Model Engineers’ Workshop – August 2019

litres and will accept most medium to
large workshop constructions.
The oven racks are an important part
of the coating process as it is necessary
to physically suspend the part in mid-air
while the powder is applied. After coating
the part needs to be transferred to the
oven for curing, so determine the size of
your spray booth by referring to the size
of your oven rack.
The most efficient way to build a small
part spray booth is to use a kitchen wall
cabinet carcass. 600mm is a standard
size. Wooden rails were added to allow
easy placement of the rack in and out. A

vent can be placed at the back with dust

filter media attached to the back. A fan

can create an airflow through the vent.

This will help control the powder over-

spray. Provision for a gun holder and

for keeping the ground line and air line

under control can prevent tangles and

jarring of the freshly coated work, as it is

transferred to the oven.

Powder Application

The goal is to have the powder exit the

gun in a party-balloon sized cloud, but

not under too much pressure. Too high a

pressure and the powder cloud is huge and

can dislodge any powder already applied

to the target object. If pressure is correct,

powder should look like light smoke. In

photo 14, the pressure was too high and

powder built up everywhere.

zTo be continued

13 14

A wall cabinet carcass and domestic oven complete the setup. Powder application.