Dirt-box dirt shrinkage help

[WoodFireMetal]

I’m building a dirt box/brake rotor hybrid and I combined some clay-filled dirt from the yard and a box of cat litter with water in a wheelbarrow and layed it smooth in the box. As it dries, it’s shrinking...which I expected. Is there anything I can do now, or should I wait till it’s dried all the way through to try and patch the top layer, or should I rip it all out and try a different method? It was flush with the rim of the rotor, but I squashed it down to try and help compact it.  

First time poster, relatively newbie to blacksmithing. Been dabbling at a museum for a couple of years, but YouTube/self-taught.

Thanks.

[Irondragon Forge ClayWorks]

Looks like your mixture was too wet. I would just mix some more clay with sand and make it stiff then put that over the top of what you have. It should be stiff enough you have to ram it in with a mallet or board.

BTW... Welcome to IFI have you read this yet? READ THIS FIRST

[Frosty]

Welcome aboard WFM, glad to have you. If you put your general location in the header you might be surprised to learn how many members live within visiting distance.

WAY too wet, you don't want to make mud, you want ONLY enough moisture the material will clump if squeezed hard in your hand. You want the lump to break clean without crumbling or leaving your hand dirty. If it leaves dirt streak on your hand it's too moist, if the clump crumbles it's too dry.

Clays absorb water slowly but given a little time moisture distributes evenly. If your test shows too moist add a LITTLE more kitty litter, mix thoroughly and seal in a bucket or trash bag and leave it over night to temper. If it tests too dry add a SPRINKLE of water, mix and allow to temper overnight. 

Don't try getting it "perfect" what I describe above is how we tempered casting sand, you don't need it that precise but crumbly isn't so good.

You want to be able to ram the clay into your forge pan with a mallet, end of a board, B'ball bat, etc. till it bounces. Do this in about 2" lifts, spread fresh clay about 2" deep and ram it hard. Repeat till it's the depth you wish then scrape depressions, channels, whatever features you need.

NO MUD, MUD B A D!!  When it dries mud WILL shrink check just like your's did. Yes? 

Say, got a handle we can call you? WFM is rife with jokes that might get some of us in trouble with Mods. 

Frosty The Lucky.

[WoodFireMetal]

Thanks for the advice. My name is Bridget and I’m in northeastern MD. 

Should I rip out the mix while it’s still soft and try ramming it in when it’s the right consistency? Or wait till it’s completely dry and, as Irondragon suggested, ram in a top layer?

[Glenn]

It is filler material, not structural material. Add more dirt to level with the rim of the brake rotor.

[Charles R. Stevens]

Damp clay can be tamped in place, if your going to puddle it you realy need to make Adobe. 30% clay, 50%+ sand. Straw, paper pulp, cow manure or horse manure also help with cracks. 

[Frosty]

A pleasure to meet you Bridget, we need more lady smiths! Just add more dry, mix it and ram it in. If it's still too wet dig some out, replace it with dry and ram it in. It's not a precise thing, get it close and it's good. Use it as it is, or take Irondragon suggestion.

Take  Glenn's suggestion though, raising the level of the forge table even with the top of the rotor will really improve how it works for you. 

It's just dirt, it doesn't have to be "perfect" the first time, it'll never be perfect. No matter how many you line or what Pro forge you use it won't be perfect.  We're blacksmiths we don't do perfect. 

Frosty The Lucky.

[SLAG]

Herr Frosty,

Has helpfully suggested, concerning clay mixtures,

"Clays absorb water slowly but given a little time moisture distributes evenly. If your test shows too moist add a LITTLE more kitty litter, mix thoroughly and seal in a bucket or trash bag and leave it over night to temper. If it tests too dry add a SPRINKLE of water, mix and allow to temper overnight."

The SLAG. suggests that adding a few drops of detergent to the water,  used in this process,  will speed up the whole process, and achieve a closer clay water hydrated mixture..

This hack is used by forge makers,   and also gardeners when preparing soil for potting.

Regards,

SLAG.

p.s.   Welcome to the forum Bridget.

[pnut]

Welcome aboard, one more suggestion. Maybe you just haven't gotten to it yet. Look at the 55 forge thread and get an idea how Glenn uses two pieces of round stock to keep fuel and ash from falling down the tuyere too easily. It's just two small pieces of 3/8 inch round stock I think. You could also use a couple screws instead. 

Good luck and have fun.

