Getting into Cerakote have an oven question

[ADClope]

I've got a shop already setup for painting, I've got a blast cabinet as well, so I figure really, I'm only an oven away from being able to start working with and practicing Cerakoting. I've also wanted to start using this for other household items as well as small car parts when I'm working on a project...


My idea was with using an electric or propane type upright smoker. Most of the electric ones that I've found sit in the 30" range, but a few of the propane versions are 36" tall, at first glance, this should be perfectly sufficient for the vast majority of what I'll come across I'd imagine (firearm related anyways), and getting up to the 250-300 range shouldn't be an issue, but my apprehension was with using propane as the source of heat. Propane gives of moisture when it burns... the paint will already be applied and flash cured however before it hits the oven, so I'm not sure how much effect, if any the propane version would have on the parts as they bake?

Was wanting to pick some of you folks' brains who maybe have more experience with this than myself.

Thanks!

[Bill DeShivs]

You mean that a product of propane combustion is H2O?
I find that hard to believe, but even if it is so I would think the heat would evaporate the moisture.
How are you going to regulate the temperature with propane?

[ShootistPRS]

Most any hydrocarbon will generate water and carbon dioxide as it burns. Even Gasoline will do that. Its just that we don't generally care to take note of it.
I use a small parts oven for my heating work but its electric. Making an electric oven is pretty easy - a lot easier than gas. You need an insulated steel box the right size and one to three heating elements depending on the size of the box. You want a top vent and a small air intake near the bottom to get rid of any flammable gases. Put a thermostat and a timer on it and you are good to go. Always preheat the oven to your starting temperature and then turn it up as required. Place the thermostat bulb (thermocouple) at the same level as what you are working on for better temperature control.

[Unclenick]

Yeah, that's the reason methane is cleaner fuel than other hydrocarbons. One carbon atom and four hydrogen atoms. Combusted with enough oxygen you get two H2O molecules and one CO or CO2 molecule for each methane molecule burned. All the longer hydrocarbons have only half as much hydrogen per carbon atom except at the ends of the chain, where they have three, so each added carbon atom in the chain gives you one water and one carbon monoxide or dioxide atom in combustion. Methane produces the most water vapor compared to the amount of CO or CO2 it produces, so its the most environmentally friendly carbon fuel.

To the OP, I think I would make my own oven in this instance, using four foot length of 8" flue pipe and setting it upright over a hot plate, then applying temperature control to the hot plate. Wrap the pipe in fiberglass insulation to make heat distribution more even (just don't use paper or plastic covered fiberglass). Suspend your work in the pipes from hangers and put a square of fiberglass on top of it to keep from losing too much heat out of the top, but still allowing a little air movement.

In full disclosure, I have not actually done this, so there may be pratfalls I have not anticipated. Some kind of air stirrer might be needed, for example. It just depends how tightly you want to control the temperature and its distribution.

[tobnpr]

Propane?
How are you going to precisely regulate temp?
You're not smoking a brisket where you just need to be in a "range" like a grill.

Use an insulated cabinet, electric heating element, and a PID controller/thermocouple to regulate temperature. A few bucks more adds a programmable timer to make it turn on and forget.

Cerakote can be unforgiving with certain colors and applications. There is a pre-coating gas-out cycle needed (,then cool down before coating), and multi-color camo requires temp/time sensitive partial cure cycles.

[4V50 Gary]

Small parts bake well in toaster ovens. Second hand shops are where you get them (so the wife doesn't throw you out).

[tobnpr]

Small parts bake well in toaster ovens.

I've had no problems with Gun-Kote in a countertop oven, which makes it convenient when I only have a few small parts to do and don't want to fire up the big oven.

Cerakote, I have experienced problems with final color/shade in a small oven. The parts hang too close to the elements- and the direct heat results in much darker color than should be. Much better for them the temp to be evenly distributed and consistent. My thermocouple is in the center of the oven (vertically) to get an "average" temp- but I do plan to add a small "convection" fan to distribute the air top to bottom.

[T. O'Heir]

Gas gives you far more precise, instant, control of the temperatures than electricity ever will. It's why professional kitchens use gas.
The only issue with an upright oven is how you'd suspend the parts.
The parts you plan on coating and with which solution matter too. The high temp solution requires 1700F. You won't get that with propane. Regular coating cooks at 400F. No problem for propane. Dunno about a smoker though. Appears most max at 400F.
I wouldn't worry about any moisture. At 400F it'll be evaporated off quickly.

[guncrank]

I use a old fridge and two hot plates

[tobnpr]

^^^
Not correct.
Cerakote "H" Series is two hours at 250 degrees or "fast cure", one hour at 300 degrees. Temp is not to exceed 300, so I have no idea where you got 400 from- and I won't even ask about the 1700 degree cure temp you state because it's either a typo, or you've been smoking some crazy...

Cerakote High Temp is an air cure (not oven cure).

[T. O'Heir]

The 1700 degree cure temp came from CeraKote's site. So did the 400F.

[Unclenick]

{Edit}

I did a search on "1700"" at their site and got this:

Special Cerakote ceramic coatings are available for tight tolerance, high-wear internal parts, such as bolts, bolt carriers, barrels, bushings, etc and for high-temp applications up to 1700°, such as suppressors and machine gun barrels.

So it's not referring to a cure temperature but to use of the cured finish. On the same page, just before that last quote it says:

H-Series is the most durable of the standard Cerakote product andprovides the best performance in hardness, wear,scratch,resistance, adhesion and rust resistance. It can withstand temperatures up to 400f degrees and comes in nearly 50 colors.

So, again, its a finished coating withstand temperature, not a cure temperature.

[oneoldsap]

1700 F is the fail temp oh their high temp (H) coating . It's air cured as well , no baking required . I built my oven using the controls and element , from an Electric range . I built the cabinet (48" H X 24 W X 24 deep) out of 18Ga. sheet metal , Rigid High temp Fiberglass 1" board . A fan is required to circulate the air so that the top and bottom of the oven are at the same temp . I built mine from a car heater motor / fan . Which required a rectifier and reduction coil . Cerakote C doesn't dry before curing , by the way . I should take some pictures of it , and post them . The timer even works , I can turn it on , and forget about it . I have a thermometer inside as the controls aren't super accurate .

[Unclenick]

Accurate controls from China are widely available on the cheap at eBay these days.

[tobnpr]

^^^
Yep...
And I've got a PID controller from eBay sitting here, free to anyone that wants it....programming/parameters instructions were ChinEnglish and impossible to comprehend. After waay too much time spent, I figured out that it was not possible to interface with a timer.

Auber Instruments. Very reasonably priced, programming instructions are real English, and they also provide examples for interfacing and how to set all the parameters.

[Unclenick]

Yes. Dead minimal instructions are the norm with that stuff. If you've used a lot of PID controllers and understand them, you can figure it out, but you probably don't want to make a career out of knowing them if you just have occasional uses. However, even if you haven't had enough calculus to know what Proportional Integral Derivative control means or what the advantage of using that type of control is, you probably still know what a thermostat is and can set one, and for most simple oven applications it is good enough.

There are a number of digital thermostats available on eBay. Just be sure you check the amps output they control and the temperature setting range. Most are for HVAC and don't adjust up hgih enough for an oven, so searching on oven controllers will help. This 5 amp contact one has a very complete set of photos when you scroll down showing the types and of the instruction sheet, so you can see what you get. There are a number of used devices in US brands, too.