Can Mod Podge gloss be used as water on foam board?

[cjp53]

Looking for a simple way to add water to foam board and wanted something easy to apply.Had asked similar question on another glue but has zero answers.Crafter's pick glue

[Chris333]

Foam will out-gas over time.

[cjp53]

Foam will out-gas over time.

I'm sorry but I don't understand your answer.I should of added that I have already painted the area with acrylic hobby paint and was going to use the Mod Podge over that surface.I don't mean to sound stupid but when I think of out gasing I think of curing.

[dem34]

I'm sorry but I don't understand your answer.I should of added that I have already painted the area with acrylic hobby paint and was going to use the Mod Podge over that surface.I don't mean to sound stupid but when I think of out gasing I think of curing.

Even with paint, the foam itself emits a small amount of gas over time. Its barely noticeable for any other thing not water related, but if you put a layer mod podge gloss over a large ish area of foam you will have a few visible bubbles in the finished product. You might be better off cutting the area you want water to sit in and replacing it with thin plywood, hardboard, styrene, etc.

[Chris333]

Start at around 1:25

[cjp53]

Thank you for the explanation,I have my bridges already in place with the track installed.I used flex track so everything is glued in.The size of my stream is 40 inches long and 8 inches wide. I have a small trestle bridge that I can't take out with the track already installed.That would be the only portion where the bents are that I could not replace the bottom of my stream bed.I could line the entire stream bed thin basswood or very thin balsa and pour the Mod Podge on that but my trestle would have to stay with the foam board under it.The bridge is about 2 inches wide and 8 inches across.So if bubbles appear they would not be noticed much.I could live with that.I would appreciate any comments.I still about a week away for the water to be poured.

[Chris333]

https://www.therailwire.net/forum/index.php?topic=34849.msg628725#msg628725
https://www.therailwire.net/forum/index.php?topic=34849.msg628771#msg628771

If you read further I linked a few shots of how I used wood for my water base.

I have no idea if there is any way to seal it. The one time I used foam and got bubbles it was a few months after it had dried and it was just a small, maybe 2x16" waterway.

[Chris333]

And the bubbles I did get looked like they could be popped and filled back in with more "water", but I have no idea if that will then re-bubble?

[Chris333]

Oh yeah to answer your question Mod Podge can be used on foam. It is water based.

[cjp53]

I think I'll try very thin basswood and line it or like I said thin balsa.I'll use a sealer on the wood and then paint it with hobby acrylic paint.The side of the stream I'll fill in with sculptamold to make a few bends in the stream.Do you think outgassing would come from the sculptamold?Sorry for all the questions but I want something that will last for my grandson to enjoy for the years to come.I don't want to weaken the whole structure if the outgassing would pose a problem like that or if it's just cosmetic.

[Chris333]

I build a lot of stuff, but rarely get to the pour water stage. On my door layout the track is up on foam, but the base of my river is the wood door itself. I had no problems.
https://photos.app.goo.gl/SzT3rHWH2QvgzMsp6
In another small spot that was higher than the door I used 1/4" balsa as a base:
https://photos.app.goo.gl/ZjxLZiahrFEMsVM79

I built this small HOn30 layout all with foam and this is where I got the bubbles:
https://photos.app.goo.gl/qNihZLpVnGcTP2yr8

Scultpamold won't out gas, but I have no idea if it will seal the foam.


If you could do a sheet of balsa I think that will work. Also if everything is mounted maybe you could cut the foam out from under the layout?  I know it's not an easy thing if there are braces in the way.

I cannot guarantee that your foam will out gas, but now that it has done it to me I will from now on always plan layout water to have a wood base.
This is my last HOn30 layout:
https://photos.app.goo.gl/De49UgzwSmj5SBdH7
https://photos.app.goo.gl/bg9NGsqQr4jtDP3y7

I'd just build your layout and see what happens   

[cjp53]

Thank you,you have helped me understand things.I could cut out the section under the trestle as it sits near the edge and line the rest with thin wood.I think I'll chance the sculptamold on the edge.I have an idea and could line the sides with wood also then fill in the edges with sculptamold in front of the wood for bends in the stream.You have been most helpful.Merry Christmas to you and your family.When I get things going I'll try and post pictures.Happy Holidays to everyone.Carl.

[cjp53]

Update,bought some 1/16 thick basswood for the bottom of the stream.After sealing it it should be bubble free unless I get them from the brush dabbing process.