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Tiny Holes Found in My Onion
Hi there!
We have a 250 gallon copper Vendome still with a large bolt on onion-shaped helmet, going directly to the line arm. The still is just reaching 10 years old. When it was 4-5 years old, it started leaking along the copper welded, or brazed joint where the flange for the line arm meets the helmet, in the back where the seam is. It also started developing pin holes in the small dimple at the top of the helmet where it flattens out. We stopped production and had the helmet sent back to Vendome. They attempted a repair, adding some copper to the seam inside the helmet, said they did “the best they could” and sent it back to us still leaking They also said there was nothing they could do about the other pinholes that had developed on the top of the helmet. The pinholes have continued to grow, despite our best efforts with flour and silicon tape to assuage them. We contacted Vendome again, and again they want the helmet shipped there, for a repair, or to size it for a replacement. That length of shut down is sort of out of the question at this time. I am not an expert welder, but I did spend a number of years teaching introductory welding to high school students. There is obvious porosity in the welds most likely from lack of proper shielding. We are disappointed in the quality of this still and the lack of craftmanship in the fix. The leaks are beginning to impact our efficiency, especially when we are running a tower due to the back pressure. We are located somewhat out in the sticks, and have had trouble finding a “tin knocker” (someone who welds copper) who will come work on site. We did have an ultrasound done to check the thickness everywhere, and there are no issues anywhere else on the still.
Outside of not purchasing from Vendome again……..
Do you guys have any suggestions for filling these pinholes without having to shut down to remove the helmet? We are growing, and so have a 5 year plan that includes a new facility and still. I have experience brazing copper to stainless. Could we braze or solder the holes with an appropriate food safe silver?
Any suggestions or questions are welcome.
Thanks,
_Will Robinson
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5 Replies
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Instead of trying to weld, soldering or brazing the pinholes seems like the better option.It should be easier and it would add some material back in without having to deal with burning the copper away with a tig torch and opening up a big hole.
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Yeah, I would not consider tigging it myself. I am leaning towards brazing or soldering, just wondering if anyone out there has attempted something similar.
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Another quality made in America product. At least they are super expensive.
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I’ve soldered enough copper to know that, it holds up fine during the distillation process. The copper should never get hot enough to weaken the solder. If you use the lead-free, it typically melts around 425F so no way your onion will get to that heat.
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Find a welder and pay him cash. Well worth it. A good TIG guy could probably address all your issues really quickly. That’s an expensive still, want to keep it looking good and as strong as possible. We use welders all the time to modify equipment and it’s really not that expensive.
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