Jeremy BSblade Posted March 1, 2016 Share Posted March 1, 2016 Ok, so me and my parter have made a few knives and are happy with our results so we think we're ready to move onto forge welding and making some demascus. I've got a pretty simple design in my head. I have an old propane tank I can cut the bottom and top out of. Going to cut a hole it, shove a weed burner in it ,fill it with a firebrick/ refractory cement mixture up to the lip and coat the outside with kaowool. I don't like doing things twice so I'd like to do it right and I've heard that most fluxes can tear through basically anything pretty quickly so I've done some research on materials I can line the inside with to protect it. Mostly what I've heard is there's nothing to do accept touch up the cement periodically, but I recently ran into a product from a company called homesaver that's used to line fireplaces. It's called "Flue goo" and I've heard a few smiths say it's suppose to be very resistant to flux. It's about $30 a gallon so I'd like to know if anyone has any experience with it and if so is it worth it? If not is there any other products you suggest that would protect the inside of my forge? Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted March 1, 2016 Share Posted March 1, 2016 Most weed burners run way to oxidizing to weld with; why are you going with that? Quote Link to comment Share on other sites More sharing options...
Jeremy BSblade Posted March 1, 2016 Author Share Posted March 1, 2016 Honestly I'm not very experienced with gas forges. Just seemed like the simplest thing to do, and I already have a rarely used one on hand. What do you suggest other than that? Quote Link to comment Share on other sites More sharing options...
jjhend28 Posted March 1, 2016 Share Posted March 1, 2016 I've Never used Flue Goo, and can't comment on it, but I am worried about just using a weed burner for forge welding. I tried it before and didn't even get close to forge welding temps. For the cost of a few basic fittings and pipes you can build a simple venturi burner that will get you hot enough, AnvilFire.com has quite a few articles on how to build them and there are a load of youtube videos if you need visual aids. As to the flux resistance, (I have a forge built from an old 20lb propane tank) I lined it 2600 degree 2 inch kaowool, hit it with some itc100, and use soft fire brick in the bottom that I replace when needed.. I would post a pic but my camera went south on me. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted March 1, 2016 Share Posted March 1, 2016 I expect you are very good at forge welding already since you are moving up to billet welding? What are you using now? Quote Link to comment Share on other sites More sharing options...
Jeremy BSblade Posted March 1, 2016 Author Share Posted March 1, 2016 Thomas, I have a little coal forge that works awesome, ive done my share of welding and had some successful faggot welds but its hard in a coal forge. That's why I'm trying to make a gas one. Wasn't really educated on the necessity of oxidation, thanks for bringing it to my attention. Thanks for the help JJ as well, defiantly looks like I need to do a little more research on that. Anything else yall think I missed? It would help a lot, like I said, I don't like doing things twice! Quote Link to comment Share on other sites More sharing options...
jjhend28 Posted March 1, 2016 Share Posted March 1, 2016 Do you research and don't be afraid to ask questions. Get in touch with your local blacksmiths association, and take a look at their builds. That's probably the best advice I can give you. also, keep on hammering! Quote Link to comment Share on other sites More sharing options...
Jeremy BSblade Posted March 1, 2016 Author Share Posted March 1, 2016 Thanks, you too brother Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted March 1, 2016 Share Posted March 1, 2016 Actually I'd suggest focusing a bit tighter yet and check out other knifemakers' billet welding forges to get something of proven utility. Are you on any of the knifemaker forums? Quote Link to comment Share on other sites More sharing options...
Crazy Ivan Posted March 1, 2016 Share Posted March 1, 2016 There is no benefit to wrapping the outside of your forge with kaowool. Look at some plans for propane tank forges. They are a dime a dozen. The most common method of insulating is to use 2" of kaowool (or equivalent) a layer of refractory cement, and a layer of IR reflective coating. I have always used metrikote, satanite, and whatever ceramic fiber blanket. Get a removable kiln shelf to put on your floor during fire welding or messy flux covered pieces. There is no such thing as a one and done forge liner. They should be considered consumables. Also, look into plans for naturally aspirated burners (I like the frosty t burners and have had great success with them) or blown burners. There are plans all over the place if you look. Otherwise you can buy commercially built ones. Quote Link to comment Share on other sites More sharing options...
