Indeed, playing and tweaking is half the fun! The main reason I decided to go with this type of still straight up is beause I really find the designing, drawing, tinkering and building to be hugely satisfying. For me, the alcohol at the end is the bonus - all the work up till this point has been equally intoxicating!
Had a massive weekend playing with my bubble caps, in total I probably only spent around 4-5 hours actually doing work on them in between family and work comittments, but it felt like I spent the entire weekend on them anyway.
I've gone with a "handmade" version of the FSD bubblecaps. This was discussed a bit in CaptianRedBeards build log a little while ago - see
here for the details, but is basically a 1" off-the-shelf end cap over a 3/4" flared riser.
I went for a screwed bubble cap because earilier in the build I had a fair amount of drama getting good results with soldered ones. A screwed system is a fair bit more work, but I'm much happier with the results. I should mention that my original soldered version was done with a propane torch - I've since invested in a decent, trigger-ignition MAPP torch. I've had much better soldering results since, so maybe if I attempted the same soldered caps now I might have a different opinion.
Anyway - this was the original concept;
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Made up the risers, they take around 6 minutes each. I have 30 caps all up so around 3 hours all up. Mounted about a foot long length of 3/4" in the lathe (mainly just using it as a vice). Squared up the end of the pipe with a file, flared the end, measured out the total length I wanted, marked all around with a scribe while manually turning the lathe, then cut with a hacksaw while manually turning the lathe. Rinse and repeat. Not hard work at all, although the lathe I'm sure makes things a bit easier. Even just having it to hold the pipe while you mount the flaring tool is a bonus, and unlike a normal vice it's very hard to distort the pipe if you over-tighten it a little - the headstock of course being designed to hold round objects without damaging them. Drilling holes dead centre is obviously a shitload easier on a lathe too.
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Once I'd finished cutting and flaring them all, I checked the measurements with the verniers and filed a bit off the top to bring them down to an exact length. In my case I was aiming for 21.6mm. I wanted them just a fraction shorter than the inside of the cap, so that they would pull tight with the bolt. Then I soldered them to pieces of scrap left over from cutting my main plates.
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Separated them all using a cutting disk on the angle grinder and a pair of decent pliers to keep my fingers out of the way. The one on the left is before filing and finishing on the lathe, the one on the right is all done including a 3mm hole in the centre to take the bolt.
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Found that even though I'd allowed for the thickness of the soldered plate in my measurements, I had to re-flare each riser just a couple more turns before they would pull tight when bolted.
I ended up using 316 stainless hardware, an M3x25mm bolt, with a flat washer above the cap, and a split washer and nut under the riser. With the split washer, you almost don't need a tool to tighten them, just something small enough to stick up the riser and stop the nut spinning until the split washer bites - then if you turn the cap itself you can make everything tighten pretty good without having to use an allen key on the bolts. All the gear came from
http://www.boltsnutsscrewsonline.com/ and was around $40 inc. delivery.
All finished, just need to cut slots in the risers and caps which I will hopefully get to next Saturday. I'd like to do my vinegar run next Sunday if all goes well. Still got to do my downcomers but these will be soldered so should be a fair bit more simple.
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Also, throughout this whole build I've kept records of all my costs. Now that I'm getting to the pointy end and I'm pretty confident I've got everything to finish this thing, I'm going to post up all my expenses in the next little while. I'd seen it asked a couple of times over the last year or so how much it realistically costs to build something like this, this might be useful to others in the future in deciding whether to build or buy. Stay tuned.
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