Forges 101

[Will2031]

Hi

im completely new to forging and I am interested in bladesmith. 

To get started I need a gas forge. I’ve been thinking about what to do for a while, and think I maybe close to making my mind up, but your advice would certainly help.

im looking at these two to start with

ebay link removed

my idea is to start with a smaller forge at first and once I get going and start increasing the size of my projects build a larger one for these. 

I also think, that if I get a smaller one first it won’t be redundant when I build a bigger one as I could use it for smaller projects instead of buying a larger one now and that being redundant when I build one to my spec in the future. 

Does this make sense at all?

if so the choice I have is one of the ones above, biggest difference I see is oval and round in shape, what would you recommend? 

Thanks again for all your help

will

[Frosty]

Welcome aboard Will, glad to have you. If you'll put your general location in the header you might be surprised how many of the gang live within visiting distance.

Your plan to start modest and move up is sound, most of us started out by building stupid too large a forge, Heck, I still tend to do that.

Anyway, both these forges have been discussed here, I believe in the "Forges 101" thread and I don't want to try covering it again. In short though they have some serious failings but can be modified into decent working forges. 

Between Forges 101 and Burners 101 we discuss making both and putting them together into GOOD forges for less than the cost of the least expensive of the two you ask about. I"m sure it won't be long and the boys will start talking about the DF line of forges. . . again.  S'okay, we like taking about these things.

Frosty The Lucky.

[Irondragon Forge ClayWorks]

Welcome, I always suggest reading this thread to get the best out of the forum

Your links to eBay will probably get deleted, don't take offense but it's against the rules to link to commercial sites.

[Frosty]

Oh good grief!  Was your question already in Forges 101 and I missed it?  If so please feel free to disregard that suggestion or heck tease me mercilessly. 

Frosty The Lucky.

[Ted Ewert]

For all you new guys like me, I wanted to present a simple alternative to the ubiquitous NA burner forge. Nothing wrong with an NA burner forge, but for you guys who want just a little more heat I'm suggesting a blown system with a ribbon burner.

Here is the simple one I built:

 

The gas line is simply a shutoff valve and a needle valve. All the fittings are standard 1/2" pipe fittings to make things easy. I have a cheap 1/8th HP blower with a 2" output flange. You don't need any more than this as I run it at only about 20% air. All the pipe is 2".

The burner is a 23 tube, 2 1/2" X 6 1/2" by 2 1/2" deep ribbon type with 5/16" holes.

The box is a failed attempt to build a hardening oven, so I cut out a hole to fit the burner and coated the inside with about an inch of Kastolite. The barn doors are an old Kastolite burner I cut in half, which works great. They really hold in the heat.

The reason I recommend a forge like this is that it gets very hot and heats material quickly. It's also gas efficient. When I put a piece of steel back in the forge after it's cooled too much to beat on anymore, it only takes about 2 minutes (or less) for it to get back up to temp. Welding temperatures are no problem.

Anyway, if a hack like me can build one you can too. Keep it open as a viable option. 

Ted

 

 

[Will2031]

Thanks for the help so far, the starting point has helped and I am trawling through as much information as I can. 

One of the biggest issues I’ve found, I might be wrong, but here in the U.K. parts seem to be a lot harder to find and more expensive too. (that’s always the case here anyway with everything)

[Another FrankenBurner]

After seeing the steveomiller's about the Plistix, I started to question the Metrikote sold by Wayne. 

The only thing I could find was for Matrikote 90AC which I believe is what we are talking about:

As you see, the alumina oxide is a few percent lower, the silicon oxide is very close, they state phosphorus pentoxide, and a bit over 5% unstated.  Below this screen shot of the MSDS is stated "*Proprietary ingredient not included in chemistry."  No stated zirconium.  It's seems to be something that is strong at high temperatures.  Like the plistix, is says nothing about re-emissivity or energy savings.  It also states a maximum temperature of 3000F.  Plistix SDS states a melting point of 3400F and further into the document it includes 0.02% Quartz, 1-5%  Aluminum Phosphate, and 1-7% Bentonite.

