# Blue foam newbie has some questions.



## traction fan (Oct 5, 2014)

After complaining repeatedly about not being able to find extruded foam in California, I finally found some. It's the blue variety. So now I'm working with this stuff for almost the first time. (Iwas able to get a few scraps earlier.) I have some questions for seasoned extruded foam users. 

1) What do you use to glue slabs of foam together in order to form hills? I tried white glue, which holds the two pieces together well enough, but I don't think it will dry anywhere but the edges. The center won't get enough air to dry out and set up. I also tried a hot glue gun. This works, but it tends to melt into the foam. That's not a deal-breaker, since it does set up quickly and holds well. In the past, I've used double-sided tape. That grabs instantly, and forever, which makes it unforgiving if you don't have the pieces lined up exactly. It's also expensive, and the tape can get in the way when you shape your hill.

2) What do you use to bond foam to wood, or plastic? Will the same adhesive used to bond foam to foam, also work with wood or plastic?

All suggestions welcome, thanks in advance;

Traction Fan 🙂


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## vette-kid (May 2, 2020)

I used mod podge to glue sheets together. Make sure you remove the plastic film from it. I don't know if it dried all the way in, but I do know it's a good solid bond.

Sent from my Moto Z (2) using Tapatalk


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## cole226 (Feb 8, 2013)

I've always used liquid nails construction adhesive. Some states foam specific but I've never had any that wouldn't hold.


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## Lehigh74 (Sep 25, 2015)

Sometimes I use hot melt glue (on the low heat setting). Sometimes I use Loctite Powergrab. Sometimes I use them both at once. The hot melt glue give an almost instant bond and the Powergrab makes sure it's permanent.


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## AFGP9 (Apr 8, 2015)

I have always used Liquid Nails construction adhesive. It is compatible with the foam whether it is blue, pink or green. I just run a bead all over one piece and spread with a wide putty knife. Kind of like spreading drywall filler. Then I will weight it with several train magazines or adjustable bar clamps and wood strips for 24 hours. Just depends upon how big a piece I'm gluing.

Kenny


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## Lemonhawk (Sep 24, 2013)

Try Liquid Nails "For projects" its for foam, while regular Liquid Nails is not. Note that if you make a ring around the foam, them put some dabs in the middle, they may not dry, a star pattern might be better.


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## Stumpy (Mar 19, 2013)

Liquid nails for projects.


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## mesenteria (Oct 29, 2015)

I use LePage's PL300 (variety safe for use on extruded foams). I have read many times that people can use almost anything and find that it works. Just not something that will 'melt' or soften the foam itself, so I think the DAP-with- silicone caulks are a no-go. But straight cheapo acrylic caulking would work, and a little goes a long way if you force the two slabs tight to each other by placing scraps of board/plywood atop them with weights, paint tins, soup cans, driver batteries...

BTW, when I go to erect tunnel portals by standing them in place on the plywood roadbed, I use a dab of PL300 under their two feet. PL300 isn't quick to cure, but it does stiffen inside of about 24 hours if you haven't placed half an ounce per dollop. As in all applications of adhesive, it is easy to use far more than enough.


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## flyboy2610 (Jan 20, 2010)

What I use to bond foam to foam is not really an adhesive per se, but a paint. It is PPG's Gripper Primer paint. It used to be made by Glidden, but PPG bought out Glidden. You can get it at Home Depot. I paid about $26 for a gallon. That sound expensive, but it will glue a LOT of foam, and the cost of Liquid Nails for projects to do the same amount of foam would be astronomical! You can also buy it by the quart for about $12.
Of course, it also depends on how much foam you have to glue. If you only have 1 sheet of foam to glue, the Liquid Nails might be the way to go. 
I paint one side of the foam, put the other piece on and weight it down. After 24 hours you will not get the two pieces apart without destroying the foam. It also works well to glue foam to wood and Homasote. It's good stuff, Maynard!


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## CTValleyRR (Jul 26, 2014)

Well, you're right -- any water or solvent based glue won't ever cure in the middle if you surround it with other glue. Use an S shaped bead to allow curing.

A few dabs of Liquid Nails holds my foam to the benchwork, and I use hot melt glue for foam to foam bonds (as well as attaching servos for turnout control).


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## 65446 (Sep 22, 2018)

Can't you simply open one of your own preset push-button 'how to's' that you always post, and simply go by that ? You mean it Isn't it in your roster; 'How to glue foam pieces', or titled 'Types of glues for types of materials ? I find it hard to believe you wouldn't have this particular instruction, what with the abundance of gluing done in MRRing..


