Options to Hard Coat Styrofoam.

dr_slurpee

Sr Member
RPF PREMIUM MEMBER
I am in need of a cheap option to give a thin hard coat to blue/pink styrofoam to protect it from the odd bump or scuff. Something home brew rather than the usually quite expensive commercial products for it.

I do realize that a thin coat can only provide limited protection, just don't want it to be instantly damaged by every little thing.

Anyone got any methods or suggestions?
 
Polyester resin mixed with auto body filler to make a paintable plastic works well on the cheap

And it will melt the raw foam... You would need to seal the foam first if you use polyester...

Brushed or rolled on layers of white glue or Mod Podge (it's just white glue) will be the cheap option...

If you want a more 'rock' like surface, a 50/50 (give or take) blend of a latex primer and plaster joint compound rolled on will get a real hard coating...
 
elmers glue

Second that, I just built my kids a 7.5 foot tall fake tree that holds a 32" flat screen for their playroom, I used styrofoam for the tree and coated it in layers of Elmers glue and brown felt, glue worked like a charm. Easy to use, non-toxic, and easy to clean up!
 
coated it in layers of Elmers glue and brown felt

On that same note you can use white glue and newspaper, basically doing paper mache with a white glue it will even provide more of a shell... Of course only if layering paper mache is applicable to the design...
 
Haven't tried it yet, but the product seems solid (no pun intended) enough: Hotwire*Foam*Factory*::*6....

And if you need extra hardness, try a pre-coat of: Hotwire*Foam*Factory*::*6....

For $10 to $20 it's worth exploring. ;)

From what I gather, several who have used the above say it's just a repackaged plaster or tile grout so an acrylic binder should be added if you want strength... The 'real' foam coat they are ripping off is calcium carbonate powder and an acrylic binder, nothing fancy either... In short if you do the 50/50 mixture of plaster joint compound and paint as I suggested you are basically getting the same type of coating in poor mans land...
 
I have used the white glue method with good results with paper towel if you need a texture. The felt is a great idea. I wouldn't think a plaster based coating would stick or be very durable.

Tommy
 
You can try playing with the variations of what is known as "scenic dope" in the theatre world. exoray already mentioned the foundation of the recipe: an even mix of latex primer and joint compound. You can also mix in additives such as latex (not silicone) caulk or water putty depending on your needs.

ControlBooth talks about coating foam a lot, and this thread is a good place to start your search: Van's Super Scenic Dope Recipie?
 
On that same note you can use white glue and newspaper, basically doing paper mache with a white glue it will even provide more of a shell... Of course only if layering paper mache is applicable to the design...

Yeah, I went with the brown felt because once the glue dries clear it gave it a nice color that I lightly painted over. Also, the felt soaked in glue made it a little more sturdier than the newspaper because it is thicker.

The felt was harder to work with though, if you have hard angles, or odd shapes, definitely go with newspaper. It all depends on what you are covering.
 
From what I gather, several who have used the above say it's just a repackaged plaster or tile grout so an acrylic binder should be added if you want strength... The 'real' foam coat they are ripping off is calcium carbonate powder and an acrylic binder, nothing fancy either... In short if you do the 50/50 mixture of plaster joint compound and paint as I suggested you are basically getting the same type of coating in poor mans land...

Heh, good to know. Guess I won't be wasting my money on stuff I already have laying around my shop... thanks for the heads-up! :thumbsup

Oh yeah, sorry for suggesting those links. I just saw it one day browsing around for foam coatings and thought it was a new formula... go figure. :unsure
 
New guy here. I've been looking around for away to hardcoat some pink/green foam insulation and stumbled on the RPF forum. I'm building a Boba Fett costume for my son for Halloween and need a way to coat some of the foam parts for painting and some dent resistance. I've got latex primer and joint compound but have one quesion. are you gys talking premixed joint compound or powdered joint compound?
 
New guy here. I've been looking around for away to hardcoat some pink/green foam insulation and stumbled on the RPF forum. I'm building a Boba Fett costume for my son for Halloween and need a way to coat some of the foam parts for painting and some dent resistance. I've got latex primer and joint compound but have one quesion. are you gys talking premixed joint compound or powdered joint compound?

Just guessing, but I would assume powdered as pre-mixed has already been mixed with water. I would think the powdered option would mix well with the liquid primer, but pre-mixed would give you something very thin and fragile due to the water thinning both the joint compound and the latex.
 
This thread is more than 6 years old.

Your message may be considered spam for the following reasons:

  1. This thread hasn't been active in some time. A new post in this thread might not contribute constructively to this discussion after so long.
If you wish to reply despite these issues, check the box below before replying.
Be aware that malicious compliance may result in more severe penalties.
Back
Top