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Waterproofing Plywood

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Posted by railandsail on Friday, August 24, 2018 1:24 PM

I don't anticipate any problem with getting some of the adheasive chalks sticking to it. I'm actually more concerned with them sticking too good, to the point that tracking laying directly to it will be unremovable/repositionable.

I guess I can use some sort of track nails on the wood plywood, but I can't use those on that masonite board I built the helix curves with,...going to have to glue that down. Rigth now I plan on tacking that track down with hotmelt glue, then some sort of ??...maybe just latex paint.

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Posted by Doughless on Friday, August 24, 2018 9:09 AM

riogrande5761

 

 
Doughless

If the plywood is waterproofed so well that water will bead-up and run off, will water soluable adhesives even stick to it?

Like latex caulk for laying roadbed or track, and glue or matte medium for ballast?  Or any type of water based senery application?

 

Interesting conundrum.  OTOH, you need to make benchwork resistant to moisture to minimzie the expansion/contraction issues reported by many which can gave adverse effects. OTOH, stuff needs to adhere to it.  What to do!

I certainly want to avoid the dreaded expansion/contraction problem so I'm going to go over mine once-over with the Olympic water sealer and at least for track and roadbed, I don't use calk, but rather track nails and ME spikes so no issues there.  Scenery, guess I'll have to take my chances.

 

When I think of water beading up on a surface, I think of a freshly waxed car or something extremely glossy.  I guess stuff will stick to it, but its not the optimal surface prep for that.  I don't know how glue would adhere, especially if its thinned at all.  I can see where nailing roadbed would not be an issue.

- Douglas

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Posted by Doughless on Friday, August 24, 2018 9:05 AM

riogrande5761

 

 
Doughless

If the plywood is waterproofed so well that water will bead-up and run off, will water soluable adhesives even stick to it?

Like latex caulk for laying roadbed or track, and glue or matte medium for ballast?  Or any type of water based senery application?

 

Interesting conundrum.  OTOH, you need to make benchwork resistant to moisture to minimzie the expansion/contraction issues reported by many which can gave adverse effects. OTOH, stuff needs to adhere to it.  What to do!

I certainly want to avoid the dreaded expansion/contraction problem so I'm going to go over mine once-over with the Olympic water sealer and at least for track and roadbed, I don't use calk, but rather track nails and ME spikes so no issues there.  Scenery, guess I'll have to take my chances.

 

When I think of water beading up on a surface, I think of a freshly waxed car or something extremely glossy.  I guess stuff will stick to it, but its not the optimal surface prep for that.  I don't know how glue would adhere, especially if its thinned at all.

- Douglas

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Posted by railandsail on Friday, August 24, 2018 8:04 AM

Metal Benchwork

Did you see my latest posting on my 'metal benchwork'?

Over the past year I have been thinking and experimenting with ideas for my benchwork for my new layout in a shed.

I was over at my local metal scrap yard this past Fri and noticed some hollow square steel tubing they use to mount street signs with. Its 2" square verses my flanged 1-1.25" bed rails, and its really strong, and its galvanized. So now I am definitely considering this stuff.

 

I was originally considering making vertical brackets at each of the wall stud location to support the plywood shelves. then I ran across these steel square tubing at the local metal scrap yard.

My contractor friend. who was going to weld up the considerable number of vertical brackets I had sketched up, came back with an interesting idea. Why not lay these square tube 'beams' horizontally along the walls and lag them into the wall studs. Then the plywood shelves (decks) could be attached along their wall edge and cantilevered out. And where the shelf/deck is of a substantial depth, the outer edge might also be supported primarily by another long piece of this horizontal square tubing with only an ocassional vertical support.

I am now planing on utilizing this 'horizontal framing' idea on my staging track level and my lower primary deck. I may even utilize the idea for my upper deck, particularly as they will be more shallow than the primary deck. I will definitely utilize the larger 2" square tubing to support the lower primary deck. For the staging level (relatively shallow), and the upper deck I may utilize my 'bed frame angle iron'. I'll document this more thoroughly as I get to building it.

Quick update,....the first piece of horizontal steel tube framing along the back wall of the shed. The large size square tubing is the type that will be utilized to support the edge of the plywood deck next to the walls.. This will be selectively placed around the perimeter of the shed. There will also be central pieces at the inner edges of the shelf somewhat like shown on this preliminary dwg.
 

