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Mud for mortar

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  • From: Harrisburg, PA
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Mud for mortar
Posted by hbgatsf on Sunday, November 6, 2022 6:04 AM

I know that some of you use pre-mixed joint compound for the mortar lines on brick buildings.  This is a method I want to try. 

Do you dilute the compound before using it?  Also, if the building as separate windows do you do the mortar before installing the windows, or if not do you tape the windows to keep the mud off them?

Rick

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Posted by gmpullman on Sunday, November 6, 2022 6:57 AM

Hello,

I don't install the windows until after the mudding is done. I have learned that a slightly glossy finish on the face of the brick is easier for me to work with since the "mortar" tends to not adhere to the glossy surface. Plenty of bottle-type DullCote can be applied later using an airbrush.

 Hadlock_tuck-point by Edmund, on Flickr

I keep a small sprayer with some wet water handy to help thin the mortar as I work it into the crevices.

 RH_grout by Edmund, on Flickr

I keep each wall section flat as the mud dries. Tipping it in any direction allows too much of the liquid to pool away from the solids in the compound.

 RH_grout1 by Edmund, on Flickr

I sometimes add a bit of tan or gray acrylic tube paint to tint the mud. When I first mix it I go for the consistency of heavy cream, maybe just a little thicker as I'll be adding a little water as I work it in.

 RH_lamp3 by Edmund, on Flickr

Once dry a little buffing with a foam makeup applicator will clean off the face of the brick. Practice on some scrap pieces. It is easy and rewarding once you perfect your technique.

Good Luck, Ed

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Posted by hbgatsf on Sunday, November 6, 2022 7:41 AM

Thanks for the info.  I can already see that I need to modify your technique some since the building I am working on has already had the walls assembled, but I haven't installed the windows yet.

Does this method lighten the brick color a bit?

Rick

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Posted by crossthedog on Sunday, November 6, 2022 9:16 AM

"Wet water." Okay, I'll bite. What in tarnation is wet water? Or should I be asking what in tarnation would dry water be?

Ed, I love that view through the loading door.

-Matt

Returning to model railroading after 40 years and taking unconscionable liberties with the SP&S, Northern Pacific and Great Northern roads in the '40s and '50s.

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Posted by santafejeff on Sunday, November 6, 2022 10:35 AM

crossthedog

"Wet water." Okay, I'll bite. What in tarnation is wet water? Or should I be asking what in tarnation would dry water be?

Ed, I love that view through the loading door.

-Matt

 

Lol. "Wet water" is water that has had isoprpyl alcohol or a drop of dish detergent, or both, added to it so that it helps break the surface tension of the water. 

If youve ever poured water on a hard surface and noticed it looks like a blob just sitting there, thats the surface tension. When you add alcohol to it, the surface tension is lowered and the water will "spread" so to speak and flow into everywhere near it. Try it, youll be surprised. 

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Posted by doctorwayne on Sunday, November 6, 2022 11:00 AM

crossthedog
"Wet water." Okay, I'll bite. What in tarnation is wet water?

[

"Wet" water is water with a little dish detergent added to make it flow better.  Without that addition, ordinary tap water tends to bead-up on the surface.

I use pre-mixed drywall mud for mortar, and apply it generously using a cloth over my fingertip(s).....

Once it dries, I take the item outdoors and use a similar cloth to wipe-off the excess mortar.  There's often more of it around the door and window openings, and for that, I use various X-Acto blades to remove the excess mortar...

Once all of the excess mortar is removed, I then brush paint the doors and window frames...

I have lots of ones with the mortar added, but even more that need the doors and windows painted...

Other than the station in the foreground, everything else is simply "stored" here until I get around to finishing them.

This one, temporarily sitting on the tracks near the the Dunnville icehouse, was a much easier build, as it's a paper-on-sheet-styrene offering from KingMill, lamentably no longer in business.

Wayne

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Posted by crossthedog on Sunday, November 6, 2022 11:14 PM

Thanks for the explanations. It makes sense. Gosh, these mudded bricks look really good, too.

Returning to model railroading after 40 years and taking unconscionable liberties with the SP&S, Northern Pacific and Great Northern roads in the '40s and '50s.

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Posted by SeeYou190 on Sunday, November 6, 2022 11:38 PM

crossthedog
What in tarnation is wet water?

Wet water is water with an agent added that removes the property of surface tension. Wet water flows easily into small crevices and does not ball up on the surface. Think of dropping water droplets onto dry dirt, it balls up because of surface tension.

Detergent will work as an agent to reduce surface tension, but it has downsides. It also does a lot of other stuff because it has materials to cut grease, make suds, smell nice, or even soften your hands while you do the dishes.

The best option for a product to make wet water is Kodak Photo-Flo 200.

-Photograph by Kevin Parson

This stuff is amazing. It makes water completely wet, and dries with no residue.

There is also Heavy Water, but that will not help with model building.

