Tracks sinking in Pink Foam

I have never seen that happen nor am I aware of it ever happening. Can you show us a photo? How thick is your foam and who is the manufacturer? Is the foam dissolving or is it denting?

I never heard of something like this. I never just used track on foam but I think many have on the forum. You mentioned it is your upper level. How much support is there under the foam and what thickness is the foam. Maybe there is no support in the area that is sagging...................Paul

It's a new one to me, also. What did you glue the foam together with?(I assume you have multi-layers).

I used the 2" pink foam for my entire layout and I use scale articulated locomotives without any problems at all.

i supported mine every 4 ft. So you either used the wrong type of foam or it is not supported well. Did the paint soften the foam? 

Can you take a closeup photo of the situation?

John has kind of identified your problem. Unlike regular O gauge tubular track, the 027 track doesn't the rolled edge on the bottom of the ties, so it will cut into the foam until the ties are flush.

If you haven't ballasted it, why not cut some fake ties out of wood and slide them under the rails. This would spread the weight out and stop the problem.

I've noticed that certain types of white foam get soft in hot temperatures, so if the room isn't air conditioned and gets quite warm, in the summer things with pressure points can sink into it. I've had this happen, though not with trains, because I don't use it for that. However, I don't think the type of foam folks use for layouts has this characteristic, but I'm not sure.

Don't ever use white foam!!

White foam has its place, just not as a layout base.  I get all sorts of dense white foam in work in shipping containers for our refrigerated medication and use it to build up scenery.  It serves as a base but is topped off with layer of pink foam.  Solid, inexpensive (free), consistent size, did I mention free.  Everything has a purpose, just use it correctly.  

I can see if cutting/compressing the foam a tiny bit, but any more, no way.  How far down?

Thanks everyone for responding on this.

The upper level is 1/2 inch plywood with owens corning pink foam on top which  I believe is 3/4 inches.

I am attaching a picture of the section where it is sinking, it is the outer section of the track tie which you can't see here but you can see the tires sinking on the model truck right next to it.  It looks like this this is the only spot on that level that seems soft.

Probably will take John's suggestion to prop up the tracks there.

George

With the Tires from that truck sinking in I'm thinking you have an interaction between the foam and the paint that made the surface VERY soft.

I generally only use acrylic paint on foam for this reason.

If that is the only spot that is soft, then there is some kind of chemical reaction taking place in that spot. The trick is to identify exactly what is causing it and then stopping the reaction. Placing something on top of the problem may only cover it up. Your foam may continue to deteriorate underneath.  

OK, curiosity as always kills the cat.

I just went outside and took a 1" piece of that same material. I put it on a solid piece of plywood and walked back and forth. I'm pushing 200lbs.

Absolutely no marks. No indentations of any kind. Which I might add has been my experience with this material over the years.

Now I have fooled with this type of foam and never seen this before. It lead's me to think exactly the way Russell is.

Some kind of chemical reaction some where???

What's funny is there are probably modelers on here that would love to get that to happen.

Larry

The paint I used was Olympic premium interior latex tinted brown.

I guess some sort of chemical reaction is happening.

I will continue to monitor to see if it deteriorates further.

Thanks for all the input it's greatly appreciated.

I have used flat interior latex tinted brown on pink foam without mishap. If it is your paint, I think it would be happening everywhere, not just in the one spot as you pointed out. Very strange.

I had 1" Pink and/or blue foam on top of my layouts for the past 20 years and have NEVER seen anything like this.   Is it ONLY this one truck?

cat pee?

Maybe the tires on the truck went flat! LOL

The truck stuck in the mud eh

As far as the truck goes, it could very well be a chemical reaction from the tires. I have seen many a model car tire melt into hard plastic.

It appears to be that one section of the foam.

The other cars and trucks in the background are fine.

Tiz a puzzlement!!!!!!!!!!

The truck sinking into the "muddy water" looks pretty sharp.

When you determine the cause, it can become, rather than a "problem", a short article

in OGR about the new "mud effect" with foam. Looking forward to it.

BINGO!!! 

