Ok... <sigh> I got a little work done this week.
Some things went better than others.
Decided to do a folding exhaust stack on this one for a couple of reasons. Mostly measurement opportunities. I am working on some methods to measure airflow and I want to do an A/B comparison. Can never truly account for all the confounding variables, but I think I want to try to look at 'flow rates at 2 different exhaust stack lengths - one that is 'recommended' by the various pit design calculators out there, and one thati's what I want it to be - which is much longer, just about double, essentially.
Now, most people doing hinged, fold-down stacks are folding their down along the length of the cook chamber. However, I have a couple of design elements that preclude this or make it a little more complex, so I decided I would fold this one vertically down toward the front of the trailer to 'hang' vertically when folded. I needed a hinge design that would allow for 180º fold, where many of the ones out there I've seen would have some problem with a full 180º. Since they only fold from vertical to horizontal, a 90º range of movement is all they need.
Well, here's what my plasma guy and I came up with:
I think it worked out well, there were some ups and downs and I had to have a new set of hinge eyeloops cut at one point because I welded them on the wrong side of the lower stack. <sigh> Sometimes when I'm feeling cocky the universe has to be sure and let me know why I shouldn't be. lol
Anyways, got the stack welded on eventually. Man that sucked. Some of the worst welds I've EVER done, I think. Luckily I have a grinder.
It was at this point I put my rolling doorhandle in, which is just 3/4" black pipe over 1/2" round bar. I was hoping having a good lift point would make the weight of the door more tolerable. Yeah... it didn't. Still quite a heavy door. I could lift it with one hand, even with my really bad shoulders, but it was a chore. With 2 hands it was much better, but I could hear my wife complaining in my head. Combined with it being a little high, I felt it would get onerous, so I decided... I was going to do a counterweight.
So here is my idea of a counterweight arm mocked up. I decided to use some flat strap to build a 'theoretical' arm and see how it fit, looked and most importantly, where it would swing and stop on the backside of the tank, serving double duty as a weight and as a doorstop. I liked where this came out and where it ended up on the back when opened, AND liked the placement of the door on the upswing and limit. Not too high, so still pretty easy to reach, for all but the shortest people.
Then it was time to cut the components of the support arms, which meant measuring and comparing angles and making sure I was cutting them on the correct side of the pieces and facing the right way - nothing like doing all your cuts and then realizing your angles are inverted on one side and you've just made yourself a bunch of welding practice coupons for another time while you repeat your work. lol
Some pics of the process:
^^^^EVOLUTION cold cut metal cutting chop saw - best. purchase. EVAR. Jus' sayin'.
Super nice, super precise cuts.
This is what 2 67.5º angles come out to - I always have to stop and REALLY spend time thinking about my angles and what direction they need to point, etc. I can't just do this stuff in my head on the fly like some folks. I'm a very visual learner and implementer, so sometimes I have to sit and draw it out. In this case, to achieve a 45º inside angle from two evenly cut pieces, you take the reverse of that (135º) and split it in half.
Some might just say cut one piece at 45º and leave the other at 90º. Well, if you do that, they don't match up in dimensions. You can do it if you're joining in along a running length, for instance if I just want a 45º piece coming up off a long run, and it's not the END of the run. If you're joining ends, they won't match up in dimensions, as the crosscut section of the 90º piece with be shorter than the crosscut section of the 45º cut. It's hard to visualize, maybe I'll do a picture of one sometime. Anyways, with a pair of 67.5º cuts, joined together, you get a 45º angle. I also did a 45 on the 'door' end, as when I mocked that up, it looked like these two combined angles at these arm lengths would leave my counterweight in about the right position where I wanted it.
Eventually I used my own homemade "Certiflat" welding table - aka a sheet of 1/4 scrap sitting on some sawhorses - to get the arms put together, then did my best to get everything level and plumb on a wobbly and NOT-flat table using shims and supports and magnets, and got my support arms attached. Then my son happened to be out there for me to swap out the interior doorhandle of his car and I made him hold it in place - the gantry held the weight, he just needed to hold the support arms at the right angle and position. I got 'em tacked in place so he could leave and I continued on.
I was absolutely drenched yesterday - I dunno why it SEEMED so bad, it was around 60% humidity and got into the low 90s. Once the sun heads west over the shop, and is no longer beaming in the east-facing doors, things get a lot more tolerable. I think I was out there about... 10 hours., From 10AM till nearly 8PM. But, I was very pleased at the end of it all when I got finished.
Sprayed it down with some saltwater and vinegar to start the rusting process on the newly-cleaned areas I had to weld and grind.
