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Static grass under “water”

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WPA
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Static grass under “water”
Posted by WPA on Monday, August 9, 2021 7:45 PM

Anyone put down static grass then cover with resin water like WS deep murky, or similar.  I was thinking of having clumps of the grass just under the surface in a river bend.  Wondering if any problems or lessons learned.  Thanks 

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Posted by Overmod on Monday, August 9, 2021 7:54 PM

I did think about this at one point.  After the grass has been glued in 'staticked' position, mist it gently with multiple coats of clear material that is compatible with the resin system, colorants, etc. that you will use.  That should stiffen the arrangement enough that the pour doesn't derange it ir begin to affect the glue...

I would mix the resin to be easy to pour, and think carefully about how to get rid of air bubbles... at a minimum, vacuum-suck the mixed resin before you start pouring it.

 

WPA
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Posted by WPA on Monday, August 9, 2021 8:37 PM

Good idea, completely seal the cluster first.  I made a small test river bank on a foam scrap with the extra sculptamold to try the ripples on befor I did the one on the layout.  Will glue a few clusters on the scrap as well and try pre sealing.  

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Posted by hon30critter on Monday, August 9, 2021 10:31 PM

Hi WPA,

I would suggest trying the grass both with and without a clear coating. My concern with the coated grass is that it will be too stiff to coax any bubbles out of it. If the grass is flexible and securely mounted I'm guessing that you would be able to run the pointed end of a skewer through the grass while the water is still liquid to dislodge any bubbles.

Pure speculation on my part. Let us know how it works.

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 SeeYou190 on Tuesday, August 10, 2021 3:04 AM

WPA
Anyone put down static grass then cover with resin

Yes, and it was a failure.

I used good old Envirotex, so I cannot say for certain what will happen with the Woodland Scenics product.

Also, this was for a piece of wargaming terrain, but that does not make any difference, just giving full disclosure.

I made a nice marshy scene with tall grass/reeds around the perimieter in clumps. When the Envirotex was poured, it climbed up the tall grass like magic, and glued the grass together into very ugly bundles.

I never tried it again.

Now, if your static grass is completely beneath the surface, it might work out better for you. We did not use static grass, but tall grass similar to Woodland Scenics field grasses.

-Kevin

Wink Happily modeling my STRATTON & GILLETTE RAILROAD. A Class A line located in a personal fantasy world of semi-plausible nonsense on Tuesday, August 3rd, 1954.

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Posted by Overmod on Tuesday, August 10, 2021 5:03 AM

Yes, you could use a flexible 'sealant'.

I wonder if there is a coating that would have zero meniscus with resin -- perhaps one of those super-hydrophobic coatings that shed water?  That would not give 'bond' to the surface of the grass blades, but would come in close contact without surface bubbling. It would be the last thing applied after the bond and seal coats...

Is it practical to pull vacuum, even using the hose from a home vacuum cleaner with good suction, on the area to help pull any 'final pour' bubbles?

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Posted by NVSRR on Tuesday, August 10, 2021 7:08 AM

I have go in a little thought and realized a few experiments needed but and answer is possible.    Resins and such that move by capillary action need rough surfaces to move.   Under a microscope flat finishes look like sand paper.  Likewise gloss finish looks like glass very smooth.   Which also effects light reflection.  Capillary moving materials don't like glossy cause there is no way for it to move.   Pour resin on glass and it just sits in a self leveled puddle.  Pour on sandpaper and it spreads out as much as it can.    The hypothelical idea is that the flat paints and coats give a surface for capillary movement.  the experiment is try a high gloss instead.   Then brush on a flat clear after wards.  Might set that up this weekend and try it. I could use a display modular anyway.

 

shane

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An optimist sees the light at the end of the tunnel

A realist sees a frieght train

An engineer sees three idiots standing on the tracks stairing blankly in space

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Posted by Overmod on Tuesday, August 10, 2021 8:55 AM

I think there is a little more to it, including interfacial angle.  Bores of capillary tubes are drawn very smooth, but that does not impair the action...

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Posted by SeeYou190 on Tuesday, August 10, 2021 10:36 AM

Overmod
Is it practical to pull vacuum, even using the hose from a home vacuum cleaner with good suction, on the area to help pull any 'final pour' bubbles?

With Envirotex, gently exhaling on the surface after the pour magically draws the bubbles to the surface and they will pop.

It really works, and requires no special equipment.

-Kevin

Wink Happily modeling my STRATTON & GILLETTE RAILROAD. A Class A line located in a personal fantasy world of semi-plausible nonsense on Tuesday, August 3rd, 1954.

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Posted by selector on Tuesday, August 10, 2021 3:27 PM

Here's what I would do to see if I could pull it off (I already know from experience that finishing epoxy, like Envirotex and Nu-Lustre 55 as examples, will wick itself up into places where you would rather it didn't):

I would do a trial (a la track clearances thread elsewhere today).  But, I wouldn't use epoxy.  I would try diluted, even heavily diluted, gloss medium, maybe in three or four pours.  Once you have the sampling of grass clumps embedded on a surface, adhesive fully cured, try a thin pour of highly diluted medium.  If the grass stays erect, and the embedded surface is intact and covered/sealed, then you can try successive pours to get to the depth you need.

