Newbie Forge

[Darren Tee 1]

Hi All,

 

This is my first post.  I am sure that as my son and I progress with this hobby there will be more posts.  After reading lots on simple forges to heat treat blades we successfully built our first forge.  Pictures below.  We used a propane torch but I don't think that it is "big" enough.  The heating chamber of this forge is very small - 2 1/2" x 9" x 4 1/4".  I think that the Frosty T design would be too big.  My question is there a smaller burner design out there, or is the Frosty T design OK for such a small forge?

 

Many thanks,

 

 

 

 

 

 

 

[Cory LA 2]

Fairly new myself, but...... I built mine with 6 bricks, so it's twice the width of yours but still pretty small. I used a 1/2" T burner and it works great. (It hits welding temps) I'm sure someone here can help you tune one to work perfect in yours.

[Alan Longmire 3,410]

Either the T-burner or a Ward reducer burner is perfect for that size forge.  I prefer the Ward reducer just because it's easier to tune than a Frosty. A little more expensive to make, but you can get all the parts from High Temp Tools for $45 plus shipping.  Or you could order a Black Beauty from Anvilfire.com at $50, ready to go.  That might be a little overkill, but it won't hurt anything.

 

Welcome aboard!

[John N 321]

Really neat looking build! - I cant advise on burners, but keep the end of the burner out of the forge chamber, or it will be eaten by the forge gods!

 

For what its worth, all forges end up looking like sh!t after you have used them 6 times and modified them 6 times. Its all part of the process

 

I don't ever want to be 'the safety guy' but if you start using propane burners (venturi or blown) invest $20 in a CO alarm. I have told a few people this in 'real life', and a couple have got back to me grateful, a bit shocked when they did, as the forge would have probably killed them!

 

Welcome to the addiction

[Darren Tee 1]

19 hours ago, Cory LA said:

Fairly new myself, but...... I built mine with 6 bricks, so it's twice the width of yours but still pretty small. I used a 1/2" T burner and it works great. (It hits welding temps) I'm sure someone here can help you tune one to work perfect in yours.

Do you have the specs for a 1/2" T burner?  I can not find them online/

 

Thanks,

[Alan Longmire 3,410]

A 3/4" will be fine.  Might have to slightly choke it, might not.

[Cory LA 2]

Darren, I'll look through my stuff and see if I can find the specs I started with. If I don't find them I'll get some measurements for you. As Alan said, a 3/4 will work, and if you decide to upsize your forge a bit you'll already have the burner.

[Cory LA 2]

3 hours ago, Darren Tee said:

Do you have the specs for a 1/2" T burner?  I can not find them online/

 

Thanks,

So I followed the original 3/4" directions,  substituting 1/2" for all 3/4", using a .23 mig tip and mine ran best with a 5" mixing tube. Once you have it together you have to adjust jet and tube length for your forge. Remember not to have the tube sticking in past the forge wall.

Edited January 15, 2021 by Cory LA

[Darren Tee 1]

Much thanks.  Will try to figure this out.  Ill keep you updated.

 

[Gary LT 199]

I have one as this for smaller blades, etc. and use a 1/2” stainless 6” nipple, 5” works also and 23 mig tip will feed enough air to gas mix to burn inside the chamber. I used a 1/2”, 3/4”, 3/4” tee. The nipple sets into a 1” floor flange with a 1” close coupled nipple in which I drilled and tapped screws to tighten and hold. (I stuff ceramic wool in the gap) This was put on the top panel at dead center. I used 1” ceramic wool everywhere else, coated with 1/4” satanite and then painted with ITC100. This setup allows more interior room than what you are gonna have. I used hard firebrick on the floor also coated with Satanite/ITC.

The front opening is about 2 1/4” square and the back I left closed.

You need to know that this burner placement will produce a hotspot but once the forge is at forging temps it’s not an issue. I easily get 1800 + degrees at 7 psi which is plenty for most all forging I do. I can control temperatures pretty easy and monitor temperatures with a thermocouple. I use a different forge for welding.

Eventually the flange screws will deteriorate and the hinge will as well. Been using mine for 7-8 years, can’t remember!

Gary LT

[Darren Tee 1]

I used 1 1/4" fire brick wrapped in 1/2" kayowool. 

 

The position of any burner will create a hot spot - no?  Should you close the small gap around the hole where the burner goes into the forge?

 

This is currently planned just for heat treating.  If the bug bites hard we may try some welding but not just yet.  Baby steps.

[Wayne Coe 71]

Fire brick will not last long and are a heat sink.

