Maybe put the towers in opposite corners diagonally. Then a chain between them would put parts in the middle of the oven.
Maybe put the towers in opposite corners diagonally. Then a chain between them would put parts in the middle of the oven.
In reply to jgrewe :
I like that. Since they will be removable on pins, I could just set up three corners with provisions to hold a tower and choose whichever ones I want.
I'm hoping for something like a tension rod like for a shower curtain, but beefier. Put it on the top peg, push up to compress, and drop it on the bottom peg, although it might just end up being some sched40 pipe and a conduit clamp.
Working on some fun fabrication. Here's what I decided for additional hang space.
I am mounting some brackets in three corners that will hold some 1" sched40 pipe, then I made some slip collars out of 1.25" pipe. To those collars I welded some heavy shelf brackets, then drilled and tapped for 1/4-20 thumbscrews to hold them in position. If I'm not confident in the thumbscrews holding things in place, I can drill holes every 4" or so in the 1" tube and throw some pins under the collars. Quick drawing below. I have most of it fabbed, just need to come up with a "pin" for the top. That way I can slide it up on that pin and drop it in the pocket at the bottom.
I got the towers installed today. I've been "battling" covid. I put that in quotes because I have zero symptoms, but nevertheless, safety first. We have a show open at the theater and the last thing I need is to infect the cast and dump revenue with canceled shows.
I think I will like these. I measured some stuff and I think I can fit four 20" wheels in at the same time. The towers just pop up on a 3/8" bolt/pin, then down into collars at the bottom. I'm running out of excuses to keep putting off powdercoating. My one holdback is that the wardrobe rack I commandeered to be my spray rack was accidentally stolen by the costume shop and it's housing a bunch of costumes for the show. I could rig up something in the meantime, but I'll just wait.
Got tired of waiting for the costume shop to return my wardrobe/powdering rack, so I built them another one and stole mine back.
I had these whipped up before. It's just a z-rack rolling base into which I stabbed some 6' sections of 3/4 black pipe to make the rack taller. I was looking for an easy peg idea and didn't want to tediously weld on 20 S-hooks or try to drill in 20 self-tapping screws. Turns out, since 16-penny nails are 0.160", and 5/32" drill bits are 0.15625", they make a dandy press fit. I drilled 20 holes in the drill press and press-fit the nails. I welded on a tab for the ground clip on the side, and tested 0.000 ohms to every nail.
Expect powdering to happen soon.
Today is the day. I started actual powdercoating today.
I started with the smaller pieces - the ratchet winches, the mounting pedestals, and the winch handles. They all got scrubbed with 1:5 simple green and a rough scotchbrite, then treated with Alumiprep 1:3 for a 5 minute dwell. Then into the oven at 450 for a half hour to outgas anything.
Once they cooled, I wiped them down with acetone, sprayed powder, and cooked. The oven did brilliantly.
Awesome! I would recommend buying a set of silicone caps and plugs to cover holes and threads. Powder will bind up threads so much you will break a 3/8" grade 5 bolt trying to tighten it up. The more expensive option and more time consuming is running a tap in any threaded hole you get powder near.
Nice job! I would just like to add that you could carefully run a 4.5" side grinder with a cutoff wheel to cut a small groove around the vertical pipes in the corners in a few strategic places for your set screws to dig into for heavy objects and that you could swing in any direction. It would be easier to use than to find a dimple drilled into the pipe in just a few spots.
Curtis73 (Forum Supporter) said:
I sure hope you are going to go back and straighten out those crooked nails? 
In reply to jgrewe :
That is the plan for future coating endeavors. Since this whole thing (except the couple bolts you see on the pedestals) is assembled with t-slot nuts and bolts, so I wasn't too worried about getting powder where it shouldn't go.
I did take your advice and used an air gun to blast some powder off places I didn't want. Worked great.
But yes, when I get around to powdercoating the wheels, they have something like 158 decorative bolts in them. They will all need silicone plugs. I also thought about plugging them with something generic and removing them before the oven. Is that a thing? Like plug them with foam ear plugs and just take them out before heating.
In reply to VolvoHeretic :
Good idea on the "ribs" of the towers.
And the nails are art, man. Asymmetry is sexy.