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## traction fan (Oct 5, 2014)

telltale said:


> Can't you simply open one of your own preset push-button 'how to's' that you always post, and simply go by that ? You mean it Isn't it in your roster; 'How to glue foam pieces', or titled 'Types of glues for types of materials ? I find it hard to believe you wouldn't have this particular instruction, what with the abundance of gluing done in MRRing..


Cute! 

Traction Fan


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## Aard D'Vaark (Aug 1, 2019)

about the only difference between the blue, green and pink extruded foams, is that the colour designates the manufacturer .. that's all ... and yes, you can mix them ..


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## Stumpy (Mar 19, 2013)

The pink that I have is much denser and heavier than the green. Probably 3x.


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## CTValleyRR (Jul 26, 2014)

Stumpy said:


> The pink that I have is much denser and heavier than the green. Probably 3x.


Then they're not the same product. The green that you have is likely florists foam (which is also an extruded foam product, and also makes good terrain), not insulating foam. I have used all three colors of insulating boards, and they're very similar, almost jndistinguishable (except by color, of course).


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## Stumpy (Mar 19, 2013)

You're right. They're not the same product. But they are (were) both 4'x8' sheets of insulation board.

This is the green... https://www.lowes.com/pd/Kingspan-I...d-Polystyrene-Foam-Board-Insulation/999972968

This is the pink... Owens Corning FOAMULAR 250 2 in. x 48 in. x 8 ft. R-10 Scored Squared Edge Insulation Sheathing-52DD - The Home Depot

The green is a much more open cell foam.


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## CTValleyRR (Jul 26, 2014)

Those are the common products, yes. I have used both, and there is no noticeable difference in the stuff I get.


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## Aard D'Vaark (Aug 1, 2019)

i have used foam quite a bit in my layout, the foam is bonded with pl300 to the flat laid 3/8 plywood ... at different points i have up to nine inches of foam stacked up, the track is glued to the foam with dap alex caulk ..
the layout size is about 16 feet by 15 feet, and depicts an up north logging / mining area in era 1890..
also attaching some photos of the layout, been up for seven years now .. the photos are somewhat misleading, as the foam is only under where the track is laid, other places are covered in dap soaked heavy duty paper towels only, and are hollow underneath


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## Mark VerMurlen (Aug 15, 2015)

Aard D'Vaark said:


> i have used foam quite a bit in my layout...


Very nice looking layout you have there! Well done!


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## Lehigh74 (Sep 25, 2015)

Here’s another example. I made a mountain with pink rigid foam. I made it in pieces so it could be removed in case of a derailment. Most of it was covered with Structolite, Mold-A-Scene or Sculptamold. Some was just shaped and covered with turf.

BTW, if you are just going to cover it with turf or paint, you can use Woodland Scenics Foam Putty to hide the seams.


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## Stumpy (Mar 19, 2013)

Mark VerMurlen said:


> Very nice looking layout you have there! Well done!


What he said. Nice work!


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## Stumpy (Mar 19, 2013)

Lehigh74 said:


> Here’s another example...


Nice work as well!


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## 65446 (Sep 22, 2018)

Though I don't care for high rail, tinplate, 3 rail, whatever, I do like your treatment of the foam; seemingly more vertical pieces of varied height and shape than horizontal... Guessing it cuts way down on the, well, cutting of the topography = less mess; less need of hot wire, if at all...
To be honest tho, I don't go for the storage shelves, I mean where it is..Looks inconvenient to reach and greatly interrupts the plausible realism below it... M


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## Rich1853 (Jun 25, 2018)

Thaat


flyboy2610 said:


> What I use to bond foam to foam is not really an adhesive per se, but a paint. It is PPG's Gripper Primer paint. It used to be made by Glidden, but PPG bought out Glidden. You can get it at Home Depot. I paid about $26 for a gallon. That sound expensive, but it will glue a LOT of foam, and the cost of Liquid Nails for projects to do the same amount of foam would be astronomical! You can also buy it by the quart for about $12.
> Of course, it also depends on how much foam you have to glue. If you only have 1 sheet of foam to glue, the Liquid Nails might be the way to go.
> I paint one side of the foam, put the other piece on and weight it down. After 24 hours you will not get the two pieces apart without destroying the foam. It also works well to glue foam to wood and Homasote. It's good stuff, Maynard!


