Winter Warmth – a diesel heater for the workshop

Seems I need a New Plan for Winter

We got the electric bill for last winter and there was a sharp intake of breath … maybe the fan heater had been on too much in the workshop and maybe I did forgot to switch it off once or twice when going to bed …  something had to change.

I did some research on diesel heaters as used in motor homes and commercial vehicles and the concept looked like it would meet my needs.  I did some calculations on the workshop volume I needed to heat as an empty shell.  With my insulation and window content this came to a figure of 3kW.   Searching on EBay revealed lots of kits and ready built units so my first thought was to order a ready built one.  This duly arrived and I decided to run it up to see what happened.

Actually nothing really happened.   

The fan came on ran for a few seconds and then the unit shut down.   The controller was showing a severe droop on the supply volts even thought the PSU was rated at 10A.   More web reading and comparing notes with other users revealed these units take a serious current surge at switch on while the glow plug is warming up.   If it sees a voltage droop it thinks it is in a vehicle and switches off to protect the vehicle supply.

Bigger power supply acquired and plugged in.   Still no joy.   I then realised I needed to prime the fuel line.    Quite a few clicks of the pump later I had a full pipe feeding the device and finally it ran up.   The fan was flat out and the pump was clicking like a French grenouille on heat.

And what a stink it made.   I guess it was burning off all the manufacturing oils but it was pretty acrid.   Finally the fog cleared and I could see the neighbours house and we had heat.  Quite a lot of heat.   Fiddling with the pump rate brought the heat and the fan rate down and all seemed good.   But it was noisy.

There now followed some serious navel contemplation.  Did I really want this fire breathing Smaug inside the workshop ?   Not really.   So how to solve the installation ?

Immediate thought was to mount the unit external on the side wall and feed the warm air from the unit into the workshop and take in air from the outside to warm.   The smelly exhaust inlet and outlet would also then be outside.   Not a good idea taking outside air and warming it unless I wanted a very rust rich environment. 

So air would have to circulate from the workshop, get heated and blown back inside.  This means two 80mm holes in the workshop wall plus a power and controller wiring duct of say 20mm.   A plan was forming and I could see where the two air ducts could be located.

Next problem the (I have to say very horrible) enclosure my ready made heater came in would not protect the contents nor would it last very long sat in the outside air. 

original heater enclosure as bought
Empty original enclosure after stripping components

New Enclosure

Much Fusion 360 playing later I had a design based on a 20mm angle iron frame and aluminium sheet covering.

diesel heater enclosure fusion 360 model
Original Fusion 360 model of the enclosure frame less the two top bracing steels

The angle iron and sheet were ordered from Aluminium Warehouse and came very quickly.   I was now going to have to grasp the nettle and refresh my TIG welding knowledge to create my first major TIG construction.   (I only have TIG as MIG scares the **** out of me).

Even though I say it myself I was pretty chuffed with the frame that resulted.  Some of the welds were far from ticketable but my angle grinder and Hammerite paint soon covered up my ineptitude.

diesel heater angle iron frame
TIG welded heater angle iron frame after clean up and painting

The aluminium covers also stretched my resources as I don’t have a formal metal bender but I do have some very long lengths of angle iron and a robust vice.   Two side walls, a front panel and drop on top cover resulted without any serious clangs.  Loving it.

The return air inlet needed an interface of some sort so a Fusion model was created and printed (6 hour print …).

3D printed diesel heater 80mm air inlet cowl
3D printed diesel heater 80mm air inlet cowl which took 6 hours to print

With the enclosure complete, I mounted all the components and ran it up again.   The new power supply also failed to do the biz so I decided to go with a meatier version inside the workshop rather than inside the external cabinet.

Installation day loomed.   I was very ably assisted by Dave who is a long time friend.   We are both cut from the same engineering mould and we usually end up with an interactive plan of action.

First job was to cut the hot air duct hole in the workshop wall.   We had a long pilot drill, an EBay 80mm cutter and a SDS drill.   Serious grief.   The workshop outside brickwork  seemed to have a Titanium content.   We finally broke through into the cavity and thereafter the inner Thermalite block was like cutting chocolate cake in comparison.   First hole finished and more to the point in the correct position.

We now offered the unit to the wall to match the routing of the hot air outlet pipe of the heater.   We put a car jack under the unit to keep it in position while we drilled the mounting holes.  Holes drilled, we then mounted it on the wall and drilled the cable duct and lined it with a piece of uPVC water pipe.

diesel heater enclosure mounted on the workshop outside wall
Re-boxed diesel heater enclosure mounted on the workshop outside wall.  The pumps is enclosed in some foam to deaden the clicks.

The circulating return air from the workshop was to come through the workshop wall and back to the heater from just over a meter away.    I had a suitable length of 80mm spiral metal ducting for the air return and a mating right angle joint to route this through the wall.   We marked off the duct hole position and drilled out a second 80mm hole (more grief, less dust as we damped it down, and hammer and chisel when we got fed up with the useless 80mm cutter).

The Cunning Plan

I didn’t want the metal spiral ducting exposed to the elements and also saw it as a source of heat loss.   There is no point in heating up the workshop and then send the warmer air outside to lose heat on its way back to the heater.   The solution was to buy a standard 1m length of 110mm soil pipe and a right angle joint with two mounting clips from Wickes.   We wrapped the 80mm spiral duct in bubble wrap (quite a few turns) to fill the space inside the 110mm soil pipe to make a coaxial structure.    As luck would have it the spacing to the wall of the soil pipe was pretty much ideal to use the standard pipe clips.   We did however have to cut down the right angle soil pipe connector to get it flush to the wall.  It then got a dose of squirty foam to seal it.

