"Best glue for building layers of insulation foam?" Topic

Okay, I've got two 4x8 foot sheetsof pink insulation Styrofoam ready to go. I think the stuff is about a quarter-inch thick and I'm planning to layer it to build a Boot Hill graveyard for my Wild West game.

Now, what's the best glue for adhering the sheets prior to cutting?

I have Elmer's, Super Glue Gel, Gorilla Glue, and Decoupage. I really do NOT want to go out any buy styro glue. So, what's the best glue?

Or, should I just use the Elmer's and then, after I'm done cutting the shape I want, sink some thin wire into it to add stability?

I'm VERY open to suggestions, here.

I've heard Liquid Nails works well.

I usually use standard PVA glue. Takes a while (overnight at least) to dry, but if you're patient then I'd suggest this.
Cheers,
Iain
thehobbybox.biz

PVA is no good, takes forever. I'd go with Liquid Nails which has a more predictable setting time.

What's the setting time for Liquid Nails? I could pick some up at Sears Hardware tomorrow…

I just finished making a mountain range using both 1.5 inch pink board and 2 inch blue board (I like blue board just a tad bit better). The different levels were glued together with Elmers Carpenters glue (the tan stuff). I also inserted thin finishing nails for added stability. The finishing nails were inserted at all different angles (Not straight in). I just let the whole thing dry overnight, and it was perfectly fine.

The next day, it was time for the box cutters, rock smash impressions, etc. But that is another story….

Tangential, but I can never find the thicker, blue stuff. All I can ever get is the pink board.

So if you liqui-nail the pieces together, how do hills look when you've cut 'em out? Are the various levels obvious?

PVA has worked a treat for me for years. Tried liquid nails but foam cutter didn't like it too much….

I'm with Grey Ronin on this. If you intend to shape later then don't use the 'rubbery' construction adhesives, they are a swine to cut through once dry.

Plan ahead and use PVA about 2 days before you need to work with it. You may get lucky and have it set in 12 hours but, for safety's sake, I'd leave it at least 24 and better 48 hours.

Use small blobs of glue and 'wiggle' the surfaces to spread the blobs a bit – don't apply a complete layer of PVA as you can get shrinkage effects and warping sometimes. Dry under weights (doesn't need much – a couple of books is what I use) and it should come out fine.

Tony Hughes

PVAs generally require air contact to dry – if you glue dense closed-cell insulation board with a glue like that then it will only stick at the edges where the glue dries and will never glue in the middle. Same applies for any air-drying glue.The majority of the tack where air-dry glues are used between closed-cell styrofoams is from surface tension(?). We've split two sheets of styrofoam apart after being glued with PVA after they have been left to stick for 4 weeks – the glue in the middle was totally liquid.

Thus – It's generally best to use a contact cement like "UHU POR" or a specialised Styrofoam glue such as "Foam-2-Foam" but if you really dont want the 'expense' then use a tacky glue: Coat both surfaces with tacky glue and allow to go semi-dry, then press together the two sheets and leave for 24-48 hours.

As with the other air-dry glues the glue will only go solid on the edges and a short penetrative distance inwards – but as the glue is aready partially dried you will get a better tack internally.

Of course PVA *does* work, albeit in the manner descrobed at the top, so you *Can* still use that – a lot depends on the end use of the materials. For simply gluing one sheet on top of another to make a hill then it doesn't really matter *that much* if you use PVA as there will be no real lateral pressure applied to the sheets.

You can also strengthen with wire but we'd advise (strong steel) Piano wire .055 from K&S in the USA is ideal.

The other key element to gluing styrofoam is the "edge Effect" of glues.
Most glues will change the nature of the material at the join, leaving a harder line throughout the foam which is often hard to disguise. This is one reason why a proper contact styrofoam glue is better as you are not forced to put glue near the edges – instead you can keep all glue a few mm or CMs from teh edge which elaves plenty of room for sanding without encountering a hard edge that will show through any groundwork/painting and so forth.

If you're not sure of the differences between polystyrene (packaging) and Styrofoam and foam board this might help: link

Obviously if the material you are using is an open-cell non-airtight product then PVA and similar air-dry glues will work fine.

Forgot to add – we always cut before gluing Styrofoam – even if you want to cut multiple sheets together, just adhere them with a waxy glue (prit-stick, modelling wax etc) or use pins.

If the insulation board is not a styrofoam based product and is somethng like phenolic foam or a PMI Hard Foam then you can use other glues, even superglue. You *can* also use superglues on styrofoam depending on density and/or the use of a sealant such as Foam-Blaster prior to gluing with cyanos.

