I have both Bernidawg's 3d printed burner cap and a quitestove burner cap that appears to have been produced using the same process. Both work really well. So my question, Is there any technical reason why the same process could not be done to produce Primus / Optimus 96 burner bells? These burner bells are nearly as difficult to find as lipstick burners. I have been looking for a burner bell for quite a while to complete an Optimus 96 sitting on my shelf and I could not acquire an original, a repro (3d printed in bronze) would be almost as good. Any thoughts on this? Stu Sanford
Hi Stu Well, here's my answer to your question. You could probably do up a 3D CAD drawing of a 96 burner bell and get it 3D metal printed by one of the two major 3D metal printing outfits, yes. http://www.shapeways.com http://i.materialise.com For additional cost, i.materialise will even set you up to do the bell in brass rather than the stainless steel and bronze blend that is in either of your caps. They use some sort of modified investment casting technique for that. Problem with all this is... you probably wouldn't do it because of the cost. Both of these firms charge you by the amount of material that goes into the model. Just guesstimating here, I'd say you wouldn't get a bell for less than $100USD. If you spring for the more expensive brass, I'm guessing 1.6x that. But, there's more! There is an additional consideration that makes this even less financially attractive. The stainless and bronze blended 3D metal printing that created your caps undergoes a 2-8% shrinkage rate during sintering. This means, as a designer, you have to draw the product slightly bigger than you want it to be when completed to allow for shrinkage. The shrinkage rates vary based on the structure. It's difficult to print an item correctly the first time. You usually have to print a dud and correct your drawing based on how it comes out. Sometimes it takes more than one dud. You pay for all the models, even the duds. Anyway, that's my answer. Maybe Craig at Quietstove will pop in and give you his take on it. Sorry to be a downer. There's rarely anything cheap, simple or easy when it comes to collecting old stoves. (You could always convert your lipstick to a roarer burner.) Cheers, BD
Another consideration using the stainless steel/bronze option would be the conductivity of the bell. This is a guess and others would know better if it applys to this material but stainless is not a good conductor of heat so may not transfer enough heat to the lipstick generator.
Yup. You called it right, Geeves. Heat conduction is a potential concern. The blended metal used to make Quietstove and BernieDawg caps is about 40% stainless steel. The rest is bronze. Personally, having worked with a lot of this stuff, I think it would conduct well enough in a burner bell, but be slower to preheat initially... I mentioned the all-brass investment-casted upgrade for just that reason. Much less of a concern and (I think) closer to the original metal alloy used in burner bells. Here's a link I have at my website to a five minute informative video from i.materialise on exactly how the process works. i6Px6RSL9Ac[/media]]3D Metal Printing
Hi Stu, The photos helped me understand exactly what you want to reproduce. A digital path will most likely take you through several iterations and may not produce a desirable end result. Since you have access to an original part an accurate method to reproduce an original would be to make a mould of an existing burner bell and produce a wax casting. The wax casting would then be utilized for a lost-wax (aka investment casting) casting in brass. The end result will be an exact measurement copy of the original with few to zero machining steps to finalize it. If there is enough interest for a reproduction part it may be something QuietStove would manufacture. All the best, Craig
Craig, I would think there should be sufficient interest among CCS members for a cast burner bell reproduction. The same burner bell works for Primus 96 and 97 and Optimus 96 stoves (plus possibly others). If you were interested, I could loan you a working 96 so you could use the burner bell as a model and test it after reproduction of the burner bell. Stu
Stu and others reading this thread... I know that I, personally, would be very interested in a source for burner bell reproductions for both the 96 and the 100 style stoves. I can fabricate burner tubes, but casting bells is a major undertaking. Before anyone gets their hopes up however... my research into the cost of doing custom-cast reproduction burner bells tells me that you are, as I indicated above, looking at a per piece cost of greater than $100 per bell. Now, I could be wrong, but... I think it would be useful if Craig at Quietstove would investigate actual real pricing for custom casting and either confirm or deny this estimation I have made - before any promises or possibilities are discussed too much further. Most stove fans I know would prefer to purchase a second stove for the missing parts and then sell the surplus parts in the open market (eBay) to recoup some or all of their costs. This would be the way I have generally seen such things done. I suspect most stove collectors would not be likely to go for a reproduction bell at the cost I've researched. But, like I say... I could be wrong about that.
Stu, Gary (& anyone else interested) What would you being willing to pay for a reproduction burner bell (in brass)? For clarity, the burner bell would be virtually identical to an original, but would be marked a reproduction. Craig
Craig, I think that an appropriate price should be in the range of what you charge for your quiet stove dampers, maybe a little more since the part restores a sove to functionality. Actually we need more input from other CCS members, is there interest in this? Stu
Okay. Well, this seems like a silly exercise to me, but, ok, I'll bite. Since Phil Beagle can do up these excellent, well-machined, and quality caps that rock the British Military #12 for $65 plus shipping... Link I'll say $65 plus shipping for a quality, well-designed bell. With the caveat that I'd not be interested were it marked "repro". Instead, bells should be bare of markings, which would clearly convey the after-market status and make them more suitable for use with any brand 96 stove. Just like Stu (loco7stove) does with his flame-plates. And, Stu (Sanford)... just a FYI... all my caps are lower priced than Craigs - most substantially so. There is no pricing connection between caps that are 3D metal printed and bells that are investment casted. The pricing is different because the production methods (and costs) are different. One does not determine the other. Sorry. So... which of the bell styles are you gonna copy? Bryan Miller's Excellent History of the Primus 96
I am not trying to dampen any enthusiasm for getting the burner heads made but the fit of the burner head to the vaporising tube is critical. The ideal fit is with the tubular part of the head in continuous contact with the vaporising tube and the jet level with the top of the tube. The continuous contact means that heat is transmitted into the vaporising tube and the fuel vaporises properly. A poor contact could produce intermittent flaming. If the jet is not the correct distance from the burner plate the fuel/air mix will be wrong and you will probably get a yellow flame although this can also be caused by an enlarged jet. The problem is that the taper and dimensions of the top of the vaporising tube could vary as could the taper in the inside of the burner head. This was very noticeable in later burner heads and vaporising tubes A reproduction burner head should result in a cosmetically pleasing stove but may not produce a good flame Good luck Regards Bryan
Why not do it the old fashioned way?originals would have been pressed or deep drawn for a short run hardwood tooling would probably suffice with a large vice or modest press spinning is also an option stem part machined separately and swaged or brased on fortunately the lipstick taper is as near to mt1 as makes no odds reamers are readily found might have a stab at it if i ever find a pattern