Finished diesel heater enclosure with coaxial inlet duct
Finished diesel heater enclosure with coaxial inlet duct using 110mm soil pipework and fittings. The 80mm internal duct is wrapped in bubble wrap.

We were both very pleased with the result.   As Dave commented it looked better than a professional install would have done.

This was the bulk of outside work done apart from mounting the exhaust inlet and outlet pipes.   Inside we had the hot in wall vent grill to fix and the controller wiring.

I still haven’t decided where to route the outward air duct but currently it sits sucking air from under the Myford Super 7 cabinet.   I am not comfortable with this (the location rather than the potential draft around my ankles) as it will tend to suck up workshop dust and particles.   Some form of filter will be needed.   As yet I haven’t mounted the new power supply on the inside wall.

We ran it up and I can describe it as toasty warm.   At least one good reason to look forward to winter, probably the only one. 

Finally thanks to Dave for helping.  Also thanks to Steve Niebel for detailing his experiences with a similar unit.

If you want to know more about the heaters then the best source I found on YouTube was Dave McK 47

Anyone wanting a very basic indoor housing for their heater components should send me a message ….. and soon …. otherwise it is going in a skip (but I might save the handles).

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Decision Making Process for buying a New Workshop Asset

While reading a hobby related magazine I saw the following note that I think speaks volumes  …..

When deciding whether or not to buy a new piece of kit for the workshop ask yourself three questions  :-

Do I need this tool ?

Do I want this tool ?

Can I justify this tool ?

If the answer to any of the above is ‘possibly’ then buy it.

If the answer to any of the above is ‘no’ then ignore it as it is probably a statistical anomaly.

If you feel you cannot afford to buy it then tell yourself you are in danger of becoming a cheapskate and buy it anyway.

Enough said ?

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Tooling Day

Each of my CNC mills has a home designed and produced tooling plate.  Both have a 25mm pitch matrix of tapped mounting holes and a further submatrix of 3.7mm tooling pin holes.   Why 3.7mm ?  So I can turn down 4mm silver steel for the tooling pins to create a retaining shoulder.

My small CNC plate has M5 tapped holes and the Tormach 440 has M8 tapped holes.   What struct me was that I has starting to create dual sets of hold down tooling, some with M5 and some with M8 mounting holes.   Not a good idea. (Entertaining and therapeutic though it might be to have ‘tooling days’).

Clearly a mounting with M8 holes was not much use with tooling having M5 mounting holes but the other way round would work if I had M8 to M5 adaptors.

As a result I have spent the day creating adaptors which you could call male and female.   Both are made from M8 hex head tensile screws with the female ones retaining the M8 head and the male ones utilising the cut off portion of thread.  I had to undercut the thread ends behind the heads so the female adaptors would sit flush.  Having undercut I then skimmed all the tops of the hex heads to be same depth.

All the turning was done with the ER25 collet chuck instead of the 3 jaw which is normally fitted to the Myford.  The male adaptor versions were a pain to turn down to M5 diameter and had to be done incrementally as the M8 threaded end could not be heavily gripped in the collet.

The female versions are quite useful if a job is being run on the Tormach that needs suspending above the table so it can machined to full stock depth.

Nothing revolutionary or original but a day well spent.

A picture explains : –

Male and female M8 to M5 adaptors

M8 to M5 adaptors in place on the Tormach tooling plate

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Microscope Update – Stand arrived

I had previously posted about the low cost HD microscope that I had bought to see if was any good.   For the price I was impressed by the microscope but not by the stand that came with it.  It only needed to be breathed on to wobble and the fixing was poor.

While browsing Amazon I spotted a more conventional looking stand for sale.  This was sold as being aluminium but when it arrived this morning this was a bit creative being mostly plastic.   However the microscope fits into the cup holder mounting and it makes a dramatic difference to the stability and therefore the usability of the microscope.   You can preset the height with a knob on the rear and then there is a rack knob to move the scope up and down.   You can focus using the microscope control or on the stand rack knob.

It is now a stable device to use and for the price of the microscope and the stand it is a useful addition to the tools available.   The stand comes with a calibration sheet to allow you get a feel for the magnification factor.   The picture below is displaying a 200um circle.

A 200um circle being displayed

 

Side view of the microscope stand

Stand link : –

https://www.amazon.co.uk/gp/product/B01HI2HYDS/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

Microscope link : –

https://us.banggood.com/Wholesale-Warehouse-Mustool-G600-Digital-Portable-1-600X-3_6MP-Microscope-Continuous-Magnifier-with-4_3inch-HD-OLED-Display-wp-Usa-1119592.html?rmmds=myorder

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Microscope Addition to Assets

I often have a look on Banggood for tooling items for the workshop but the other day a low cost microscope caught my eye.   I regularly get thin slivers of brass and steel in my hands and fingers and they are a real pain to find never mind remove.   I thought for the price being asked this microscope might make a low risk purchase to help my failing eyesight.

It arrived today, looked really cheap and nasty out of the box yet I am staggered by what it does.   The screen is HD and there is a card slot for local storage.   You can record stills or video.   Have a look at the following link : –

https://us.banggood.com/Wholesale-Warehouse-Mustool-G600-Digital-Portable-1-600X-3_6MP-Microscope-Continuous-Magnifier-with-4_3inch-HD-OLED-Display-wp-Usa-1119592.html?rmmds=myorder

I will be using it for media shots on my blog that’s for sure.

Microscope set up out of the box showing part of a US 1 cent piece

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