You’ll see a variety of foams used by professional and home finishers - ranging from styrofoam to building insulation board. At its simplest, you want to use a sturdy foam that’s between a half inch and two inches thick (depending on the size of the stand up). But what foams are the best, and which are actually archival quality? I’ve done a deep dive into foam, what plastics the most accessible foams are made of, and which will last the longest. 

There are a lot of strong opinions on archival quality when it comes to using glue in needlepoint finishing. However, I haven’t seen discussion on a lot of the other materials used in finishing - foam being one of them!  Before we dive in, I want to include a caveat - you don’t have to be concerned about archival quality if you don’t want to be! As I talk about in my article on using glue in finishing, many needlepointers aren’t that concerned with their piece lasting hundreds of years. If you’re happily finishing your own stand ups and are just looking for an easily accessible foam, then choose a foam that’s easy to cut, and has the thickness and weight you want (I personally love a little denser foam that creates a heavier stand up). 

That being said, in an ideal world, we’d be using a foam that doesn’t off gas or degrade over time. 

I’ve ranked popular brands and easily accessible foams from best to worst. Below my rankings, I’ve expanded on the actual type of plastic these foams are made of, how they change over time, again ranked from best to worst. 

Popular Foams

Ethafoam:

Ranking - Great! Used in museum storage and conservation. It is stable and chemically inert. While it’s harder to get a hold of you can find it in our Stand Up Took Kit and on Finishing Fabrics.com. 

Styrofoam:

Ranking - Not the best. This is a polystyrene foam. It’s not stable but not your worst option either. Available at many craft stores like Micheals and Hobby Lobby. 

Insulation board (used in building, the kind you get it at Home Depot etc):

Ranking - Bad. Insulation board can be either polyurethane, polystyrene, or polyisocyanurate. None of these foams are archival. Additionally they can be treated with flame retardants. However, it has been used by professional finishers. Available at home/building and hardware stores. 

Floral Foam:

Ranking - Very bad. Many are polyurethane and absorb water and crumble easily. I would totally avoid floral foam as it’s not archival and also not that practical.

If you’ve picked up a foam that isn’t on this list, use the profiles below on different types of foams/plastics to see if it’s archival or not. Simply google, or do a little digging on the foam’s brand site to figure out what it’s made out of and compare it to the profiles below.

A deeper dive into the actual foams/plastics these popular foams are made from

Polyethylene

Polyethylene is stable and chemically inert (in other words, it doesn’t off gas). Not all polyethylene foams are created equal depending on the manufacturing. Ethafoam is specifically used in museums and conservation. My understanding is that blowing agents are used in manufacturing (which creates the cells of the foam). Depending on the blowing agent, or the purity of the blowing agent, it can introduce impurities that speed up deterioration. While this would be important for a museum (trying to preserve artifacts and art for as long as possible without degradation), I’m guessing that for a personal item that will be stored in your house the difference between a polyethylene manufactured with a pure blowing agent versus one that isn't, is negligible. BUT if you want the best of the best - use Ethafoam.  Volara is another brand name but this foam is denser, harder to cut, and doesn’t come in an easy to finish thickness. 

Polystyrene

Polystyrene is less stable and also off gasses acidic vapors. It degrades (it gets yellow and brittle) when it’s exposed to light though this shouldn’t be an issue for your stand up. 

Polyurethane

Polyurethane off gasses acidic vapors and crumbles over time. Some can get brittle in a few years and degrade complete in a few decades. It can also get sticky, though this might not be an issue since the foam is inside the stand up with layers between it and the needlepoint. 

Polyisocyanurate

Insulation board is sometimes made of "polyiso," however it was never even mentioned in any of the research I did through conservationists and museums as it’s primarily used in housing insulation. I would avoid it. 

My Favorite Foam

I recommend Ethafoam. I’ve personally used styrofoam and various polyethylene foams in the past. My favorite was a hard to get polyethylene with a dense structure and therefore heavier weight, heavier than Ethafoam (the density made the stand up feel and look fantastic). However, the density also made it harder to cut and insert the weight. Because I have a big roll I’m sure I’ll continue to use it but Ethafoam is my top choice. 

I hope this article was helpful to you! Comment with your thoughts and questions! (Note: we currently don’t have the capability to comment back on the blog - if you comment, be on the lookout for an emailed reply!). 

Xo Abby