-Kevin

Living the dream and happily modeling my STRATTON AND GILLETTE Railroad in HO scale. The SGRR is a freelanced Class A railroad as it would have appeared on Tuesday, August 3rd, 1954, in my personal fantasy world of plausible nonsense.

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Posted by gmpullman on Sunday, November 6, 2022 11:39 PM

hbgatsf
I can already see that I need to modify your technique some since the building I am working on has already had the walls assembled,

That's OK and I often do structures this way. Simply brace them so the wall you are mortaring is on a level plane then, once dry, move on to the next.

hbgatsf
Does this method lighten the brick color a bit?

It did considerably more when I was using a flat "primer" type of paint. Imagine grouting tile, the glazed tile would resist any grout while porous tile would absorb some. Of course just the application of the mortar will lighten the overall appearance of the brickwork. This is part of the reason I tone down the bright white of the joint compound.

Sometimes I'll use a very light application of various Pan Pastel powders to enhance a particular color of face brick. This is done on a matte surface and not too heavy as to obscure the mortar joint.

crossthedog
Ed, I love that view through the loading door.

Thanks Matt!

That was actually just a quickie while the roundhouse was under construction. Later:

 Roundhouse1 by Edmund, on Flickr

Regards, Ed

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Posted by hbgatsf on Wednesday, November 9, 2022 9:42 PM

I haven't seen any pictures of buildings with lighter color brick.  When working on those do you tint the mud to be darker before applying it or do you add a wash to darken it after you have wiped it down to the way you want it?

Rick

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Posted by gmpullman on Wednesday, November 9, 2022 9:58 PM

I tinted the mud beforehand.

 Boss-wants-toseeya by Edmund, on Flickr

Good Luck, Ed

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Posted by PC101 on Wednesday, November 9, 2022 10:03 PM

hbgatsf

I haven't seen any pictures of buildings with lighter color brick.  When working on those do you tint the mud to be darker before applying it or do you add a wash to darken it after you have wiped it down to the way you want it?

 

Lighter color brick warerhouse with dark mortar. No mud used here, just a dark wash.

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Posted by cowman on Wednesday, November 9, 2022 10:42 PM

The only modification you need to do is laying your building on its side and do one side at a time.  If iyour building has a roof overhang or some other protrusion, be sure to level it up before you start.

Good luck,

Richard

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Posted by Firedad4132 on Thursday, November 10, 2022 7:43 AM

santafejeff

 

 
crossthedog

"Wet water." Okay, I'll bite. What in tarnation is wet water? Or should I be asking what in tarnation would dry water be?

Ed, I love that view through the loading door.

-Matt

 

 

 

Lol. "Wet water" is water that has had isoprpyl alcohol or a drop of dish detergent, or both, added to it so that it helps break the surface tension of the water. 

If youve ever poured water on a hard surface and noticed it looks like a blob just sitting there, thats the surface tension. When you add alcohol to it, the surface tension is lowered and the water will "spread" so to speak and flow into everywhere near it. Try it, youll be surprised. 

 

 

 I've had good luck also with a drop or two of Cascade or Finish "Jet dry", and I have also used it when cutting water tension after my daughters and I go panning in Colorado and need to clean up our concentrates.  

We work with what we have, and while that is less than some it is more than others

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Posted by hbgatsf on Friday, November 11, 2022 6:59 AM

doctorwayne

 

 
crossthedog
"Wet water." Okay, I'll bite. What in tarnation is wet water?

 

[

 

"Wet" water is water with a little dish detergent added to make it flow better.  Without that addition, ordinary tap water tends to bead-up on the surface.

I use pre-mixed drywall mud for mortar, and apply it generously using a cloth over my fingertip(s).....

Once it dries, I take the item outdoors and use a similar cloth to wipe-off the excess mortar.  There's often more of it around the door and window openings, and for that, I use various X-Acto blades to remove the excess mortar...

Once all of the excess mortar is removed, I then brush paint the doors and window frames...

I have lots of ones with the mortar added, but even more that need the doors and windows painted...

Other than the station in the foreground, everything else is simply "stored" here until I get around to finishing them.

This one, temporarily sitting on the tracks near the the Dunnville icehouse, was a much easier build, as it's a paper-on-sheet-styrene offering from KingMill, lamentably no longer in business.

Wayne

 

 

Wayne -

I found this post of yours in an older thread.

 

doctorwayne

I use drywall mud on most of the Walthers structures, applying it with a rag over my fingertips, but let it dry completely before wiping off the excess.

Here's Tuckett Tobacco, with a nice coat of Reefer Orange...

...and with pre-mixed drywall mud applied...

...and after a little dry-cleaning...

...and now with a wash of well-diluted Pollyscale, with a little dish detergent added...

 

I really like how this building came out.  What was the color of the last step of adding the Pollyscale wash?

Rick

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Posted by doctorwayne on Friday, November 11, 2022 12:05 PM

hbgatsf
I really like how this building came out. What was the color of the last step of adding the Pollyscale wash?

It's hard to say...I have trouble recalling what I was doing yesterday, let alone several months ago.

