# powder coating oven



## savarin

As if I didnt have enough on my plate I've had to start another project.
Thats right, I have to.
I've almost finished the refractor and its essential that I paint all the black parts.
Now as paint will scratch I have decided to powder coat them. 
There is no way the minister for war and finance will release the funds necessary to pay the exorbitant prices that attracts so it only leaves me with one course of action.
YEAH! build one, but, it has to be virtually cost zero.
There are no plans so its suck it and see.
Luckily I had a pile of almost new 25mm angle iron, with a bit of care it should be enough.
First an outline frame, I have a bunch or 2 meter sheets of old dexion sheet from some shelving. so fold up the inside lining to see it it will fit and work.


Thats the mirror grinding machine in the background.
Looks as if its a simple job.
So make a base and sheet it in.
A couple of bits of strapping to help support the base sheet.


In my old profession there was a term used.
Rechaufe. In its basic meaning it just means re- heated but for the industry it really means "The utilisation of left overs".
So in keeping with that philosophy I sheeted in the base.


Not pretty but serves its purpose and it wont be seen.
This was then covered in a layer of insulation fibre and sheeted to become the inside base.
Tacked first then continuous welded seams.
	

		
			
		

		
	



Those two vertical lengths of angle iron will be the rails for the shelf that will protect the heating elements. 
Its not often I get this much done in a day so I feel good so far.


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## FOMOGO

Good, you needed another project.  Sound like you will be going electric, I've kept the burner assembly's from a few furnaces and ovens with plans for a fair sized one. You might consider a small fan and wall duct to move air from the top down (convection style). Will be following along with interest. Cheers, Mike


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## savarin

Yep, looking for an axial fan from an old aircon, I have a heap of old olive oil tins that could make the duct.
The idea of the shelf is to have large holes on one layer with smaller holes on the next layer without any of them lining up so nothing drops on the heater elements and it should slow the air stream down so as not to disturb the powder.
I've got a length of copper tube to make a water drill for the earth as well.
The insulation is a heap of left over batts from the roof void of the house that was just filling up the space doing nothing.


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## sanddan

Subscribed!


Here's a link to a great PC oven build. It might give you some ideas.

http://www.powdercoatguide.com/2014/09/how-to-build-powder-coating-oven.html#.WLL-nmfTnIW


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## savarin

Theres a ton of good info on that site.


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## Mark_f

I have used the kitchen oven ( only when SHE is not home). It works good as long as the parts fit.


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## savarin

I just looked at what I think will be th largest part I want to powdercoat and made it half again as large.
(well I might get aperture fever, it has been known)


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## savarin

Starting on the inlet louvre, first off a cardboard template.


Transfered to the sheet and cut with a sharp chisel.


some bending in my poor mans sheet bender.


one of the side pieces in the bender with a hammer and steel dolly


all clamped in place prior to welding and riviting.
This is the section the heating elements will be sitting in.


Thats all for today


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## RandyM

That is going to be really nice. I myself went the cheap and easy route, I bought one for $25 off a Craig's List add or might have been a newspaper add, don't remember anymore. Mounted it on a rolling chassis. My problem is that the I can always use a bigger one. Looks like your is going to be bigger than my 30 inch.


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## 12bolts

Charles,
Have you ever checked out the recycling depot at the Stuart tip? They have anything and everything

Cheers Phil


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## savarin

I had thought of them Phil but I think I will use new elements.
The glass from an oven door would be nice but I would get a fair bit of grief bringing a complete cooker to dismantle for a few bits.


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## Groundhog

I started designing a powder coat oven from an idea I saw somewhere. Sample picture of a drawing (TurboCad, but can convert) here. To be made from steel 2x4 (or 2x6) studs. Pop riveted or tack welded together. Filled with regular house rolled insulation and sheathed with sheet metal. Elements would be recessed and circulation via exterior fan and duct work. That way the interior is unobstructed. I have a half dozen or so drawings - almost but not complete. Would be happy to share if it would help anyone.


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## RandyM

Savarin,

Don't forget to incorporate some type of hanging racks and hooks.


