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).

 Similar or related subjects : –

New Welding Table – BuildPro Fixture Point

Got a bit frustrated trying to practice welding with a half baked working position so I splashed out on a BuildPro Fixure Point table and I have to say I am impressed.

TIG welding, FixturePoint, stronghandtools
FixturePoint Welding Table with Modular Fixing Kit

The concept is good in that you can have the welding surface sat directly on an existing workbench area or you can fit the supplied legs and make it a stand alone table.

Working area is 90cms x 60cms (just under 3′ x 6′) and the working surface has 16mm tooling holes on a 50mm matrix.

The kit comes with a starter set of clamping parts designed to fit the 16mm tooling holes.   You can opt for a square or round tubing holding version.

modular fixing kit
Tooling Kit as supplied with the table

The product comes in from Strong Hand Tools in the US and is marketed in the UK by Clwyd Welding Services.  The quality of the packaging was excellent and delivery was next day by TNT.

What I love about it is that the feet are inset on a 80cms x 49cms matrix and it just fits on my workshop mobile island.

I did a quick modification to my TIG torch holder to match the 16mm holes and I am now ready to blow more holes in pieces of steel with no excuse about my working position ….

 

Similar or related subjects : –

 

TIG and MIG Welding and a Jasic AC/DC inverter

 

We have had 5 weeks of our welding course so far and have focused on MIG only.   It has been a steep learning curve but we are now able to produce reasonable looking joints.   Coping with so many variables  takes some getting your head round.

Talking to the other guys on the course they all commented that for what I am doing I might find TIG more appropriate.  The tutor on our course suggested that TIG was like using one hand to pat your head while the other hand was rubbing your stomach and you were jumping up and down all at the same time.  I can now see what he means.

After many hours of YouTube watching I have invested in a Jasic TIG welder that does both DC and AC so I should be able to do aluminium joints.  It is a nice piece of kit and I am slowly learning its functionality.

So it’s back to practice and more practice but I quite like TIG.  It is gentle and focused without all the sparks you get with MIG.  It reminds me of my school days when I was doing gas welding.

No projects as yet but it is only a matter of time.

Similar or related subjects : –

Heading home from France and Welding Course

Well we came out for the New Year to France with lots of jobs to do and both ended up totally incapacitated with flu.  Not felt so miserable in a long time and now totally weak and wobbly.

We did manage to get the new office sorted and it’s nice to sit here working in it.

We have decided to leave early and stay overnight near Tours on the run to the ferry.  The prospect of the normal 7 hour drive in one hit did not appeal to either of us.

You know what, if you are going to be ill, it is best done at your home with your own bed and I am really looking forward to unlocking the front door on Tuesday.

Wednesday night looms exciting however as my mate and I have registered on a 21 hour introduction to Welding Course over the next 7 weeks.  Got to get back on my feet ready for that.   Hopefully some new skills to be added to my very mature CV …

Similar or related subjects : –