Check out the Build a Gas Forge and the Ribbon Burner attachments on the Forge Supplies page at

www.WayneCoeArtistBlacksmith.com.

Let me know if I can help you.

About $100.00 plus the hose, regulator and burner using a 20# Propane tank.

 

[Daniel W 90]

That is a really nice compact idea for a forge, and probably an overall good size!

 

Hot spots, I think with your design of having that burner come in from the side, you will not notice it.  I look for a hot spot at times, but I'm not as much a knife maker. I'm usually looking to make a swirly thing and sometimes everything hot is problematic.

 

I would add to John N's suggestion of 20 bucks for a CO alarm, and say if you can get one with a digital read out even better.  Typical CO alarms go off around 30ppm, but the digital ones can give you a read out of lower levels. Read the instructions that come with it. Biggest thing is to ventilate your working space with the forge as much as possible.

 

 

[Darren Tee 1]

5 hours ago, Wayne Coe said:

Fire brick will not last long and are a heat sink.

 

I used thermal insulating fire brick rated up to 2600 degrees.  Sorry if I wasn't clear - its not Home Depot fire brick.

[Darren Tee 1]

1 hour ago, Daniel W said:

Hot spots, I think with your design of having that burner come in from the side, you will not notice it. 

 

My though was that if the flame comes from the top it is directly impacting the work (creating a hot spot), while if it comes in from the side, and the work is on the bottom of the forge it wont be directly impacted by the flame.  But, admittedly, I know nothing about doing this so I will learn and the burner location may change.

[Alan Longmire 3,410]

Side entry is good.  You are correct, top-entry burners make the flame impinge directly on the work, creating not only a hot spot, but potentially an oxidizing spot if your burner is not properly tuned. This leads to heavy scale and decarburization.  I think a lot of commercial forges do this because the makers don't know or care about how gas forges are supposed to work, which is to heat the lining which then heats the steel.  

 

In a larger forge you can get an absolutely even heat by having a cylindrical chamber and letting the burner enter the chamber at a tangent to set up a swirling flame.  These little forges are hard to do that with, though.

 

As Daniel points out, it's also nice to have a hot spot for some operations.  There's advantages and disadvantages to everything.

[Darren Tee 1]

So the burner I selected came in.  Two questions about this:

 

1. How far from behind the front of the brick should the tip of the burner be?  See pic below, its about 1/4"
2. There is a ring around the burner tip where it goes into the forge, about 1/16 to 1/8".  Are you supposed to seal this or is it OK to have that gap?

We have cut our first blanks but not yet done the bevel.  Once that is done we are going to use the forge so time is soon.

 

Thanks,

[Alan Longmire 3,410]

The end of the burner sits just inside the brick, so that's fine. Seal that gap with a bit of kaowool. If you leave it open the burner tube will heat up and cause pre-ignition issues.

[Darren Tee 1]

1 hour ago, Alan Longmire said:

The end of the burner sits just inside the brick, so that's fine. Seal that gap with a bit of kaowool. If you leave it open the burner tube will heat up and cause pre-ignition issues.

Thanks Alan, will update on the progress.

[Darren Tee 1]

So, we have made progress.  Needed to order more Kaowool for the gap so haven't fire the forge yet. 

 

I thought I would share some things I have made to help myself with the knife making that may be beneficial to others.  Note that I am working on a tight budget.

 

For a belt grinder I bough the Harbor Freight unit for $36 with coupon.  I made a larger table with some steel I had in the garage.  I welded two studs on the bottom of the plate and drilled holes in the original platen/table and bolted it into place.

 

For a bevel jig I used a piece of angle iron I had in the garage.  Its thick, 1/4 inch, so it could be tapped.  I tapped it with 3/8 fine thread.  I decided to put it in the center to get the angle since it will not rock.  For pins I tool 1/4" bolts and rounded the heads by putting the bolt into the drill chuck and sanding it with the drill running.  You also need to reduce the thickness of the bolt head to be thinner than the steel blade stock.  I learned this because I couldn't get a even grind.  Simple but effective.  Worked quite well I think.

 

This is not about forges but I don't know where else I would post it.

 

Next up will be the heat treating.

 

 

[Darren Tee 1]

Just following up.  Temps today were above 30 so I decided to fire up the forge for the first time and just heat my blade and normalize it.  I burned the tip grinding.

 

Anyway, here are some videos:

 

Forge Fire Up

Blade Heated

 

On the second video you can hear the burner making popping sound.  I tried opening and closing the choke, and increasing and reducing the pressure but couldn't get it to run consistently for any period of time.

 

Making progress..