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ARMORTHANE PROTECTING YOUR WORLD

PROTECTING YOUR WORLD

ARMORTHANE PROTECTING YOUR WORLD

Spray Foam
Proportioners:
How to Choose

How a plural-component proportioner meters, heats and pumps foam and polyurea, the main machine types, how to size one for your work, and what to check before you buy.
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Buying your first machine? Let us spec it.

Tell us what you will spray and how much. Our equipment team builds proportioners into complete rigs, with training included.

  • Foam, polyurea or both
  • Typical job size
  • Power on site or generator
  • Rig or shop setup
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1:1
Typical A to B mix ratio by volume
Product data sheets
2,000+
psi spray pressure common for polyurea
Product data sheets
~150°F
Typical material heat range starts here
Product data sheets
3
Machine drive types: electric, air, hydraulic
Industry practice

The proportioner is the heart of every spray foam and polyurea rig. It decides how much material you can spray in a day, how well the A and B sides mix, and how much downtime you lose to pressure and heat problems. ArmorThane designs and builds spray rigs in Springfield, Missouri, and this guide explains how proportioners work and how to pick one without overbuying or underbuying.

Quick answer

A spray foam proportioner is a plural-component pump that draws the isocyanate (A side) and resin (B side) from drums, meters them at a fixed ratio (usually 1:1 by volume), heats both and pushes them at high pressure through a heated hose to an impingement-mix spray gun. Machines are driven electrically, by air (pneumatic) or hydraulically. Choose by the output you need in pounds per minute, the heater wattage to reach your spray temperature, the hose length you will run and the power available on site.

What's in this guide
  1. 1How it works
  2. 2Machine types
  3. 3Sizing a machine
  4. 4Buying checklist
  5. 5Care and shutdown
  6. 6FAQ
Start here

How a proportioner works

Spray foam and polyurea are two liquids that react when they mix. The proportioner keeps them apart until the last moment, then delivers both at the right ratio, temperature and pressure so they mix completely in the gun. Get any of those three wrong and you get off-ratio material: soft or brittle foam, tacky polyurea, poor adhesion and wasted chemical.

Pump

Metering pumps

Paired pumps move equal volumes of A and B on every stroke to hold the ratio.

Heat

Primary heaters

Heat each side to the spray temperature on the data sheet, which lowers viscosity for a fine mix.

Hose

Heated hose

Keeps material at temperature from the machine to the gun, often over long runs.

Gun

Impingement gun

A and B collide at high pressure in a small mix chamber and leave the tip reacting.

Feed

Transfer pumps

Feed the proportioner from the drums at steady pressure so the pumps never starve.

Control

Controls and alarms

Display pressure, temperature and imbalance, and shut down before off-ratio spraying.

Compare

Electric vs air vs hydraulic

Drive typeHow it worksStrengthsWatch-outs
Pneumatic (air)Air motor drives the pumpsSimple, lower cost, light; good for smaller jobs and trainingNeeds a large compressor; output and pressure limits
ElectricElectric motor drives the pumpsEfficient and quiet, steady pressure, common in mid-size rigsNeeds adequate power or generator capacity
HydraulicHydraulic power pack drives the pumpsHigh output and pressure for big foam and polyurea workHigher cost, weight and generator demand
Typical characteristics. Machine manuals and manufacturer specs govern.
Polyurea needs pressureMost spray polyurea systems need higher pressure and heat than spray foam. If you plan to spray both, size the machine for polyurea.
Size it

How to size a proportioner

Output

Pounds per minute

Match maximum output to the biggest jobs you will spray, not the smallest. Commercial foam and roofing need more than small residential work.

Heat

Heater wattage

Cold climates, cold drums and high output all demand more heat to hold spray temperature.

Hose

Hose length

Long hose runs add pressure drop and heat loss. Plan for the farthest point on a typical job.

Power

Power on site

Electric machines need a generator sized for the proportioner, hose heat and compressor at full load.

Material

Foam vs polyurea

Polyurea and coatings usually need higher pressure and temperature than foam.

Support

Parts and service

A machine you cannot get parts for is downtime. Ask who stocks pumps, seals and heaters.

Our standard spray rigs pair the proportioner with a generator, air compressor and dryer, heated hose and drum storage sized to run together at full load. See spray foam rigs and polyurea spray rigs.

Buying

Proportioner buying checklist

  • What you will spray: open-cell, closed-cell, roofing foam, polyurea or all of them.
  • Output: maximum pounds per minute at your spray pressure.
  • Heat: primary heater wattage and hose heat for your climate.
  • Hose: standard length and how far it can be extended.
  • Data: pressure, temperature and ratio monitoring with job reports.
  • Training: who teaches your crew to set up, spray and troubleshoot.
  • Service: parts availability and response when the machine is down.
New vs usedA used machine can save money, but check pump hours, seals, heater condition and records. A rebuild can erase the savings quickly.
Keep it running

Proportioner care and shutdown

  1. Keep moisture out

    Isocyanate reacts with moisture. Use desiccant dryers on drums and keep the A side sealed.

  2. Watch the gauges

    Rising imbalance between A and B pressure is the first sign of a feed, filter or pump problem.

  3. Clean filters and screens

    Check inlet strainers and gun screens on a schedule.

  4. Lubricate pumps

    Keep the throat seal lubricant (TSL) cups topped and clean.

  5. Shut down correctly

    Park the pumps and follow the short and long term shutdown steps in our proportioner shutdown guide.

Spray equipment

Get a machine built for your work.

ArmorThane builds proportioners into complete foam and polyurea rigs and trains your crew to run them. Tell us what you will spray.

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FAQ

Spray foam proportioner questions

What is a spray foam proportioner?

It is the machine that meters, heats and pumps the two components of spray foam or polyurea to the spray gun at a fixed ratio and high pressure.

Can one proportioner spray foam and polyurea?

Yes, many machines spray both. Size it for polyurea, which typically needs higher pressure and temperature than foam.

Electric or pneumatic proportioner?

Pneumatic machines are simpler and lower cost for small work. Electric machines give steadier pressure and more output for production foam and polyurea, but need a generator sized for the full load.

How much does a spray foam proportioner cost?

Price depends on drive type, output, heat and controls, and whether it comes as a bare machine or a complete rig. Contact our equipment team for current pricing.

What causes off-ratio spraying?

Starved feed pumps, clogged screens, worn pump seals, wrong temperatures and pressure imbalance are the usual causes. Watch the gauges and stop spraying when pressures drift apart.

AT
Written by the ArmorThane technical team. We have manufactured polyurea, polyurethane and polyaspartic coatings, spray foam and plural-component spray equipment in Springfield, Missouri since 1989. Settings vary by product and machine; always follow the material data sheet and the equipment manual.

Sources

  1. Spray Polyurethane Foam Alliance, industry guidance and training. sprayfoam.org
  2. U.S. EPA, spray polyurethane foam safety information. archive.epa.gov/epa/saferchoice/spray-polyurethane-foam-spf-insulation-and-how-use-it-more-safely.html
  3. OSHA, isocyanates safety and health topic. osha.gov/isocyanates

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