# Concrete bridge pillars....



## Biblegrove RR (Jan 4, 2008)

*I am needing to build some CONCRETE Bridge pillars about 2' tall. Squared triangle type. Similar to pic below but square.
*1. At 2' I can place them on square concrete stepping pads, on top of the ground. OR should I make them taller and put them in the ground? Maybe set in more concrete etc.....

2. I can make the forms out of blue foam or 3/4" plywood (got plenty) but worry about woodgrain from plywood and the instability of the foam.... which is better?

3. At 2' from the ground to the girders... what size square should they be at the 2' mark to look most prototypical? ANY ideas will help guide. Maybe I should make pre-forms out of the blue foam to guage what looks right to the eye, then copy to the plywood for the real job? 

4. Going to be using 2 1/2" bar channel for each side of the box plate girders. How far in between the pillars should the span be? Marty's looks to be about 2 feet. The steel will span farther without sag, but what looks best? Mine will be in a 20' curve BTW










*PLease include pictures if you can, any suggestions appreciated allot! * 
Thank you.


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## Totalwrecker (Feb 26, 2009)

I'd use the same taper as your wooden bents. The piers start narrower at the top (Tie width under the girder feet) and so never get as wide at the base. The symetry of the lines will look right (to me). 

It's better to determine how much curve each section can support before the outside edge unbalances the load. Once you know that you can juggle the number and spacing until your sections are equal.

Variables are diameter and length of arc/ chord.

Curves are trickier. Train size, loco weights and speed can also be factors, good ol' centrifical force y'know







You might consider an asymetrical bent; taperd to the outside and nearer vertical on the inner side of the curve.

John


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## noelw (Jan 2, 2008)

Hi John....No sure what you want, but here is a bridge pillars I did and I think you are trying to do in cement. 
I formed my own pillars. There 3 foot long by 3 inch X 11 inches at the bottom and 3 inch X 9 inch at the top.. The sides are 1" X 3" pine.

Has two pc. of re-bar in side before poring the cement. I wet the form down and let set for a few min.
I just used post hole bag of cement and beat on the side to get a smooth sides. Let it set up for two weeks and keep wet before unscrewing the side of the 1/2 inch plywood mold. I put my pillars approx one foot in the ground. My steel bridge was made in three section then welded to a total of 10 foot long.

So these were the center pillars.
Bridge is shimmed up with plastic sheets. Helps keep the bridge from being damp and not to rush setting on cement.











What nice about it is the sides are bowed out a little. Make sure you put a flat wide pc. of plywood on the top of the form and turn it upside down to use as a foot or stand 
before poring cement.











Hope this helps.. This was a fun bridge to put in. It can be lifted out after un-pluging the Signal sys. cables that gose thru the 1/2 inch sq.tubing.









A short slide show of the bridge.
Install Bridge ends.

These should do fine for a 20 foot curve bridge. May have to make quite a few of them tho. But a cheap way to go.


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## Totalwrecker (Feb 26, 2009)

If you use rebar make sure no bare metal is exposed. Use rocks or bits of broken concrete to hold the bar about an inch inside the surface. Those bits become part of the cast, chose wisely. 
John


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## John J (Dec 29, 2007)

This is what I built.

The one blow is a is a simple T design. I made the forms out of OSB with a 1x2 frame on the out side. of the form. 

The footings were poured seperate from the columb. 











This one here is a simple rectangualr box. I put some rebar in side and poured concrete. There are about 2 bags in each columb












A view of the first bridge from the other side.


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## NTCGRR (Jan 2, 2008)

I have some in my photo section, but need to head to work now.


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## SE18 (Feb 21, 2008)

Nice photos; all. I'd caution against using rebar from personal experience. They rust and expand over several years time, causing cracks and structural failure. If you feel you must use rebar, find yourself some aluminum poles from an old folding chair or something. I've been reinforcing my concrete with pieces of leftover ceramic tiles.


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## Biblegrove RR (Jan 4, 2008)

yes, thank you gentleman! Noel has what I had in mind but more square in thickness. The pillar next to his form looks oval shaped? Now THAT is a unique idea! 
Can't I just shim track at a bank to prevent roll over? 
Doesn't rebar have to be the painted type to keep from corroding etc? Would sticks of pvs pipe work?