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## savarin

already on it Randy.
I'm also considering using a poly liner to the oven for a spray booth in the oven so the parts can stay grounded from start to finish and do not have to be moved or touched.
The liner will collapse down to the bottom so excess powder can be collected.
Maybe this is a silly idea but I wont know until I try.
The sort of things I will be coating are too large for more than one item at a time.


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## RandyM

savarin said:


> already on it Randy.
> I'm also considering using a poly liner to the oven for a spray booth in the oven so the parts can stay grounded from start to finish and do not have to be moved or touched.
> The liner will collapse down to the bottom so excess powder can be collected.
> Maybe this is a silly idea but I wont know until I try.
> The sort of things I will be coating are too large for more than one item at a time.



Sounds like you have it all under control. Let us know how your system works out. I know I have pushed my little oven to the limit for the size of some items, sure wished it were bigger.


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## Bill Gruby

We had a really big one at GM. Used it to coat the Saturn Water Pumps. The Pumps were hung, sprayed and sent thru on an overheat conveyor.  Coated 12oo pumps at a time.

 "Billy G"


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## RandyM

Bill Gruby said:


> We had a really big one at GM. Used it to coat the Saturn Water Pumps. The Pumps were hung, sprayed and sent thru on an overheat conveyor.  Coated 12oo pumps at a time.
> 
> "Billy G"



Now, there's a power bill I'd not want to pay.


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## Bill Gruby

Parts started thru at 10:00 AM and were out, ready to finish assemble in 2 hours.  The oven ran on all three shifts. 3600 finished pumps went to Brentwood, Tn. every day 7 days a week.

 "Billy G"


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## savarin

I dont think I will get very close to that kind of output Bill


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## Bill Gruby

You say that now but I remember the Binoculars.. LOL

 "Billy G"


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## Firestopper

Cool build or should I say HOT build.


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## savarin

I hope so Paco.
I'm at a stop for the moment as I believe I need all the electrics first to wire up correctly before I fit all the sheeting just in case there are routing difficulties.


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## savarin

Managed to fit the first of the inside section today.
It was really weird, something kept stroking my leg and my face inside the helmet.
Every time I started welding something brushed my face.
What on earth were these ghostly wafts?
Eventually I found it.


It seems the U.V. was attracting it.
I folded this inner wall in three, welded one side to the frame then clamped the other side so I could cut it to size.




I used a chisel to shear it to the corner.


then welded this side.




Its starting to look the business.
I think I have a couple of fans arriving tomorow.


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## savarin

The fans were no good so I'm still searching.
Got the ceiling made, insulated and welded in both sides.



Note the spot welds? I decided to use the holes all round the edge ans just spot welded them to the bracing bar.
I now have to grind the welds flat but got caught out through a lack of concentration


Made a cool noise.


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## FOMOGO

Have trashed a cord or two over the years myself. I think the plug welds should work well for your build, fast and easy, with a pretty good finish. Mike


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## savarin

All the inside sheeting is done and I decided to spray the inside with exhaust manifold white paint.
Hopefully it wont chip off. The can ran out at this point so I knocked up the outer frame for the door.
I need to find an oven door with a glass front. so I can add a window. (I want to watch paint dry)


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## savarin

Found an element, 1x1000Kw and the other 1x1800Kw.
I think I will wire the 1x1000 on a separate circuit so it can be switched in and out as needed. My calcs appear to show 1700Kw is sufficient for the oven so got some power to spare.
	

		
			
		

		
	



The bottom shelf is a protector for the element so nothing can fall onto it.
The criss cross design is on both sides but the gaps on one side are covered by the sheets on the other so the air from the fan that feeds to the element can flow through it with ease.


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## savarin

A wee bit more done during 34'C and 82% humidity and no wind.
Clamp a side sheet between 2 lengths of angle iron and use my trusty hammer to fold it at 90'
Then release it and hold it against the angle to get the fold to 45'


I want this sheet to have a lip to hold the next sheets lip into so its flattened with a spacer inside the fold.
That orange aerosol capped can is the most important in the shop, mosquito repellent


So I've got this far.