 

 

 

 

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Posted by railandsail on Friday, August 24, 2018 8:00 AM

rrinker

 Pretty sure he means the steel studs have unbsupported spans of 14 feet, easily doable with metal framing materials, or even wood in L girder or other girder configurations. I plan much the same at least on the along the walls parts of my layout, I don't want a forest of legs along the aisle side ofmy layout to get kicked, or get in the way of working underneath or then, once completed, of using the under layout area for storage with everything organized into plastic totes.

The foam itself - on my last layout with sections up to 24" wide, I had just one cross brace in every 4 foot section I built, so 2 feet on center support and there was no sag whatsoever. I wouldn;t go much further than that though. 

                                         --Randy

 

 

I am a little confused by your reply?

At one point you seem to OK his 14 FEET of unsupported span, then go on to say you supported yours every 2 feet,...or 4 feet ??

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Posted by riogrande5761 on Friday, August 24, 2018 7:21 AM

Doughless

If the plywood is waterproofed so well that water will bead-up and run off, will water soluable adhesives even stick to it?

Like latex caulk for laying roadbed or track, and glue or matte medium for ballast?  Or any type of water based senery application?

Interesting conundrum.  OTOH, you need to make benchwork resistant to moisture to minimzie the expansion/contraction issues reported by many which can gave adverse effects. OTOH, stuff needs to adhere to it.  What to do!

I certainly want to avoid the dreaded expansion/contraction problem so I'm going to go over mine once-over with the Olympic water sealer and at least for track and roadbed, I don't use calk, but rather track nails and ME spikes so no issues there.  Scenery, guess I'll have to take my chances.

Rio Grande.  The Action Road  - Focus 1977-1983

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Posted by rrinker on Friday, August 24, 2018 6:47 AM

 Pretty sure he means the steel studs have unbsupported spans of 14 feet, easily doable with metal framing materials, or even wood in L girder or other girder configurations. I plan much the same at least on the along the walls parts of my layout, I don't want a forest of legs along the aisle side ofmy layout to get kicked, or get in the way of working underneath or then, once completed, of using the under layout area for storage with everything organized into plastic totes.

The foam itself - on my last layout with sections up to 24" wide, I had just one cross brace in every 4 foot section I built, so 2 feet on center support and there was no sag whatsoever. I wouldn;t go much further than that though. 

                                         --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by railandsail on Thursday, August 23, 2018 9:54 PM

bing&kathy
......
   I have no supporting legs on my beachwork with spans of uo to fourteen feet with no problems.



Wow, that unsupported span is unbelievable. Do you haver some photos?
 


 
 
 
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Posted by bing&kathy on Thursday, August 23, 2018 7:54 PM

railandsail

I'm not sure how to answer that question because there can be some confusions on how to properly use the 'solvent' wording,...ie
"As opposed to oil-based paints, water-based paints (sometimes referred to as “latex paints” or “acrylic paints“) do not use solvents; the carrier for the pigment is primarily water"

The water in the paint is used to carry the paint pigments to the surface being painted, then evaporates away.

A second coat of paint (water soluble) will stick to the stained surface, so I imagine water soluble adhesives will as well.

    I built my benchwork with metal studs and 2" to 4" of foam on top. My building is also subject to temperature and humidity swings and felt this would be the most "stable" construction. If you are going to use plywood in a damp enviroment I would go with marine plywood. Using regular plywood you would use up the savings tring to waterproof it. As far as using oil or latex or acrylic paint to seal the wood, oil will seal out moisture and seal in any moisture already in the wood. Water based paint will let moisture in and out of wood (ie breathes). Water based paint will also asorb moisture so water based glues may lose their grip. That's why there is Elmers glue and Carpenters glue. Carpenters glue is more suitable for damp locations. Of course there is always marine glue, think boats.
   I have no supporting legs on my beachwork with spans of up to fourteen feet with no problems. the foam has stayed as solid as a rock, some rocks are made of foam. Temperature and humidity swings are murder on layouts. So far, so good on mine.
   Don't over think what you are going to do! You'll only confuse the issue. Good luck on your upcoming construction.   

God's Best & Happy Rails to You!