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## SE18 (Feb 21, 2008)

if you use regular rebar, it should be 2 to 4 inches inside the concrete from the edge, including the portion under the ground 

some rebar is galvanized


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## Biblegrove RR (Jan 4, 2008)

ok but.... isn't it the concrete that corrodes and causes the steel to rust?


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## Totalwrecker (Feb 26, 2009)

If rebar were a culprit we have bridges falling down everywhere. 
Rebar does work, the time it takes to cure is the only chance the rebar could rust... But the cure goes off with heat driving moisture out. 
Concrete does not corrode, mostly stain from metal corrosions. Concrete gets harder with age. 

The unbalanced curve sections can tilt outwards, unless counter balanced. Think of a straight line between each bent/pier, now lay your curve over that and see how much off center it is at the middle of a section. The longer the chord the more will be off the true support. Curved trestles work because the span is only 16 feet or so... and 3 wide stringers still support the rails. To justify an expensive bridge the spans are longer when straight because they can carry the load. Curves open a can of worms.... 

Shimming (superelevation) won't take the load off the rails outside your support, might even add to it at velocity. 

Most folks run into rebar problems when they let the rebar stick out, then it rusts and expands causing the cracks... if encapuslated by crete it stays dry, thus no rust. 

John


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## Biblegrove RR (Jan 4, 2008)

thank you John. Just found out I will be neeing $550 in steel for the bridge projects I have planned! Using 2 1/2" bar channel for each girder I will have to anchor them to the pillars that need to be anchored in the ground! Spacing every 24 inches should be plenty. It is a huge loop that is all welded together and would take allot of weight to tip it! I think I could walk on it when finished, at least that's the plan


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## SE18 (Feb 21, 2008)

Rebar in bridges is embeded in the concrete nowhere near the surface. 

Go ahead and use it and good luck: 

http://www.onepetro.org/mslib/servl...NACE-06334&soc=NACE&speAppNameCookie=ONEPETRO


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## John J (Dec 29, 2007)

I like Noelw's pillars too. They look nice and gracefull


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## noelw (Jan 2, 2008)

Posted By Biblegrove RR on 27 Oct 2010 10:53 AM 
Doesn't rebar have to be the painted type to keep from corroding etc? Would sticks of pvs pipe work? 

................................................................................................
I've use a lot of 1/2 PVC instead of Rebar sometimes.. It works great in short pc. . Long pc of PVC is hard to fill in the center of it. Leaving air space. but not sure it hurt it or not.. My rebar is coated with Penns oil and set in place after I have about 2 inch of cement in the bottom of the mold. So rebar is sealed.. But you know even here in Cal where they make over freeways bridges the rebar still goes away in time. I may not be around when my bridges fad a way.. laf.


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## Biblegrove RR (Jan 4, 2008)

Now considering a curved concrete viaduct since the 2 1/2" bar channel is over $300 for this project! Anyone have something like that?


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## John J (Dec 29, 2007)

John 

Is it going to connect with the wooden trestle? 

What about doing towers like Marty only do them out of wood?

Think BRIDGE ON THE RIVER KWI. ( That is a long I pronounced EYE) 

It don"t have to be done roped together with jungle vines.

If fact is could be done with wood like your trestle.



PS You don't have to dynomite it like at the end of the movie. Just don't think that far.


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## Totalwrecker (Feb 26, 2009)

Yes there have been some fine viaducts shown here.... however none quite so grand! 

Yes you are also right that such a long structure tied together would offer the counter balancing I mentioned earlier. 

I think you'd be better staying with wood. For your piers I'd suggest a cluster of bents and bridge sections wide enough to hold an arc of track, with train clearances... Say 5-6 close together bents and deck bridges between 'em. 

You have so much nice wood work already.... get a new blade and start ripping. Cheap cedar fence boards make long lasting bridges. A HF pin nailer and some tightbond.


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## Biblegrove RR (Jan 4, 2008)

It is going around my burn pit and must be sturdy. Originally I wanted to build bench brackets off the inside of it for people to sit on next to the fire. $$$$ Goolm, despair and agonay on me!


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## Biblegrove RR (Jan 4, 2008)

As for ripping MORE wood... RRRRRRRRRRR the trestle you see took 6 months to complete!


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## Totalwrecker (Feb 26, 2009)

Sorry Big Dreams cost more...