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Posted by selector on Tuesday, August 10, 2021 3:30 PM

SeeYou190

 

 
Overmod
Is it practical to pull vacuum, even using the hose from a home vacuum cleaner with good suction, on the area to help pull any 'final pour' bubbles?

 

With Envirotex, gently exhaling on the surface after the pour magically draws the bubbles to the surface and they will pop.

It really works, and requires no special equipment.

-Kevin

 

It's absolutely true.   I have always used a plastic soda straw, the wider ones.  I have also pursed my lips and blown over a tiny place that I had missed.  It's risky, though, using pursed lips.  Spittle doesn't help on the epoxy.  I just guess at this...I didn't muff it up when I did it, but I could easily have.

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Posted by HO-Velo on Tuesday, August 10, 2021 4:55 PM

Caution advised, but depending on resin pour location and surrounding scenery a propane torch can make short work of those bubbles.  No worries about errant spittle or breath condensate from a straw.

Regards, Peter

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Posted by selector on Tuesday, August 10, 2021 5:57 PM

I guess both would require some courage and some care.  Personally, in several goes at the straw now under my belt, I have never seen any condensate.  ???  It could surely happen in some instances, but not so far for me.  I'm not sure I would trust my pour with my clumsy hands holding a butane torch or equivalent.  Maybe a hair drier?

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Posted by hardcoalcase on Tuesday, August 10, 2021 9:21 PM

selector

I guess both would require some courage and some care.  Personally, in several goes at the straw now under my belt, I have never seen any condensate.  ???  It could surely happen in some instances, but not so far for me.  I'm not sure I would trust my pour with my clumsy hands holding a butane torch or equivalent.  Maybe a hair drier?  

Has anyone had good results removing bubbles by using an airbrush?

WPA
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Posted by WPA on Wednesday, August 11, 2021 7:23 AM

Was planning for the grass to be completely under water.  Will do my test piece first. Did not think of poking it with pick to get bubbles out so will help.  Have been taking step by step photos so will post when done but as things go, a little each week is an accomplishment in these summer months.  Thanks

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Posted by speedybee on Wednesday, August 11, 2021 3:56 PM

Breathing on the Enviro tex works due to the carbon dioxide in your breath. That's why a torch works on it too. Using a hair dryer or poking it with a stick will probably just make a mess without solving the bubble problem.

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Posted by SeeYou190 on Wednesday, August 11, 2021 9:41 PM

speedybee
Using a hair dryer or poking it with a stick will probably just make a mess without solving the bubble problem.

I can't speak for the hair dryer, but I can verify that poking Envirotex with a stick is a completely terrible thing to do.

Envirotex + Stick = Mess

-Kevin

Wink Happily modeling my STRATTON & GILLETTE RAILROAD. A Class A line located in a personal fantasy world of semi-plausible nonsense on Tuesday, August 3rd, 1954.

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Posted by Overmod on Thursday, August 12, 2021 5:39 AM

The Born Paint Company notes that CO2 accelerates bubble removal but, infuriatingly, says nothing about why that works.  Perhaps they consider it a 'trade secret' that would be exposed if they told why.

Born also notes that a thinned coat of white glue (or presumably PMMA) can be used as a seal coat under Envirotex Lite.  I see no reason why thinned glue could not be sprayed from an airbrush for this... but clean all traces promptly out of the equipment!  In this specific case, it ought to hold the static grass very firmly against being tilted or dislodged in the pour, or floating up as the first pour of resin sets.

https://bornpaint.com/envirotex-lite-tips/

Gougeon (West System) recommends preheating the work (this can be done with a hair dryer instead of a CO2-emitting source).  They also note that a mist of alcohol across the surface will reduce the surface tension.

I have seen references that light 'pouncing' with baby powder can accelerate bubble removal.  

 

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Posted by richhotrain on Thursday, August 12, 2021 6:35 AM

I have no idea how Envirotex Lite will react after being poured over static grass, but I do have experience with a large pour over a 12' x 30" section of plywood.

To reach nearly inaccessible portions of the pour, I used a Shop Vac extension tube and blew through it to reach and free bubbles. That extension tube was plenty long enough to avoid having any condensate reach the pour.

Also, I used a bamboo stick to poke at bubbles and it works. It is not messy and does not cause a mess.

Rich

Alton Junction

WPA
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Posted by WPA on Thursday, August 12, 2021 10:10 PM

Picking my battles so think I talked myself out of it.  Will stick to sticks and stones and maybe a log or two and an old car.  Worried blades my loosen and float mid depth. A lot of work and worry for some grass under murky water.  Will still post final pics.  Thanks

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