The electrics are a circuit breaker, a switch and warning light for the fan, each element and the thermostat.
The copper pipe is the hanger and earth for the items being baked.
I opted to screw the sides on with tecs.
Its too uncomfortable to do any more. I got through 2 litres of water just folding those four edges of one sheet.


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## RandyM

Looking good! Are you sure it is big enough?


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## savarin

RandyM said:


> Looking good! Are you sure it is big enough?



 If I was still building bikes then no but hopefully its large enough for any future projects such as the trusses for the binocular


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## ch2co

What? Not using carbon fiber tubing for your trusses?  Shame shame, that thing is going to weigh a ton.
Unfortunately I have a great powder coater just 4 blocks (easy walking distance) from my house and they work with me so well.
My Surrier Truss plans for my little 10" are  probably going to be alum tube, but carbon fiber is sooo tempting.


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## turnitupper

1000Kw element Sav. I didn't know of any privately owned power plants in Townsville.


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## savarin

turnitupper said:


> 1000Kw element Sav. I didn't know of any privately owned power plants in Townsville.


OOOPS!, oh well I'll just sling a couple more panels on the roof


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## savarin

ch2co said:


> What? Not using carbon fiber tubing for your trusses?  Shame shame, that thing is going to weigh a ton.


I've worked with carbon fibre before and didnt like it much (building windsurfers) but it sure looks cool.
I dont mind heavy as it dont vibrate in the wind but then inertia starts rearing its ugly head.


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## savarin

Found a fan at last, I hope its strong enough to take the heat, its from an electric oven and used to circulate air to cool the outside of the oven. It obviously gets hot in use but can it stand the temps I want.
I guess I will find out.
Made the holder to fit it to the oven wall



In place and a quick test shows it produces plenty of puff.


Now on to the ducting but I have a full calendar this week so not much more will get done.


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## savarin

Got the ducting done



Now working on the outer insulated cover


The top section needs a box for the wiring and also be easily removable in case I have to replace the motor.
I'm still in two minds as to whether I should insulate the motor of leave it exposed.
It would be the only place where heat could leak away but its not a large area. Hmmmmm.


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## RandyM

I am thinking that unless the motor is rated for that kind of heat, I'd leave it exposed.


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## Mark_f

Randy is correct. Tbe motor needs to be exposed as the heat will ruin it. You could insulate the squirrel cage fan housing and leave the motor exposed as it is on the end of the fan housing. ( That's the way it looks in the photos ).


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## FOMOGO

Coming along great. Oil-lite bushings, or bearings on the fan? If oil might want to make up some oiler tubes and give a drop or two every once and a while to help it live. Not too much too often, or it may cause issues with your finish. Cheers, Mike


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## ch2co

Maybe you need  blower to cool your blower?


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## savarin

Bad grammer, I actually meant just insulate the housing.
I will block all the side holes and gaps in the housing so no hot air will suck or blow.


RandyM said:


> I am thinking that unless the motor is rated for that kind of heat, I'd leave it exposed.


The blower has a weird silicone type bearing opposite the motor so I have a doubt it is although the fan rotor is metal bladed.
Looking at some oven parts diagrams they appear to be for blowing air over the outside of the oven towards the door, possibly to actually cool the door???
So maybe it wont stand up to the heat. The major problem as I see it is the silicone bearing plate will deform or the motor windings will get too hot.
If that happens its relatively easy to make a new end plate for the rotor and extend the motor shaft getting it well away from the heat but I dont want to do that unless its necessary.


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## savarin

Finished the rear of the oven


Now started on the door.
I stripped the glass out of the old oven and cleaned it but in the end I decided to rebuild the original door and set in in to my door.


All so I can watch paint dry.


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## savarin

Got both sides of the door sheeted and in the process it twisted.
Closed at the top but wide open by 5" at the bottom so I placed a wedge at the top and clamped the bottom to twist it the other way



It worked spot on



Finishing off the wiring and door lock. Cant wait to fire her up.


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## savarin

Finished. (Well almost)
The door shuts and holds tight,
The door gasket has to harden fully then I can trim the excess off,  I used a high temp silicone as the gasket and greased the door frame so I could clamp them lightly together without them sticking.



