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  • #76
    Hi Sasquatch--Glad to have you along. I am part way through the second assembly tonight. My soldered joints are still lumpy, but I did get a lot better "flow out" of the silver solder using the larger torch tip. I would have been finished today, but helping babysit a two year old grandson and having a sore back has cut into my day quite a bit. I hope to finish the second assembly tomorrow morning.
    Brian Rupnow

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    • #77
      I was warned that the citric acid pickling would leave a very definite mark on any part of the steel which was not completely submerged in the acid bath. In the interest of science I stuck a piece of steel in the bath I have, with part of it not submerged. Who-ever told me was absolutely right. It leaves a very visible demarcation line, which can not easily be sanded out.
      Last edited by brian Rupnow; 09-12-2017, 09:24 AM.
      Brian Rupnow

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      • #78
        The use of the 3D to figure out all the process steps is freaking BRILLIANT! I know you've shown us the same thing before but I guess it really hit home for me on this job. Love the legs and how you fixtured all the bits. Very nicely thought out.....

        For parts the size of what you're doing here I've got a different swirl style torch. It's far hotter than even the larger optional head on the regular style torch. It's my "go to" for getting drill rod tooling up to the red heat needed for proper hardening. I was going to give you a link to it but apparently Bernzomatic doesn't make the model I've got any longer. But they do have a TS-4000 that is described as a longer swirl path mixing tube for high heat requirements. If you don't have such a thing I think you'll find it will give you a better flow of the solder into the joints.

        When I use my own swirl torch and get the metal up to a dull red the solder flows like water and forms small even smooth fillets in the corners consistent with the amount of solder I use.
        Chilliwack BC, Canada

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        • #79
          BCRider--A lot of this design stuff is very easy for me, and I'm good at what I do. But Jeez, I've been doing it for 52 years now---I should be good at it. A lot of the machining I've gotten quite comfortable with over the last 6 years. However--There are always new things for me to learn. Silver soldering is a bit of a black art. I use my oxy acetylene torch as a heat source, and I don't have much trouble with the smaller bits that I generally silver solder together. When I get into something with a bit heavier wall and greater mass like this current project, you can see that I still have a LOT to learn. I love it that you guys follow my posts and say Hi once in a while.---Brian
          Brian Rupnow

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          • #80
            And from all the comments it's clear that we love seeing your posts.

            So you used an oxy-acetylene setup? That's odd because it should have been EASILY hot enough. I wonder if you might have gotten a couple of the parts a little too hot and that caused the silver solder to go a bit funny?

            I'm hardly the silver soldering and brazing expert but I do find I can usually produce a nice enough job. Not that great at forming really nice fillets though. So I tend to go for a good flow and small "natural surface tension" super small 1/32" radius sort of fillets or even smaller. I also find that the silver solder I've got flows out just right around the time the very first bit of really dull red is starting to show in dim light. If working in brighter light the metal would still look dark. As a result I like to do my silver soldering in dim light so I can see that really dull red coming on and hold the heat back a little further so as to not end up with a hotter bright red spot or small work piece.

            Like I say, I'm hardly the expert. I think I've only ever silver soldered about 8 or 10 things. And done about the same amount of brazing over the years. But if there's something there that helps then you're more than welcome.
            Chilliwack BC, Canada

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            • #81
              I use an oxy acetylene torch, because the only other torch I have is a Propane torch which simply doesn't get hot enough. I'm always a bit shy of getting things too hot, because brass is just like aluminum. It doesn't really change colour that much as it gets hotter and hotter, and suddenly it just isn't there anymore. I try and get enough heat into what I'm silver soldering so that touching the tip of the 1/16" wire to the part melts it and it begins to flow. If you put the torch flame on the silver solder wire, it just melts a round ball off that sets on the metal and won't flow anywhere. If you heat the ball of silver solder too much then you get a flash back in the torch that scares the Bejesus out of you with a large "POP" and the ball of solder disintegrates. I find it to be a very delicate balance between "hot enough to flow" and "no flow at all". I have to get better at this. Someone over on Model Engine Maker has suggested that I am using the wrong flux or that my flux is too old. I have to investigate that.
              Brian Rupnow

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              • #82
                I didn't show this set-up for slotting the stand when I posted about the first one, so I'm showing it here. The 1.5" diameter is held in the 3 jaw chuck on my rotary table. It's a bit hard to see, but I have a machinists jack under the outboard end. The legs are set to "level" with my machinists level. A hole is drilled thru to 7/16" diameter at each center of the slot, then I plunge thru with a 1/2" endmill at each end, then plunge thru every 1/16" then take one complete pass with the endmill down full length so it is cutting the top and bottom all in one pass. You will notice with this stand that the "feet" are equal in thickness and there is no slant on the top of either foot. That is because I found a better way to fixture the feet before I soldered them on.--Yes, an old dog can still learn new tricks. I still have to machine and file my lumpy solder joints before I part the stand off from the main 1 1/2" diameter, but I think I will save that for tomorrow.
                Last edited by brian Rupnow; 09-12-2017, 07:57 PM.
                Brian Rupnow

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                • #83
                  Originally posted by brian Rupnow View Post
                  I use an oxy acetylene torch, because the only other torch I have is a Propane torch which simply doesn't get hot enough. .
                  hmm, not really. Propane/air is plenty hot enough (temp), but on large assemblies it sometimes doesn't give enough heat. That's when you switch to O/A. You have to pay attention with O/a as the higher temps makes it easy to burn the flux. where the size permits, propane/air is easier with a couple of insulated fire bricks making a corner. That would be my guess why its not working, you're burning the flux off with too high a temp. Use the torch indirectly - at the material but not the joint.