Matrikote MSDS: http://alliedmineral.com/app/docs/pdf/reverberatory-furnace/MATRIKOTE 90AC.PDF

Plistix SDS: http://plibrico.com/uploads/MSDS/sds Plistix 900F.pdf

Move on to ITC-100HT:

The mix is not stated, but the product use is.  It states "Energy saving ceramic coating" and has a melting temperature above 4000F.  I tried to follow the CAS number and found a lot of "Proprietary Formulation" road blocks.  I did find this page: https://www.lookchem.com/Ceramic/ which mentions ceramic but that page is above my chemistry pay grade.  It doesn't seem like it is talking about ITC though.  

ITC MSDS: https://www.norheatinc.com/wp-content/uploads/2017/11/ITC-100HT-SDS-2015.pdf

I am looking for a good kiln wash with for re-emissivity.  I have read that ITC has kaolin clay which doesn't get hot enough to vitrify.  The alternatives that Wayne offer don't seem to have the re-emissivity as their intended goal.  I can't seem to find the source but I had read that Matrikote was not to be applied to hard refractories but to the ceramic blanket directly.  I am wanting two to three inches of rigidized ceramic blanket, 1/2 inch of Kast-O-Lite, and a kiln wash.  I have read that several people have applied the Plistix or Matrikote directly on Kast-O-Lite without problems from either and most say they did help with heating the metal.

A few questions which I know are dabbling to the experimental side.  Some of which I may have to do.  Does adding Zircopax Plus to either of the above, probably Plistix, scream out a bad idea to anyone who knows more then I do about this stuff?  Is the Zircopax Plus with 5 % bentonite a better idea still, aside from being cheaper? An alternate idea, does adding either of the above between the Kast-O-Lite and whatever re-emissive wash I end up using make any sense to anyone?  Possibly to protect the Kast-O-Lite.  The Kast-O-Lite is pretty tough stuff.  

Has the dust settled on the Zicopax Plus with 5% bentonite or with the veegum?  A question for Frosty, have you produced any sort of a hot face wash with the Kast-O-Lite mixed with Zircopax that you are happy with?  Zircopax is inexpensive so I am willing to experiment.  Based on previous readings about, I believe Mikey, using water to separate some ITC, I am guessing the Zircopax Plus with the finer Zirconium Silicate is going to be what I want over the plain Zircopax?

Forgive the long legs and overthinking on this one.  Forgive me if any of these questions have been answered elsewhere.  I have read the Burners 101, Forges 101, Narb, and T burner threads and so there is a lot of overlapping information in my head.

[Mikey98118]

22 minutes ago, AnotherCurtis said:

A few questions which I know are dabbling to the experimental side.  Some of which I may have to do.  Does adding Zircopax Plus to either of the above, probably Plistix, scream out a bad idea to anyone who knows more then I do about this stuff?  Is the Zircopax Plus with 5 % bentonite a better idea still, aside from being cheaper? An alternate idea, does adding either of the above between the Kast-O-Lite and whatever re-emissive wash I end up using make any sense to anyone?  Possibly to protect the Kast-O-Lite.  The Kast-O-Lite is pretty tough stuff.  

Matrikote and Plistex are low priced products of proven worth and reliability.

Zircopax mixed with bentonite, etc., are high temperature ceramic mixtures that have to be worked out by the user; not ready to use products. Zircopax has great utility as a re-emissive coating, and as a hot-face thin armor plating. It is not a snap-your fingers-solution to anything.

[Another FrankenBurner]

I do not mind having to work or experiment in order to use the Zircopax.  I am looking for other members advice/experience on the subject before I start experimenting.  I am looking for the re-emissivity for the energy savings.  I used ITC on my last forge and from what I have read here, because of the kaolin clay, it sounds like it may not be the best thing to use for forge purposes.  While I have read Matrikote and Plisix are used with good results by others, they seem to be more of an armor then an energy saving re-emissive coating.  I may be missing something.  They both are missing Zirconium Silicate or might have very low unstated percentages of it.  I thought I had read that ITC has a very high percentage of Zirconium Silicate.  I am seeking a kiln wash for re-emissive qualities, not for armor qualities.  If I can have both in one, that would be great, but if I can't, energy saving is more important then armor for me.  

