Pouring 2-Part Polyurethane Liquid Foam

Our 2-Part PU (Polyurethane) Liquid forms a high strength, rigid, closed-cell foam – perfect for filling cavities from 50mm-300mm wide, and for buoyancy applications. It expands to up to 25 times its original volume, reaching its maximum rise in just 150 seconds!

Take a look at our video below, as you will see – 2-Part PU Foam is very simple to use, and if you’re a bit short on your first pour it’s definitely not the end of the world – just top it up!

A step-by step guide to mixing and pouring 2-Part Polyurethane Foam

You will need:

Use two plastic cups to measure out an equal volume of each part.
Aerate part A by agitating vigorously with a mixing stick.
Then pour both components into a larger mixing container.
Stir thoroughly but quickly - the mixture will begin to foam in 25-35 seconds.
Pour into the cavity to be filled.
Leave to set! It will reach a sticky condition in about 4 minutes and will be completely cured in about half an hour.

NOTES:

Deep cavities should be filled with layers of foam about 25mm deep, as the exotherm (internal heat) generated during the curing process increases with greater volumes.
The uncured mix is highly adhesive and will bond to most materials.
Whilst the mixture is foaming, take care not to inhale the fumes.
Insufficient foam may be generated due to:
- incorrect proportions of components
- inadequate mixing
- too low working temperature (optimum working temperatures is 20^oC) - do not use below 10^oC or using a restricted mould.

How to calculate the volume of PU Foam Liquid required

We supply our 2-Part PU Foam in several pack sizes to make it easier to buy the right amount.

To calculate how much 2-Part PU Foam you need, follow the steps below.

Measure the length, width and height of your cavity or mould in metres. Multiply to get the volume, then divide by 0.0283 to find the weight of liquid foam required to fill it.

(Length (m) x Width (m) x Height (m)) / 0.0283 = Weight (kg)

e.g. 0.5m (l) x 0.5m (w) x 0.5m (h) = 0.13m³

0.13 / 0.0283 = 4.59kg of liquid foam (5kg Pack)

0.0283m³ of hollow buoyancy tank provides 28kg of positive buoyancy in fresh water and about 30kg in sea water.

Polyurethane foam gives about 27kg buoyancy per m³.

What are the benefits of 2-Part Polyurethane Foam?

It’s very simple to use - immediately after mixing, it is simply poured into the cavity to be filled, then left to foam and cure.
Fast curing – completely cured in 30 minutes.
It is extremely buoyant – 1kg of liquid mix will produce approximately 0.08m² of rigid foam, which will support about 27kg in fresh water (30kg in sea water).
It’s very stiff, while also being lightweight.
It has good thermal insulation properties.
It’s resistant to benzine, diesel oils, acids and alkalis (in normal concentrations).

What is 2-Part PU Foam used for?

Filling masts and booms
Buoyancy chambers on small water craft
Filling the bow and stern sections of canoes
Producing lightweight moulded items
Acoustic and thermal insulation

How to produce PU foam mouldings

The foam can also be used (with a suitable release agent) to produce lightweight moulded items. Wood, fibreglass, or metal moulds can be used and are produced in the same way as those for fibreglass laminating. However, due to the pressure generated by the foam, the mould needs to be considerably stronger than normal, and with a split mould, the separate parts must be securely bolted together.

A typical use for this technique is in the construction of sailboard hulls, in which case a suitable laminated shell is required to provide the necessary strength. (The foam mix, being designed to produce maximum buoyancy, is of comparatively low density so it is not overly strong).

Storage, handling, and safety measures

The two separate components will remain stable for at least six months, if stored in sealed cans in dry conditions.

Storage temperatures should not exceed 20^oC.

Contamination of the materials by moisture must be avoided.

Part B compound is an isocyanate - care must be taken to avoid contact with the skin or eyes.

You should also avoid breathing the fumes.

Always work in a well-ventilated room or in the open air.

If the foam mix is in contact with the skin or eyes, flush IMMEDIATELY, with copious amount of water. If irritations persists, consult a doctor.

Medical aid should also be obtained if excessive inhalation occurs or if any material is swallowed.

Always exercise care when opening cans, as pressure can build up in the container.

In case of fire, always use dry powder extinguishers.

Spillage and disposal

Spillages should be soaked up in rags or cotton waste, and the area sprinkled with sand or sawdust. This should be left for at least ten minutes, then swept up and the area washed. The waste should be soaked in water before disposal. When dealing with a large spillage, protective clothing and respirators should be worn because of the danger of fumes.

We hope you have found this guide useful. If you'd like any further information or need some help, please call us on 01209 821028 or email us.