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## wigginsn (Jan 9, 2008)

Your layout is going to be fantastic when you're done. 

What about some flat "sitting" rocks on the ground instead of constructed benches? 

Cheers 
Neil


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## Biblegrove RR (Jan 4, 2008)

hhhhhhhmmmmmm the wheels are a turnin' 

thanks Neil


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## noelw (Jan 2, 2008)

Posted By Totalwrecker on 28 Oct 2010 04:27 PM 
Yes there have been some fine viaducts shown here.... however none quite so grand! 

Yes you are also right that such a long structure tied together would offer the counter balancing I mentioned earlier. 

I think you'd be better staying with wood. For your piers I'd suggest a cluster of bents and bridge sections wide enough to hold an arc of track, with train clearances... Say 5-6 close together bents and deck bridges between 'em. 

You have so much nice wood work already.... get a new blade and start ripping. Cheap cedar fence boards make long lasting bridges. A HF pin nailer and some tightbond. 
....................................................................................................

Like Totalwrecker said.........I didn't know that you was going to tie into your existing Trestle. I think other pillar or anything else would not look right.. I would keep it with the same theme you have now.. Ya. .. It's a lot of work, but that a nice looking trestle you have already.. I would make more bents and cont. with the new run.
Maybe make a few wooden bridges to put in every so often.. Curve trestles look great. Just my two cents worth.


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## Biblegrove RR (Jan 4, 2008)

RRRRRRR I still have 3k ER bill from ripping my thumb on that dang table saw!







It would be prototypical to have added another line at a later time out of another material? 
I kinda like this and it would be cheap enough - ripped it off someone on MLS and saved it because I liked it...

















HOW would I pour the top?


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## SE18 (Feb 21, 2008)

John, I see why you want a concrete viaduct; the one pictured looks simple but very nice; natural weathering too, I suspect 

My only criticism would be it wasn't mixed too well, with aggregates settling on the bottom.

Best to use a special mixer that can attach to your drill that cycles material from bottom to top; it's helix looking


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## aceinspp (Jan 2, 2008)

Looks good but could end up being a back breaker. Later RJD


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## John J (Dec 29, 2007)

It looks like it would be a two pour job. You would make the arches first with the first pour and the cap second with the second pour.


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## SE18 (Feb 21, 2008)

A gent on this forum (In-koh-pah?) did something similar using wood forms and for the arched areas he used cardboard rolls they sell at HD/Lowes that are used to fill holes with concrete for deck pilings etc 

It's almost certainly 2 pours. Probably cast in place. 


If you want to float the track in ballast, you could cast the top piece so that there are some sidewalls, but you'd have to probably add a few small drain holes. That way you could float the track if you wanted to. Either style would be good.

I can generally tell a styrofoam viaduct from pretty far away b/c specks of blue, white or pink are showing where someone accidently kicked it


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## John J (Dec 29, 2007)

Sono cones? I think that is the name. They are carboard tubes used to make concrete pillers. The tubes could be cut in half to use as a form for the arch . You can get them at HD.


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## SE18 (Feb 21, 2008)

Almost sounds like snow cones  

Here's a link to Ray's site; you can modify what he's done to suit your needs. I'd cast in place if it were big. He had problems moving his. 

http://www.raydunakin.com/Site/In-ko-pah_Railroad.html


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## SE18 (Feb 21, 2008)

Here's how I'd do it. The squarish thing would be a piece of styrofoam tucked inside the wood form. It would form a neat depression in the viaduct. 

The top is not the form but how it would look if you were to include ballast and the edge could be a walkway


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## Biblegrove RR (Jan 4, 2008)

look at my pic of the viaduct again.... I thought of making ONE mold to cast all the arches. Stick them in the ground, level and mate them together where the TOP of the arch comes together. Then pour the top, with sides (thanks) but how would I form them without pouring upside down? 
(thanks for the impression idea as well, that would look great and allot more detailed/unique.


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## SE18 (Feb 21, 2008)

In my crude sketch to the left, the curve should be more pronounced so that the uprights are side by side and nearly touching each other. The top plate would bridge them. I'd leave some rebar sticking up from the mold so the top plate holds fast 


The possible problem of joining each segment as one piece would be weakness at the connection, unless you let rebar or something else stick out sideways for the next pour to cling to, but then the rebar would have to pierce the mold. This could be easy if the mold itself were styrofoam and not wood. 