                  The horse is out of the barn, but next time consider soft solder. There is plenty enough surface area for the strength required and its not a boiler that has to perform at higher temps. The reason is ss temps are well above brass's annealing temps which often can be a problem....you end up with a dead soft piece.
                  Last edited by Mcgyver; 09-12-2017, 08:30 PM.
                  .

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                  • #84
                    Thank you for the suggestion Mcgyver. I find that soft solder gives me the opposite problem from silver solder. The darn stuff runs all over the place uncontrollably. I learned that fact building carburetors. After filling a couple of small carburetors completely full of soft solder while trying to attach a sewing needle to the knurled brass adjusting knob on the top of the needle I switched to silver solder because it doesn't "wick" so severely.
                    Brian Rupnow

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                    • #85
                      .....I switched to silver solder because it doesn't "wick" so severely
                      That suggests that you aren't using the right stuff then. Or that it's died of neglect or some other malady. I found that while it doesn't form large puddles it DOES wick and form a foil thin coating on just about everything if I don't really control the amount I use. Like just enough to fill the gaps in the joint and no more. And with a nice fitted joint like you have that's precious little needed.

                      For me doing the joints you showed I'd have liberally fluxed the parts and then laid a 1/4 to 3/8" long piece of the .030 wire SS I've got in the corners. Then I would heat it using the broader part of the flame to slowly heat the parts. Just before or about the time I notice a dull red in the dim light the two pieces of wire would melt and wick into the joints. I'd confirm that they were filleting on both sides with a small 1/128" fillet radius and then remove the heat and allow to cool. Doing it that way is about the only way I've managed to not end up with SS skin on the metal, be it steel or brass.

                      The flux I'm using is Handy Flux by Handy and Harmon. A good Canukistan outfit with both English and French on the label. The amazing thing is that when I do a search I found them right away. H&H is now a cover company for a wide array of outfits. But they still make Handy Flux ! ! ! ! !
                      Chilliwack BC, Canada

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                      • #86
                        a good way to get neat solder joints with soft solder is to tin first then only use the smallest amount to join. With SS I do as BC suggests and use a small bit of 1/16 dia ss laid in flux at the joint. SS works great, but often you want the brass to stay in its 1/2 hard state
                        .

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                        • #87
                          No work on this project for a couple of days. I have a severe case of Sciatica and the pain in my lower back keeps me from standing at my machines. Fortunately it doesn't bother me when I'm setting down, so I can still do cad work. I did buy material for the engine base, but haven't done anything with it yet. I am anxious to get the last stand finished and move on to machining the base.
                          Brian Rupnow

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                          • #88
                            There are also strategies for masking off areas you don't want solder to stick to. The old timey method with an acetylene torch was to turn off the oxygen to get a sooty flame and coat the part with soot. Either wipe off and flux where the solder should be, or flux and assemble first, then soot up the surroundings. IIRC I've hear people say they've used the White-Out stuff but I've not tried it myself. And, in this enlightened age of endless specific products, there's probably a commercial product somewhere designed just for that.
                            .
                            "People will occasionally stumble over the truth, but most of the time they will pick themselves up and carry on" : Winston Churchill

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                            • #89
                              And now we have two!! The second stand turned out a bit nicer than the first one, mainly due to using a larger torch tip when soldering the joints. Although my solder joints on the second piece I built were quite lumpy, I also had enough build up of solder that when I machined/filed/sanded away the solder I didn't want, I had very few "craters" left below the finished surface. These two stands were probably the most difficult pieces to build. I'm looking forward to machining the aluminum base in the coming week so that I have something to mount these two pieces on.
                              Brian Rupnow

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                              • #90
                                The base for this engine is going to be Ahhhh---Interesting. Nothing horribly complex, just a lot of milling and drilling. I am going to make a simple jig to hold the soldered "towers" in the correct position and mark thru with a transfer punch to establish the 8 tapped holes which hold the towers in place. I find it a bit strange that the pillow block bushings for the crankshaft are mounted 'upside down' to what I consider normal practice. I still have not fully recover from the sciatica pain in my lower back, but at least I feel improved enough today to do a bit of CAD work. I was supposed to be working in my office on the other side of town today, but I phoned over and begged off for today.

                                Last edited by brian Rupnow; 09-18-2017, 12:28 PM.
                                Brian Rupnow

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