Choosing between closed cell foam sheets AFP30 and AFP45 is mainly about how much structure and load-bearing resistance the project needs. Both are cross-linked polyethylene foam grades, but AFP45 is denser and resists compression more strongly, while AFP30 is the lighter general-purpose option.
The two grades can look similar in sheet form, so it is easy to assume that the higher number is always the better choice. It is not. The correct grade is the one that matches the load, thickness, environment and required rigidity without adding unnecessary stiffness.
The quick comparison
All Foam AFP30 has a nominal density of 30 kg/m³. Its current technical data gives a compression value of 62 kPa at 25% deflection.
AFP45 has a nominal density of 45 kg/m³ and a compression value of 100 kPa at 25% deflection under the stated test method.
In practical terms, AFP45 needs more force to reach the same level of compression. That makes it useful where an insert, gasket, liner or protective layer needs greater resistance under load.
AFP30 remains the better starting point for many lighter protective, lining and spacing jobs where the extra rigidity of AFP45 is not required.
What do AFP30 and AFP45 have in common?
Both products are cross-linked closed-cell polyethylene foams. The closed-cell structure gives them a different behaviour from flexible open-cell polyurethane used for upholstery and many cushioning applications.
They are both:
- lightweight compared with solid rubber or plastic
- structurally stable in sheet form
- suitable for clean-edged protective inserts and liners
- available in a wide choice of thicknesses
- supplied as unbacked sheets
- intended for applications where lower water uptake and a firmer structure are useful
- not sold by All Foam as fire-retardant grades
If you are still deciding between open-cell and closed-cell materials, read the open cell vs closed cell foam guide before choosing a density.
AFP30: the lighter general-purpose polyethylene grade
AFP30 has a nominal density of 30 kg/m³. It is a rigid cross-linked polyethylene foam with a sealed cell structure, supplied by All Foam in black or white.
Its current data sheet identifies it for industrial and commercial packaging, medium-weight impact protection, flotation aids, marine applications, thermal and acoustic insulation, anti-vibration mounting, and general gasket or seal stock.
That list does not mean one sheet is automatically suitable for every job in those categories. Load, thickness, contact area, temperature, movement and any regulatory requirement still have to be considered.
For ordinary protective lining, separators, simple case inserts and medium-weight packaging, AFP30 is usually the logical grade to compare first.
AFP45: when greater resistance under load matters
AFP45 raises the nominal density to 45 kg/m³ and has a higher stated compression value than AFP30.
All Foam's technical data describes it for heavier industrial and commercial packaging, more rigid case inserts, structural gaskets and seals, marine and outdoor applications, and higher-density insulation work.
The important phrase is "where the load-bearing performance of AFP30 is insufficient". AFP45 should be selected because the project needs the additional resistance, not simply because 45 is a larger number.
A heavier instrument, dense metal component or narrow load-bearing contact area can place much more stress on an insert than a lightweight product with a broad base. In those situations, the firmer grade may hold its shape more effectively.
Density is not the same as thickness
Density describes how much material is present within a given volume of foam. Thickness describes the physical depth of the sheet.
A 10mm AFP45 sheet is not automatically a substitute for a 25mm AFP30 sheet. Changing thickness changes the available cushioning distance, geometry and stiffness of the finished assembly.
Choose density and thickness together.
For protective packaging, the packaging foam thickness guide explains why item weight, fragility, clearance and journey conditions all matter.
Which grade is better for case inserts?
For a lightweight tool, sample, instrument or presentation item, AFP30 can provide a clean, firm insert without unnecessary rigidity.
AFP45 becomes more relevant as the item gets heavier, the contact area becomes smaller or the insert walls need to resist greater deformation.
Think about the complete insert:
- base thickness beneath the item
- side-wall thickness
- narrow sections between cavities
- lid clearance
- direction in which the case is carried
- whether the item is repeatedly removed and replaced
A case insert fails as a system, not simply because one density number is wrong. A well-chosen grade can still perform poorly if cavities are too close together or the base is too thin.
For more detailed packaging guidance, see closed cell polyethylene foam for protective packaging.
Which is better for gaskets and seals?
AFP30 and AFP45 can both be used as firm gasket or seal stock where polyethylene is appropriate.
The choice depends on the required compression and movement. A seal needs enough compression to make contact, but a foam that is too stiff for the joint may not conform properly.
For applications that need a more flexible rubber material and resistance to UV, ozone or weather exposure, EPDM closed cell rubber foam may be the better material family to compare.
Do not select a gasket solely by density. Check the joint design, mating surfaces, expected movement, exposure and any pressure or regulatory requirement.
