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Foam board adhesive

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Posted by Daniel on Friday, March 18, 2022 8:05 PM

its a bit expensive at HD or LOWES.....but try GORILLA construction adhesive, (white) quick strong bond, foam to foam, Ive used it for years...cork to foam, track to cork , good stuff!!

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Posted by speedybee on Saturday, March 12, 2022 1:40 PM

I don't think anyone has yet mentioned in this thread that there is a huge difference in exactly which DAP acrylic latex caulk you use.

In my experience, both using it for trains and for its intended purpose of filling cracks, the clear/translucent version is completely different from the white or coloured versions.

The clear version takes longer to cure but sticks much better in the long term. I just lifted a section of track laid down with it and it shredded the foam roadbed rather than separate from it.

The white version cures fast but turns into a papery substance that doesn't provide a strong bond.

I highly recommend the clear dap acrylic latex caulk for anything foam building. And it cleans up easy (before curing) and it's super cheap

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Posted by kasskaboose on Saturday, March 12, 2022 11:56 AM

I swear by liquid nails.  It goes on super easy and you get it it most anywhere.  After I'm done, you can carve until you've made it rain pink/blue foam.

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Posted by hon30critter on Friday, March 11, 2022 10:49 PM

DigitalGriffin
Some will say "Liquid nails FOR PROJECTS"  I built my first layout that way.  But it's hard to "Squash perfectly flat" and an even bigger pain in the tail to remove.

Same with PL-300. It is super sticky, and it will not totally flatten even when the foam is weighed down. You have to use a putty knife to spread it.

I strongly recommend having something available to catch the drips when you put the caulking gun down. I found that even after I released the pressure in the caulking gun, the PL-300 still tended to drip.

Mark - something I would suggest that you take into account is that your canyon walls will be quite tall. I question whether or not basic Alex caulk would be appropriate for scenery with such large areas. A few years ago I did an experiment by making a mountainside out of 2" pink foam. It was about 12" high. Initially it seemed to be pretty solid, but when I picked it up a couple of years later, it basically just fell apart. Having that happen to your canyon walls would be a disaster!

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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Posted by DigitalGriffin on Friday, March 11, 2022 10:39 AM

Some will say "Liquid nails FOR PROJECTS"  I built my first layout that way.  But it's hard to "Squash perfectly flat" and an even bigger pain in the tail to remove.  I had to toss the plywood as it left the surface unsable.

Stick with good old fashioned caulk.  Cheap easy, flexible, washable, and removable.

Don - Specializing in layout DC->DCC conversions

Modeling C&O transition era and steel industries There's Nothing Like Big Steam!

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Posted by jjdamnit on Thursday, March 10, 2022 6:03 PM

Hello All,

Pruitt
Interesting.

Yes, I too was surprised that the yellow Carpenters glue worked.

I just wanted to throw it out there for consideration.

For the Woodland Scenics risers on my pike I did use a dual-temperature hot glue- -on the "low" setting to adhere them to the foam base.

I used the hot glue like spot welding. I only ran beads around the outer perimeters, not on the actual mating surfaces.

Even with the low-temperature hot glue (there's an oxymoron for ya) I suspect it might set up faster than you can place the item(s) in their final position.

Thank you for considering my "out of the box" solution.

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

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Posted by BATMAN on Thursday, March 10, 2022 1:42 PM

Pruitt
I'll probably use the caulk mostly. Hot glue if I need something to be cured fast.

That's what I did, the glue gun with low temp glue was always handy to quickly tack things down but I used mostly caulk.

Brent

"All of the world's problems are the result of the difference between how we think and how the world works."

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Posted by Pruitt on Thursday, March 10, 2022 1:16 PM

jjdamnit
For my elevated section that supports the coal unloading shed, I used Yellow Carpenters glue to hold the foam layers together.

Interesting. I remember trying yellow glue years ago, and it took weeks to dry in the middle, since the foam effectivly stopped any air circulation more than about 2" in from the edge of the foam.

I checked the caulked and the hot glued pieces this morning. Looks like either one will work fine. The caulk gives some working time to adjust the foam pieces, while the hot glue gives less than a minute. 

I'll probably use the caulk mostly. Hot glue if I need something to be cured fast.

Thanks for all the input, everyone! It was helpful!

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Posted by jjdamnit on Thursday, March 10, 2022 11:06 AM

Hello All,

For my elevated section that supports the coal unloading shed, I used Yellow Carpenters glue to hold the foam layers together.

I needed to make an undercut with an overhang for the section of Tyco track with the hopper door opening mechanism.

To do this I used a Surform blade. After the glue had dried, I let it cure for 24-hours, it did not foul the blade.

I don't know how a hot wire cutter would fair against the dried Carpenters glue.