Some things went better than others.
Decided to do a folding exhaust stack on this one for a couple of reasons. Mostly measurement opportunities. I am working on some methods to measure airflow and I want to do an A/B comparison. Can never truly account for all the confounding variables, but I think I want to try to look at 'flow rates at 2 different exhaust stack lengths - one that is 'recommended' by the various pit design calculators out there, and one thati's what I want it to be - which is much longer, just about double, essentially.
Now, most people doing hinged, fold-down stacks are folding their down along the length of the cook chamber. However, I have a couple of design elements that preclude this or make it a little more complex, so I decided I would fold this one vertically down toward the front of the trailer to 'hang' vertically when folded. I needed a hinge design that would allow for 180º fold, where many of the ones out there I've seen would have some problem with a full 180º. Since they only fold from vertical to horizontal, a 90º range of movement is all they need.
Well, here's what my plasma guy and I came up with:
I think it worked out well, there were some ups and downs and I had to have a new set of hinge eyeloops cut at one point because I welded them on the wrong side of the lower stack. <sigh> Sometimes when I'm feeling cocky the universe has to be sure and let me know why I shouldn't be. lol
Anyways, got the stack welded on eventually. Man that sucked. Some of the worst welds I've EVER done, I think. Luckily I have a grinder.
It was at this point I put my rolling doorhandle in, which is just 3/4" black pipe over 1/2" round bar. I was hoping having a good lift point would make the weight of the door more tolerable. Yeah... it didn't. Still quite a heavy door. I could lift it with one hand, even with my really bad shoulders, but it was a chore. With 2 hands it was much better, but I could hear my wife complaining in my head. Combined with it being a little high, I felt it would get onerous, so I decided... I was going to do a counterweight.
So here is my idea of a counterweight arm mocked up. I decided to use some flat strap to build a 'theoretical' arm and see how it fit, looked and most importantly, where it would swing and stop on the backside of the tank, serving double duty as a weight and as a doorstop. I liked where this came out and where it ended up on the back when opened, AND liked the placement of the door on the upswing and limit. Not too high, so still pretty easy to reach, for all but the shortest people.
Then it was time to cut the components of the support arms, which meant measuring and comparing angles and making sure I was cutting them on the correct side of the pieces and facing the right way - nothing like doing all your cuts and then realizing your angles are inverted on one side and you've just made yourself a bunch of welding practice coupons for another time while you repeat your work. lol
Some pics of the process:
^^^^EVOLUTION cold cut metal cutting chop saw - best. purchase. EVAR. Jus' sayin'.
Super nice, super precise cuts.
This is what 2 67.5º angles come out to - I always have to stop and REALLY spend time thinking about my angles and what direction they need to point, etc. I can't just do this stuff in my head on the fly like some folks. I'm a very visual learner and implementer, so sometimes I have to sit and draw it out. In this case, to achieve a 45º inside angle from two evenly cut pieces, you take the reverse of that (135º) and split it in half.
Some might just say cut one piece at 45º and leave the other at 90º. Well, if you do that, they don't match up in dimensions. You can do it if you're joining in along a running length, for instance if I just want a 45º piece coming up off a long run, and it's not the END of the run. If you're joining ends, they won't match up in dimensions, as the crosscut section of the 90º piece with be shorter than the crosscut section of the 45º cut. It's hard to visualize, maybe I'll do a picture of one sometime. Anyways, with a pair of 67.5º cuts, joined together, you get a 45º angle. I also did a 45 on the 'door' end, as when I mocked that up, it looked like these two combined angles at these arm lengths would leave my counterweight in about the right position where I wanted it.
Eventually I used my own homemade "Certiflat" welding table - aka a sheet of 1/4 scrap sitting on some sawhorses - to get the arms put together, then did my best to get everything level and plumb on a wobbly and NOT-flat table using shims and supports and magnets, and got my support arms attached. Then my son happened to be out there for me to swap out the interior doorhandle of his car and I made him hold it in place - the gantry held the weight, he just needed to hold the support arms at the right angle and position. I got 'em tacked in place so he could leave and I continued on.
I was absolutely drenched yesterday - I dunno why it SEEMED so bad, it was around 60% humidity and got into the low 90s. Once the sun heads west over the shop, and is no longer beaming in the east-facing doors, things get a lot more tolerable. I think I was out there about... 10 hours., From 10AM till nearly 8PM. But, I was very pleased at the end of it all when I got finished.
Sprayed it down with some saltwater and vinegar to start the rusting process on the newly-cleaned areas I had to weld and grind.
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