Frosty Posted March 1, 2016 Share Posted March 1, 2016 Jeremy: Crazy Ivan has the basics of a gas forge right, he's made and used enough to k now. I've posted the basic plans for the T burner here on Iforge but keep losing the link. I was using W8.1 and recently "up(?)" graded to W10 and am having a bucket of hyper active worms fun time getting files and such sorted out. Anyway, The basic burner to forge volume is 1ea. 3/4" burner nozzle for 300-350 cu/in furnace fire chamber. That's assuming a pretty uni-dimensional chamber, long and narrow requires either more smaller dia. burners or a different burner type. Probably the most common naturally aspirated burner type as seen on the program "Forged in Fire" on the History Channel are Ron Reil's adaptation of a linear burner. Another good type is the "Side arm" adaptation of the "jet ejector", the "T" is my adaptation of a "jet ejector" and probably one of the easiest builds if you have some basic shop skills and a minimum list of tools and equipment: Drill press, drill bit index, a tap set and skill sets to do basic precision work. It isn't mahcine shop tight specifications but you need to be able to drill a straight hole and tap it straight. Mike Porters "jet ejector" adaptations are more technically challenging builds but are commercial burner efficient. There are a couple threads here about various methods of lining a forge for thermal efficiency and reasonable durability. Typically an insulating outer liner, ceramic blanket or insulating castable or rammable, refractory or soft insulatig fire brick and a hard refractory inner liner and various kiln washes including IR reflective washes. are being actively discussed. A number of "designs" better called plans have been posted and discussed in the gas forge sections. those of us who submitted plans and discussions are happy to answer questions but REALLY prefer to answer questions from folk who have done enough reading to ask good question from folk who have done enough reading to use and understand the jargon and answers. Oh, pull up a comfy chair, pack a lunch and beverages, there are hours of good reading. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted March 6, 2016 Share Posted March 6, 2016 You can find excellent burner and forge building instructions on Wayneco.com. You can download a pirated PDF of Gas Burners for Forges, Furnaces, & Kilns. You can also get good directions for building a Freon bottle forge and the burner to run it from Ron Riel's burner pages (this is one of the optimal designs for a knife making forge). At least check out these free sources of information; they will cause you to dump most of your faulty building plans, and keep you shy of real trouble. I forgot to include Larry Zoeller Forge for instructions on building an effective coffee-can forge All this material amounts to a free education in burner and forge building. Frosty's "T" burner is probably the easiest effective burner to build. Finally, reading all this free and concentrated information from different people will proved perspective and confidence ss you see many ideas held in common by these different sources. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted March 6, 2016 Share Posted March 6, 2016 That should read "provide." Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted March 7, 2016 Share Posted March 7, 2016 Wayne, Isn't 2300 F reached at white heat? Of course the indications of heat after that are too subtle to do any good, but couldn't the operator adjust flame amounts to keep the forge pretty close, visually? This is just a guess on my part. Quote Link to comment Share on other sites More sharing options...
WayneCoeArtistBlacksmith Posted March 8, 2016 Share Posted March 8, 2016 Mikey, as I see it 2300 degrees is a bright orange to yellow. For welding billets without flux or even welding mild steel projects I want to know what the temperature really is. Light conditions, etc. can really effect the colors. Also remember high carbon welds at a lower temp than mild steel. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted March 8, 2016 Share Posted March 8, 2016 Wayne, This is one of my favorite disputed confusing brain-teaser subjects; I'm right glad you brought it up Yes, using the same amount of ambient light to judge incandescent colors is fundamental; I suspect this may be why videos and still shots can be so misleading. I like to do my color judging on overclouded days or at twilight in summer months. So, how to resolve this? There are color charts available on a few blacksmith sites, listing degrees by color. But to match up one of the colors on the chart a test is needed; most of these charts start with 1200 degrees as barely luminous when seen in poor light. Aluminum melts at 1175 to 1200 degrees, depending on the alloy. An aluminum welding (not brazing) rod will suddenly slump, telling you when that heat is reached. There are also "heat sticks" available in or through some welding supply dealers to indicate when various temperatures are reached; you can choose one for red heat (1500 F), and experiment with the shop lighting until your chart's color heat matches with the heat stick, then use that level of ambient lighting to "calibrate" your color chart with desired temperature. For me, in my shop, with the same lighting. yellowish white is 2000 F, blinding white is 2300 F...more or less, and temperatures above that are too much for this old man's eyes. Anyone can refine the system as much as desired. Some people are partially or completely color blind, but I haven't run across any evidence that we all see colors differently. So, by giving the color chart source being used (because they don't all agree) running a test, and keeping the same amount of ambient light, during color judging, blacksmiths should be able to agree on what colors go where, and why. If any of us care that much... Quote Link to comment Share on other sites More sharing options...