Pnut  

[Glenn]

These grates can be used with coal fines or coal dust.  Works well with small pieces of coal or jumps.

This is just 4 holes drilled into the air tube and 2 pieces of 1/4 inch round stock inserted into the holes.

[pnut]

Much obliged Glenn, my phone doesn't like to post links for some reason. They're never active. Those are the exact pics I meant.

Pnut

[Glenn]

The air tubes are auto exhaust pipe 2-1/4 inches or 2-1/2 inches in diameter. One 1/4 inch rod is usually enough. For 3 inch air tubes I use 2 pieces of 3/8 rod.  Does not take much pressure, just soft air going to the fire. Only use as much air as you need to make the heat you need from the fuel.

[Ridgewayforge]

Welcome to IFI, Bridget!  And, welcome from north central MD! Glad to see more smiths here in MD. If you need any help, don't hesitate to reach out! 

Cheers, 

Patrick AKA Ridgewayforge

[pnut]

I used to live in Edgewood MD years ago. Nice place.

Pnut

[WoodFireMetal]

Hi all, and thanks for the welcome! I ended up digging up some more dirt from the yard and pounded it in on top the previous layer. And yes, I made it flush with the rotor. I fired it up yesterday and it all worked like a charm!  The only problem is the refractory cement I used has craters in it. That explains the tiny pops and burning bits that kept hitting my arm. I used 3000* cement and had a chicken brooder heat lamp on it on and off with a timer for most of the week. I guess that wasn’t enough. Can I patch it with more cement? Or will it eventually crater itself to nothing? 

Having never worked with an electric air source, I couldn’t believe the heat and power coming from the hair dryer on low (cool setting)! I definitely need to upgrade to real tongs because my pliars are all too short.....and not the right shape for holding anything, of course. I have fallen oak trees in the yard and I need to cut one to size for the track anvil I was given so it doesn’t rattle around so much.  It has a nice base to strap it down, at least. I also have a block of granite I was given. Hopefully they both last me until I can afford a real anvil.  

I don’t have a wide repertoire of things I can make yet, but I make a xxxx good leaf keychain since that’s what I demonstrate most often at the museum. Suggestions for items to practice making would be appreciated. Hooks and bottle openers are on the list. The cross was a pre-cut  blank given to my by one of my museum mentors to practice with. 

Thanks again! 

Bridget

Oh, and I made a round grate with holes in it from 16 gauge sheet metal. It survived, but I made a 2nd if the first burns up. 

[pnut]

24 minutes ago, WoodFireMetal said:

. I used 3000* cement

What for? Dirt is good enough. High clay soil works great. My whole forge is dirt , firepot  and all. A wood box a pipe and dirt. It's a side blast trench type forge but there's no need for refractory cement. Good ol  dirt is free and does the job. When you have to rebuild your forge you can fill the table with dirt and it's going to be just as good.

Your forge and work looks good. Glad to see it.

Pnut

[Irondragon Forge ClayWorks]

That is looking very good and seems to work well. I have 2 suggestions though. You need to find a way to control the air flow to conserve fuel and prevent burning the steel. One way would be make a sliding valve between the blower and pipe. The other would be to move the blower away from the pipe so it can be rotated to blow off center to it.

The other suggestion is to cut notches in the sides so long stock can be placed in the fire at the right angle. Don't know if you have seen this thread but it does a good job of explaining what I'm trying to say.

https://www.iforgeiron.com/topic/30887-forges-and-fires/

 

[WoodFireMetal]

Pnut- to protect the bolts in the fire pot and to round out the bottom corner of the rotor to reduce fuel usage. I assumed dirt and clay would be kicked up each time I stuck the poker in the fire pot to loosten the coke. 

Would a rheostat work to cut the power down even further? I see one for routers at Harbor Freight for about $20

Irondragon- I realized yesterday that I would need to cut notches in the wood. 

[pnut]

Clay will vitrify and get hard. Either way you're going to have to replace it periodically. I haven't used a roter before. You may be able to skip the clay or refractory inside the firepot. Ash will build up and soften the hard angle at the bottom of the rotor. Someone more familiar with brake drum forges will be able to tell you if you really need to protect the bolts or not. 

If you disconnect the hair dryer From the pipe and aim it more at the pipe for more blast or angle it away from the pipe for less blast it will work fine just like IF&C said above. I don't know if a rheostat will work for a hair dryer or not.

