New-Old Metal Shop Oven Status (calling Powder Coaters)

Metal Shop
#1

The new-old Metal Shop oven was wired in tonight, and tested. It is functional, but before general use it needs some tweaking. The previous users added an additional controller that set a hard temp cap of 250F (this was for their specific process, not a general safety feature) and this has to be bypassed; once we determine the ideal maximum temperature the unit should run at it will be reprogrammed for that purpose.

Things to note:

  • It will require basic training, similar to the cold-cut saw in the Machine Shop the power will be locked out with a padlock and can be spot trained.
  • Like the old oven loaned by @dallasmagna, this currently shares the 3 phase outlet with the Induction Heater; only one can run at a time. When the expansion hits we will look at fixing this scenario.
  • The PID controller manual will be made available on the committee drive, along with some simplified instructions for common use, in the near future once we finalize any possible controller/operational changes
  • This oven is big. You can fit a truck bumper in it (I know the first thing I’m powder coating is mine).

If you have any questions, post here or ask someone from @Team_Metal_Shop

If you have something you can use the oven for this week, let me know if you are willing to have it be a test case.

Cheers,
-Jim

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What color/pattern should I use
Testing the new Powder Coat oven
#2

Awesome!

If someone can provide me a photo, and a few hints about whether it is one of the listed items (or a new one) in the Tools list, I’ll update the wiki. (Last section of Metal Shop tools is “Forges and Furnaces”).

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#3

If only 1 item can be plugged in it would not be excellent to unplug the oven because you want to do some induction forge work.

Maybe a sign can be hung on the induction forge when the powder coat oven is in use?

#4

Maybe on something on the plug of the oven. Let’s avoid hanging stuff on the forge.

And there again, the forge has been sharing power with other things in the metal shop for some time with no issue, so I’m not sure this isn’t a solution looking for a problem.

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#5

It shares with PlasmaCam if someone using at the time you’ll know immediately. But ovens run for hours unattended - I agree hanging on plug is best option.

Problem is when oven finishes cycle and person doesn’t come back till next or later day. Need indicator light that shows off on on during cycle.

#6

It shares with the glass oven too, which has the same issues as the current oven. I agree that some way to know when that thing is in use would be helpful.

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#7

It doesn’t share with PlasmaCAM; Plasma uses a single phase outlet.

The other oven from Chuck, which is going, used 3 phase. The glass oven shares PlasmaCAM’s single phase.

I agree a sign of some kind is required, and I’m working on some options to run by the committee. The PID controller always shows the temperature and run status when the unit is powered up as an interim notice.

Working on taking a proper photo and confirming the manuals I have are correct. Will report back either to you or directly edit the wiki depending on time.

Cheers,
-Jim

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#8

Here is a photo of the Oven.

It will be training required, and I have to go get some warning signs and an easier to use padlock. The training can be done on the spot, or it can be included in part of a class using the oven.

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#9

“Ideal” Temperature for powder coating is 400 degree F. I looked at this unit and it is nice… but also scary. It seems to have a spring lock and that is a good thing. That means that anyone… well any adult, can open it from the inside. As stupid as that sounds let’s remember that refrigerators on the curb were potential deathtraps for kids who were curious. Why an adult would walk into this thing and close the door… I can’t even fathom but when has that ever stopped anyone?
While this is an exciting development, there is one thing lacking and something that I have asked for; a decent powder coating booth. Something that can capture the over spray. You mentioned a padlock… I assume that is for the power switch of power cable?

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#10

It’s on the power box lever

We have some folded up cardboard with a filter and box fan. It can be stood up on the welding table or elsewhere. It works very well, as the gun operates at a very low pressure and with good spray technique overspray is pretty low.

#11

Well yeah, cardboard box is fine but I don’t think you can do a large piece in it. Someone mentioned a bumper. Maybe a bicycle frame. The harbor freight Red is actually a really great powder to use. I use a small flashlight and examine the piece all around to see any missed or only lightly coated parts. I built a powder coat oven and that allowed me to put a window on it. Powder coat takes 20 minutes after it flows out. This oven doesn’t have a window but it still looks really nice. At 400 I suggest 5 minutes for flow out and then the 20 minutes so… 25 minutes if the oven is heated to 400 degrees, Hope that helps.

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#12

The point is we usually just improvise such booths; it doesn’t make sense building a large permanent one or reserving an area since the movement to the oven would be disturbing the coat, on top of most people are doing small parts. I’m going to just get some plastic and tape up a few posts when I do my bumper but, again, the way the powder flows from the electrostatic charge makes overspray not a huge issue unless you are doing unmasked multi-colour

I use a flashlight myself, and whilst the harbour freight paint gives pretty good results I tend to get mine from Summit Racing. I’m currently picking out a selection that will be available by the ounce/gram, similar to what 3dfab does for filament. Weigh the jar before and after use.