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

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Posted by rrebell on Thursday, March 10, 2022 8:41 AM

Just use caulk but don't use painters caulk, it will cruble over time. My whole layout was done with foam and hot wired. Hot wire though caulk works but is very slow. The best way is to do basic foam cutting up front before gluing and the finish up once glued.

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Posted by Track fiddler on Thursday, March 10, 2022 7:14 AM

Hi Mark

Did quite a few experiments on foam before using it a lot and found Polyseamseal to be best for gluing it permanently.  Alex plus for gluing foam layers or anything else you possibly might change one day.

You just want to leave the caulk back from the edges if doing any carving or the caulk lines give you problems gripping a razor. 

A hot wire you're planning to use will cut through Alex Plus no problem as it dries but doesn't ever harden.

 

Here is an area around where a lake will be that foam layers were used.  Some of the layers were left exposed on purpose to form plateaus.  Others, some foam was added to hide the layers.  The rectangular shapes are where footings will be placed for a removable Timber Trestle.

On this area the foam was stacked up right.  There's a lot of steep cliffs on the layout where this technique will be used because it works better.

 

These are the best tutorials I have found on foam cliffs.  Part one drags so just skim through.

https://youtu.be/MQ_PF27nA4s

https://youtu.be/-I8Qk6E4RNU

This guy is obviously extremely talented.  I can't replicate what he does but I'm going to give his technique a shot.

Here's a couple of pictures of Rick's rock cliffs.  His trees are really something else as well.

Images courtesy of Pinterest

 

 

 

 

TF

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Posted by hon30critter on Thursday, March 10, 2022 4:10 AM

Hi Mark,

Like selector, I used PL300 to build the mountains for my old club's layout. After it sets up it can be cut with a hot wire cutter but the process is rather slow.

Here is one of the mountains:

They were covered with Woodland Scenics Shaper Sheet which worked okay, but I wouldn't use it again. It is too expensive, especially for the size of the areas that you want to cover.

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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Posted by selector on Thursday, March 10, 2022 3:03 AM

Mark, if you decide you'd like something a bit more durable than DAP caulks, I have used Lepage's PL-300 with good effect.  It does end up being quite hard, but not if you carve your stacks within about four or five weeks.  Is that enough time for you?  Geeked

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Posted by MidlandMike on Wednesday, March 9, 2022 8:27 PM

Whatever adhesive you use, make sure it is compatible with foam board.  Read lables, some will react and start melting foam.

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Posted by Pruitt on Wednesday, March 9, 2022 8:22 PM

BATMAN
Using caulk instead of glue makes the mountains wiggle when you bump them resulting in less damage.

Hmmm. Something vaguely risque about that... Embarrassed

I put together a few layers with the Alex Plus. I'll see how solid it is tomorrow.

On a whim I also tried low temp hot glue. In five minutes I had a really solid bond! If I were to use the WS sticks, it would be pretty expensive. But I can order five and ten pound boxes of the sticks from Home Despot for a decently low price - maybe even cheaper than the caulk...

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Posted by York1 on Wednesday, March 9, 2022 8:20 PM

I used DAP painters caulk.  I didn't use a hot wire cutter, so I don't know how that would work, but I did use a surform and a serrated knife, and I had no problems.  I covered it with sculptamold.

 

York1 John       

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Posted by BATMAN on Wednesday, March 9, 2022 8:14 PM

I use the DAP caulk to glue layers with great success. I don't go near the edge I will be carving as it does not carve well so I just apply it an inch or two in from that edge. I use DAP drywall filler on the cracks when I am done. I also dab the filler all over the rock face with my finger.

Using caulk instead of glue makes the mountains wiggle when you bump them resulting in less damage.

Brent

"All of the world's problems are the result of the difference between how we think and how the world works."

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Posted by tstage on Wednesday, March 9, 2022 7:52 PM

Mark,

I would go with the DAP Alex Plus.  Maybe try it out first on a couple of pieces of scrap foam to confirm that a hot wire cutter will cut through the DAP and not just create a gooey mess with it...

Tom

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Time...It marches on...without ever turning around to see if anyone is even keeping in step.

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Foam board adhesive
Posted by Pruitt on Wednesday, March 9, 2022 7:43 PM

I'm about to start scenery in my Wind River Canyon. This will involve stacking up layer upon layer of pink foam board. I'll need to shape it after it's laid.

What's the best adhesive? A rock hard adhesive won't work, since I'll be carving after cutting. Ideal would be an adhesive that a hot wire cutter will go through just like it does the foam itself. But at the least it has to be easily cut using a serrated knife.

I went through the search function and found a couple threads, but there was no discussion (that I saw) about the carvability of the adhesives.

Will DAP Alex Plus latex caulk with silicone do the trick, or do I need a true adhesive?

I did this 15 years ago and it worked out great, but I have no idea what I used to glue the sheets together back then (bad memory).

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