That is what I've used on my blue foam. The local home depot only sold that foam in 2 x 2 ft x 1 in and used it to butt join it in to a 8 x4 sheet. Very strong and happy with the results.


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## Rich1853 (Jun 25, 2018)

Rich1853 said:


> Thaat
> That is what I've used on my blue foam. The local home depot only sold that foam in 2 x 2 ft x 1 in and used it to butt join it in to a 8 x4 sheet. Very strong and happy with the results.


Edit added
My was made by Glidden p/n GPG-0000 and the volumn was 31.5 fl oz / 930 mL


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## Traindiesel (Sep 8, 2015)

Traction Fan, where did you find the extruded foam? I'm also in the San Diego area and all I could find was the compressed beaded foam.

On my layout when I lived back east I used the Liquid Nails For Projects to glue the foam together.


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## Maddog (Jan 14, 2016)

Traindiesel said:


> Traction Fan, where did you find the extruded foam? I'm also in the San Diego area and all I could find was the compressed beaded foam.
> 
> On my layout when I lived back east I used the Liquid Nails For Projects to glue the foam together.


Both the pink and blue seem impossible to find here in Southern California.


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## flyboy2610 (Jan 20, 2010)

Home Depot sells 2 foot x 2 foot sheets of 1" thick foam board as project panels. 








Project Panels Formular 1 in. x 2 ft. x 2 ft. Rigid Foam Board Insulation Sheathing PP1 - The Home Depot


FORMULAR insulation Project Panels has a variety of uses. You can add thermal insulation to attic and crawl space access panels and pet houses. or protect items that you are transporting. They can also



www.homedepot.com





They could probably order you some larger panels, but there may be a large minimum order.


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## Maddog (Jan 14, 2016)

I've seen the 2 x 2 foot pieces. Was hoping someone might have an inside connection on getting a 4' x 8' sheet. I only want one sheet.


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## AFGP9 (Apr 8, 2015)

Whether using blue, pink or green foam board it doesn't matter. I've used all of them. They are all of the same density with regards to our use as a model train base. There is a lumber yard near where I live that has all 3 types. I've compared broken parts set side by side and there is no visual difference in density. I used 2" green on my current 10 year old layout. I have also mixed all three from my stock pile of left over sheets when building up terrain or mountains. Makes no difference. The green floral foam somebody mentioned is absolutely not the same as green foam board. The thing I found using the green board was that it makes ground cover easier to do with less paint. Pink or blue not as easy. Bottom line, they are all the same for our purposes. As I said, I had a choice from the lumber yard as to color. This foam board is used a lot in house construction also. I used to do some of that and can say that all 3 colors were used with no rhyme or reason as to which color was used. Just a matter which was available. I will say the pink or blue are most often used because it is the most commonly found. Think Menards or Home Depot. I've only seen green at lumber yards. 
To each there own. I am 74 years old and have used a lot of foam board in my various layouts and construction. My preference is the green for the reason already stated. 
When going to buy foam board of any color, ask if they have any broken sheets or pieces. Sometimes you get lucky and get a huge discount or, the best price, it's free. Except for my base 2" sheets, the rest of my terrain was all free. Pink, blue, or green, it will all get covered with something. Why pay for and cut up a perfectly good sheet to make rock formations or mountains when you might get free pieces of broken sheets or an almost full sheet at a reduced price.
I forgot to mention. Always use 2" of foam whether 2 1" sheets glued together or 1 2" sheet. You may think you don't need 2" but later on you'll wish you had some below grade depth and 1" isn't near enough. 

Nice terrain you have there, Lehigh74 Bob.

Kenny


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## Aard D'Vaark (Aug 1, 2019)

up here the most common is sheets 2 feet by eight feet, mainly in two inch, although 1 inch and half inch are also in stock ... it's kept in both stepped edge and straight edge ..


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## Original Woody's Workshop (Jan 29, 2020)

Aard D'Vaark said:


> about the only difference between the blue, green and pink extruded foams, is that the colour designates the manufacturer .. that's all ... and yes, you can mix them ..


