Author Topic: Protecting One's Assets  (Read 5164 times)

Offline steampunkpete

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Protecting One's Assets
« on: December 04, 2014, 04:03:07 PM »
I only have a work area at the end of brick built garage, which means in winter it gets cold and damp.

To protect my mini-lathe from the dreaded rust I cam up with a cunning plan - build a heated greenhouse for it.

I had a few lengths of aluminum tube left over from a fruit-cage build, and these were used to create a frame just big enough to drop over the top. A space blanket from Milletts folded over the top (looks just like an early Christmas present) gives a cheap heat retaining skin.

But how to provide some heat? The smallest greenhouse heater that I could find was 40 Watts, and that would be more than necessary for rust warding off and cost a pretty penny to run. The cunning bit was to wire two 40 Watt heaters in series. Wiring the two in series meant that each would only consume 10 watts, and I could use one to protect my lathe and one to protect the pillar-drill. A 10 Watt heater is only warm to the touch, so no fear of damage.

The two heaters are wired together in a junction-box with suitable glands and plug into a mains supply with the usual protections. Those few Watts are just enough to keep the greenhouse a couple of degrees above the surroundings. Voila.

Offline awemawson

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Re: Protecting One's Assets
« Reply #1 on: December 04, 2014, 04:28:48 PM »
An incandescent light bulb always used to be the heater of choice for keeping machine tools above the dewpoint. Best built into the base assembly and available in a huge range of wattages
Andrew Mawson
East Sussex

Offline nrml

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Re: Protecting One's Assets
« Reply #2 on: December 04, 2014, 05:16:10 PM »
Instead of insulated covers and a heater, why don't you just use a dehumidifier to reduce the relative humidity in the enclosed space? That combined with a humidistat would probably be more effective, consume less electricity and be less of a fire hazard than a heater.

Offline awemawson

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Re: Protecting One's Assets
« Reply #3 on: December 05, 2014, 02:47:56 AM »
Dehumidifiers don't work very well in cold weather, I've had to use a fan heater in the past to get mine started. Once it starts drawing moisture however the motor in the dehumidifier keeps the temperature up. Get pricey on running costs. Mine's a big commercial unit that I run through a humidistat when I use it.
Andrew Mawson
East Sussex

Offline steampunkpete

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Re: Protecting One's Assets
« Reply #4 on: December 05, 2014, 02:49:35 AM »
Thanks for the comments chaps:

I thought about light bulbs, but incandescent bulbs are increasingly difficult to get, are relatively fragile and designed to produce light. To minimise power consumption I wanted to use all the power consumed to be manifest as heat.

Dehumidifiers: I didn't consider this idea I must admit. I've had a look around for dehumidifier specs. I can't find one that uses as little as 20 Watts. The lowest consumption seems to be about 60 Watts, but this is for a small unit that I couldn't be certain would cope with my (very cold) detached garage. If it did, it would have been a solution that was three times the purchase cost and at least three times the running cost of the greenhouse-heater-in-a-box.

If my warm-box doesn't work the dehumidifier idea certainly is worth another visit at least.

The greenhouse heaters are designed to the appropriate regulations (one hopes!) and have been de-rated by me by a factor of four. They are thus even less likely to fail. We've used the same design in our potting-shed / greenhouse for years and is hasn't burned down yet!  The surface temperature of the heaters is such that they are just warm to the touch; they can be comfortably be tightly gripped in the hand. There is no appreciable fire hazard here.

Offline DavesWimshurst

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Re: Protecting One's Assets
« Reply #5 on: December 05, 2014, 01:18:41 PM »
I've used two 75 watt bulbs wired in series and tented over the lathe with plastic sheet.  Worked well, the bulbs only glowed orange and lasted for decades.