Bing  (RIPRR The Route of the Buzzards)

The future: Dead Rail Society

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Posted by railandsail on Monday, August 20, 2018 12:13 AM

I'm not sure how to answer that question because there can be some confusions on how to properly use the 'solvent' wording,...ie
"As opposed to oil-based paints, water-based paints (sometimes referred to as “latex paints” or “acrylic paints“) do not use solvents; the carrier for the pigment is primarily water"

The water in the paint is used to carry the paint pigments to the surface being painted, then evaporates away.

A second coat of paint (water soluble) will stick to the stained surface, so I imagine water soluble adhesives will as well.

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Posted by Doughless on Sunday, August 19, 2018 9:20 AM

If the plywood is waterproofed so well that water will bead-up and run off, will water soluable adhesives even stick to it?

Like latex caulk for laying roadbed or track, and glue or matte medium for ballast?  Or any type of water based senery application?

- Douglas

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Posted by railandsail on Saturday, August 18, 2018 10:40 PM

I just don't like the 'beaded foam'.

And I'm sure it would not work in some of the cantilivered situations I will be imposing on my roadbed/benchwork. I'll be covering that subject over here,...

http://cs.trains.com/mrr/f/11/t/269136.aspx?page=3

BTW so far I have been able to coat two full sheets of 4x8 plywood with 2 coats on both sides using 1/2 gal. So I expect to coat 4 sheets with this one gallon

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Posted by rrebell on Saturday, August 18, 2018 3:00 PM

railandsail

In the beginning I was seriously considering 2" foam subroadbed shelves held up with some pretty nice metal brackets from Home Depot. The 2" foam is not so readily available here in FL, so I looked around for options.

Found what I thought was some decent plywood (called Blondwood) at Lowes. I monitored a stack of it at their store and i became less impressed,...and thought perhaps 3/4" rather then 1/2". I had also inherited a 1/2" piece of 4x8 from a friend and stored it in my carport, both on its edge and flat on the cement floor. I became even less impressed. It went thru all kinds of gyrations.

Then I ran across some 7 ply, 3/4" plywood from Chili being sold at Home Depot. It was the best looking stuff I had seen,....Radiata Pine

It was a little thicker (and heavier) than I had originally planned, but then again I am not supporting it with 3" wood framework on its edge as in many conventional benchworks, so a little extra thickness could be helpful for both stability and extra cantilivered strength. And if I paint it all around that should help seal it against some of the moisture of humidity.

 

You can ussually get beaded foam in warmer places, works great.

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Posted by railandsail on Friday, August 17, 2018 11:48 PM

Never did cosider cement board as I felt it would be too heavy. But I'm sure it is likely NOT affected by temp/humidity.

When you see my 'unique steel framing/benchwork' I will be using, you will likely see that I might have been able to use cement board.

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Posted by BATMAN on Friday, August 17, 2018 11:28 PM

It will be interesting to see how the treated plywood holds up over time. I hope it goes well in the heat and humidity. I was worried about heat where my layout goes over the fireplace so I used cement board. It cuts with a circular saw like plywood, heat and moisture have no effect on it. 

Did you ever consider cement board?

  

 

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 railandsail on Friday, August 17, 2018 11:04 PM

I had not priced out the retail price. As you said a bit pricey. I got it at some estate or yard sale.

I picked up a nice dehumidifier at our local flea market (and one with an external fitting for automatic discharge), but I discovered that it puts out a fair amount of heat in order to function. So I would have 2 cross purpose machines working in a faily small space,...one adding heat, one taking heat away. ...dehunidifier and AC

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Posted by riogrande5761 on Friday, August 17, 2018 7:24 AM

It's a bit pricey at $37/gal.  At this point I'm planning to go with the much lower cost Olympic Water Guard at about $10.50/gal.  I am running a dehumidifier to keep the basement at a fairly constant humidity.

Rio Grande.  The Action Road  - Focus 1977-1983

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Posted by railandsail on Thursday, August 16, 2018 11:55 PM

In sunny Louisiana, the same climate you're in. 

I built a wooden privacy fence in 2011, and used this product from Behr.

https://www.homedepot.com/p/BEHR-Premium-5-gal-Natural-Clear-Transparent-Waterproofing-Exterior-Wood-Finish-50005/100172793

I can tell you the fence looks like the day I stained it, water literally will not stick. Direct sunlight all day, and from 20-105 degrees with 60% humidity. This product has lasted 2 years past the manufacturers estimate of 5 years, and still going strong. May be overkill for your application, but you asked. 