You are misinformed, Sir. Dow can, and will, make extruded from in density of 10 to 120 foot pounds per square foot (That I have seen personally) 
They standard runs include 20, 40, 60 and 90 in the blue in thickness' up to 3". Last I knew, Pink was only done by orders, but big box stores had standing orders for the pink.
There may be other manufactures other than Dow that make blue and pink XPS, I'm just not aware of them.
I can't speak about any "green" extruded either as I've never seen it. It is most likely a regional item not available in my region.
Being in Michigan, many Engineers and Architects have specifically specified a color, density, size of the units to be used in specific area's, and number of fasteners and plates, and where to put them.
I can only speculate they own stock in that part of Dow, are perhaps get a kick back or something. Because it is by far not the best choice in the applications we used it in.
We even had specs that required 4' x 4' pieces to be hot wire cut for inside and outside valleys and ridges in tapered systems at 1/4" per foot, more if the deck was not flat. And straight tapered panels at the same slope.
EPS is altogether different. It starts out like hard bb's and introduced into a 32' x 4' x3' chamber under air pressure and circulated with steam.
The longer you leave it, the more soft it gets as it swells. They pull the block out and stand it on end and put it in a drying room between 7 & 20 days depending upon how much moisture was put in the mix. The blocks shrinks, and when ready they cut it on hot wire machines where they cut the 3' high, 4' wide in the required shapes in one single 32' pass. At the required intervals, a guillotine hot wire passes vertically to make the required length cut. I had the opportunity some yeas back to tour Falcon Foam in Byron Center, Mi. They were gluing EPS to panels that would make up insulated garage doors. They were glueing the plastic face to the EPS with an ultra violet curing system. I found it fascinating at the time. 
Those panel would been be shipped to who ever ordered them.
For train building, especially the substrate. I'm not impressed with XPS for much of anything in modeling. But I'm old, and I guess I'm Old School. 
And if you ever want to change something, High density (even low density) XPS glued down solid is much harder to deal with than a few cup up pallets, window screen and cheap plaster mix.
Put you money in track, wiring, controls, locomotives and rolling stock to get the most enjoyment when it's done. You gotta cover the XPS with something like plaster anyways.
And if you want to make a real looking cement wall, mix up some watered down fast drying plaster mix with wife's mixer like egg whites and pour it home made molds.


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## Railtwister (Nov 5, 2015)

For gluing foam sheets, I use Gorilla glue, which is itself a polyurethane foam when cured. Since it expands in it’s curing process, you need to clamp or weight the pieces to keep them from moving. Round toothpicks can be used like nails to hold alignment, if needed.


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## Rich1853 (Jun 25, 2018)

Maddog said:


> I've seen the 2 x 2 foot pieces. Was hoping someone might have an inside connection on getting a 4' x 8' sheet. I only want one sheet.


When I searched the home depot site for that foam in my local (Melbourne Fl area) the 4x8 ft sheet was listed in Kissimmee about 40-50 miles away, than I would have to rent their truck. So instead I purchased those 2x2 squares and a quart of the Glidden sealant to butt joined them together. I used many gallon containers of water and 2x4s for weights and for the wall banking surface. Did two pieces at a time (subassembly) for the construction than connected the subassemblies one at a time over a two or three day period.
My TT layout still work in progress.


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## CTValleyRR (Jul 26, 2014)

flyboy2610 said:


> Home Depot sells 2 foot x 2 foot sheets of 1" thick foam board as project panels.
> 
> 
> 
> ...


Probably not, because it's something they already have in their distribution system. I guess they don't keep it in stock in warmer climates, but they can get it from their own warehouses without too much trouble.


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## Railtwister (Nov 5, 2015)

Rich1853 said:


> When I searched the home depot site for that foam in my local (Melbourne Fl area) the 4x8 ft sheet was listed in Kissimmee about 40-50 miles away, than I would have to rent their truck. So instead I purchased those 2x2 squares and a quart of the Glidden sealant to butt joined them together. I used many gallon containers of water and 2x4s for weights and for the wall banking surface. Did two pieces at a time (subassembly) for the construction than connected the subassemblies one at a time over a two or three day period.
> My TT layout still work in progress.


