature, they have never felt anything other than slightly warm. I think that if they had reached 65 deg C it would have been far too hot to touch would it not? Maybe I'm a bit out there but isn't hot water from the tap supposed to be around 60 deg C? Anyway, the effect on condensation has been nothing short of marvellous, ie absolutely none and the lathe has never had that bone chilling numbness that cold metal can achieve. Furthermore, the bright surfaces now remain rust free, prior to fitting the heaters I had to regularly spray them with WD40 after removing the rust patina.
I've looked at the specification you pointed to, and it isn't the same as what I first saw, although there is one phrase under Product Details which I think explains it – "Mounting on an aluminium plate increases power consumption and decreases surface temperature proportionately". And that's what I'm relying on. In terms of the lathe, that means a continuous 38W, 24/7/365. For me, a small price to pay.
In respect of the milling machine, I've only one fitted, and that is to an aluminium plate about 150-200 x 100-120 x 13mm. This plate is wedged underneath between the bottom rails (sides?) of the base. Yes it feels warm, but nowhere near hot. In fact, it is not generating enough heat because I discovered the other day that the table top had a slight covering of rust – it's been cleaned and now is sprayed with WD40, something I haven't had to do to the lathe (yes, correct word) for many a year. Which is yet another problem to overcome – how to fit an electric heater to a chunk of metal that slides around!
As an aside, I've even taken to using a fishtank warming mat underneath a sheet of aluminium on a shelf. Resting on the aluminium are two chucks, one T -slotted topslide and a vertical milling slide. No idea what the temperature is, but they are remaining rust free.
Zeb (etc!),
Where do you get a name like that? Just curious!
Anyway, thanks for the confirmation – that appears to be exactly what happens to mine. Which suggests that the answer is indeed the extremes of temperature. Which brings be back to the original question of how to stop it.
Peter G. Shaw
p.s. Just an afterthought. I can only report on my experiences. Ie, if it works, so be it.
Edited By Peter G. Shaw on 10/10/2018 11:53:27