My Grand Terrain Mat Fiasco '14 (updated 20/7 - Finished!)

[Sangennaru]

Aww matt, sorry to hear about your misadventure!

The Grant's road technique looks pretty sweet anyways! ^^

[FramFramson]

Using a large joint compound knife (drywall knife) will help tremendously. Most important is to use water to wet your tools. a knife, your gloved hands, whatever you use, wet them down first as it will keep the acrylic caulk from sticking so much. It will also extend your working time a bit. Experiment witht your caulk on a small scrap first, so you get a feel for its properties.
Hope this helps.

The thing was, I ended the first experiment when I realized that even if I had a way to spread the stuff better, it would still have looked like crap as a terrain mat. It was so sticky that it wasn't ever going to settle properly or flatten. And for whatever it's worth, doctor_ocks original tutorial specifically mentioned he was able to spread everything by hand.

However, I think I have the answer. I was able to find some DAP Alex 100% acrylic after all. Apparently it was stored off to the side under "crown moulding" at our Home Depot. On the label this stuff has a MUCH shorter drying time (which also reassures me, because doctor_ocks' tutorial also mentioned having to work in stages due to a short working time) and is mercifully water-soluble. Hopefully I'll have the chance to try this stuff soon instead.

[FramFramson]

I can confirm that the DAP Alex (NOT the Alex Plus, which is part silicone) "crown moulding" caulk is in fact the right stuff. Works beautifully, spreads perfectly well, etcetera, etcetera.

So not just any acrylic caulk will do, but that specific brand and variety.

[Papa Spanky]

Wonderful, sounds like you are on the right track! Show us how the next attempt come out please.

[Mr. Peabody]

Terrific news...

Also I just reviewed the two tubes of caulking I had bought for my project. I had bought the dreaded 'plus'. 

Would have been in a world of hurt without you breaking the trail first. Sincere thanks for taking a hit for the team and sticking with it until the riddle was solved...

[gary42]

Should say paintable on the tube.  Most of the silicone stuff isn't.

[FramFramson]

I haven't used the Alex Plus myself - it might be okay-ish (the silicone content is pretty low, but I know know exactly how much, but it's maybe paintable?), but no matter if it's useable and paintable, it'll be worse than the plain Alex (crown moulding). The proper stuff is only $4 a tube and 2.5 tubes should cover a 3' x 4' area, so there's no real reason to go with the other stuff. FYI, two tubes is just short unless you're spreading it really thin.

I suppose you could always experiment with the stuff, but if you have your receipt it's probably best to just take it back to the store and get the regular Alex.

[snitcythedog]

Sorry to hear about the first mat.  Sounds like the batch of caulk was old too and had thickened.  Hopefully your next attempt goes better. 
Snitchy sends.

[FramFramson]

It was new enough, it was just the wrong formulation.

Just as you can get all sorts of different carriers and still call acrylic paint 'acrylic paint', so there are all sorts of different carriers for caulking. The MONO had a very heavy solvent-based carrier, as it's the sort of stuff you would use to seal the outsides of your windows. The DAP Alex is meant for much finer interior work and so was vastly easier to spread and was significantly less sticky. But they're both "acrylic caulk'.

In fact, the DAP Alex was almost the same consistency as thick acrylic craft paint.

[BigB]

Going to go down to Home Depot again to see if they have the DAP Alex or not. Maybe I just missed it last time

I was able to buy a case of tubes of Alex at Walmart of all places.  $2 a tube.  The stuff works great (just repainted my home and had to caulk like a madman for a couple days.)  I got the white color though it comes in clear, black and tan as well.

[gary42]

We refer to it as "Carpenter's Helper" 

[FramFramson]

So far so good. First we had the caulk & sand layer:



Then the initial acrylic. I mixed up some raw sienna, burnt sienna, a little blue to tone it down, a little white and painted it on.



It was pretty saturated for dirt (moreso than this pic shows). So I tried some different spraypaints to tone it down. I have a nice chestnut that I wound up using for the most part. There's more colour variation than shows in this image, because some of the initial reddish brown shows through.



It's still a little bland for now, but some flock and scatter will get us there.

[gary42]

Wash and a drybrush.... 2 bits?!

[FramFramson]

Funny you should say that. I was tempted to go back and do a thin wash with a little yellow ochre/raw sienna or something to bring it just a hair closer to my existing basing. but I think this colour is as close to universal for dirt as I can manage with a single main colour theme (dirt is of course many many different colours, often quite different). This isn't dark, isn't light, has a little yellow, has a little red (when you see it in real life), is of middling saturation, etc.

I still might though. I'm not sure there's enough variation in tone.

[Mr. Peabody]

Looks spot on Fram... Glad this is turning out so successfully!