I use Aleens Tacky Glue nfound in many craft stores in a gold bottle. I find it adheres better than Elmers. I also use bamboo skewers to pin the foam. I make a pilot hole, fill with glue and push the skewer through and into the next piece. I do so at an angle and then put a second parallel piece in the opposite way. I use the skewers on angles because it is similar to a rough framing carpentry technique when nailing to keep the pieces of wood from separating. The excess skewer is clipped down to the surface of the foam and reused for subsequent pins. I usually only pin the corners and along the sides of long pieces to prevent separation when handling the terrain.

I just finished a project with white glue – it worked alright, but as noted above it took forever to dry.

My brother called me last night and said that he just tried a spray adhesive that he has (sorry, don't know the name, but I can get it for you if you like). Supposedly it worked beautifully. I was sure a spray would ruin the foam but it looks like it doesn't! Next time I'll use the spray for sure.

I would advise against PVA for the reasons that Antenociti mentions. I experimented with it and found that after 23 days PVA was still liquid for the most part in a 2'x2' area.

I often have shape things from foam that make pre-cutting the foam impossible and don't like liquid nails due to the problems with cutting through it, but it can work for terrain, I know some RR modelers that won't go any other way. I just find it a pain.

I'm often tasked with building large terrain models (up to around 300 square feet) in 3-5 days with need to match a survey for accuracy. The only way I can get these done is by using spray adhesives. For years, I used 3M super 77, but they have changed it chemically such that it can attack polystyrene insulation board. It can still be used, but the can has to be held at such a distance from the foam to allow for whatever the attacking agent is to evaporate or react otherwise prior to making contact with the foam. I have also experimented with several different brands of foam spray adhesives that you can buy at some of the large craft store chains, and all have worked well with no delaminations after at least 18 months. The foam insulation spray sold at DIY stores did not work very well as it is low tack and very thick, it readily pulled apart after setting up and make thick irregular seams between layers of foam.

The downside of spray adhesives can be cost, overspray which makes quite a mess, and a minor case of the surface hardening mentioned by Antenociti (who based on my experiences knows what he's talking about).

Also, in rare instances, I've used long drywall screws in place of nails or metal pins to help stabilize foam laminations.

With regard to bbuggeln's comment on foam and spray, be sure to test the spray on a piece of foam before working with it if you are not sure that it works. Read the info on the can as most that attack foam will state as much, some that will don't mention it though. Some like 3M's Super 90 will leave you with a puddle. Two that work (and that I have on hand and thus can mention by name) are Surebonder's Flora Bond, and 3M Spray Adhesive for Styrofoam (cat no. 6070). These were purchased at craft stores. When picking out a spray, be sure to look for one that yields a permanent bond. Some are designed for low tack application allowing repositioning and temporary bonds.

I second 3M spray adhesive.

mmitchel

Gosh, all this advice over glue.

Here you go:
1) Don't use PVA
2) Use the following VERSION of Liauid Nails (I'm readking the container now):

Liquid Nails Adhesive PROJECTS & Foamboard, part # LN-604

That's it. Done. You will get a perfect bond AND you can even glue other items such as metal wood etc.. TO the pink or blue board should you have the need.

We use 2 part epoxy. Works like a dream.

KAM

..(if even lists "Styrofoam board insulation" on the side)..

I've done this for years, buy a 2.00 applicator and you'll never look back.

Should say …(IT even lists….)

I have used Gorilla Glue with pink insulation foam and it works extremely well.

Excuse my ignorance but what is a 2.00 applicator?

The two adhesives I have started to use on large and small terrain projects using foam are:

FOAM-LOK Adhesive which is a spray adhesive designed for the foam industry. Good and fast drying

Titebond Polyurethane Liquid Glue which is a foaming glue similar to Gorilla Glue. The nice thing about this stuff is that it does not spread the foam apart like gorilla glue can do. This stuff is my favorite. Drys in about 4 hours (I like to leave it longer).

Both of these glues work best when the items to be bonded are weighted down following gluing (helps reduce the limited warping that may occur). Also, both glues can be used and cut with hot wires and hot knives, reducing effort on some projects.

I sell both of these and have them in stock if interested.

Foam-Lok Adhesive is $9.00 USD (must ship UPS due to flammability)
Titebond is $10.00 USD and can ship USPS.

After much trial and error I prefer these adhesives over all others, so I have started carrying them. I prefer these over liquid nails. I have found that the bond on the Titebond will not break, the foam will fail before the glue bond.

Doug
BTC

PVA is what I have used on a significant number of projects which have all dried adequately within 48 hours for some pretty rough shaping methods (even used a wood rasp on one).

Maybe it is the small air gaps produced by the blobs that allows it to set enough, or the rough surfaces of the sheets, I don't know. What I do know is that it worked, that's enough for me.

