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First keg build

PostPosted: Wed Jul 05, 2017 5:09 pm
by Psykamaholik
Evening all,

I finally stopped stalling and started on building my first keg boiler (we all know there will be another one at some point!) and I feel like I'm chasing my tail a bit trying to solder on the fittings for the heating elements. I seem to get the solder just right in one section before moving onto the next and then buggering up the satisfactory job I had done by applying heat to the next bit.

I did manage to work out I get a better result pointing the MAPP gas at the inside thick part of the fitting and not directly at the solder, but I still seem to be having the problem that the heat needed to melt the solder is hot enough to vapourise the flux for the solder thus making it impossible to stick :angry-banghead: :wtf:

So for the moment I've put a pause on it to regroup and watch more videos on soldering stainless to see if I'm missing something before another attempt, and of course to keep you lot informed :handgestures-thumbupleft:

Some pictures of my half-arsed soldering:

20170705_164638.jpg


20170705_164714.jpg


20170705_164828.jpg


20170705_165036.jpg


Those pics are of the 2nd element mounting I attempted (you don't wanna see how crap the first one looks! :shifty: ). The overall plan is to have 2 x 2400W elements with a 4" porthole to fill and just leave the original keg tap fitting for the home made still I started years ago. I'm using plumbers lead free solder and matching flux I picked up from the big green shed.

Re: First keg build

PostPosted: Wed Jul 05, 2017 5:21 pm
by scythe
By lead free solder do you mean aqua safe100 and matching flux do you mean bakers liquid flux?

601 flux will not work, it melts at a much higher temp than the solder which melts at about 400ish.

Re: First keg build

PostPosted: Wed Jul 05, 2017 5:33 pm
by Psykamaholik
I used these ones:

20170705_172524.jpg


Which now after re-watching a video on youtube ( https://www.youtube.com/watch?v=OpMFQFi6Hh4 ), I'm sure was the wrong choice of flux definitely and quite probably the wrong solder... I also didn't clean the stainless with acetone first. At least all I have to do to get the solder off is point more heat at it! 8-}


And some pictures of where I'm at in general with the boiler for those interested:

20170705_172549.jpg


20170705_172603.jpg

Re: First keg build

PostPosted: Wed Jul 05, 2017 5:40 pm
by bluc
I am doing mine with weldless fitting. Scythe is correct you need the right flux. I think harris stay clean is the one most use for stainless stainless joins..

Re: First keg build

PostPosted: Wed Jul 05, 2017 5:43 pm
by Psykamaholik
That seems to be the one mentioned in a few youtube videos, I'll try and hunt some down tomorrow. Maybe a different solder too.

Cheers for the feedback

Re: First keg build

PostPosted: Wed Jul 05, 2017 6:00 pm
by Fishleg
Maybe mig or TIG weld? Much easier, I have found stainless frustratingly difficult to solder

Re: First keg build

PostPosted: Wed Jul 05, 2017 7:13 pm
by woodduck
Also I don't recon you've cleaned the stainless enough, it needs to be nice and shiny. You might need to sand it a bit to get it free of the hard to get off grime.

I think you will have better luck with the idea of no direct heat at the join. Just heat both sides of the joint. If your flux is going black it’s too hot. Stainless can be a pain but keep at it and you'll get the hang of it. :handgestures-thumbupleft:

Re: First keg build

PostPosted: Wed Jul 05, 2017 7:24 pm
by Psykamaholik
I don't have access to a TIG or MIG welder, only a dodgy stick welder that I'm not convinced works properly.

I was just relying on the job the grinder did for cleaning it, so I'll remove the fittings, clean it until I need sunnies to look at it and then redo the job with hopefully the right flux that can take a bit more heat. The flux was literally vapourising when I tried to add more at the temperature solder was melting.

Re: First keg build

PostPosted: Wed Jul 05, 2017 8:54 pm
by Lowie
Google silver soldering a ring on a keg (or something like that). I watched it a few months back, it gives a really good tutorial. They basically start with a ring made out of silver solder and sit it between the ring and the keg and evenly heat both parts together. I'm wondering if plumbers solder (what you're using) would be strong enough for this application :think:

Re: First keg build

PostPosted: Wed Jul 05, 2017 9:01 pm
by Sam.
I personally wouldn't trust a soft solder join of stainless to stainless with a product that is designed for copper.

But if it works and your happy with it go for it :handgestures-thumbupleft: