Specifications

Introduction
The various types of hose used to
carry compressed air and fluid
material to the spray gun are
important parts of the system.
Improperly selected or maintained
hose can create a number of
problems. This chapter will review
the different kinds of hose and
fittings in use, provide guidance in
selecting the proper types for the
job and cover the maintenance of
hose.
1. What types of hose are used in
spray painting?
There are two types: air hose –
used to transfer compressed air
from the air source to the gun, and
fluid hose – used only in pressure
feed systems to transfer the
material from its container to the
spray gun.
(NOTE: Do not use air hose for
solvent-based materials.)
Figure 1 - Basic Hose Construction
2. How is hose constructed?
DeVilbiss hose is a performance
designed combination of three
com-ponents: Tube A,
Reinforcement B and Cover C.
The tube is the interior flexible
artery that carries air or fluid
material from one end of the hose
to the other.
The reinforcement adds strength to
the hose. It is located between the
tube and cover, and it can be many
combinations of materials and
reinforcement design. Its design
determines pressure rating,
flexibility, kink and stretch
resistance and coupling retention.
The cover is the outer skin of the
hose. It protects the reinforcement
from contact with oils, moisture,
solvents and abrasive objects. The
cover protects the reinforcement,
but does not contribute to hose
performance.
3. What type of tube is used in
fluid hose?
Since the solvents in coatings
would readily attack and destroy
ordinary rubber compounds, fluid
hose is lined with special solvent-
resistant nylon material that is
impervious to common solvents.
4. What sizes of fluid hose are
recommended?
Figure 2 - Recommended fluid hose
sizes
5. What sizes of air hose are
recommended?
The hose from the regulator to a
gun or tank should be a minimum
of 5/16" ID. Tools requiring more air
may need 3/8" I.D. hose or larger.
Figure 3 - Recommended air
hose sizes
6. What is pressure drop?
This is the loss of air pressure due
to friction (caused by air flow)
between the source of the air and
the point of use. As the air travels
through the hose or pipe, it rubs
against the walls. It loses energy,
pressure and volume as it goes.
7. How can this pressure drop be
determined?
At low pressure, with short lengths
of hose, pressure drop is not
particularly significant. As pressure
increases, and hose is lengthened,
the pressure rapidly drops and
must be adjusted.
All air hose is subject to pressure
loss or drop. For example, 1/4"
pressure drop is 1 psi per foot and
5/16" is 1/2 psi per foot. This
pressure loss may result in poor
atomization.
Too often, a tool is blamed for
malfunctioning, when the real
cause is an inadequate supply of
compressed air due to an
undersized I.D. hose.
4. Hoses & Connections
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RED or TAN ...........air and water
GREY............air w/static ground
BLACK ..........low pressure fluid
DeVilbiss hose is color-coded:
Type Length Size
General 0' - 20' 1/4" ID
Purpose 10' - 35' 3/8" ID
35' - 100' 1/2" ID
100' - 200' 3/4" ID
Type Length Size
0' - 10' 1/4" ID
General 10' - 20' 5/16" ID
Purpose 20' - 50' 3/8" ID
50' - 100' 1/2" ID
0' to 20' 5/16" ID
HVLP 20' - 50' 3/8" ID
50' - 100' 1/2" ID