Forges 101

[Mikey98118]

4 hours ago, Another FrankenBurner said:

Originally our molds were hot wire cut blue foam.  It makes a great mold that it is water proof and can be easily removed with a hand torch.  We are currently using 3D printed molds for forge pieces and nozzles.  

I think the blue foam and hot wire would appeal to most newbies

[Another FrankenBurner]

I like the idea of writing a book so that people can hold the information in their hands but there is a lot with that.  First, would anyone buy it?  Do people buy books anymore?  I was recently asked why I still buy books.  Second, I would want lots of color pictures to really explain everything in too much detail.  Thirdly, with the ease of piracy, would it be worth the extra effort?  I could skip the middle thief and put out a free PDF version without the extra effort of publishing.  

You are currently writing a book, aren't you?  What keeps you motivated?

The blue foam is great.  We have a lot left over from lost foam casting which we don't usually do anymore.  It can be cut with utility knives, into any shape.  It's even easier to work with a hot wire cutter which can be built quite easily.  It works well for forge molds.  It doesn't steal water from the refractory and you don't have to worry about refractory sticking to it because it easily disappears with a small hand torch.  

I'm not pitching cast forge liners yet.  Not until we have a better handle on Kast O Lite.  We have used 120lbs in our experiments.  

[Mikey98118]

All of those objections have much to do with paper print books, and little to do with electronic books at reasonable prices.

As to pirating, if you keep prices down, only idiots would choose a 'free' pirated copy over a legitimate one. You know; the kind that doesn't come with a load of fleas...of course there will always be the usual suckers who will jump on the something for 'nothing' band wagon, but they wouldn't pay for a book if it was fifty cents.

 

[Another FrankenBurner]

Thanks Mikey.  I know nothing about electronic books.  I will look into it.  

[teenylittlemetalguy]

On 8/3/2020 at 9:01 AM, Another FrankenBurner said:

This is very cool.  I am picking larger and larger projects to see what I get away with in the mini forges.  

Saving the fuel really makes me happy.  Large shepherd hooks was another fun project with it.  I still use a really small forge for as much as possible, but not quite that small anymore. I have been making mine convertible, so I can open partially and heat big stuff for bending. I think that oval one would be prime for that. Also the use of blue board for the mold is genius, I am going to make a foam cutter now for sure!

[Frosty]

What do you use for the DC for your foam cutter? Can I get away with a 12v trickle charger and appropriate wire?

Frosty The Lucky.

[Mikey98118]

On 8/3/2020 at 6:09 PM, Another FrankenBurner said:

You are currently writing a book, aren't you?  What keeps you motivated?

I'm currently writing three books. It is the subject matter that keeps my interest; nothing else. One thing that helps when you hit a patch of hard writing, or you get handed disappointments, is refusing to have many fund distractions. It is a truism that "writers write"; all others need not apply. What do that mean anywho?

Just think back on all those boring obfuscation filled textbooks written by college professors seeking tenure that are spewed on the market, and then force fed students  (while they mainly learn to despise reading) and you know just how to write a GOOD textbook.

[Another FrankenBurner]

5 hours ago, teenylittlemetalguy said:

I have been making mine convertible

Convertible as in split so the top can be raised?

3 hours ago, Frosty said:

Can I get away with a 12v trickle charger and appropriate wire?

If the trickle charger puts out enough current, the cutter could be built to match it but it is much easier to build with a variable voltage supply.  I have built a few hot cutters with a straight DC source but the length of wire has to be calculated for the desired current.  It's easy to do.  Variable supply allows you to change the current as needed so you can dial in the wire temperature to match feed speed and ambient temperature.   Originally we had a dimmer switch driving a small step down transformer which was a little clunky but it did work.  Now we use a variable dc power supply.  They are inexpensive on amazon/ebay and make the hot wire smoother to operate.

They are very easy to build.  Ours is a piece of pvc pipe, a spring, and a board.  It functions like a bandsaw.  

2 hours ago, Mikey98118 said:

Just think back on all those boring obfuscation filled textbooks written by college professors seeking tenure

This one made me cringe.  I have been required to waste many hours with my nose in these books.  Absorb the few paragraphs of substance after distillation and remember several hundred pages of the other stuff just long enough to pass a test.  I did not learn to despise reading or learning.  I love both of these things.  I learned to despise school.  

How am I supposed to avoid distraction when almost everything is so interesting?  

[Mikey98118]

There remains a viable method for the none "writerly" author to pursue excellence; that is with as few words and as many photos as feasible

Just remember that the two main pluses needed to author an excellent text is actual knowledge of a needed topic, and actual desire to communicate it; both of which are usually more absent than present in 'educational' textbooks. Be honest with your reader and most of them will love you for it (add some humor and you could end up with a best seller').