[Mikey98118]

The way Plistex and Matrikote both work is re-emission from incandescent services, which is natural to all substances. So how did they get to stack up so well against ITC 100? Because the percentage of reflection from zirconium particles drops badly as particle size increases. The original ITC 100 formula had particles from a large sieve; why? Because it was cheap; the original description claimed " up to" such and so percent of reflection. In other words it was B.S. advertising. So the other manufacturer's salesmen retaliated with their own B.S., which was just as "true" and just as misleading, but at least their products weren't criminally overpriced!

Plistex and Matrikote  are both good finish coats for ceramic fiber insulation; they both will reflect heat at around 80% or a little more; how does that stack up against a high alumina refractory? About the same. 

[Frosty]

ITC-100 was developed to keep things from sticking to furnaces and survive high temperatures. I don't know how it got invested with properties that are desirable in propane forges, the first I heard about it was about the time the internet went public, mid '80s(?). The data from the site doesn't say a thing about it being an IR reradiating finish, it lays out the chemistry it will survive at furnace temperatures.

I still have about 1/2 the pint can I bought back when. Even after living on the inside walls of my forge it'll still rub off. It works about the same as kaolin clay mixed like slip, it doesn't fire in my forge either. It was only expensive when I bought it, now it's completely off the radar.

That's about what I know about ITC-100.

Frosty The Lucky.

[Another FrankenBurner]

Thank you Mikey and Frosty.  I will purchase the Plistix because of it's higher melting temperature for the current forge.  I will also be purchasing some Zircopax Plus, Bentonite, and Veegum, just for some experiments.  

Here is an image of a refrigerant jug, small and large disposable helium cylinders, and a 20lb propane tank incase anyone wants to see a size comparison:

The smaller helium tank is the same size as the refrigerant tank but it is lighter weight if you worry of wall thickness.  When I cut it open, I will measure it's thickness compared to the refrigerant tank.  They are both 9.5 inch cylinders.  With the ends cut open/off you get between 10-12 inches in length depending on how much you cut.  The larger helium cylinder is pretty much the same size as a 20lb propane tank.  It is 12 inches in diameter and gives the same 10-12 for length.  Quite thinner wall then the propane tank which would make for a lighter forge.  

You can see part of my first forge which is a refrigerant jug forge.  

 

[Frosty]

There's no good reason to cut the whole end off the tank. Unless you have a good reason that is. The opening in the tank only needs to be a LITTLE larger than the door opening. I like enough extra to wrap the insulating refractory around the edge and armor it with castable. This prevents the edge of the steel tank or whatever shell you use from getting HOT and warping.

Frosty The Lucky.

[Mikey98118]

I like to leave enough of the cylinder's end portion to keep the forge shell stiff, and make it a big enough opening to keep the tank's steel end well away from exhaust gases. Either ceramic fiber board ($$$) or Kast-O-lite refractory (cheap, semi-insulating, and tough) can be used  to help keep the hot gases at least 1" or more away from the steel shell. There is always a maximum opening for a given burner; 4" x 4" is plenty. You will still want a brick baffle wall in front of the opening much of the time for efficiency. What I don't like is end openings growing red from exhaust gases.

[Mikey98118]

Secondary air and oxidation

Up until recently, burners tended to fall into two main categories; awful junk burners, or efficient and hot burning types. The later burner designs tend to come from a few sources that also give good advice about their proper mounting and maintenance, while the junk burners provide such heavily reducing flames as to make very little scale anyway. But over the last year more and more "just acceptable" burners with small secondary flames have become available.
 And in recent months I'm hearing an increase in concerns about scale on work pieces.

There could be a cause and effect going on here. When a burner is mounted in a port tube, or just through a forge wall, the opening can provide an airway for the burner's flame to induce excessive secondary air into the forge. So, if you won't manage secondary air for efficiency, maybe you'll do it to lower your cleaning work.

[Mikey98118]

What castable refractory for a hot-face?

There are several excellent castable refractories on the market, and some of them have a higher alumina content than Kast-O-lite 30. I have preached long and hard about how important high alumina kiln shelves are as forge floors, rather than alternatives like clay bricks. Nevertheless those high alumina refractories are far less insulating than the Kast-O-lite is; the reason for their higher alumina content is that the alumina in Kast-O-lite 30 is heavily mixed with glass bubbles, which form voids in the refractory; thus creating greater insulation than more alumina content can.