Frosty Posted March 8, 2016 Share Posted March 8, 2016 Isn't this a perfect example of why using color to judge temperature a purely subjective thing subject to more variables than a politician's honesty. On the big Island the lava on the Pali is running 2,000f-2,100f and we stood in front of the flow at night for the full affect. I'd call that low orange. My golden bullet burner melts 3,000f hard fire brick and that's high yellow in a dim shop. Outside on an overcast day it's low yellow. Our eyes are different, see different colors, shades, intensities, etc. I've always wondered if this is the reason some cultures seem drawn to colors that make me cringe. Culture or genetic propensity? Anyway, the reason judging by color worked for so many centuries is because the person who told you "that's cherry red" wasn't describing it over the internet, she/he was pointing to the color with the student standing right next to him/er. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted March 9, 2016 Share Posted March 9, 2016 Frosty, I think we can do better than a politician's honesty with color charts, but question if we will bother to. Quote Link to comment Share on other sites More sharing options...
Frosty Posted March 9, 2016 Share Posted March 9, 2016 30 minutes ago, Mikey98118 said: Frosty, I think we can do better than a politician's honesty with color charts, but question if we will bother to. Still have the variables and they affect reflective colors differently than radiant colors. Being the refractory and stock are radiating visible light rather than reflecting it is why automatic cameras always show forges and steel so much "hotter" looking than they are. A good chart and some practice and we can learn to judge within acceptable limits for most things but using a good pyro takes all the guesswork out of it. I can beat a politicians honesty with my eyes closed judging by feel. Non contact feel that is! Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted March 9, 2016 Share Posted March 9, 2016 Thanks Frosty, That was a handy hint about why colors show up so different from cameras. Quote Link to comment Share on other sites More sharing options...
Frosty Posted March 9, 2016 Share Posted March 9, 2016 23 minutes ago, Mikey98118 said: Thanks Frosty, That was a handy hint about why colors show up so different from cameras. Three semesters of photography, no telling when something will turn out useful eh? It's the difference between using additive gells (colored light) as opposed to subtractive (filters) for color compensation. Here's another tidbit Mike, your eyes are cameras and are affected in the same ways by the same rules. Our brains are just better at compensating than cameras, a camera can't be fooled by expectations though. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
JHCC Posted March 9, 2016 Share Posted March 9, 2016 Side note on old man's eyes and judging color: I've started wear safety goggles with welding shade #3 whenever I forge. It totally screws up the whole blood red/cherry red/orange/yellow/white range, but I've found that since I've gotten used to a different (and much more green) heat color spectrum, I can judge temperature and forgeability just fine. What I don't do is switch back and forth between goggles and bare eyes; that's just too confusing. Quote Link to comment Share on other sites More sharing options...
AdamG Posted March 10, 2016 Share Posted March 10, 2016 Yeah, apparently digital camera sensors pick up some near infrared as well as the visible spectrum, so looking at hot metal makes the image brighter on the sensor even though the radiation is outside the visible range. Quote Link to comment Share on other sites More sharing options...
MonkeyForge Posted March 10, 2016 Share Posted March 10, 2016 AdamG, that is correct. I use this to find out if a remote control is infra red or radio frequent. Try it out, take pic of the remote while pushing the buttons. Ambient light will influence where your camera focusses (and it's settings) so take that into account. It is hard to get a picture of the inside of a forge with no ambient light. (I have not yet mastered this, even knowing how it works. see other threads for failures ) Quote Link to comment Share on other sites More sharing options...
Frosty Posted March 10, 2016 Share Posted March 10, 2016 On 3/9/2016 at 3:37 AM, JHCC said: Side note on old man's eyes and judging color: I've started wear safety goggles with welding shade #3 whenever I forge. It totally screws up the whole blood red/cherry red/orange/yellow/white range, but I've found that since I've gotten used to a different (and much more green) heat color spectrum, I can judge temperature and forgeability just fine. What I don't do is switch back and forth between goggles and bare eyes; that's just too confusing. A person can adjust to most light conditions or folk couldn't wear sun glasses everywhere. I don't stare into the forge so I'm not concerned with IR caused cataracts but judging the temp is again a matter of experience. I've tried wearing shade 3 glasses but my shop is too cluttered and kind of dim to start with. To your point though, it is just a matter of spending time in consistent conditions and our eyes, brain actually, will adjust. It's still going to be imprecise to a degree. some folks are very good judges of temps though not necessarily what degree. It's like evaluating salvaged metals, without having it lab analyzed we have to use it's original purpose and working characteristics to come to an opinion about it's utility. What it can be used for and how to work it in other words. But NOT what it really is. Is it hot enough to weld? Yes, no, maybe, is where the Mark one Eyeball gauge puts us. Some have better eyeballs for whatever reasons and there are lots. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.