Water and damp environments
AFP30 is described in the current All Foam data sheet as waterproof and non-absorbent. It also has WRAS approval for cold-water use.
AFP45 has a stated maximum water absorption of 1% by volume in the current technical data and is used where a denser closed-cell structure is required.
These properties make both grades relevant for suitable damp or water-related projects, but they do not mean every installation is automatically approved for drinking water, marine safety, flotation or another regulated use.
The complete assembly still needs to meet the requirements of the application.
What does WRAS approval on AFP30 mean?
The current AFP30 technical data states that the grade is WRAS approved for cold-water use.
That is useful product information, but it should not be stretched into a broader claim. WRAS approval for the material does not automatically certify every finished product, joint, tank, flotation device or drinking-water installation made with it.
For regulated or safety-critical work, confirm the exact requirements of the complete system before ordering.
Which grade is better for outdoor projects?
Closed-cell polyethylene can be considered for suitable outdoor-related applications because of its low water uptake and stable structure.
AFP45 is identified in the All Foam data sheet for marine and outdoor applications where greater load-bearing performance is needed. AFP30 is also listed for marine uses.
However, polyethylene and EPDM solve different problems. Where ongoing UV, ozone and weather exposure is central to the job, the current EPDM foam sheet is specifically described for weather-resistant sealing applications.
Choose the material family first, then choose density and thickness.
When AFP30 is usually the better starting point
Consider AFP30 first when the job involves:
- lightweight or medium-weight protective inserts
- case and drawer lining
- separators and spacers
- general protective pads
- medium-load packaging
- a black or white rigid polyethylene sheet
- a project where AFP45 would be unnecessarily stiff
This does not make AFP30 a "soft" foam. It is still a rigid cross-linked polyethylene material compared with flexible upholstery foam.
When AFP45 deserves closer consideration
AFP45 is worth comparing when the project involves:
- heavier tools or components
- firmer reusable case inserts
- industrial protective packing
- structural gasket or seal stock
- narrower load-bearing areas
- higher resistance to compression
- a project where AFP30 compresses or flexes more than the design allows
If you are uncertain, the most useful information to provide All Foam is the item weight, contact area, finished dimensions, available foam depth and expected use.
What about Plastazote LD33?
Plastazote LD33 sits between AFP30 and AFP45 numerically at a nominal density of 33 kg/m³, but it should not be treated as "AFP33".
It is a nitrogen-expanded cross-linked polyethylene foam with a fine cell structure, several colour options and good fabrication qualities. It is particularly useful for presentation inserts, shadow boards, props and projects where appearance and workability matter.
Read the Plastazote foam sheets guide if the project needs colour, detailed fabrication or a more presentation-focused finish.
Fixing AFP30 and AFP45
The current AFP30 and AFP45 sheets are supplied unbacked, so the fixing method can be selected separately for the finished application.
Backing can simplify installation on clean, dry and compatible surfaces, but it is not always the right choice. If a liner needs to be removable, repositioned or replaced later, plain foam may be easier to work with.
Adhesive also does not make an unsuitable surface suitable. Dust, moisture, texture, plasticisers and surface coatings can all affect bonding.
Common mistakes when choosing AFP30 or AFP45
- Assuming AFP45 is always better because it is denser.
- Choosing density without considering thickness.
- Using a rigid PE foam where flexible EPDM is actually required.
- Treating WRAS approval as approval of the complete installation.
- Assuming closed cell means fire retardant.
- Making case insert walls too thin.
- Ignoring the item's weight and contact area.
- Choosing a bonding system without checking the surface.
- Copying another project without comparing loads and dimensions.
Quick answers about AFP30 and AFP45
What is the main difference between AFP30 and AFP45?
AFP30 has a nominal density of 30 kg/m³, while AFP45 has a nominal density of 45 kg/m³. AFP45 also has a higher stated compression resistance, so it is chosen when greater load-bearing support is required.
Is AFP45 always better than AFP30?
No. AFP45 is useful when additional rigidity is needed. AFP30 is often the more appropriate general-purpose grade for lighter protective, lining and spacing jobs.
Is AFP30 waterproof?
The current All Foam AFP30 data sheet describes it as waterproof and non-absorbent. Product suitability still needs to be checked for the complete application.
Can AFP30 and AFP45 be used outdoors?
Both can be considered for suitable water-related or outdoor applications, with AFP45 specifically listed for marine and outdoor uses in its current data sheet. Where UV, ozone and long-term weather resistance are key, compare EPDM as a separate material option.
Are AFP30 and AFP45 fire retardant?
No. All Foam does not offer AFP30 or AFP45 as fire-retardant grades. If the project has a fire-performance requirement, confirm the required classification before choosing material.
