# Expansion/Contraction factor of Sintra



## Hornet (Dec 1, 2005)

Ran headfirst into Sintra's biggest downfall last night,it's expansion/contraction factor.

I set my latest project up,a ThunderStorm,while it was rainy and cool,and i had the furnace running.
Tracks surface temp was 76/77F when i set the car up tire wise.
We've warmed up a fair bit in the last couple of days,so i've had the basement windows open for the last couple of nights,and the tracks surface temp last night was 72F.

Threw my Thunderstorm on the track,and it did nothing but spin.
I had to go up 4 thous in tire height to compensate for the 4 degree change in the tracks temp.

Sure glad i glued the rails now.

Just something for you guys thinking about a sintra based track to keep in the back of your mind,if you're building with sintra,and the room isn't dead stable temp wise,i'd glue the rails.

The rails will be just like the rocks in a farmers field,they're gonna move with temp changes.
Mother nature keeps rocks coming to the surface in a field with her temp changes,and the same thing will happen with un-glued rails in Sintra.

So guys that claim Neo mags are moving the rails on un-glued sintra tracks,are most likely wrong,it's more likely the room temp changes that are moving the rails.
I've personally tried moving the rails with the Neo mags that we use,they ain't gonna budge a rail,but temp changes will.
If you're building with Sintra,i'd plan to glue the rails:thumbsup:


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## partspig (Mar 12, 2003)

Hmmmmm, Interesting!! Had a Max Trax for years and never has that problem with changes in rail height due to temperature. I had more problems with Tomy track than the Max Trax! pig


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## Hornet (Dec 1, 2005)

My old Tyco tracks all changed with temp,but not as much as i'm noticing with Sintra.
Put a piece of sintra in the sun and it'll curl up and change shape to beat hell,and it's worse once the rails are in,then it really warps if you get it above 110F in the sun.
Been there,done that.
I watched a piece literally curl before my eyes when it started getting hot in the sun,when it hit 130 surface temp,it was unbelievable the warpage it had.
Try it,if you've got a spare piece laying around,throw it in the sun and let it get hot,it'll amaze you the changes it goes through, the warmer it gets,and watch it return when it cools down:thumbsup:
Rick


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## NTxSlotCars (May 27, 2008)

This would make me not want to ever build a track out of sinatra. The temp swings we have here would just kill it. Is there another material folks use?


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## wheelszk (Jul 8, 2006)

I guess I can't have an opinion. Thank you


I deleated my post


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## Hornet (Dec 1, 2005)

Okay then don't glue the rails.
LMAO,you try to give guys a heads up about something,but maybe it ain't worth it,to many other guys got better heads up.
Hell i don't care if your rails are moving or not,that wasn't the purpose of the post,it was just a tidbit of info for guys to have at their disposal,that they can keep in the back of their minds
Al's kinda ruining my mood abit,so maybe i'm a bit testy,though:wave:


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## NTxSlotCars (May 27, 2008)

So...... MDF rules?


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## Hornet (Dec 1, 2005)

Rich here's a bit of info on Sintra's charastistics.
If you read through the article it's pretty good,but down towards the bottom is the info about it's expansion and contraction factor.

Ted had this link posted in the track routing post on the second page,but it looks like a few guys didn't bother checking it out much.
There's a bunch of good info in here if you can find it.

http://www.tri-dee.com/Sintra sheets information.htm


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## Hornet (Dec 1, 2005)

To save guys a bunch of reading i pulled up some of the info that i think applies to this post.
I'm in a bad mood as it is,so here Bill and PG read this,then argue the fact



• Sintra expands and contracts with temperature changes. This must be taken into account when mounting large sheets of Sintra outdoors.

• Sintra, like most plastic materials, has less impact resistance in cold conditions. Thinner gauges have less impact resistance than thicker ones. For this reason 6mm should be the minimum gauge used for outdoor signage.

11. Why must I keep Sintra under 150F?
Foamed extruded plastics contain internal stresses. These stresses relieve themselves at elevated temperatures. If Sintra is allowed to reach 150F it will no longer remain flat and will warp and bow.


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## tossedman (Mar 19, 2006)

I'd keep your windows closed in the basement Rick. Won't get too cold over night and too hot during the day. Don't leave it in the sun and it'll never get up to 150° F (unless your house is burning down - but then you've got bigger things to worry about!).

Wonder how the epoxy changes with the temperature. Could that be causing some of your rail lifting? Is it the rail itself or the Sintra?

Just asking...

Todd


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## Rick Carter (Dec 2, 2008)

Slickety Rickety,

Don't let cats ruin your day. Life's too short -I'm one to know, LOL!

Good Post! 

I had a race on September 25th last year. Check out the pictures on the site. All week I had been practicing with my G and would joke to myself by saying, "They are not going to like me when I finish pulling this guide pin out dat azz," LOL! 