-Dean

 

That link you provided no longer worked properly.

I was looking back thru some products I had collected up from various yard & estate sales and found the full gallon of  Behr waterproofing outdoor wood stain. Just a shaking test said it was a more liquidy product than many paints. I like that idea as it indicates it will penetrate the wood surface more easily. (harkening back to my boating days, I recall our diluting/thinning the first coat of varnish on wood surfaces to get a 'good grip')

 

Decided to give this product a try. First trial is the plywood sheet I will be cutting up in half to make the 'floor panel' of my helix structure. As I suspected the first coat seemed to soak into the wood surface really well. I will be applying a second coat tommorow.

 

I did 2 coats of this 'stain' on both sides and edges. I might even add another coat (&color) of regular paint eventually.

Was pretty happy with results, so today I did my first sheet of 3/4 plywood that I will be cutting up to make my staging track subroadbeds.

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Posted by railandsail on Sunday, July 8, 2018 7:57 AM

Timber Pro Stabilizer

BlackAdder

Over many years of outdoor projects, pine, cedar, and fir furniture, fences, and chicken coops I've used many 'water seal' products.  All have needed to be resealed over time.  This product (https://timberprocoatingsusa.com/products/internal-wood-stabilizer/) is amazing.  Over six years of use and I've never had to reseal or found any rot.  Because it worked so well outdoors, I used it in building my present benchwork.  It might be worth a look or give the company a call and tell them what your doing. 

Thanks for that reference. I wrote them an email today.

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Posted by rrinker on Thursday, July 5, 2018 1:15 PM

 I might need that Zinnser stuff to paint my basement concrete block before I put up the walls.

                                    --Randy

 


Modeling the Reading Railroad in the 1950's

 

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Posted by NWP SWP on Thursday, July 5, 2018 10:09 AM

Olympic seems to be the the equivalent to Thompsons WaterSeal, available in clear, and dyed versions, I can attest to the "waterproofness" of the stuff, back in 2016 Louisiana had what we call "the great flood" anyways we got about 3-4" of water in our shed, which has a 3/4" pressure treated plywood floor that was coated with Thompsons WaterSeal, no mold or anything and that was what years ago.

Steve

If everything seems under control, you're not going fast enough!

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Posted by riogrande5761 on Thursday, July 5, 2018 8:56 AM

I'm liking the description and price of the Olympic Waterguard a lot:

$10.48 a gallon at Home Depot and cleans up with water.

Rio Grande.  The Action Road  - Focus 1977-1983

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Posted by railandsail on Thursday, July 5, 2018 8:41 AM

Thanks Randy

I was doing a little looking at Zinsser products the other day and ran across this one,...

And then this mold & mildew-proof waterproofing paint, ...name would imply it will do the job,....& 15 year waterproofing guarantee
https://www.walmart.com/ip/Zinsser-270267-1-gal-Mold-and-Mildew-Paint-White/47647744

Zinsser 270267 1 gal. Mold and Mildew Paint, White

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Posted by rrinker on Wednesday, July 4, 2018 11:50 AM

2 pound cut means it's 2 pounds of dry lac cut into the alcohol, per gallon.

The higher the 'cut' amount, the thicker the shellac(less liquid, more material)

If you intend to paint over, you need dewaxed shellac.

If the goal is to prevent moisture penetration, then all surfaces would need to be coated, not just the edges. 

                               --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by railandsail on Wednesday, July 4, 2018 9:30 AM

Dewaxed Shellac

 

maddragon


 

Greg, this topic always gets a lot of responses, most of them wrong. I've been a woodworker for longer than I've been a model railroader and that's a long time.

The best sealers are de-waxed shellac. or clear polyurethane. They're about equal but poly takes hours to dry and shellac takes minutes. Applying poly in a closed environment is harder on your lungs than shellac - unless you wear an appropriate mask.

For both reasons my first choice is the de-waxed shellac. It used to be that had to be mixed up from flakes, but for several years now Zinsser has marketed a 2 pound cut of dewaxed shellac as SealCoat. That's what I use.