[Buzzkill]

On 8/4/2020 at 6:57 PM, Frosty said:

What do you use for the DC for your foam cutter? Can I get away with a 12v trickle charger and appropriate wire?

I used a power supply from an old PC for the one I built a few years ago.  Most of them show which wires carry the various voltages.  I believe I used a 5 volt output for mine since the 12v output turned the nichrome wire I used red/orange quickly.  IIRC I scavenged the nichrome wire from the heating element portion of an old hair dryer I used for an air supply for a forge for a short period of time.  Hard to get all the waves out though, so I did buy a couple feet of wire cheap off Amazon later.

[Frosty]

A buddy and I were looking at making some foam models and looked at a lot of "plans" online, some are just stupid complicated. I was hoping I could get away with an old 3 amp trickle charger and wire with less resistance than nichrome.

It was just a thought, I have thoughts all the time, can't help it but where it comes to electricity I like to bounce them off folks and maybe save the burns and scars.

Thank you gentlemen. 

Frosty The Lucky. 

 

[Mikey98118]

I think you have a 60/40 chance that a trickle charger will work well enough...easy enough to find out

[Another FrankenBurner]

You sure can power one with that trickle charger.  You just have to choose an appropriate wire to match the length of hot wire you want with the available power.  

Current is what heats the wire.  The current required depends on the wire gauge, the ambient temperature, and desired wire temperature.  As the wire gauge gets smaller, the required current lowers and the resistance per length increases.  The right wire will require less amps than you have and have a high enough resistance, at the wire length you want, to throttle the current to the proper level.

If you do want to experiment with any old wire, just make sure the resistance is high enough to not exceed the 3 amps available.  If the trickle charger runs 13.5 volts, divide by 3 amps gives you 4.5 ohms, at a minimum.   This is just to prevent charger overload.  Three amps is probably under or over what you need.  Far over is fun because the wire can melt down.  The easy way, connect one lead to the end of the wire and clamp an alligator clip to the other end of an expected too high a resistance, then you can slide the alligator clip to shorter wire lengths until you get a wire temp you like.  

Nichrome wire is good because it resists oxidation and you can select the gauge and type that will work with what you have.  Also, because it is used for heating applications, there are charts to help with the figuring.  

[Frosty]

This little charger is protected six ways from sundown, I don't think the smoke will get out.  I can tune the temp by moving the contact and varying the length of the bridge. Shorter is hotter?  I could wrap a way too long bridge wire around a non conductor and tune the cutter like a crystal radio? I could save myself some cypherin that way. 

Frosty The Lucky.

 

[teenylittlemetalguy]

19 hours ago, Another FrankenBurner said:

Convertible as in split so the top can be raised?

Yep! I use a turnbuckle to lower  raise it. Holds it in place wherever I need it without tools or touching  hot stuff

[Another FrankenBurner]

If your charger is too smart, it may not output.  I previously bought a cheapo Harbor Freight 10 amp charger for an electrolysis tank.  I wanted a dumb charger but when it started, it would sense voltage and not output if there was none present, assuming no battery was connected.  I ended up connecting 5 volts from an old phone charger to it's leads to back feed it so that it would kick on.   

Your experiments would work.  Shorter is less resistance, more current, hotter, yep.  If you start with small gauge wires, you will probably make and exceed a few fuses.  I did this several times in the beginning when I was experimenting with copper wire strands.  I did eventually make it work but the copper wire was longer than I wanted and it oxidized quickly enough to not survive long.  I've seen people on the tube use guitar strings.  I went right to nichrome 80 because it was cheap and consistent.  

Once you get it figured and plan a build, don't forget a light spring.  The wire stretches when heated.  Also, no soldered connections, that doesn't work for long.  We used small bolts so the wire is mechanically fastened and the bolt can be adjusted to control wire tension.  

14 hours ago, teenylittlemetalguy said:

I use a turnbuckle to lower  raise it.

Now you are just teasing us.  Any chance you can put up a picture or two?  I have been thinking about the split forge for a while.  I just haven't figured out suspension of the cast upper liner.  

[teenylittlemetalguy]

Ha, I am a tease!

These pictures  take a little explaining as I did a lot different to suit my needs. My forge folds down, into the stand so I can stow it hot and drive home from meetings without setting my car on fire. One end of the turnbuckle is mounted to that pivot point. The other end mounts to the arm on the lid. 

The doors pivot  independent of the top.

I took special pains to mount the kast o lite rigidly to the frame to avoid it shaking loose in the car. I welded in screws around the kaowool so the kastolite hangs on by about 20 points. It's been very reliable.

I found that the joint between top and bottom doesn't need to be perfect to work. Under 1/8" won't let out enough heat to matter at all, the housing doesn't even get hotter there.