The main insulation value in a hot-face is to help protect the ceramic fiber insulation that rests against its cold-face on the outer side of this tough flame wall. Speaking of tough, Kast-O-lite 30 is famous for it. I have never had a crack develop in one of my forges or casting furnaces in nearly twenty years using it. 

So what is the point of the higher alumina content in refractories like Greencast? Mostly they have higher resistance to melted glass (considered a super acid) and corrosive atmospheres. Of course that will also include hot flux. 

[Mikey98118]

But than, the idea should be to keep hot flux from touching your forge's floor as much as possible in the first place, since it will create a sticky mess if it does. 

[Mikey98118]

A KISS valve

he question has come up about idle circuits elsewhere on this forum, but from a different perspective. A fella asked if it was okay to shut off his forge, using a shutoff valve, by which I'll presume he meant a ball valve. And the answer came back as yes-no-maybe; a good answer, as it depends on a lot of things.

Then someone else mentioned idler circuits.

I still think that the best answer is found hallway between the two. Nothing stops us from mounting a ball valve on a piece of plate and screwing in a small bolt to limit how far toward closed it can reach, making a simple idler valve from it, instead of building a whole idler circuit, with pipe or tube parts and two valves (both ball and needle valve).

I built this valve back in 2003 for a book; it worked fine, but I prefer the idler circuit, because I'm a perfectionist.

According to the KISS principle that makes me kind of stupid; guilty as charged 

Nowadays, I would go for the idler valve, because it is sleeker; what, you thought I smartened up?

[Frosty]

8 hours ago, Mikey98118 said:

According to the KISS principle that makes me kind of stupid; guilty as charged 

I disagree Mike, disregarding the KISS principle doesn't make you stupid it makes you "unprincipled." 

Frosty The Lucky.

[Mikey98118]

The thing I've enjoyed most over the last few years is how often my views have been improved here. old dogs can learn new tricks, with a little help from ibuprofen 

[Daguy]

On 7/2/2018 at 2:57 AM, Frosty said:

This is from a post I made a while back regarding Kastolite 30 and forge welding flux. As it turns out I must have already kiln washed my forge before running the above test. Results other folk here have experienced with it and flux caused me to retest as their experience was much different. As it is Kastolite 30 is NOT proof against borax containing forge welding fluxes. Evidently %30 high alumina isn't a high enough % to be very resistant to hot flux, it dissolves Kastolite into a rather sticky paste. 

If it's available I'd love to hear how one of the Kastolite refractories with a higher % of alumina tests against fluxes. Now though you REALLY need to kiln wash it to protect it against hot flux. 

Frosty The Lucky.

So I'm about ready to insulate, then cast a refractory and as I review this portion of the thread (The last few posts from this post on page 30), I'm now assaulted with a bunch of questions that can boil down to a few.  Is Kastolite 30 good for the floor or not? Should I coat the floor with something like Greencast? And/or would an IR Reflective coating over the floor provide protection lacking in the K-30?  And as long as I'm asking stupid questions, is there a practical difference between 20 Mule Team Borax and the fluxes touted as "Forge Welding Fluxes"?  Sorry to bring it up if it's been discussed elswhere, but I can't remember reading about fluxes in any thread. Then there's the fact that my memory sucks and because it's time to actually put the water in the refractory, I'm nervous when I was sure about the K-30 thing and would just like a little reassurance from the people who used to be perts.  Could someone, anyone,  just tell me that everything will be all right?

(Because this post is public on the internet and not face to fac, I feel obligated to point out that though it started out serious, I kinda got sarcastically humorous towards the end.  Please answer the questions and laugh at the humor)

 

Daguy

[Frosty]

The Kastolite is fine for the refractory inner liner it just benefits greatly from a kiln wash. Plistex or Matrikote do the job perfectly even if they don't contain a zirconium component. 

The welding fluxes, special forge welding fluxes, say Black Magic, Swan, etc. or the Peterson's blue I use all contain anhydrous borax and boric acid plus something propriatary to make it their special formula but seems to have zippo effect on welding. Well, some contain powdered, iron oxide. I can't explain that one. Laundry borax will foam when it gets to about 212 f. up to 230 f. when the last of the hygroscopic moisture is driven out. after which it melts. 

