In a recent posting, I described a situation involving a few pounds of epoxy and a steel pressure can. [stderr] Commentariat(tm) agent MattP (must mock his crappy brain) suggested a cross-bar and a threaded rod, and I liked that idea.
I’m very familiar with the sometimes-unexpected mightiness of epoxy and was worried because we’re talking about nearly a square foot of surface-area for it to grab onto. That’s “a lot” – I’ve seen major projects hold together for 40 years on less – so, I went a bit “overkill” (I know you’re shocked) with the rod and bar and everything. I have lots of cut-off steel tubing from the forge table project [stderr] so I picked a chunk I knew would not bend easily, drilled a 3/4″ hole through it, cut a piece of 5/8″ threaded rod, and – for good measure – used a bunch of West System G-flex and another piece of plywood to sink the rod into the plywood and resin.
If you look at that and mutter, “something’s gonna give…” you are forgiven – that’s exactly what I was muttering. Since I have time, I gave it a couple of days to cure and even topped off the air-space in the hole with more resin, because why not?
Place your bets! What do you think happened? Remember: there’s a big silicone pan at the bottom of all that, so the binding surface of the epoxy has a fault-line where the silicone pan-edge touches the can. The can is pretty heavy duty – it’s a pressure pot, after all – it’s 16-ga steel. And the cross-beam and threaded rod are also non-lightweight material. You can see the large crescent wrench sitting next to it; that was the first torque-tool I planned to use.
Actually, it popped out pretty easily. I started wrenching away and there was a woody-sounding “snap” and the nut was turning freely. I expected to see the threaded rod had ripped the entire top off the plywood, but, nope:
I looked down into the pot and it’s not bad, really: there’s a 1/4-1/2″ ring of epoxy around the bottom and a textured epoxy floor. It’ll still be usable though I am going to have to remember to put parchment paper under anything with adhesive that goes in there; the epoxy ring is basically a grab-point for new trouble.
The silicone peeled right off, and now I can’t wait to get this thing on the lathe. Best of all, I have a really solid plywood mounting at the top that I can grab with the lathe chuck.
Since I am a righteous scientismist, I don’t believe in being “jinx”ed so I don’t feel I am risking anything when I discuss my plans for this object: I am going to try to lathe it down into a sort of rounded lenticular shape, centered on the wood-edge. That sounds pretty vague, but then that’s how most of these projects go: vague input, vague output, vague output allows me to be accepting of a wide variation of outcomes. As Buckaroo Banzai says: “if you don’t know where you’re going, how do you know when you get there?”
I probably won’t get this thing on the lathe for at least a week, since I am busy with many other things on my TODO list, but I’m comfortable predicting you’ve not seen the last of this thing.
Thanks again, MattP.
Do any of you know those screw-topped flip-over catches are on the pressure pot – what are they called? I want to get a couple of them and use them as door-latches for my forge but since I don’t know what they are called, it’s hard to search for them. I had a similar problem finding out what those ratchet handle bolts are called (I wanted to replace my wood lathe’s rest-bolt with something a bit more positive) – once you know what it’s called (“ratchet handle bolt”) then it’s easy to find them, otherwise you’re rummaging through google image search trying different names and seeing what comes up.
I have noticed that “water clear resin” has a quality range to it. Some of the stuff I’ve seen billed as “water clear” hardens with fog or lots of bubbles. Slow-cure is definitely the way to go, but I’ve learned not to buy the cheapest stuff on ebay. This is “Art Resin” slow cure, which takes 24hr to cure, but is absolutely gorgeous, very strong, and – most importantly – does not shatter like a glass bomb when you hit it with a chisel on the lathe. Since I try to be safe with the lathe, I don’t wear a sleeved shirt or gloves, and razor-sharp resin chips hitting your knuckles at speed is no fun at all let me assure you on that score.
I don’t know how helpful this might be, but I’ve hear the term hatch dogs in the context of a warship watertight door.
@Some Old Programmer:
Someone on Ebay is selling a complete hatch 6′ by 2′ with dogs and spring hinges, in case someone has $1000+shipping and is making a warship.
There are “hatch dogs” available but they look more like door latches/catches than the thing I am looking for. Thanks for the try!
Doesn’t really seem to have a specific name other than “pressure pot screw clamp” sometimes with “clevis pin” in the description. It is basically just a C-clamp with the fixed end cut short into an ‘r’ and formed for a pin pivot.
“KK-5057” appears to be a replacement kit name that could get you more specific search terms.
Lid clamps? I tried that and got similar results that kinda sorta look like what you have pictured.
I’m glad you could get that levered out of there. Looking good so far!
Yay for MattP (must mock his crappy brain)’s suggestion working, it looks as if it’s going to be lovely however it ends up.
Any chance of removing the residual epoxy? maybe acetone? or putting in something softer than the pot, but harder than the epoxy (aluminum? copper? even limestone?), and putting it on a shaker table or in a tumbler or something? Going at it with a propane torch in a fume hood? long-term, high-temp oven bake with heavy ventilation?
Glad the piece was salvageable, it does look quite nice. I’m sorta surprised it came out as it did, reading the beginning, I was expecting the plywood to delaminate, or maybe even the metal pot or strut to buckle. Congrats!
Hmm. What went through my mind was those closures I’ve seen on lorries and larger flight cases. Slightly different to that pot, but similar-ish principle. Google image search for “hatch fastener” seems to be mostly full of what I’m thinking of (the ones with a pivoting bolt and a wing or burled nut, and a C shaped plate on the other side.) Variously called a t-bar hatch fastener or porthole/portlight fastener.
Try this page:
http://clemtex.com/products/breakdown/binks-83c-2-gallon-paint-tank-breakdown
A bit like Trump’s Cabinet, they’re just a Yoke Assembly.