Hey RICH1853,
When you said “TT layout” did the TT stand for “tabletop” or does it refer to the scale 1:120?
Bill in FtL


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## Railtwister (Nov 5, 2015)

Rich 1853,
I found your original post from a couple of years ago, and see that your reference to “TT” is indeed to the scale of 1:120. Have you joined <ttnut.com>, which is a web group specifically for TT scale modelers of all prototypes? Personally, I have a couple of pieces of TT scale, but no layout (yet). I’m in Ft. Lauderdale, a few hours South of you.
Bill in FtL


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## Rich1853 (Jun 25, 2018)

Hi Bill, I remembered your name from the TT Nut site. Yea I joined I guess in May 2018 after suffering a stroke in March and just coming out of rehab. I needed a hobby to keep me busy. I never owned trains before, however my father had a 1936 tin plate set that is in my brothers closet still pristine and in original boxes. I refurbished and modernized some circa 1946 Lionel type RW and 2 type S transformers for this coming Christmas as the whistle didn't operate from that stand alone controller IIRC p/n 66 last season.
As for the reason I chose TT it's because of the scale 1:110 or 1 to 10 feet. Being a newly retired Aerospace Quality Engineer and Metrologist I could actually see the size of the prototype. Also I needed a challenge getting my week right hand, wrist and arm back to normal. What a challenge it was to disassemble, clean and relubed even replaced cracked gears as every thing was purchased used from eBay Germany. I about 80% now. My layout now is a storage depot of many projects from my Lionel train parts, slot cars from storage and the last 3 weeks or so getting my unused tunnels, portals and bridges to somehow work with my Godson Thomas and Friends trains and tracks. He is 4 and lives in the PNW and there is no dimensions listed. Mattel constomer service told me that there is no documentation with the dimensions. I told them that every manufactured item has a blueprint drawing with dimensions.
I had to add about .5 inch of a modified pier to the bottom of Auhagen portals for the track thickness and than modified the NOCH tunnels to accept the new ones. I drew a footprint of the curve tunnel and used my beam compass to connect the two portals (75° apart)and figured out the cord length at 90° (cord=2rsin (theta/2)
I finally got lucky one of the ebayers had a ruler adjacent to the curve and in the discretion it was from the avalanche escape set. But I wasn't going to pay $11 for a track. I search Mattel and found replacement parts and using the item number that I got from the set instructions it cost $1.00 got it wednesday, it fits, delivered today in Washington tomorrow is his Thomas and Friends theme birthday party. Wow, time to relax


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## Railtwister (Nov 5, 2015)

Rich1853 said:


> Hi Bill, I remembered your name from the TT Nut site. Yea I joined I guess in May 2018 after suffering a stroke in March and just coming out of rehab. I needed a hobby to keep me busy. I never owned trains before, however my father had a 1936 tin plate set that is in my brothers closet still pristine and in original boxes. I refurbished and modernized some circa 1946 Lionel type RW and 2 type S transformers for this coming Christmas as the whistle didn't operate from that stand alone controller IIRC p/n 66 last season.
> As for the reason I chose TT it's because of the scale 1:110 or 1 to 10 feet. Being a newly retired Aerospace Quality Engineer and Metrologist I could actually see the size of the prototype. Also I needed a challenge getting my week right hand, wrist and arm back to normal. What a challenge it was to disassemble, clean and relubed even replaced cracked gears as every thing was purchased used from eBay Germany. I about 80% now. My layout now is a storage depot of many projects from my Lionel train parts, slot cars from storage and the last 3 weeks or so getting my unused tunnels, portals and bridges to somehow work with my Godson Thomas and Friends trains and tracks. He is 4 and lives in the PNW and there is no dimensions listed. Mattel constomer service told me that there is no documentation with the dimensions. I told them that every manufactured item has a blueprint drawing with dimensions.
> I had to add about .5 inch of a modified pier to the bottom of Auhagen portals for the track thickness and than modified the NOCH tunnels to accept the new ones. I drew a footprint of the curve tunnel and used my beam compass to connect the two portals (75° apart)and figured out the cord length at 90° (cord=2rsin (theta/2)
> I finally got lucky one of the ebayers had a ruler adjacent to the curve and in the discretion it was from the avalanche escape set. But I wasn't going to pay $11 for a track. I search Mattel and found replacement parts and using the item number that I got from the set instructions it cost $1.00 got it wednesday, it fits, delivered today in Washington tomorrow is his Thomas and Friends theme birthday party. Wow, time to relax


Hi Rich, 
Good to hear there’s at least one other TT Nut in this corner of the country. I remember reading one of your posts about being a Ferrari fan and why over on TT Nut. It sounds like you’re entering model trains in retirement in order to keep you busy is working. 

This group makes private email contact difficult, so in order not to hijack this thread about foam and glues for TT, why not use the TT Nut site (my user name is railtwister) to send me a private email? Then we can talk without boring everyone else here...
Bill in FtL


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