I will gladly admit that, in theory, it shouldn't work as well but I was only gluing items up to 300mm square and that MAY make all the difference. I also tend to press the surfaces together and then separate them for a few minutes before the final bond – that may also make a difference.

Personally I find that PVA makes by far the best all round adhesive and sealant. I use it for basing, temporary tacking of figures to bases for painting, sealing MDF and plaster and gluing flock to bases as well as building paper models and on wooden bits on buildings. I even find it works well enough for small metal parts where they won't get knocked about. It has the added advantage of being removable in most cases with a firm blade and some leverage.

Tony Hughes

""Maybe it is the small air gaps produced by the blobs that allows it to set enough, or the rough surfaces of the sheets, I don't know""

sounds like expanded polystyrene and not styrofoam – ExPS is not air tight.

See link for images for you to tell the difference link

"Excuse my ignorance but what is a 2.00 applicator?"

Probably the cheapest caulking gun frame available, since Liquid Nails comes in a caulk tube.

Re Foamboard -

I have found that Home Depot carries the pink and not all stores have the 2" thick stuff and Lowes carries the Blue and has the thick stuff.

I got the blue through Home Depot, though only via a special order. I think it depends on regional supply.

Liquid Nails or Goop (there are lots of variants of Goop, but the only real differenece is the label).

I've used Rubber cement. The stuff that kids would use in grade school to make fake boogers. There is a trick. You have to 'Dry Mount' it. Put a layer of rubber cement on each side that is going to be fixed together. Let them dry completely. After they are dry line the two sheets up and press them together. It is almost impossible to separate the two sheets. You can sand, saw, cut, and shape the glued together sheets. I've made subtractive sculptures for a 3-D design class using this method.

Last time I glued large amounts of blue board together, I used PVA. I was reshaping some hills a couple of months ago and the bond broke, so it's not the greatest method of glueing (but as mentioned above, you don't usually put alot of lateral stress on hills, so it doesn't matter).

What I do remember, is that the blue board I had, had a thin "skin" which you could peel off. When you peeled this skin off before glueing, it stuck much much better.

Trade names – always gets you in trouble identifying stuff between continents. I used the polystyrene stuff but it was denser than the stuff used in most packaging and had smaller 'lumps' as well.

I tried to get hold of the other denser stuff you mentioned, a mate in the trade gave me a UK trade name, but I couldn't find any local stockists and the firms on the net will sell you a lorry load but not a couple of sheets.

Buildings are made of different stuff here in the UK so maybe there isn't much call for it. The underfloor insulation laid in the building just being built over the road is the same as I bought (I know that, I checked) but much thicker.

I have seen 'Foamcore' board in artists' suupliers but it seemed very expensive.

Tony H

"""I tried to get hold of the other denser stuff *snip* will sell you a lorry load but not a couple of sheets."""

You can get most from sheffins.co.uk who supply a good range of insulation boards from 10mm to 75mm thicknesses, but you're right that often they will only sell in bulk or pallet.

We sell 10mm sheets of it (Styrofoam)… will soon have 5mm, 25mm and 50mm also.

Wow. Lots of advice to ponder! Thanks, guys.

Here's some more info:

I have sheets of 1/2 inch thick Extruded Polystyrene insulatio sheets. I bought them at Home Depot. I have peeled off the think plastic layer and will be applying the glue to the Polystyrene itself.

I plan to shape with a hot wire cutter made by Woodland Scenics (it's sold for model trains). Any experience on how the glue will react to the heat? I plan to do it outside and will use a high-quality painters mask for the fumes.

——————-

By the way, I have created three small hills with PVA glue, but have decided I want to make something bigger and more impressive, so I'm going to start over with something else. I will, however, keep the three hills and test them tomorrow or Friday with the hot wire.

MMitchell, don't worry about the plastic layer you can cut through that. Gorilla glue will work like a champ. So will some spray adhesives and contact cements. PVA will work, it just takes a while to dry. I've used PVA,Gorilla and spray adhesives to excellent effect. Good luck on your project.

What plastic layer, is this just on the thin boards because the 1 inch and above pink boards have no such layer. I've seen a metallic like layer on some thin boards, is this what you mean?

paneling cement or gorilla glue is probably the best. The better white glues will work too.

I've removed the plastic layer (a clear plastic sheeting) from both the thin and thick versions of the blue board. I don't remember it being on the pink board.

The plastic layer (on the 1/2 inch pink board) was a VERY thin, transparent layer of plastic. It was very easy to peel off, and I think it was there to keep the company info from smudging off during transport.

I wound up using watered Elmer's Glue and it seems to have done a great job.

Here's some VERY preliminary photos of my progress thus far:
link