During practice, I didn't get on the track because I "thought" that I was set until the last minute. When I put my car on the track, all "internal" panic set in and I was like WTF happened to my car??? I wound up having to scramble to get something working and ran my Storm. 

I did manage to win but would have definitely lost had I not tried my car out and remained in my false sense of reality.

There were 22/3 people there and my basement was as hot as a branding iron. The fans were just equally distributing the heat amongst everybody.

After the race, I looked at my track on the front and back straight and they both had worped out of shape and I had an unintentional hill climb design -LOL!

I didn't think about the heat factor when I was practicing and wasn't aware that a routed track would do that, so that's why I couldn't figure out initially what had happend to my car.

If you look at our schedule, you'll notice that all of my races are held when it's cold outside due to the experience of that September race.

www.tsrho.com


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## Rick Carter (Dec 2, 2008)

Oh, I forgot to mention that I sat a few weighted objects on the track afterwards for about a week so that it would flatten back out.


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## Hornet (Dec 1, 2005)

Nothings lifting Todd.
What happens is the sintra shrinks more then the rail does.
It's not a problem if the rails are glued,but if your rails are unglued,the constant expanding and shrinking of the sintra will eventually walk the rails up,that's what the original post was about.
Todd you know me,my basements pretty well controlled,but i was amazed at the differances in things with just a few degree change.
Basically all i was trying to do is give guys a heads up,if your gonna route a track out sintra,it's probably wise to glue the rails.
And i think Bill and PG haven't checked their rails close enough.
The rails aren't moving,but their sintra based tracks sure are gonna shrink slightly or grow slightly with temp changes
I know Wizz trac changes with temp,so how a Max Trac doesn't change is beyond me.
When the room temp drops at the local Wizz Trac,you have to go up in tire sizes.
So if they're not noticing anything differant in their tire set-ups set-ups,then their race set-ups need improving in the tire tuning department:wave:
A good racers gonna kick their butts.:wave:


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## Hornet (Dec 1, 2005)

Sum-bitch,i love ya Rick,finally somebody who's a good racer:thumbsup:

Rick


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## Hornet (Dec 1, 2005)

Todd,i know you,you'll worry about things,lol.

You'll be glad to know,the basements warmed back up to the 76/77 range,and everythings back to the same set-up as last week,including the laptimes.:thumbsup:.
As long as things are glued,it seems to come back to it's orginal shape

Now i'm glad i glued the rails in,and used 70 dollars worth of silicone+ a few screws to glue the sintra sheets to the plywood table top.
I haven't noticed any lifting/warping of the sintra since it's been glued down,but after listening to Rick C's experiences with his lifting,i'll be watching it closely.
Thanks for the heads up C:wave:


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## partspig (Mar 12, 2003)

NTxSlotCars said:


> Is there another material folks use?


Try concrete or asphalt Rich! Clay is good too if ya can stand the dust!


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## Rick Carter (Dec 2, 2008)

Yeah Slick, you better keep an eye out for it because if I ever make it out there to race, I'm shipping in a massive heating unit 'cause I know that it gets cold up there.

Oh, I'll be the one racing with the full blown snow suit on -LOL!


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## tossedman (Mar 19, 2006)

Rick, here's how to get to Rick's house:


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## tossedman (Mar 19, 2006)

I live south of there by the way. :tongue:


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## Rick Carter (Dec 2, 2008)

LMAO! Nice!


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## Hornet (Dec 1, 2005)

Todds just south of the pole,and i'm just slightly north of it,LOL:wave:

Them things you think are the northern lights,that's the front porch light,when i ferget to turn it off:wave:


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## Hornet (Dec 1, 2005)

Bill most times i enjoy your posts and opinions,but for the life of me,what you and PG posted and why you posted it,is beyond me.
You figure guys are gonna re-route their Max tracs or something because of my post
What were your intentions,and how did you figure those 2 posts even applied to this post.
I was trying to give out a heads up about my experiences,that's all,was i bashing your guy's tracks or something,if i was,i sure didn't mean to.
If you don't want a heads up on things ,let me know and i'll quit posting
BTW,you picked a bad day,i started out in a good mood this morning till i started reading,and then things seemed to hit the fan and come from everywhere:wave:
Rick


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## partspig (Mar 12, 2003)

I usually have trouble with expansion and contraction immediately before and after Thanksgiving and Christmas dinner!! Just my two cents!  :thumbsup: pig


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## NTxSlotCars (May 27, 2008)

Maybe there are different densities of Sinatra?
Aren't there different brands of expanded pvc foam?
Maybe Max Trax is made with different material?

I've been wanting to route a track for a couple of years now.
For the temps in my garage, looks like MDF is the ticket.
I hear that humidity in places like Florida is the killer of MDF,
but it's not a problem if you seal it. I have seen several larger
scale tracks that lasted a long time made from MDF.


