Electricity-free forge (and other ideas)

[ohowson]

Ok, let's get one thing out there: I'm not looking at a hand-blower! I don't mind physical labour but that feels like "exercise" which does not appeal to me.

 

BUT I was thinking; we have these great first that take just a little bit of air, and let's face it, most of the heat goes straight up the chimney. So I was thinking, has anybody tried (or thought about):

1. Using peltier heat exchangers to power the blower. Mine currently runs at 3-12v and less than 1A - not a lot! Once the fire is lit it should swiftly produce enough heat to generate that much.

2. Using a heat exchanger to warm a working area. I've not had my forge long enough yet but I forge outside under a shelter (no sides bar the rear wall) with the forge further out so as not to melt the roof or the overhanging pear tree. As we know, heat goes up, could we surround a chimney with heat-exchange pipe and throw it through a car radiator/heat exchanger with another fan to warm the area?

 

I'm thinking this partly because I like the idea, partly because one day when I can find someone daft enough to sell me a tiny bit of land I want to build a little off-grid forge. Somewhere in Buckinghamshire, between Banbury and Milton Keynes, preferably.

[pnut]

I haven't considered that. It's an intriguing idea though and definitely warrants some further research. Depending on location there's many options for powering your blower/shop. Wind powered generators arent very complicated but is location dependent as is water power. Solar is much more complicated than any of the other options but is worth looking into. 

I'm going to do some research on the system you described. Thanks for posting this as I'm unfamiliar with this method of generating power.

Pnut

Edited September 16, 2019 by pnut

[ohowson]

With issue 1, I'm trying to figure out how hot the peltier units can take (and I'm not sure how hot forges would get inside a chimney etc as I don't have a chimney at the moment) and the cooling aspect. If we can get things just-so it would probably be possible to use the water bucket as the cooling. I need to do some maths, may be a car battery could be used as a power source and then peltier units used in conjunction with others to charge it up. That way could include lighting and the like.

[Glenn]

The solid fuel forge chimney (side draft) moves a LOT of air. It can, at times, be cool enough to put your hand against the chimney skin 4-6 feet above the fire. The air going up the chimney is room air. How much air? Go outside and look at how much smoke is coming out the top of the chimney.  The make up or replacement air to the room comes from the outside. 

You need to waste some heat or you kill the draft of the chimney. 

You can reduce the amount of room air loss by piping outside air directly into the blower to the fire. Outside air can be used to be drawn across the top of the fire to channel the smoke and exhaust gasses (solid fuel forge) into the chimney.

A car battery can be used as the electric power source for both the fan and the shop lighting. All can be salvaged from a junk vehicle. You then just need a way to recharge the battery when needed.  This can be as creative as you like or as simple as charging the battery from you cars electrical system on the drive home.

[JHCC]

"Under the spreading pear tree" doesn't have quite the same oomph.

[Anachronist58]

"Under the partridge populated pear tree"?

[ohowson]

We're not allowed guns over here but any birds that try to eat my pears are getting a lump of iron in the face.

[pnut]

I made a wind turbine in school using an ac motor from a treadmill. It was very simple and would definitely power a blower. It's been thirty years ago. I don't remember if an automobile alternator was involved. I got the plans from mother Earth news.

Pnut

Edited September 16, 2019 by pnut

[ohowson]

not enough wind - our garden is quite sheltered (mainly due to the 40' trees!). Ditto solar. 

[pnut]

That's too bad. It would have been the simplest solution. 

Pnut

[BIGGUNDOCTOR]

Just go full Steampunk  and use the forge to create enough steam to power what you want.

[Anachronist58]

ohowson, look up "teg stove" (Thermal Electric Generator).

Stove top TEG fans also describe the technology

TEG is the current descriptor for Peltier.

Robert Taylor

[BillyBones]

9 hours ago, Glenn said:

charging the battery from you cars electrical system on the drive home.

If you have an older vehicle that is an option, however on the newer vehicles, '07 and up, that is a huge no-no. Todays cars the alternator is designed to maintain the charge not recharge a battery. Doing this can reek havoc on the cars electrical system. I have had more than one customer complain that there tranns is not working right only to find out that the battery ahd gone dead and they just jump started it and went. The fix was charge the battery. A car only needs 10 v or so to start and run but with all of todays gizmos and gadgets on cars they need the full 12 v and xxx amps to work properly. Even if you do not notice any drivability issues it will greatly reduce the life of the alternator. And if you have seen where they put some of these things now a days... 

[Glenn]

Then take the battery home and use a charger to top off the battery.

[Irondragon Forge ClayWorks]

Can't remember who, but they posted about using one of those battery jump starter packs to power some things in the forge.

[pnut]

I use a jumpstarter/power station to power the electric mattress pump I use for the air supply to my forge. Unfortunately the 120v outlet doesn't have enough amps to run much else. It will only power things under six amps. I found a little generator at horrible freight for 95 bucks that I've been thinking about buying. It's not much bigger than the jumpstarter.

Pnut

Edited September 17, 2019 by pnut

[Mikeyn]

 I wonder if wiring a few up in series/parallel could influence things further, help dial in what you need?...

 I think if you could find areas on the forge and or chimney, where you could attain a steady temp in the right range to produce 12v steadily, (im sure i remember reading up on Peltier`s before and for some reason 200 degrees Celsius is ringing a bell as a max temp?, dont quote me though there must be different types and ranges available now) then you could power a travel hair drier or mattress inflation pump etc, on the system.  The fiddling would be fun and as a interesting side project i can see its merits, but would a small solar power 12v system trickle charging an old car battery be more straight forward and easier to repair/maintain?. . either way, I love the idea of collecting the thermal energy and making use of it in other ways...

I would love an off grid place to live and tinker!! best of luck! 

Keep us posted !

Mikey

[ohowson]

You can definitely lump them together. A voltage regulator will sort out variations of course. If there was one which ran at 100c most effectively then the easiest thing would be a water boiler. 

I do like the idea of a steam engine running off it as well!

[Steve Sells]

many of these ideas are not non electric tho  lol

[ohowson]

No but they’re electric free. As in free electric

 

(ok I put the wrong title on)

[Daswulf]

"Off grid" would be a good term to use. Even off grid is not always free. Basicly not being dependant on the electric company/landlines. (Also sans water, gas, sewage companies/lines.)

[BartW]

I've seen the old workshops of Dave Budd (youtube) and Pavel Rihacek (pictures), both of which didn't have electricity (landline; Dave had a generator if I recall correctly) nor running water. Pavel used to use only a drill as electrical tooling. 

But instead of trying to recycle the heat to power a blower; how about a gasforge with venturi burners ? You could even make a ceramic chip forge with the burners below, if you want it feel like a solid fuel forge. Doesn't use electricity, but you don't need to recycle the heat either because you use the venturi effect of the gas burners.

 

mvg; Bart

[ohowson]

Although I'm considering a gas forge at the moment in other thoughts, I really like the idea of a coal forge in my dream relatively-traditional-ish off-grid building. They smell of Yorkshire! 

But I do want a gas forge so I'm going to look into venturi burners. What I'm struggling to see is how long a gas bottle will actually last, they're not particularly cheap over here!

[pnut]

Have you considered charcoal? It makes a clean fire and was the fuel for most of the history of blacksmithing. 

Each forge will consume propane at a different rate depending on the efficiency of construction and insulation and what you are working on not to mention how the burner is designed and constructed.

Pnut

[ohowson]

I already have a coal forge. Smells better than charcoal.  The reason I’m considering a propane forge at some point is the ease of sliding long pieces of material in and heating a reasonable size length evenly.