OTOH If the entirety (top plate and bottom, full length) were to be poured at one time, there wouldn't be that drawback of having the seam present. Unfortunately on a big viaduct, you'd need a lot of helpers or a cement truck. I'm thinking you will be doing this in phases. 

I'm glad you like the impression idea. That's my plan for next spring. The reason for styrofoam would be to prevent mold lock. I forgot to mention that the wood form in the left photo should be screwed together so it can easily be demolded and used again. I'd let it set up at least 2 or 3 days depending on the weather. A lot longer in cold. Dave


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## SE18 (Feb 21, 2008)

http://www.flickr.com/photos/hanneorla/70663441/ 


http://www.flickr.com/photos/photography_by_shangri_la/4497729039/



http://www.flickr.com/photos/innusa/329765196/
On the wood form itself you could add molding to make designs that are either raised or depressed. If you had a router, you could route out the wood mold and this would add raised pieces; or you could buy molding and nail/glue it to inside of form Variations are endless 
you could insert thin PVC in the mold itself and pour concrete around it for decorative effects.


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## SE18 (Feb 21, 2008)

Here's a view inside a viaduct

Note the sidewalls hold in the ballast, tracks, grass and trespasser 

http://www.flickr.com/photos/[email protected]/4250284863/ 

Whatever you do, take your time to think it through, draw out sketches, maybe do a test segment and post your plans and photos; this would especially help me as I've been thinking this over now for some time and have yet to experiement


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## Biblegrove RR (Jan 4, 2008)

If I pour in place (build forms and call in a truck) how do I get the side walls on the top to hold in ballast etc.? 
Man, this is getting to a grand scale, real fast! lol


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## John J (Dec 29, 2007)

I wonder. Just before WWII the Key system in San Francisco and Oakland was dismantled. It ran on the lower deck of the Bay Bridge where cars now run. The street cars were either burned or shipped to South America. I wonder if that tram pictred could be one of them still running


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## John J (Dec 29, 2007)

Posted By Biblegrove RR on 29 Oct 2010 10:26 AM 
If I pour in place (build forms and call in a truck) how do I get the side walls on the top to hold in ballast etc.? 
Man, this is getting to a grand scale, real fast! lol 


What you would do is have a board ready about 2 inches thick and a little wider than the ties on your track. It must follow the curveature of the Viaduct. Stop about 2 inches from the top ( What ever the board thickness is.) Lay the board on the concrete then pour around it. This will give you a depression for the ballaast. 


Solution #2. take some rain gutter and form it to the curvature of the viaduct ( I assume it's curved.) Pour to the level when the gutter is put in it is level with the top of the form.

Then pour around it.


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## SE18 (Feb 21, 2008)

John has the right idea. I've got to go. Please sketch out your plans and post here before you do anything. It's best to really think this thru well. It's hard to alter after the fact. 

If you really want to get elaborate, you can embed PVC and wires into the bridge if you're going to do a single pour; and then, have boxes embedded in the concrete so you can hook up lighting. A $50 transformer from Lowe's will provide you with low current DC. Then you can light up the sides or even the top. It would be spectacular at night. 

Lets talk more later 

Dave V


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## SE18 (Feb 21, 2008)

John has the right idea. I've got to go. Please sketch out your plans and post here before you do anything. It's best to really think this thru well. It's hard to alter after the fact. 

If you really want to get elaborate, you can embed PVC and wires into the bridge if you're going to do a single pour; and then, have boxes embedded in the concrete so you can hook up lighting. A $50 transformer from Lowe's will provide you with low current DC. Then you can light up the sides or even the top. It would be spectacular at night. 

Lets talk more later 

Dave V


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## John J (Dec 29, 2007)

You could build this off site with a form made up side down. What you cold do is buld the from from the Crest of the Arch to the base of the columb the the crest of the next arch. Much like a "T" You could have to put something on each end of the Cross bar of the "T" to mate with the next one. Like maybe a 1 inch diamater x 6 inch shaft. Once the concrete cured you would pull the shave out and you will have a hole. When you assemble the two arches you would put the shaft back in one hole and glue it. 'then insert it in the hole of the next arch as you assemble it.


