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About tinkertim

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    Advanced Member

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    Bristol, England
  • Interests
    Electronics, Mechanics, Robotics, KnifeForging, reverse-engineering.

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  1. AFB I really like where you are going with these mini-Forge designs. Elegent and functions design. Keep up the good work. Tink!
  2. AFB that is a cracking little Forge!! and the efficiency ticks all my boxes as a hobbyist Smith. Pnut is totally right. If you could simplify the construction to save yourself assembly time it would be a very sellable product. If not, your proven efficient burner design has customers waiting already (me for one!) Keep up the good work and have a cracking New Year matey! Tink!
  3. Hi NS, The burner is a single 3/4" AMAL gas injector with 8 inches of black iron pipe feeding into the Plenum chamber of my DIY Ribbon Burner. The Burner is normally aspirated with 27 x 5.5mm holes drilled into the Insulating Fire Brick (IFB) that makes up the burner face. As a hobbyist I wanted a Propane forge that was quick to heat up and economical to use. I decided to try the technique suggested by Dan Rotblatt, so instead of using a cast refractory lining inside the forge, I used a Zirconium Silicate / Colloidal Silica slurry to coat the rigidised ceramic wool. This forms a layer only a few mm thick on top of the wool, which is then hardened by the Ribbon burner. It gives me a lining that is not as strong as a cast refractory, but is easy to patch if I do crack it, but crucially has very low thermal mass. I didn't want a forge to use all day, every day, but one I could turn on and off whenever I wanted to do some metal bashing. So to answer your question, it was up to welding temp in about 5 mins, and is very responsive to turning the gas up & down between bashings. I will probably sort out an Idle Bypass circuit at some stage, to make it more economical and easier to turn down between heats. Anyway I hope this helps. Tink!
  4. I like the flexibility of reducing the volume of the forge to save fuel, or to let it get hotter for forge welding. This looks plenty hot enough! Good luck, Tink!
  5. Hi North State, Do you mean something like this? This worked well for me. I used Insulating Fire Brick (IFB) and coated it with a Colloidal Silica/Zircopax slurry to give the IFB surface some protection. It worked really well for me. Tink!
  6. Hi David, My burner is a drilled-IFB NARB, so no blower. I am using an AMAL 3/4" Propane injector, which is a very efficient Fuel/Air mixer and is very adjustable, so I do get a nice hot flame, and a very even heat. Tink!
  7. Dan's Colloidal Silica / Zircopax slurry has worked well on my Drilled-IFB NARB hotface, as well as on the Ceramic blanket on the walls, and IFB on the floor. Definitely hot enough to weld I think! Tink!
  8. What's even more interesting is that they are bringing out metal-loaded filament for these 3D printers. This lets you print a prototype that is 80%~90% metal content, and then you can Sinter it in a furnace (Forge?!) to burn off the plastic binder and leave behind a solid metal part ready for use. You have to allow for a shrinkage factor as the plastic binder is burnt off, but you can put that factor into your Slicer program and it will scale your design appropriately. They have Brass, Copper, Iron, Ali and varieties of Stainless. They are still pretty expensive as they are new, but once you have more suppliers in the market, the costs will drop. If you want to make a one-off it makes sense, if you want to make a few then the lost-wax(plastic) method makes more sense. Google: markforged Google: thevirtualfoundry Can't wait as this gets more mainstream! Tink!