Offline hermetic

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Re: Protecting One's Assets
« Reply #6 on: December 05, 2014, 02:52:40 PM »
Go to Jewsons and buy a bundle of 1" x 2" tannalised tile lath, and a few 8 x 4 x 2" (measure up) jablite polystyrene and dry line it out! You will be warmer, quieter and dry. Screw the laths to the walls @400mm centres, put polystyrene between the laths, cover the lot with a damp proof membrane such as visqueen builders polythene, and then dry line it all with 3mm plywood (you can get surplus seconds or damged for about 4 for a 8 x 4) and paint. Cost should be less than 200 for a standard garage size. Remember to always put the DPM on the WARM side of the insulation or you will get condensation!! I have done many buildings like this, it is a permanent cure.and you can work all year round without heating except in the very coldest part of the year, If your ceiling is exposed do that as well, but use glasswool, as it is cheaper (but not as good, you will need at least 4" glasswool to be as good as 2" of jablite) Heating by whatever means costs more every year. Condensation is a pain! INSULATE!

Online chipenter

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Re: Protecting One's Assets
« Reply #7 on: December 05, 2014, 04:49:39 PM »
I use a 12 volt halogen light with a computer heatsink stuck to it in the bottom of a small fridge , it works a treat no rust last winter and if I drop a 6" chuck and smash the light its only 12volt .
Jeff

Offline vtsteam

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Re: Protecting One's Assets
« Reply #8 on: December 05, 2014, 09:58:46 PM »
I like the series idea -- wouldn't have thought of it.

I've been thinking of how to keep greensand from freezing without heating a whole shop continuously. There may be something here.
I love it when a Plan B comes together.

Offline awemawson

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Re: Protecting One's Assets
« Reply #9 on: December 06, 2014, 03:36:19 AM »
Steve, I presume that the greensand is for casting? If so would mixing in salt detract from it's moulding characteristics - I suspect not but I've not tried it.
Andrew Mawson
East Sussex

Offline vtsteam

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Re: Protecting One's Assets
« Reply #10 on: December 06, 2014, 10:43:29 AM »
I don't know Andrew, but sub freezing  sand would be unpleasant. Warm properly tempered greensand is a pleasure to work with. For small or thin parts, chill is also a factor in filling the mold well.

I'm thinking of something , low wattage, with, say, a 24 hour timer that I could turn on the night before molding. But you'd want it to be safe enough to trust unattended.

I've got an old unused portable cooler/ice chest that I could store the sand in. It would only take minimal wattage to  warm it up overnight. But what to use?
I love it when a Plan B comes together.

Offline awemawson

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Re: Protecting One's Assets
« Reply #11 on: December 06, 2014, 10:53:06 AM »
A zig zag of copper tube, or (to prevent corrosion) a coil of plastic heating pipe, with water from your clone Lister engine circulating through it under the sand ?
Andrew Mawson
East Sussex

Offline RussellT

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Re: Protecting One's Assets
« Reply #12 on: December 06, 2014, 10:55:39 AM »
If it's one of the portable coolers based on a Peltier device I think you could just reverse the polarity to make it a heater - you might need some way to distribute the heat away from the device.

Russell

Offline vtsteam

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Re: Protecting One's Assets
« Reply #13 on: December 06, 2014, 11:06:34 AM »
No Russell, it's just an ice chest.

Maybe something like this?

http://www.amazon.com/Hydor-25w-Hydrokable-Substrate-Heater/dp/B0006JLPGI
I love it when a Plan B comes together.

Offline steampunkpete

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Re: Protecting One's Assets
« Reply #14 on: December 06, 2014, 02:35:40 PM »
Quote
No Russell, it's just an ice chest.

Maybe something like this?

http://www.amazon.com/Hydor-25w-Hydrokable-Substrate-Heater/dp/B0006JLPGI

That Substrate heater looks like the kit for the job; I wish I had known about these.

If Russell has got a nice chest I would refrain from mentioning it - that sort of post could get you into trouble!

 :)

Online chipenter

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Re: Protecting One's Assets
« Reply #15 on: December 06, 2014, 04:28:44 PM »
I don't know Andrew, but sub freezing  sand would be unpleasant. Warm properly tempered greensand is a pleasure to work with. For small or thin parts, chill is also a factor in filling the mold well.

I'm thinking of something , low wattage, with, say, a 24 hour timer that I could turn on the night before molding. But you'd want it to be safe enough to trust unattended.