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## toddalin (Jan 4, 2008)

Do you really need all that strength from concrete and rebar?

The _clean_, _simple, non-back-breaking_ way is to make your pier out of styrofoam in _any shape you desire_. Use yellow glue to build up the pieces if needed. If you want lighting, run a piece of PVC up the center. Then just sift hydraulic cement over the styrofoam and mist it with a spray bottle. This will for a hard candy shell around the foam and because the styrofoam is now insulated from the elements, will probably last forever. (It lasts almost a lifetime even uncoated.)

One forum member is currently working on structures for his railroad using this technique and reported that he _loves_ it. Watch for my article using this technique in an upcoming _Garden Railways Magazine._


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## Biblegrove RR (Jan 4, 2008)

Need MORE info Todd..... I am an expert at the foam stuff! lol


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## toddalin (Jan 4, 2008)

Posted By Biblegrove RR on 29 Oct 2010 01:27 PM 
Need MORE info Todd..... I am an expert at the foam stuff! lol 

Can't put it on-line as Kalmbach now has rights to the article. If you send me a valid e-mail, I'll get you something.


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## Biblegrove RR (Jan 4, 2008)

well.... I already have a 4" round form I had planned on using elsewhere and can barely afford to make the girders out of PVC Vinyl board like my other bridges.... ? 
Would square look allot better? Talked to a concrete guy today at church and a complete, 1 pour concrete viaduct would be grand! A grand job indeed... 
P.S. By God's grace I hit my goal this month and earned $623 in bonus money! How I know it was God? Because the wife had just ordered $620 in propane the day before and would have to juggle bills to try and cover it, putting us in a bind. I'm still in the hole, but should have heat! ;~)


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## SE18 (Feb 21, 2008)

So the one grand will put you out of the running for concrete?

You can do it a lot less yourself using bags of 80lb. Yesterday all day I worked concrete patio extension, after building a patio of rock I tried one using cement and forms (see photos).

I also designed a 30 ft long concrete viaduct a couple years ago and a concrete canal this year that's about 45 ft long.

So i was thinking of you last night and with some leftover concrete, I did a quick model (shown here). I'll try to strike the mold tomorrow.

I suggest you make some of these little models. I inserted PVC in mine for a decorative hole. You might try sections of soda straw.

Better to fail in your model first.

Dave V

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## Biblegrove RR (Jan 4, 2008)

DUDE! Thank you for your help! Especially for posting your concrete molded patio picture! I also found a deal on some pavers for $150 to go around the burn pit. BUT you reminded me that I HAVE one of the plastic molds like yours in the garage! Much cheaper to do this! how did you get seperate stones within the mold a different color? Sprinkle on the powder after pulling the mold?


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## SE18 (Feb 21, 2008)

thanks. I used liquid concrete dyes from Loew's and individually mixed about 3 types (buff, charcoal and another color I can't recall as it's at home). Also experimented with combining mixings for different colors. Hand-poured each and tried to randomized. 

Used rubber construction gloves. 

The mold from Lowe's is $13. You can make circles around your pit using the mold but filling only selected cells. 

The last photo area near house (for left) too close for mold so I'm pouring using the full mold on some thick plastic. Will set these individually in cement. 

Using mortar when fully dry to fill in the cracks. You can leave the cracks if you like and let grass grow between, or put fabric cloth under and maybe sand in cracks. 

I found that over time, fabric weed barrior fails as weeds can be tricky as squirrels. 

Keep us posted, Dave


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## John J (Dec 29, 2007)

Liquid? Concrete? Dye? Lowes? I will have to check that out. I need concrete dye . lots of it.


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## SE18 (Feb 21, 2008)

I replied to your IM. I pour undyed concrete and only dye the top 2 inches. Less than a bottle of 3 colors (less than 3 bottles at $5 each) were all that was needed for what you see. Vary the amount for variety. 

BTW, getting back to trains, you can do this for concrete rock scenery as well, using dyes. Mine from Lowe's were liquid; HD has the powdered form. Generally, 1 80lb bag concrete per mold. That's $3.80 each.

Store above freezing, which reminds me I have to remove my dyes from the outside shed as it's getting cold out now. 

Dave V


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## John J (Dec 29, 2007)

My Local HD only has three shades of brown. (two iwth in a 10 mile area ) I will have to check out lows slection.


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