All the wiring is done and it works.
Each item has its own warning light.


A splash of bolognaise and it almost looks edible!
The thermostat actually turns off the power at its lowest setting, turn it up and the power light comes on, flick the switch for the second element and that light comes on, turn the fan on and that light comes on.
The thermostat controls both heating elements so both lights turn off when the thermostat trips.
Both heating elements get hot.
I have to install the thermometer so I can read it outside the oven.
First job is to calibrate the thermostat, then I can fully cure the exhaust white paint inside and then its flat out powder coating the bits for the telescope to finish that.
Only another 6973 projects in the pipeline


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## savarin

first test is a possible let down.
According to the new oven thermometer it only gets to 185'C, I need 200.
But, when I opened the door and tested a metal bracket inside it read 204'C with my infra red thermometer which I would believe more than the cheap dial one.
However, the door warps at temp so heat leaks out there and the fan also pumps a bit of heat out its sides.
So, still work to do.
Think I should also add another element.


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## Mark_f

With a door that long, you need a latch near the top and another near the bottom. ( Connect them with a common rod so they work together).


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## savarin

And a more pronounced gasket.
I will re make the door latch with 4 in total hooks to close it all the way down and add another hinge in the middle.
Cant do anything for the next two days, hosp appointments.


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## savarin

at least I got the all clear from the hosp this morning so all is well there.


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## RandyM

savarin said:


> at least I got the all clear from the hosp this morning so all is well there.



Now, that is great news.


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## savarin

The oven is finished and works. No more leaks and gets up to temperature.
Built a spray booth from wood and plastic sheeting.


and test sprayed a can


That looks a nice shiny black to me.
Now to strip the spray paint off the scope pier and sand blast a few parts and get them coated.


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## savarin

No photos for the next bit but I decided to make a dedicated earth post.
I silver soldered two x 1meter lengths of hard drawn copper tube to make a 2 meter length, connected it to the hose pipe, turned it up full and started pushing it into the crap stuff we call soil here.
The top 500mm is dry sand/soil/gravel, next came a 800mm layer of dry clay finishing in fine sand.
Total time was approx 20 mins. Going through the clay was hard and was a sort of punch out a plug, lift to clear and re do.
I have never done this before and was totally surprised at how easy it was.


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## sanddan

I had to pound in ground rods for my shop back in the day. Code at the time required them to be 6' down and at least 3' apart. We have clay soil so it was a bear to get that deep.


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## ch2co

I'm impressed! What a project. 
I don't remember, do you use electrostatic attraction in your spray booth? If so what do you use to power it, two balloons rubbed together or maybe a neon sign transformer? ;-}


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## brino

ch2co said:


> If so what do you use to power it, two balloons rubbed together or maybe a neon sign transformer?



I think he had a cat in a wheel bolted to the side, isn't that right @savarin ?
-brino


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## savarin

I have a cheap gun from Eastwood with no choice of Kv.
The major test of large parts will be this week hopefully.


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## ch2co

Keepin' the fingers crossed. 
You've gotta show us the results right away no matter how bad they are.


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## savarin

The very first powder coated project.
All the black parts of the telescope stand and I must say I was extremely  pleased with the finish and not difficult to do although its a bit messy with excess powder to clean up after spraying even in the booth.


Being gloss black it doesnt show in the photo but everyone who has seen it remarks on the glossy finish.


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## ch2co

Wow! beautiful job, and yes I can see reflections i.e. gloss finish.  A major accomplishment albeit maybe a bit messy?
Very cool.  Congratulations. The first time even!

Charles,  AKA the grumpy one


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## kd4gij

savarin said:


> If I was still building bikes then no but hopefully its large enough for any future projects such as the trusses for the binocular




 Famous last words.


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## savarin

Thanks Chuck. I am most impressed with the ease of use.
One lesson learnt is to make sure the hooks holding the items in the oven are strong enough to hold up.
The long section of the stand was held up with brass hook that straightened in the oven allowing the item to fall.
No damage to the oven but it did mar the paint at the top of the tube but it cant be seen as its covered up by the top aluminium casting. Phew!


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