DIY Powder Coating Oven for £100

• 205L Drum with a cover and steel collar (45 Gallon Drum). £38
• Professional Hot Air Gun with variable temperature control. £25
• Digital Thermometer food probe. £10
• Loft insulation (we used Rockwool Thermal Insulation). £30

205L (45 Gallon) Steel Drum

We started by buying a clean 205-litre (60 x 60 x 86 cm) oil drum from Amazon for £37 delivered. We purposely didn’t want an oil drum that had been used with oil because it may create fumes or catch fire when curing. We also selected a drum with a lid and snap ring to keep it shut.

First, we drilled a 40mm diameter hole 80mm up from the bottom and a 5 mm hole halfway up the drum. The 40mm hole will be used to insert the hot air gun through, and the 5mm hole will insert a food probe.

As a nice feature, we also fashioned a bracket to support the hot air gun out of some mild steel plate.

 We made sure the bracket didn’t obscure the air intake of our hot air gun.

After fitting the bracket with screws (but rivets would be ok), we wrapped 100mm thick insulation around the drum with a cutout where the hot air gun and bracket are located. We initially held the insulation in place with duct tape, then wrapped it completely with black packaging wrap. This wrap held the insulation secure and prevented the annoying fibres making your skin itchy!

 When handling loft insulation, it would be advisable to wear gloves and a partial P2 paper mask.

We then fully inserted the food probe and secured it with some tape.

With the heat gun, we inserted the first step on the nozzle into the hole and let it rest in position without securing it.

Finally, we fitted a handle to the lid to make it easier to lift off.

Okay, so the oven is built! But we now had to think about how to suspend parts in the oven. Initially, we fixed two Riv-nuts opposite each other near the top of the drum and fixed some Mig wire in-between them so we could suspend parts. This could equally be a mesh frame or lugs mounted to the wall sides such that a frame holding the part (like a wheel) could be lowered into the drum for curing. We will be featuring this oven in future blogs, showing some different methods of supporting parts in this style of oven.

So, we’re now ready to cure parts. After putting the part in the oven and clipping the lid on, we started the heat gun up on full power and air flow. Once our oven reached 180 °C in around 10 minutes, it then continued to climb in temperature; thus we turned the heat dial on the gun down to number 6 (on this model). At this setting, it held the temperature within in +/- 10 °C of 180 °C and was ideal for the part we cured.

If we didn’t have a variable heat gun we would have had to manually control the heat gun temperature for the 10 minutes cure time.

 That with thin gauge parts, the air temperature is roughly the part temperature; however, with thicker gauge parts like brake callipers, you may need to wait a little longer for the part to match the air temperature before starting your 10-minute timer. This is best checked with an infrared probe. We would create an access window by adding a small hole in the lid (around 40mm) and having a rotating plate to cover it when not in use.

After the curing cycle was complete, we unclipped the lid and (carefully) lifted the lid off, wearing a leather glove as the handle was still hot and let the part cool down.

The results were perfect! Thus, we can fully recommend this build of oven. We have used this oven many times now, and it never fails to surprise us how this simple, lowcost build can produce such professional results.

Improvements
We added wheels to the base to make it easy to move around the workshop. The ones we used were 2” diameter non-braked (braked ones catch the lip of the drum). We drilled and bolted these through.

This addition did bring with it a problem, though... We found that lifting the drum off the floor reduces its insulation and slightly increases the heat-up time. The simple solution to this was to drop a disc (we used 1mm aluminium) in the base, and it insulated the base. We tried to improve this by adding insulation to between the base of the drum and the aluminium disc, but it didn’t make any difference; thus we just stuck with just the aluminium disc in the base.

One of our next improvements is to add an aluminium wrap around the insulation to make it look better and less vulnerable to knocks.