foam board not holding paint and has holes

Did you peel the slick poly skin off the pink construction foam before paint, glue,etc?

my kids wanted to and I thought it needed to stay, was that part of the problem?  I guess the plastic does not hold the paint?  Why the holes though?

Did you use only water-based paint? Paint[or adhesives] containing spirits will eat the foam--holes!

I also suggest using basic Elmer's white glue which we know from years of experience is compatible with about everything O-gauge. Many if not most scenickers use 50/50 mix of wet water and white glue for groundscaping. At times I have painted on white glue full strength and then sprinkled on the ground cover, followed later by dribbling on the 50/50 mix. Some folks spray the 50/50 mix effectively but I dribble from mustard and ketchup squeeze botles from the Dollar Store--$2..

"Wet Water' is about 5-6 drops of dishwasher liquid per gallon of tap water and enables breaking the surface tension of plain H2o in preparation for absorbing the following 50/50 mix application.

Alcohol or Matte Medium will do the same prep but I have good luck with cheap wet water.

A water based primer on the non-waterproof side would seal it. Then apply anything to it. The shiny covering is a moisture barrier. Roger Dewey's point on the spirit based products

When doing foam scenery you can mix very thin hydrocal and brush it on to seal also. Kind of tedious for a 4 x 5 though.

Dewey's post "I also suggest using basic Elmer's white glue which we know from years of experience is compatible with about everything O-gauge. Many if not most scenickers use 50/50 mix of wet water and white glue for groundscaping."

IMO is the best way. I have never had a problem. I have tested it with a high power shop vac after it dried and was impressed how very little came off.

Reference the pink foam. I removed the poly skin off before painting it with Behr latex flat paint I had mixed with my chosen color. It has been very tough. I don't know how many times I washed plaster and other materials off it and never removed the paint. As far as the holes I can't figure that out. It will take quite a  bit of abuse unless we are talking sharp objects.

The plastic covering should always be removed before painting or applying any scenery.

Yes...the plastic should have been removed for a variety of reasons....

Alan

Was the "pink foam" Extruded Polystyrene?  That is what should be used.  Comes in 4x8 sheets either 1" or 2" thick.  I've never seen this foam come with a clear barrier skin attached, but perhaps that's how it's offered in some areas.  If it does have such a covering, peel it off.

If it was true Extruded Polystyrene, you should seal/paint it with a cheap, earth-colored, water-based latex paint.  That paint will not eat into or otherwise harm the foam.

My guess is that you used the wrong type of pint, but that's only a guess based on what you described.

Your right Allen, I was guessing it was extruded because he said Pink. I'm working with 4  2 inch sheets now and have never seen the plastic covering on any of it here in TN, but all the 1 inch I have used has it.

Larry

Just a general FYI:.

I've not seen any coatings on the pink or the blue foams here in the Northeast. The green however usually does. Generally thinner types have the film, I suspect for adding strength (green at Lowes come in 1/2 inch, and definitely has a film on both sides)

A sheet of 1/2" pink that I just bought at Home Depot was skinned.  Stuff I bought about a year ago at the same place was not.