I used to mix my own flux before reading the cans at the local welding supply and buying a can of Paterson's. Anyway, I mixed approx. 3 pts. 20 Muleteam borax to 1 pt. Boric acid powder. available at the pharmacy section of most any store or in the pest control section under the name Roachpruf. Boric acid has a lower melting temp so forms a coating oon the steel to keep the oxy off and prevent the formation of iron oxide  (scale) like you pay for in the REAL welding fluxes. Anyway, the boric acid improves flux effectiveness.

I found the Paterson's in the gas welding section of the welding supply one day. The uses on the can list virtually every type of gas torch welding process I know about, from cast iron, steel, stainless steel, copper, brass, bronze, aluminum, titanium and more. (it says) I've been using it to flux bronze I've been torch welding.

Anyway, I can't say how well Kastolite will resist fluxes, what I thought wasn't so. Mike makes a good point about flux on ANY forge surface will make a sticky mess when hot. A pan or shelf to keep it off completely is only sensible. Removable stainless steel floor pans were or are popular and effective.

Frosty The Lucky.

[Mikey98118]

Let's change the question around, and ask why anybody would prefer Kast-O-lite 30 to a typical high alumina refractory like Greencast? Because it is semi insulating. Well, why do we want insulation in the refractory when it is backed with highly insulating ceramic fiber? Why not just use a thicker layer of fiber instead?

The flame face layer of cast refractory has a hot-face side that faces the flame and a cold-face side that faces the ceramic fiber insulation. High alumina refractory has poor insulation (compared to Kast-O-lite); this allows a higher heat transfer rate into its cold-face side; that allows a higher temperature to accumulate against the ceramic fiber. Ceramic fiber "ages" through shrinkage that is due to high heat. More heat means faster aging. Most people employ very high forge temperatures when welding...

On the other hand, a finish coat like Plistex will protect a cast refractory just fine, because it has a high alumina formula.

So, what do we care if the ceramic fiber shrinks a little? We care because when it shrinks the fibers also start breaking up into dust!

[Daguy]

Great info, Dynamic Duo! Simple and to the point, without a bunch of extra info to wade through. You've come through again.

Frosty, I don't think I've run across that info on the fluxes before. I will be getting some Boric Acid to mix in for sure.  I am intrigued by the removable SS floor pan idea, which I know I've never heard before. Wouldn't forge temperatures warp or melt one almost immediately?  Or is that another one of "those" questions that reveal a little too much about my lack of experience?

Mikey, I remember running across the Hot Face / Cold Face info earlier in the thread but I either didn't remember or else forgot it in relation to refractory chosen to use.  The good news is, I bought Kastolite 30 and ITC100 (Before I'd read about Plistex or Matrikote being less expensive, quality alternatives)  with my first order of supplies for the build, so fortunately I don't have to buy something else.  I'll coat the entire interior with IR Reflective coating and maybe take out the insurance of procuring a kiln shelf or, depending on Frosty's answer to the opening paragraph above, a SS pan

[Frosty]

Zircopax flour is easily obtainable, the closest to me is Seattle Pottery Supply and inexpensive. Evacuated glass spheres (bubbles) are commonly available at masonry supplies to make light concrete and mortar.

Thinking back on it that may be why my forge isn't effected by flux. It may have been a test subject when I was messing with screening out the aggregate larger than a 50 sieve from Greencast 97 and mixing it 1pt. to 3 with zircopax flour as the flame face. Greencast 97 is a water setting HARD 97% alumina refractory with a max working temp of IIRC 3,400 f. maybe higher, I'm not sure. 

However it doesn't really matter flux will stick to darned near anything and whether it dissolves the liner or not the gooey stuff will be there. I know I have a puddle in one of my forges. I scrape it regularly but it's never actually clean and bentonite doesn't absorb it so it stays messy.

One of the guys in our club has been experimenting with bentonite and zircopax. Not to the extent that one of our IFI members in the Netherlands I believe was. However in my playing around I found that sticking it in a HOT forge about tooth paste consistency made ceramic foam. Looks more like bread than whipped cream but it was IIRC about 80% zircopax and doesn't care about flux. 

And that's my more recent experimenting to think on.

Of course a boy could just buy Matrikote or Plistex and use it according to the instructions but I'm dying to mix it with about 5 pts. zircopax. 

I can't help myself, really I can't. 

Frosty The Lucky.