What is a 'two pound cut'?

I looked up the qt and gallon prices on this stuff and they want $20 per quart or $60 per gallon. Not exactly inexpensive.

Does it go a long way? Is it likely one only needs to seal the edges of the plywood, rather than the whole sheet front and back??

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Posted by railandsail on Monday, July 2, 2018 8:58 AM

railandsail

Deck Type Sealers

I had some Thompson water sealer product setting around I had acquired from some estate sales. I looked up info on the product, and I was NOT very impressed with its capabilities for protecting outdoor decking. Seems as though many folks were unhappy with its performance.

But that said, I do NOT intend to utilize it in an outdoor situation,...where UV can be a big problem. I ran a few test samples on a portion of my outdoor wood deck, and some wood shelves I had made of plywood. I did note that it seemed to soak into the wood much more thoroughly than paint would have. That would seem to indicate a 'sealing function'?

Has anyone had experiences with sealing up plywood with deck coatings?

Can they subsequently be painted over??


Found this on another forum...

Here in Southern California all wood warps unless it is sealed with something.  I say it is the dryness.  So, in 1998 I built a special computer desk which later turned into a train workbench.  Sense I had experience with specialized homemade furniture  and prior layouts warping and the cork roadbed crumbling I tried Thompson's Water Seal left over from another project.  I hit a home run!  Wood does not move!  Cork does not deteriorate.  19 years on my train workbench.

If you want to try it here is how you use it.

Make sure you use water soluble type.  Makes clean-up easy.  Last time I bought it it came in three tints plus clear in a metal gallon can.  I bought it at Home Depot.

Build your bench work or module as usual. When you are past the glue and screw portion stop. Apply Thompson's over all wood including legs, braces, etc. Use a 0ne and two or three inch brush. Clean with water in sink. If you are going to paint over the water seal wait four days for the water seal to finish gassing off.

I now build in modules so they have legs and braces that show. I paint these and around the edges of the module rattle can flat black.. Looks good. On the inside of the module I paint rattle can white. However, I now build the rectangular portion with the track and scenery as an insert held in with screws but I still paint the underside white so I can see. The insert I still paint with water seal as I use thin plywood for the insert.

I don't like the weight of the modules, too heavy, so I am going to try the foams for the insert on new modules.

An Aside: The way I water seal the cork roadbed is

Buy a box at a time

Tear the entire box and finish the beveled edges (I'm in N Scale)

Use a shop rag saturated in water seal and rub along and all over. Hang on a line outside. Use gloves. When dry remove from line and leave in a sheltered area outside for four days to gas off. Fumes could be bad for you.

Your done. I put back in box

So, for me these two procedures are bulletproof for me. Give it a try and see what you think.

Mike Lee

 

Thanks Mike, I was looking for someone who had first hand knowledge about these 'wood deck sealers'.

So you have actually painted over some of your sealer treated wood? Did you happen to make inquiry with the home company about doing that procedure? Or how did you come to that decision??

In a little experiment I made it did appear that Thompson Water Sealer did soak into the plywood samples I used. It was at that point that I wondered about subsequent adhesion to those surfaces??....by paint, by glue, etc??

Brian

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Posted by danno54 on Sunday, July 1, 2018 12:17 PM

I’d consider a garden railway in the backyard. Rather than fight the weather I’d embrace the weather outside year round.

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Posted by SouthPenn on Sunday, July 1, 2018 10:54 AM

Don't you have pressure treated plywood in your area?  

South Penn
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Posted by zstripe on Sunday, July 1, 2018 6:33 AM

You should have bought exterior grade plywood to begin with........end of story!

My layout is built with exterior grade ply...one side smooth.....never had any problem's with it since the early 80's. As a matter of fact, I have used the same plywood on outside projects and still do not have a problem in 38yrs. I also live in the Midwest with all four season's. Glue it and screw it. I also do not buy any lumber from a big box store......just to save money.....In the long run, you are wasting your money. Exterior grade/Marine grade is the only kind I use....there are no voids in that type of ply, adhesive is moisture proof........... I also did My 27ft. cabin crusier with Marine grade for the leather covered seating, engine cover, which covers a 350 chevy engine......works like a charm. Hull is all fiberglass......

Take Care! Big Smile

Frank

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