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I Forge Iron


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About D.Rotblatt

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    Los Angeles, California

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  1. Just my 2 cents. I'm using a NARB with 123 holes 1/8" in a small 225 cu inch forge. The burner is pointed straight down from the top about 6" from the floor. Burner is powered by a 3/4" NA burner of my own design, but I've used a Reil burner on it as well. I forge weld 4 lb billets in it running at 12-15 lbs with a .032 jet. It's no problem tuning, with the reil burner it just works fine. Look at page 21 of this thread for a video of my first experiments that worked. DanR
  2. Sorry to disappear for a bit. It's easy to get that kind of colloidal silica, but it's not the same as the colloidal I'm using. I tested that kind, and it makes the ceramic fiber melt. What I'm using is a colloidal silica binder for ceramic shell casting. Look up "Remet colloidal silica" (Remet is a company that makes it). They don't have what I used to buy, Adbond II, but I think their Remasol is the same type of thing. I used to buy it in 5 gallon containers. Don't really see it sold in smaller lots. It's a completely different animal than the fused colloidal silica we use to r
  3. Thanks Tink! Haven’t been pushing the ZS just cause finding the right colloidal in small quantities is nearly impossible here. The one person who was selling it doesn’t anymore. Already got the cordierite, it looks the same but we’ll see. BUT, I have another plan...it just requires drilling 500 holes LOL. But that’s what a CNC mill is for. I’ll spill more if it works. Dan
  4. I went ahead and bought a codierite one for $10. It looks a different color than this, so I might have gotten a 2000f one, not a high temp one. Hopefully I can remove the burnt up one and put this in its place. I hope it works! Dan
  5. Good point, but I'm not sure. The flames looked pretty even throughout.... but there is definitely a relation to the gas flow and the melted part. If you look carefully at a zoomed pic, every center hole on the bottom of each dimple is starting to melt. It might be that on the edges the gas is flowing at an angle or more turbulence or something. I'm not willing to continue down the line with this material, it failed too quickly and I'm afraid it could fail catastrophically. It does confirm for me that the small hole concept is a winner, and I'm going to try some other approaches.
  6. Failure... I got excited and posted too soon . The honeycomb melted at high temps... BUT... before it did, I got 130F extra out of it at 5 lbs compared to my NARB - same burner, same forge, etc. My NARB gets to 2170 at 5 lbs, the honeycomb was sitting at 2300. So lots of tiny holes work very efficiently. Analysis: First I preheated at 5 lbs for 20 minutes or so, everything looked fine. I turned it up to 12lbs, heating up a canister for welding. Failure happened only about 5 minutes in, the canister was just turning red. The a thin line along the edges of the honeycomb, where i
  7. Should be. They are made to run at low temps like that. They are, after all, mostly used as infra red heater blocks. Some specs say 1000-1200C. I saw one video showing the burner in use, was red on one side and when he picked it up the other side was not red. In addition, the small holes will not allow the FAM to burn back into the block. At HT temps, which is 1450 to 1650 for normalizing that's in the range of it's normal specs. It should be fine at low temps. It's the high ones that I'm concerned about. First, I have no idea how to re-tune our burners to get a lower end. We've w
  8. Correct, the refractory is just a way to hold the ceramic plate. It's also to allow the plate to extend 1" or so from the plenum so the plenum doesn't get hot. The shape of the plastic mold, i.e. the slope of the pieces is just so it will release from the refractory easily. When I cut the square tube (rectangular) for the plenum I left some lips, the metal extends over the refractory 1/2". It's the same way we always do ribbon burners. Yes, I think that was mentioned. Probably a better google search. Yea, it's pretty cool . Earlier in this thread we talked about the
  9. My 2 cents. With a single burner you will always have a hot spot. The central area of the forge will be hotter. You need a ribbon burner or multiple burners to get a full forge even heat. This is not a catastrophe, in fact it's kind of nice to have a hot spot to work with so you can heat the section you are working on. On the other hand it is not so great for heat treating a blade. IMHO: In a forge of your shape, if you want to maximize the spread of the heat, I would aim the burner almost horizontal. The flame will curve down the side of the wall. At the spot where it hits the floo
  10. Hey guys! Still around, and still playing around . Was browsing Amazon and found a extruded honeycomb heat resistant ceramic plate for a gas BBQ oven, 7.8x5.5", about $20. Lots of tiny holes, refractory, made for a gas flame.... HMMMM. So I bought one. I had a test plenum sitting around, and I worked up a mold, and made a NARB. I've only test fired it once, but it looks really promising! My only concern is that it is only 1/2" thick. The flash point of propane is 1100F, so if the back gets up to that heat it'll backfire. Here's some pics, I'll do a 4lb Damascus billet this w
  11. In the early days I used brazing flux. It worked great. Probably anhydrous borax as well. DanR
  12. OK...I took a video of casting the burner head, but when I try to download it I'm getting a -200 error immediately. I know I can't put a youtube address, but you can look on my website listed in my profile in the "Studio Tour and Video" section. The new burners work like a charm. The front one has a large baffle, the rear one doesn't. I think on this design a small baffle would have been appropriate - I went the two extremes. Either way, they both work. I haven't run it for more then 30 minutes or so, do I don't know about backfiring when it gets hot. The plenums get a little hotter
  13. Flux? 20 mile team borax at your market in the laundry section. DanR
  14. Pics coming. Was working on the burner lines today. I used lithium grease first time, and A&D (a bottle of diaper ointment I found in the back of a cabinet...my son is 17yo now It’s basically Vaseline, wax, and lanolin). They pulled out easy like they were greased DanR
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