I really hope this info can help you, especially since I plan on blatantly ripping off your oval forge idea on my next version. 8-)

[Another FrankenBurner]

That last sentence was good for a laugh.  So long as it's blatant, I think it will be alright.  I may have borrowed the idea from Mikey's posts about mufflers for shells and such.  A flat oval split forge is what I am after. 

I like your forge and stand build very much.  Clever engineering.  Thank you for the info.  

When you say you welded in screws, are they protruding inside the shell and cast into the refractory liner?  Or do they trap the liner?  Where are they mounted?  How thick a layer of refractory?  What locks the door position?  

So is the metal teeny or the guy?  Or is it a metal guy?

[Frosty]

You should see Tristan's forge in action, it's rarely anything but screaming hot and it stows crazy small. If we ask he'll show some better angles and how it folds into the stand. 

Tristan's not teeny by a moderately long shot. The only mistake he made building his first T burner was not turning it quite high enough. Yes, it's supposed to be LOUD. All he needs is a look to adopt a design and he can't help modifying it as he goes. Usually genuinely improves on them as he does to.

Frosty The Lucky.

 

[teenylittlemetalguy]

On 8/6/2020 at 7:49 PM, Another FrankenBurner said:

When you say you welded in screws, are they protruding inside the shell and cast into the refractory liner?

Thank you, nice to be called clever and not " that nutter that uses little forges" 8-)

I drew a little diagram of how I did it. My biggest concern was all the guts falling out while driving down the road so I have internal features for the Kastolite to grip on and the shape is an arch. The flat bar running down the length is set in the Kastolite on both sides giving the arch a toe to hang onto. The screws are there to brace the external facing ends. Overall my Kastolite was 1/2-3/4" thick, except for the edges which are thicker to add strength, but nothing over an inch. Underneath is  2" of wool (also held in with a few screws. I probably went overboard, but it hasn't failed) 

I actually don't like the door locks, I just used a bolt with the very end bent in a U shape to pin the door rod down, a wing nut loosens the grip when needed.  I have been forging cam latches for various things in my shop and my next version of the portable forge (v4, I think) likely will  have cam locks for the door stops.

My name is actually Tristan as Frosty kindly mentions me above. I am a fan of the Teeny Little Super Guy on Sesame street so I just co opted it.

The kind of messing about you are doing here is very near and dear to my heart. Obviously you are taking it to a higher, more refined level which is really exciting. Can't wait to see where you head with your ideas. If there is any way I can help out please let me know. 

 

[Another FrankenBurner]

Thank you for all that.  Frosty now has me wanting to see your forge all folded up.  Any chance you have any pictures of that?

Name is Curtis over here.  If only I lived closer to the two of you.

Have you had any issues with cracking where the metal and the refractory interface?  Have you noticed any differential expansion issues?

I like the cam lock idea.  You said you have already forged several, any pictures of those?

Thank you for the kind words.  You have already helped out.  I have been inspired to keep after the split forge.  As you said, it adds some pain to the process but it seems something that will be worth the extra effort.  

[teenylittlemetalguy]

That would be really cool if we were all closer. It would be nice to bounce ideas off each other in person.

Folded it can stand upright,  but this is how it rides in the car, keeping the forge above the carpet.

The metal bar doesn't go super deep, maybe 1/2" or 5/8". After 2 years of regular use and 12 road trips (90 mins each) it wore out partially along that line where the bar is, but only on the side where the flame hits directly. The screws are deeper near the side door openings and have held up well, which surprised me, I expected issues there but they have been stable. It might be from not putting them all in one exactly straight line. Just randomly placed. 

Your foam cores have me excited to possibly try another build this winter, if the world doesn't get any nuttier than it is... 

Cams- first small one with coil spring, happy with the action. Then I scaled up and made several hold downs using leaf springs, very strong solid lock. 

 

 

 

 

[teenylittlemetalguy]

Curtis, 1AM here... I just remembered, I was going to use a flat bar, but ended up using expanded sheet for the toe support on the kastolite. 

[Another FrankenBurner]

1 AM, you are a dedicated giver.  Thank you again, your toolbox is filled with good ideas.  I am thankful for the forum which allows us all to bounce ideas.  

I'm going to have to borrow your use of forged cam locks in my contraptions.  It is such a simple action to produce and makes operation much smoother.  I am surprised I never thought to forge my own.  

The expanded metal makes absolute sense.  I first saw it used with Frosty's NARBs and I asked Frosty, back then, why expanded metal.  He is also a dedicated giver, full of good ideas.  My mind never linked that data with forge construction.

[teenylittlemetalguy]

12 hours ago, Another FrankenBurner said:

He is also a dedicated giver, full of good ideas.  

Thank you curtis!

I am forever grateful to Frosty, he has been a true treasure to me.