However, I'd guess that it would have been Pollyscale paint, perhaps grey left-over from a previous project (with the grey likely including some black and/or some white, too)
I probably have at least a half-dozen bottles of grey paint mixed to represent various things such as mortar, but also concrete, weathered road pavement, and pretty-well anything that was in need of being some sort of grey.
A lot of it is useful for weathering locos and rolling stock, and structures, too, usually done with an airbrush.

I think that this one is likely the first structure on which I used drywall mud for mortar, and it got a very light wash of well-diluted grey-ish water-based paint.

I was worried that the wash might remove the mortar, but fortunately, that didn't happen.

I've re-done a number of on-layout structures with the drywall mud, but it's a somewhat finicky procedure with all of the doors and windows installed, and in some cases, more difficult because some of those structures are fairly large and difficult to handle.

Here's one that needs the mortar treatment...


The clean-up procedure, after the mortar has dried, is always done outdoors, so none of that will be happening until next year.

Wayne

 
 

 

 

 

Wayne -

I found this post of yours in an older thread.

 

 

 
doctorwayne

I use drywall mud on most of the Walthers structures, applying it with a rag over my fingertips, but let it dry completely before wiping off the excess.

Here's Tuckett Tobacco, with a nice coat of Reefer Orange...

...and with pre-mixed drywall mud applied...

...and after a little dry-cleaning...

...and now with a wash of well-diluted Pollyscale, with a little dish detergent added...

 

 

 

I really like how this building came out.  What was the color of the last step of adding the Pollyscale wash?

 

hbgatsf
I really like how this building came out. What was the color of the last step of adding the Pollyscale wash?

It seems that my reply has migrated from where it should have been...right here...but is included somewhere above in this particular thread.

I dunno if it's the Forum, or just stoopid Wayne.

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Posted by hbgatsf on Friday, November 11, 2022 8:56 PM

Thanks.  That wasn't what I expected to hear so I am glad I asked.  

I originally thought that the wash was to put another, probably darker, color on and would have guessed highly diluted black.  Since you used a grey does that mean that the main purpose of the wash was to remove mud from the brick face?

Rick

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Posted by doctorwayne on Sunday, November 13, 2022 3:33 AM

hbgatsf
Since you used a grey does that mean that the main purpose of the wash was to remove mud from the brick face?

No, the mud had been wiped off the bricks  using a cloth, and the grey wash was meant to simply tone-down the orange brick, as it otherwised looked like it had just been cleaned with a sand-blaster.
The next step is to put a chainlink fence around that property (and a lesser one at National Grocers siding in Dunnville).

Wayne

 

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Posted by hbgatsf on Saturday, November 19, 2022 6:51 AM

Here is an update on two buildings I have been working on, and of course another question.  These are DPM buidings that I painted with primer before reading the tip about a more glossy paint working out better.

After applying the mud and working to get it off the face of the brick, I wanted one of the buildings to have a very dark look so I just started adding applications of alcohol and india ink to tone down the look.  I don't want the second building to be as dark.  Using one of Wayne's projects as an example how do you go from this:

 

to this:

without darkening the brick too much?  Is that just the result of applying the wash vertically with the building standing in place so that it doesn't pool?

Rick

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Posted by gmpullman on Saturday, November 19, 2022 8:58 AM

hbgatsf
I don't want the second building to be as dark.

Try starting with an india ink wash that is much more diluted. I keep two or three jars of the stuff at differen't "strengths" and sometimes I'll just use some off the top without stirring the settled pigment.

I also have some that is made with sepia India ink for a little variety.

I just found these that I think I'll try out:  https://a.co/d/d8MX6C8 They look interesting. Then there's the variety of Vallejo washes you could try as well.

https://acrylicosvallejo.com/en/category/hobby/model-wash-en/

 

Good Luck, Ed

 

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Posted by hbgatsf on Saturday, November 19, 2022 11:39 AM

gmpullman

 

 Try starting with an india ink wash that is much more diluted. I keep two or three jars of the stuff at differen't "strengths" and sometimes I'll just use some off the top without stirring the settled pigment.

I have a couple of extra wall sections that I have been using for testing purposes.  Results on the buildings don't come out exactly like on the test pieces but it gives me an idea of what to expect.

On this second building I had tinted the mud a tan color.  When I put a more diluted india ink wash on the test piece I wasn't happy with the mortar color change.  I then made washes with burnt sienna and burnt umber and tried those.  I think I am going to get what I want using a heavily diluted burnt sienna wash and applying it a couple of times.

Rick

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Posted by doctorwayne on Saturday, November 19, 2022 11:44 AM

hbgatsf
Is that just the result of applying the wash vertically with the building standing in place so that it doesn't pool?

Yeah, I apply the wash (well-diluted Pollyscale paint) while the structure is upright, so that the wash runs downward, like dirt and rainwater on a real building. 

I originally thought the "dirt effect" to be too dirty, but I've come to accept it as-is. 

If I ever get finished doing model work for friends, I've got lots of structures that still need the mortar treatment, and a follow-up for weathering, too.

Wayne

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