The cure time for the harbour freight is 15 minutes when the part is at the desired temperature of 400F; depending on the part that is going to vary wildly as it heats up.The summit powder only needs 8 minutes when part is at 392F. Unfortunately, unless you have some good probes determining when your part is at temperature is a wild guess, as right now we only have the air temperature of the oven.

Cheers,
-Jim

#13

My personal preference is eastwood powders. That’s why I was surprised by the harbor freight and the amazing results I got. It is just my experience that makes me have to honestly say that the harbor freight might be all anyone needs. If the majority of parts will be small, the space should get a toaster oven and dedicate it to powder coating. The big oven is way too big to justify small parts. I had offered to do a powder coating “demonstration” since it can hardly be called a class, but the lack of a good air booth has been a stumbling block. I use a no contact infrared thermometer to check the temperature on a part in the oven. I built in a small door in our oven which allows me to open it and take a temperature without losing all the heated air. That’s a problem with this oven but I like it a lot. While we can talk at length about the exact temperatures and times, rule of thumb will have to do with this oven and I believe 25 minutes at 400 degrees will be the best starting parameters. With all due respect to summit powders… not sure how you can be 392 accurate and how much difference that is to 400. 8 degrees? Can that really be so relevant? As you have noted, we only have air temperature so that test will probably never be practical. I have found that powder is very forgiving as long as it gets a good melt. I think curing is the result of additional time. There are a lot of tutorial on line and I tend to favor the eastwood demonstrations.

#14

We have a smaller oven for smaller parts. The big oven allows for larger parts, but also has a better controller.

I like the summit powders since they are only a few dollars more than harbour freight and have a better finish for some colours. For things like the red and black I still just get harbour freight if I’m making another trip their anyway.

As for that slight temperature difference, it really only matters on larger parts where it will spend longer getting to temp. Otherwise I just run it at 400 anyway

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#15

Powder coating a pelican vacuum can with Candy Purple. Also adding some easier to read colour to the hot sign.

This was a preheated part to release additional oils; candy colours are particularly sensitive. Base of metal was already silver.

On an unfortunate note I found out our Eastwood gun is not adequate for candy except on a material that is already an appropriate gloss silver underneath. It can’t do multiple layers properly. This also means it can’t do any media that needs a primer, nor a clear coat.

I’m looking at options. @Will1 do you have a gun recommendation by chance?

Cheers,
-Jim

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#16

Looks great! I’ve got a few long parts to powder-coat. Is there time this week to meet and get trained?

#17

Bottom line on both the Harbor Freight and Eastwood powder coating guns. They are DIY guns. which means they don’t reach the voltages that commercial guns can reach. It is a matter of safety at that point. The companies don’t want to be sued for a bone headed misuse of their product. You can do two coats with the Eastwood but you have to properly prepare the item and that takes a bit of Patience to strip, sometimes, sand and then immediately apply the first coat. I’ve done multiple coats but I have found that one full coverage coat is usually sufficient for my applications. Still, I have found that two is very doable but, as I have said, takes patience. On the plus side, Eastwood have several very good videos on their website using their gun that really helps to learn what to do. I suggest watching them. They actually use the equipment in question so there can be no doubt that what they say works.

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#18

Even with a stripped, cleaned, prebaked, then cleaned again part the Eastwood we have can’t do any of the multilayer stuff we’ve tried. And for the good corrosion resistance where someone may want a primer for their material (making a 3rd layer) is for sure not happening.

Not a single attempt out of several with different preparation methods has gotten that Eastwood to do a second coat evenly. And that’s with “good” summit and prismatic powders, not the HF stuff.

#19

I told you what I have done. If you want to argue with my experience, then you argue alone. I’m done.

#20

This isn’t an argument, this is a statement of fact that with what we have on hand, in our shop environment, that multiple coats with the Eastwood on hand have yet to come out properly regardless of preparations we’ve tried with a number of powders.

If you want to help test out our hardware with a variety of powders, do it then share the results; I’ve been trying different powders from different vendors, with different preparation styles for different metals and both voltages on that Eastwood for the past week.
It doesn’t matter for the purpose of this discussion what experience anyone, mine or yours, has if it can’t be repeated in the environment of our shop with what tools we have without providing some possible explanation to help determine what the cause is or guidance on what we could be missing.

I’m even at the point I’m looking at running heavier grounding rods in the metal shop to use to try and get the Eastwood to do multiple coats reliably in case it’s a matter of a poor ground in the room (which I would hope not given our welders operate there, but it will eliminate an additional source of uncertainty)

So if you want to be constructive, experiment with what we have and report back. But don’t get argumentative about what are purely factual reports about what we have tried what we are doing, and the results.

Regards,
-Jim