I've got an old unused portable cooler/ice chest that I could store the sand in. It would only take minimal wattage to  warm it up overnight. But what to use?
Trace heating cable is designed for to keep pipes frost free 30 watts a metre .
Jeff

Offline vtsteam

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Re: Protecting One's Assets
« Reply #16 on: December 06, 2014, 04:53:42 PM »
Jeff I actually use that stuff on pipes, but the instructions I've seen warn not to cover it with anything and keep away from constant mosture.

The aquarium stuff is meant for installation under sand soil and in water.
I love it when a Plan B comes together.

Offline awemawson

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Re: Protecting One's Assets
« Reply #17 on: December 06, 2014, 05:13:14 PM »
You can get a similar wire / tape for horticultural purposes  that's intended for direct burying in soil, which obviously potentially gets wet and is covered.

http://www.simplycontrol.co.uk/shop/soil_warming/2_39_0_0/default.aspx

Andrew Mawson
East Sussex

Offline Jonny

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Re: Protecting One's Assets
« Reply #18 on: December 06, 2014, 05:13:46 PM »
Is it really protecting ones assets when its probably cheaper to write off the lathe every 4 months when using 30W forms of heating.
http://www.sust-it.net/energy-calculator.php  Tap in 30W comes up 46p/hr usage then times that by 24 that's 11 cost a day! How many weeks call it 20, see where im going.

Offline awemawson

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Re: Protecting One's Assets
« Reply #19 on: December 06, 2014, 05:18:40 PM »
Hang on the maths is wrong there  :bugeye:

I pay 14 pence per kW/Hr now 30 watts is 0.030 kW/h or 0.42 pence per hour. I think you are confusing watts and kilowatts
Andrew Mawson
East Sussex

Offline steampunkpete

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Re: Protecting One's Assets
« Reply #20 on: December 06, 2014, 05:32:42 PM »
I think you've mis-read the output Andrew. I've just put 20 watts for 24 hours into the calculator for which you provided the link, and the answer was 7,3 Pence (not pounds).

7,3 pence x 7 days x 20 weeks = about 10

And that protects my lathe and my pillar drill - well worth it.

Offline awemawson

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Re: Protecting One's Assets
« Reply #21 on: December 06, 2014, 05:39:04 PM »
0.03 x 14 x24 = 10.08 PENCE per day however you else may calculate it  :scratch:

NOT 11 per day as as was stated above
Andrew Mawson
East Sussex

Offline steampunkpete

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Re: Protecting One's Assets
« Reply #22 on: December 06, 2014, 05:54:30 PM »
Quote
I use a 12 volt halogen light with a computer heatsink stuck to it in the bottom of a small fridge , it works a treat no rust last winter and if I drop a 6" chuck and smash the light its only 12volt .

That's a really good idea - up-cycling a defunct fridge into a heated cupboard for tools and such. I like it a lot.

As for peltier elements - I would avoid them for this sort of application. Peltier refrigerators have two advantages, firstly no moving parts (simple, light, rugged, maintenance free), secondly they can be run off standard 12 Volt or 24 Volt vehicle supplies. The MoD use such fridges for a couple of specialised battlefield applications. The down side is that they are very inefficient.

10 for four months worth of electrickery is certainly a bargain.

Online chipenter

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Re: Protecting One's Assets
« Reply #23 on: December 07, 2014, 04:55:43 AM »
The UK supply of trace heating cable is 3\4 of a mile from me , a chat with the boss man he said that iff the end caps were fitted corectly and sealed with silicon rubber it can be used under water but not permonantly , there is two types of cable self regulating and non regulating which needs a thermastat , I have it taped to the under side of my mill oil tray with a layer of insulation under , and a stat on top it comes on at 9 degrees celcius and it has to be realy cold to stay on very long usualy on for ten minutes and off for five .
Jeff

Offline S. Heslop

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Re: Protecting One's Assets
« Reply #24 on: December 07, 2014, 09:34:46 AM »
For dehumidifying you could use silica gel or something similar. You can get the kind with cobalt chloride in it that turns pink when exhausted. Then you can dry it out in the oven.

Also.