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## Hornet (Dec 1, 2005)

There could be,there is also Komatex,which is similiar to sintra.
If you check this link out,they have other stuff listed at the top of the site,that might be worth looking into for use as a track surface.
The other thing is if you do it in strips and sections,it's probably a little more stable,mines done in sheets,and if you do it like that,i'd reconmend gluing everything.
That's only my opinion though:thumbsup:

http://www.tri-dee.com/Sintra sheets information.htm


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## Hornet (Dec 1, 2005)

Has anybody ever tried using PuckBoard for a track.

The stuff used to build snowboard ramps/portable hockey rinks etc. 

Rich if you do a google search for Puckboard,it should come up.
It might be another median to look into for a track.
It's realitively easy to get,and up here north of the border,is about the same price as sintra per sheet.

I've used it,not as a track material but for lots of other things,and it's tough stuff,with a really smooth surface,and i don't think it has the warpage problem as bad as sintra has,at least not from my experiences with the stuff.

It stays flat laying in the sun,:wave:


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## tossedman (Mar 19, 2006)

Rick can you get puckboard thick enough to route a track? Also, how do you clean the puck marks off of it?

Todd


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## Hornet (Dec 1, 2005)

LOL,you got me on that one Todd:wave:

The UFA out here has it in 1/8" and 1/4" (6mm) thicknesses.

Last time i priced out the 1/4" sheets was when i picked up the 1/8" stuff for you and me,and it was right around 75 bucks a sheet if i remember right.
That was last year,and they had some in stock then.
I'll try to get a price for you,do you want me to grab you more syringes while i'm there.
25 syringes are about 30 bucks with tax,you got lots of the screw on needles,but i think you're short on syringes:thumbsup:


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## Tsooko (Oct 15, 2009)

Doesn't one of those other commercial tracks use an " L " shaped rail and slides into an " L " routed grove with the 90 degree part, parallel to the track surface but at the bottom of the groove?
Course you can't get a continuous rail like that, because it has to be pushed in from one end, and would be too hard to push it in for 65'.
Another point is that a big sheet will be affected by heat / cold but a smaller piece not so much.
Could be why guys like Brad cuts his tracks out to the lane width? Hummm?
Just guessing here.
Sintra tracks are very popular and I haven't heard of any complaints till now.

A guy could experiment forever!!!

Hey Todd : We tie dogs to the front of our toboggans.

Ted


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## joegri (Feb 13, 2008)

jeez all this talk of rails and trak shrinkage got my attention. i think it doesnt matter what material you use they,re all gonna move around a bit. i have experienced masive movements in my mdf trak and i had to learn how to fix any damage, and believe me there has been damage!thanx for all the info on the sintra material. i am a rookie at routing and have only made 2 traks but i always watch what you guys are doing and file it away to be used later on my next trak build. keep posting and building!!


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## NTxSlotCars (May 27, 2008)

Maybe it's the *rail* that's shrinking and expanding so much?


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## Grandcheapskate (Jan 5, 2006)

You discuss how temperature affects the Sintra - how about humidity changes? We can get huge daily swings in humidity here in NJ. Obviously mostly in the summer

Also, how do you think temperature/humidity changes would affect a Sintra track using braid instead of rail?

Thanks...Joe


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## NTxSlotCars (May 27, 2008)

What if we just made a laser cut stainless steel track?


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## tossedman (Mar 19, 2006)

Tsooko said:


> Hey Todd : We tie dogs to the front of our toboggans.
> Ted











Sorry Ted, like, I forgot eh. But since you live north of both Rick and I you'd know for sure eh.

Cheers eh,

Todd


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## Hornet (Dec 1, 2005)

Rich
Steel shrinks and expands too,but not to the extent plastic does.
That's why you use heat to loosen rusty nuts,install/remove bearing carriers etc.
Pretty well everything has some change in size from heat or cold.
Pay attention to your plastic tracks,even they change.
My old Tyco track is solidly glued together,and routed into a plywood pocket,and when my basement cools off to under 70F it develops cracks in the glue and paint,as soon as the basements back up over 72F they disappear

Joe,by the reading i've done,humidity isn't one of sintra's downfalls.

I haven't had any warpage of the sheets since they've been down,but i glued the crap out of them with RTV silicone,6 big caulking gun tubes of the stuff,and it's fairly stable warpage wise.
But no matter what you do,it's still gonna expand and contract with heat and cold,that's a matter of it's physical properties,and you ain't changing or fixing them easily.
If you glue everything,you'll be okay,that's what i was trying to get across to anybody thinking about routing a track from Sintra.
Also if you do it in smaller sections ,then i don't think the warpage factor will be as big a deal either.
It's when you do it in big sheets,that you gotta pay more attention to the gluing details.

But you'll never get rid of the expansion/contraction factor,unless it's in a room that doesn't change temp:thumbsup:


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## penly (Aug 27, 2011)

First big crash


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