Give that man a cigar...that's my bet too... some plastics and that's what the pink foam is.. plastic.. react that way with each other..

Yes, tires can react with a variety of surfaces, but let's not forget that the OP's metal track is sinking too.

Has anybody else used Olympic acrylic paint, whether or not you had a problem?

Maybe your truck is overweight.  Better send him to the scales.

I was just painting an engine yesterday and I sprayed a little paint (Rust-o-leum for  wood, metal, and plastic) into a styrofoam plate and it melted the plate.  I think it was the paint.

Rick

Rick,

As you discovered, solvent based paints will melt foam. 

Also, latex paint would create a barrier between the tires and the foam.

I'm of the thinking that something accidentally got onto that section.  The cat pee remark made me laugh, but is none the less valid.  Other culprits might be over spray from wd40 or some similar product.  I've seen several penetrating oils use the fact that they melt foam cups as an example of how much better they are than other products.  

You say that is the only spot? Hope so, but you may need to wait longer to see.

And Id get rid of that section and an inch around it by knife. Quickly too!. It might be creeping.

 Ok, My guess is you painted in more than one session, or began there. The reaction was your brush cleaner from a previous session was still not fully dry. Solvent caught in the heel, and under the ferrule, didn't evaporate. So the fist belly full of paint, was contaminated.(these are technical terms)

 If in doubt use primer first. It will seal it better, and may even allow you to spray the top coat. 

I used green foam. Still doesn't like spray paint without primer, but the damage was immediate, then done. Not too severe really. (I tested)

 I used left over Behr latex, on a non-layout sheet. No primer, no issue.  

The paint types have different components. I notice a slight sheen to the paint. If it's Eggshell, it is a vinyl acetate ethylene latex. (Olympic doc attached)

So, check the can for the series and look up the tds/msds for it's specific makeup. Depends on the type whether it's acrylic latex or the vinyl acetate. here's the link.

Olympic premium  look up the TDS.

It's a chemical reaction. primer or a 100% acrylic latex would prevent this.

This is fascinating.  I've painted foam for years with flat latex and never noticed any problems.  Very interesting and potentially useful information here . . . 

I think Adriatic may be on to something.

Have seen the tires "sink" into foam via reaction, never track work.

These are all the same foam?

Painted with the same water paint?

Will be interesting to follow progression and solution.

I use a scrap (about 1’ X 1') piece of pink rigid foam insulation to lay over the track and kneel or sit on to reach areas in the back of my layout and avoid damage to the track.  That leaves an impression of the rails in the foam.  You did say the problem is on the upper level, but is it possible that someone (perhaps a child) stood on the track or the truck to reach something higher in that area?

Okay some one get a tow truck for that truck befor we can't get it out at all

I pulled out the paint can and it is Interior Latex Olympic Premium Low Odor Flat which was tinted brown.  I did not use a primer.  I also used the correct adhesive for foam to the plywood so i don't think that should come into play.

The foam used came from the same sheet, but the sinking section was pieced from the sheet to fit the dogbone shape.  There I think is where my problem lies.   Perhaps the paint softened the foam or was not fully dried when I worked on it.

If no other areas are affected after a while, I will probably cut out another piece of foam but will prime it fist then paint it. I know that will be a mess scrapping off the adhesive with the foam.

Thanks again all for your very helpful suggestions.

George

Interesting discussion.  Foam board is a material whose primary purpose is insulation, IMO.  I have always questioned structural integrity of foam, probably never designed to support weight, in the real world, though it seems to work well in the model RR world.  I have seen 3" or more of iso-board installed on roofs before waterproof cover is installed, so it does support some weight.

Looks like a similar problem to what fishermen sometimes have where their artificial plastic worms will melt into some types of molded plastic tackle boxes. In the photo, only the semi truck tires seem to be sinking, not the tracks, as the thread's title suggests (or did you mean to write "trucks" instead of "tracks"?

I'm surprised this happened when the foam was painted with latex paint, could the latex be acting as a sort of catalyst to start the reaction, or will the same truck also melt into unpainted foam? Can the truck be removed from the layout without showing damage to the tires?

Bill in FtL