Nice Work Curtis!!
Your parts look fantastic!
They make a high temp tape that can survive the cure process. You can also cook the part to when the powder starts to melt, pull it out of the oven and remove any kind of masking.
I did these rims for a friend of mine. I hit parts of the rim with black and let him tape off the design he wanted, then hit it with white all over. Masking was removed when the powder started to melt at about 300F.
When I did the winch/ratchet strap, I wanted the shaft to not have powder since it rides on a plastic bushing. I ended up coating and then blowing off the shaft. It worked, but my original idea was to just use masking tape and peel it off before baking. The only downside to that plan was... I wouldn't have anywhere to hold the part while I pulled off the tape.
I did try one with an empty toilet paper roll, but there was enough space and static that it didn't prevent much powder. Not a very good masking.
gsettle said:Nice Work Curtis!!
Your parts look fantastic!
Thank you! I'm super-pleased. There are some flaws, but this is a roof rack and not a highly-scrutinized thing. One of the pedestals had a bit of outgassing/bubbles, but it's on the underside. Another one has an anomaly that I will post a picture later. I'm curious if any of you might be able to identify the mode of failure. It's a 1/2" long discolored and rough spot. I have zero concern for it, but it would be nice to know if it's an obvious thing I can prevent in the future.
The only anomalies so far:
Outgassing, I suppose? It's going under the rack and I'm sure zero people will notice.
And this one is the only strange part that I don't know. Again, really a non-issue cosmetically, but would like to learn how to avoid it before I tackle something like wheels or a project for someone else:
I had always planned on adding a window, and I'm finding that will be almost a necessity. Opening the doors to check part temps is fine, but I was noticing that even a brief opening of the doors to scan a couple representative parts will send the temps from 400 down to 350 pretty quickly. That just wastes time raising part temps. Then I'm also wondering when I finally open up and see that it reached the curing temp, how long has it already been there? With a window I could test more frequently without disturbing the heating and know right when to set the timer.
I'll be looking for a junk oven on trash day that I can scavenge the glass from the door.
Curtis73 (Forum Supporter) said:In reply to VolvoHeretic :
Good idea on the "ribs" of the towers.
And the nails are art, man. Asymmetry is sexy.
Here's a quick sketch for you.
In reply to VolvoHeretic :
That's exactly how I pictured it. It also gives me an excuse to research metal lathes. Imagine how sexy it would be if I had a 1/16" groove every 2 inches on those pipes.
For now I didn't weld a nut on the outside, I just tapped the pipe wall itself. I imagine the ductility of the steel will come back to bite me on that one. For now, it seems to work well because the thumbscrew is below the arm, and any weight on the arm just adds pressure to the thumbscrew. I guess my big honkin 20" off road wheels will be the real test there.
Update. Last four pieces got coated last night. I saved the largest and clumsiest for last so I could at least be 20% more confident. I still have a TON to learn.
Redline 100J powdercoat gun is pretty good. Not as good as I expected after seeing impartial reviews online... at least they claimed they were impartial. The variable kV output is clutch. Crank it up for big pieces, crank it down for tough nooks and crannies. My only gripe is the fluidizer. It's very inconsistent. It sends powder much like a quickly percolating coffee pot. Bursts of powder followed by just a little bit of dust. Makes it a little difficult to get a consistent cover, and it did leave some heavy spots. Even after tracing over every square inch with a bright light, I still need to learn how to be consistent with my coverage. I think it's partly the gun's fault (spurts), but also my inexperience. There are several places where I didn't get a good, full coat and you can tell they're a touch lighter (aluminum showing through). Fortunately they're all in places that were hard to reach with the gun, therefore hard to see when you look at it.
Overall, I'm super happy with how it turned out. It's now all assembled and could go on today, but I want to play around with deck boards on the top to see if it's a weight I can live with.
Is the powder clumpy? Do you need a flour sifter?
In reply to VolvoHeretic :
Not clumpy. It's almost as if the two "jets" that fluidize the powder are unequal. It seems to blow the powder in an ellipse around the cup instead of evenly.
those wheels are kooky!
In reply to AngryCorvair (Forum Supporter) :
Um... thanks?
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