Pnut

 

 

[Irondragon Forge ClayWorks]

I read somewhere here that rheostats only work with motors that have replaceable brushes, so if the hair dryer you have has brushes the rheostat should work. I have one on my single speed Dremel that has been working for years. Looking at the picture (blown up) of your hair dryer, I don't think it has brushes.

[Glenn]

Raise the height of the anvil to fit your body and hammer swing.  There are several threads on the site explaining what is the proper height.

Find a better way to secure it so it does not move around. 

Cut a slot in the side of the box to let longer stock pass through. If you use long stock, 14 to 30 inches or so, you do not need tongs. BP001 Easy to make tongs

As mentioned above, set your blower so it is NOT directly connected to the air pipe. Leave a 3-4 inch gap.  Aim the air toward the air pipe for more air, and not so directly for less air. You will be surprised how little air is needed for the forge. A 3 inch expandable aluminum dryer vent works great to direct air from the blower to the forge twyere.

When you get your air control in place, double the amount of fuel in the forge that you use now.  It will insulate the fire to keep it hot and take less fuel over all, as you will have cut down on the air flow to where it is soft air.  Use just enough air to get the heat you need from the fuel to heat the metal.  Then play with the sweet spot of the fire (about 1/2 to 2/3 up the height of the fire ball) so that the sweet spot is level with where you insert the metal into the fire. You may have to build a rim on the top edge of the rotor depending on the depth of the rotor.  Height adjustments can be clay, a ring of metal, or whatever works. Once you have the height right, back fill the area between the ring and the edge of the wood frame. Dirt, clay works good for back fill material.

You can see where two rows of house bricks were used to raise the sweet spot of the fire for the project I was working on. You can also see the natural cone of ash that was formed.

 

You can see the fire is plenty hot and the right depth for the stock (3 inch wide leaf spring) being heated in a 55 forge.  Notice the soft air just heats the fuel and there is not a lot of flame dancing around on top of the fireball.

There is no one type and size fire that will do everything. Modify your forge as needed to do what you want. 

No one said you could have only one forge. I have 3 forges that I use most often, a 4 inch diameter firepot that is maybe 4 inches deep, a rotor in a 55 Forge, and the original 55 Forge that the fire pot changes depending on the project at hand.

Bottom line is to build your first forge and get it to working. You are already there, just needs tweeking.  Next build a second forge with the improvements you think will make it better. Those improvements (grin) can be anything. You are hunting for something different from what you have now, such as a different design, smaller, larger, deeper, less deep, round, square, rectangular, what ever strikes your fancy and you want to try.  Compare it to the original forge to see which you like best. And yes, you can have both forges going at the same time to make the comparison.

The fun is in the challenge of trying new things and improving.

 

[Irondragon Forge ClayWorks]

More forges = more fun. We have three working forges a permanent bottom blast coal/charcoal forge, a portable bottom blast pack forge coal/charcoal and a propane forge. I am in the process of building a side blast charcoal/coal forge (really need to get at it) all that's left is to clay the firepot & table. I like coal and my wife likes propane but has been learning to get dirty with coal. She learned to build and maintain the coal fire amazingly fast.

[prok-master]

On 6/24/2019 at 10:51 AM, WoodFireMetal said:

I don’t have a wide repertoire of things I can make yet, but I make a good leaf keychain

Sumptuously. The same key chains are made by Tatyana Kamaeva from Russia ... You have golden hands.

 

[pnut]

One last suggestion. I noticed you don't have any stretchers between the legs of your forge table. You may want to add some. They will strengthen the wood structure and you can put expanded metal grating on them and use it for a shelf for hot steel, tools, or whatever. Other than that it looks great.

Pnut

[WoodFireMetal]

On 6/25/2019 at 5:55 AM, prok-master said:

Sumptuously. The same key chains are made by Tatyana Kamaeva from Russia ...

Wow those leaves are neat looking! 

On 6/25/2019 at 8:37 AM, pnut said:

One last suggestion. You may want to add some stretchers between the legs of your forge table.

That is my intention. I couldn’t add a shelf until I knew how far down the pipe would go.  

Glenn and pnut- I was under the impression that ash build up led to a dirty/inefficient fire, which is partly why I used refractory in the firepot. The other reason being protection of the bolts connecting to the flange. 

Wouldn’t physically blocking the airflow from the hair dryer put more pressure on the motor? 

The anvil height seemed to be really comfortable with that amount of blocks (I’m short), so that height was where I was intending to cut a stump.