Mod Podge VS "PVA+H2O+acrylic mix"


dgrafix

dgrafix

Well-Known Member
I am at a point of sealing my foams on a section of my layout.. and am thinking on prepping & sealing it.
I know modpodge is probably the winner but A)it's 2-3x the price and B) I can only order it online, which is even more expensive with postage and generally a pain in the bum..because C) I want/need it N😫W!
So I was wondering if I could use a "water, PVA and acrylic mix"? Is there a massive difference?
Does anyone have any good recipes for this, like how much of each and what colour etc.
The foam is a mixture of XPS 300 with a blueish cyan colour and in some parts I'm using that expanding insulation goop, which is yellowish, and have filled the spongey holes with a rough grade filler after carving it.. the XPS though carved/fractured really nicely so now I just want to seal it.

Edit.. actually maybe this belongs under scenery rather than construction.. sorry if that the case and maybe a mod can move it if it belongs more there 😁
 
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I like to use light-weight spackling compound for filling cracks and small voids in foam. It's about as easy to work with as the foam itself.
Then, an earthy-colored flat latex house paint (tan, gray, grayish-tan, etc.) makes an excellent sealer and color primer for future scenery work. Heck, I'll even paint plain, flat, uncarved blue or pink foam just to get rid of that nasty, un-earthly color, and then lay track/roadbed on it. I can always come back later on and carve away/add on to the foam when I get around to it. Sometimes years later.

But, if you must, I think that Mod Podge and water/PVA/acrylic mix is really about the same thing. And not too much different from latex (acrylic) paint for that matter - water soluble when wet, and water-proof when dry.
 
Have ordered some modpodge as someone said it is better as a finisher after you get your base colors down 😕
Not there yet so I have made 2 experiments the blue is just a 3 in 10 PVA +water mix with 10 drops of black acrylic to make it dark greyish. The brown one is this brown colored polystyrene spray primer I bought with the same solution applied on top.
It's still drying so will let you know which came out better when I paint them tomorrow. 🙂
Both feel more solid/hard already which I was informed is a good sign
 

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Mixed Freight said:
I like to use light-weight spackling compound for filling cracks and small voids in foam. It's about as easy to work with as the foam itself.
Then, an earthy-colored flat latex house paint (tan, gray, grayish-tan, etc.) makes an excellent sealer and color primer for future scenery work. Heck, I'll even paint plain, flat, uncarved blue or pink foam just to get rid of that nasty, un-earthly color, and then lay track/roadbed on it. I can always come back later on and carve away/add on to the foam when I get around to it. Sometimes years later.

But, if you must, I think that Mod Podge and water/PVA/acrylic mix is really about the same thing. And not too much different from latex (acrylic) paint for that matter - water soluble when wet, and water-proof when dry.
Click to expand...
I actually tried a light spakel on the yello spray foam first, but it cracked when it dried unfortunately. That is why i went for a more gritty one as i figured the "material" in it would act like a kind of concrete rather than a cement + add a bit of texture. It seemed to do the job.
For the yellow foam it seems the sandy spackel is going to be all i need there It seals it just fine and now feels like plastercloth would.
Its the XPS i want to seal most. I do not really want to use plaster on that because my cliffs on my layout have been carved quite nice (better than those quick samples in my last pic, those were just 5 minute knife hacks and gluetogethers from the "waste"/odd bits pile)
 
Lots of people use watered down glue and paper towels. You could use acrylic matt medium instead of Elmer's Glue. It would give a better finish. The glue will be a bit glossy unless you add something to remove the shine.

I used plaster cloth.

Either would work. I ended up using a lot of cast plaster rock outcroppings, so using the plaster cloth made sense

Once the plaster cloth dries, I went around and refined the terrain even more by brushing on drywall joint compound with a stiff paint brush.

It all got painted as the first step of doing the scenery anyway.
 
I never "seal" the foam, I use regular flat latex paint to paint the foam. I use foam to make hills, etc. Then I use "ground goop", a mix of Cellu-Clay or Permascene, vermiculite, the latex paint and water to make the contours. If need be I can then apply a coat of paint over anything. I use a mix of PVA glue and water painted on to attach ground foam or static grass or will apply the ground foam, spray it with a water-dish soap or waer-alcohol-dish soap spray and then dribble a PVA water mix on top of it.
 
Here is the rough result, the one on the left was with my mix direct onto the foam. The right one was with the foam primer first and then the mix added to that. (same post sealing technique and paint mix was used on both)
Personally I like the right one better as it doesn't look as "cold" & cartoonish.
What do you all think? The bottom of the right peice was done with same samey and a bit of burnt umber in the mix which is probably where i will go.
 

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Yes true, they were just glued together from cut off bits.. it was more about getting the color right, i am trying to achieve a base limestone :)
 
Oh PS if anyone is wondering: Seems my best efforts so far has been to 1. use brown foam primer (it only seems to come in brown lol)
2. then use a mix of 1-part black acrylic, 2- parts glue, 2 parts ipa, 5 parts water to both give a blackish wash into cracks and seal the foam at same time. After this is fully dry it feels hard and stable like paper mache, or plaster cloth. The brown primer definitely kills the cyan of the foam.
Rock Paint was 49-50-1 of neutral grey and grey umber with a drop of black. The cliff in the front I went over with a light burnt sienna & umber wash after the grey was dry and like that result the best so far.

Grass is hemp rope fibers cut and then dyed and the bush is a car sponge I ground up with 2 shades of green acrylic.
Not used any modpodge but my mix doesn't seem to dry too glossy so think i'm onto a favourable experimental path...
Still lots to learn though 😁
 
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