  9. Hi Dan (D.Rotblatt), Had some issues with my Colloidal Silica slurry / Zircopax mix. I had tried to mix it 50:50 by volume, but made the mistake of adding Zircopax to a fixed volume of Silica slurry, to try and double the volume of liquid. This gave me a mix with much more Zircopax in than I expected. It coated pretty well for the 1st coat of the Ceramic blanket and the IFB floor as it was so thick. The downside was when I came to re-use the rest of the Zircopax Colloidal Silica mix for the next coat, was that the majority of the Zircopax had set solid in the bottom of the jar! So I've probably wasted ~1/3 of my Zircopax! Ho-Hum, at least there was plenty that would come up in suspension, so I could recoat the inside of the Forge and the top of my IFB raised-floor inside the Forge. I think next time I will measure out a dry volume of the Zircopax to match the wet volume of Colloidal Silica slurry. Its all about learning! Here are some pics of progress. My new Forge with a raised floor made out of IFBs, coated in Zircopax / Silica slurry. Firing up the NARB to finish the curing of the Zircopax / Silica slurry coating. Ramping up the gas for initial testing. The raised flooring worked really well and with the whole inner lining glowing bright yellow, the centre of the raised floor was running just slightly hotter than the rest, and you could see particles that I assume are Zirconium Silicate just glowing a little brighter. The flame also circulated really well and gave a really even heat everywhere else. Overall I'm very pleased with the results of using the Zircopax / Colloidal Silica (ZCS) mix to coat the inside of the Forge. It is hard, but as it's not very thick I would expect it to crack a little if bashed by accident, but as you said, just patch up with a couple of coats of ZCS where the crack is and all will be well again. I also found that with the raised floor, I had to adjust the jetting of the AMAL propane injector and the 110 sized jet was giving me too much Dragon's Breath (DB) when I turned the gas up. Going to the default 90 sized jet gave me a more neutral flame with only a little DB. The most useful thing is how little gas pressure I need to get the Forge up to hammering-steel temperature. The inside all radiates at the same level and the heat is really even. It might not be so useful if you need a hot-spot, but I can accept that if it runs more efficiently. Thanks for all the suggestions and support Dan. I'm a convert to your forge lining technique! Tink! ps. I've dug out an old digital camera with a decent zoom, so I'm going to see how well it captures high-heat pictures.
  10. Good progress Ig, I'll keep watching. Tink!
  11. DIY forge / NARB update. Initial Forge Shell 1 Initial Forge Shell 2 Spraying rigidiser 1 Spraying rigidiser 2 Second layer rigidised Initial NARB lit to cure Colloidial Silica slurry / Zircopax Hotface. Curing Hotface 2 Curing Hotface 3 Curing Hotface 4 Dan's (@D.Rotblatts) Colloidial Silica slurry / Zircopax mix seems to work very well as the Hotface coating. I've probably mixed too thick a solution of the coating initially, but the Ceramic Wool, the NARB flame face and the Insulating Fire Brick (IFB) took the Hotface coating well, in fact the IFB & NARB have a near-glazed appearance. I will be adding some extra layers with some glass bubbles in it at the weekend, as well as a few tweaks to prevent flame leaks around the ends of the IFB. I will also be making a raised floor to reduce the working volume for smaller jobs. Very pleased with it so far. Tink!
  12. Hi Bart, Sounds useful stuff, but as a hobbyist I cannot justify the ~£240 for a 25KG bag delivered to the UK. I'll continue on with Dan Rotblatt's Silica investment slurry + Zircopax technique. Although it might not be as strong as Kast-o-Lite, but with a lower thermal mass & IR re-emissive Zircopax, it should make for a quicker & cheaper forge heat-up for a hobbyist's use. Tink!
  13. Hi Dan, Bits have arrived and I've been busy, and I have the Forge lined with 2 x 1" Ceramic blanket and have rigidised both layers successfully. So now comes the Heat-face layer. I have the Morisol-X30 Silica base, Zircopax flour and glass bubbles. I know you suggested adding the Zircopax until you get the consistency of Latex paint, but I wondered if you had any insight about how much glass bubbles to add, to get a suitable mix to apply. Any suggestions regarding ratios? Nearly there. Cheers, Tink!
  14. A British Bulldog!!! NARB!, NARB!, NARB! (and I do have a head-cold at the moment! ) Tink!
  15. I've had good results with my drilled K26 IFB NARB (Buzzwords!!!). The new forge I'm building for it will be faced with D.Rotblatts Collidial Silica Investment slurry, mixed with Zircopax. I'm going to use this to treat the flame-face of my driled IFB NARB, to see how it hold up to the heat, long-term. I'll post up results. Tink!