To me it looks like you could just modify small G clamps, forge or grind down the anvil end into a pivot point.
Way to go, guy. Another chestnut saved from the fire. Maybe a dremel tool to remove the residual epoxy? Or a small air chisel? Maybe you could just flip the pot over and bang on the bottom with a hammer. (Low-tech, that’s me).
I should have said – I probably need to rig up a vacuum chuck for this one. It’ll be that
or hot-gluing a tenon on the curved face when I flip it around and then removing the tenon without scratching the resin. Fortunately, I have all the parts except for a bleed manifold-thing and a mechanical coupler that I can put through the lathe’s mandrel. I’m scrounging parts and it’s going to be a while before I am ready to attack that problem.
publicola@#9:
I have a needle scaler and an air hammer. That ought to shred the stuff to powder in a jiffy! Good suggestion.
Clear resin just utterly fascinates me.
Also hurray for the planned and successful disassembly!
One other item on Lofty’s link would have been useful: number 23, paint tank liner.
I’m curious as to whether silicone or cooking oil spray would be an effective non-stick treatment for the pot. Just curious, mind you, but not enough to put my own hardware on the line.
Marcus @2 That sounds perfect, you just need to build a bigger forge to go with it :P
Wut? A Googling reveals that to be a common aphorism in business management seminars. No, Buckaroo Banzai said, “No matter where you go… there you are.” [yt – they were all so young then!] A variation on that, “wherever you go, there you are,” seems to have been wildly embraced by the “mindfullness” crowd a decade ago.
You may know this already but on the cloudy GlassCast (or similar) issue, this can happen to the not-the-hardener part if left in the cold. Solution is to place the container in a tray of just-boiled water and leave. The cloudy crystals should re-dissolve.
astringer@#17:
You may know this already but on the cloudy GlassCast (or similar) issue, this can happen to the not-the-hardener part if left in the cold. Solution is to place the container in a tray of just-boiled water and leave.
I did not know that, completely. Usually the water clear stuff generates enough of its own heat that it cooks the bubbles and inner crystals out while it’s curing. Mostly, my concern is to keep it from boiling so, depending on the weather, I put it where there is or isn’t a breeze.
Dave W@#16:
Wut? A Googling reveals that to be a common aphorism in business management seminars. No, Buckaroo Banzai said, “No matter where you go… there you are.”
I remembered the “no matter where you go…” one; I thought he dropped the other, but it’s been a long time and many miles for my poor old brain. Now I suppose I will have to re-watch it.
Cross-wiring memories by mistake is a predictable outcome of an activation propagation model of memory (similar to a neural network’s) apropos nothing. If you don’t have a good clean memory of where something comes from, and you reinforce an incorrect memory, you can pretty quickly train a new memory chain that makes you feel confident in the incorrect memory.
And here I was thinking you might use explosives and … awww shucks … you got her done with the mechanical advantage of a threaded rod. It is a more pedestrian approach but as they say ‘that which works is, by definition, “good”‘.
I was thinking a small platter charge near the top facing out to create a vacuum and a baldric underneath to get things going in the right direction. Timing would be the trick. With a little discretion on charge size I think we could pretty much guarantee the pot would be okay, a bit scuffed and blackened but okay. A bit of concavity would make it sit steadier on an uneven floor. Finding it might be a bit harder sometimes but ‘it’s an art form’ so allowances must be made; and who doesn’t like a treasure hunt? Mostly similar items come down within a hundred yards or so. Three hundred max.
Might need to time it so we don’t prang it off the belly of an airliner. What are the odds it FODs an engine? That would be one for the record books. Oh well … life is 100% fatal and faint heart never won fair maiden. Either way a story for the grands.
Think of all the fun … the the giddy nervousness of handling things that go boom in the night, the bang, pressure wave and dust, the ringing in the ears, the counting of limbs and digits (even better when they are all still attached), the thrill of the shrapnel lottery (y’know Shrapnel was a guy’s name? Interesting story for another time.), the visits to the ER. Pretty nurses. Meeting ATF agents (you’ll never meet a finer bunch of fellows). The growth process of learning to use rolling papers with nine digits. I knew a guy we all called “Nine” for just that reason. Ohhhh … the good times that could have been.
Glad it worked out for you. Looks good.
lorn@#20:
Finding it might be a bit harder sometimes but ‘it’s an art form’ so allowances must be made; and who doesn’t like a treasure hunt? Mostly similar items come down within a hundred yards or so. Three hundred max.
Are you familiar with the account of the underground nuclear test that may have sent a manhole cover out of Earth’s orbit?
Gizmodo destroys the story [here]
I think I read something about that. I vaguely remember a physicist being asked how fast it was moving when photographed and he used the phrase ‘like a bat out of hell’. No doubt in my mind that some day they will find that steel plate. Perhaps on the opposite side of the world, maybe the moon, wherever it is someone will find it.
I figure it is the nature of humanity to be curious, to explore, and to solve riddles. I think of all the missing ships and submarines found in the last few decades. I read an article that essentially said that almost all of the missing German U-boats have been accounted for. To me that is amazing. Lost in war, the most chaotic of human endeavors and underwater. Often with just the vaguest of operational clues as to where they were going and how they they planned to get there and, with determination and good sonar they eventually find find them.
Sometimes I can’t find my keys. I guess I need better sonar.
The kiss-off into oblivion is always the same: It involves me putting something somewhere unusual because ‘I can’t possibly forget it there’. As long as I put stuff in the usual place I don’t lose it. Hang a key on a brad in an ‘unforgettable’ location and it might be a decade before I find it again, if I find it at all.
Some day that several tons of steel is going to show up.