Comparing Foam Board (updated)

by rcspaceflight | June 15, 2013 | (20) Posted in Reviews

Intro:

I want to keep this article as scientific as possible. I don't want my opinions in it, but rather just the facts. In wanting to keep my methods of testing pure, I will first share with you what I did.

Weighing:

I bought an OXO Good Grips food scale from Target. It has a pull out display which turned out to be a blessing. The only real way for me to get the entire sheet of foam board on the scale and not touching anything else was to center it on the scale. Which left no room to actually see the display. So I hung the pull out display from the end of a table allowing me to look under the foam board to see the reading.

I'm not sure how accurate the scale I used is. Sometimes I would get one reading, then re-measuring I would get one gram higher or lower. All of the weights I have on this articles are the ones that came up the most and that I felt like was the most accurate. I did measure all of the weights multiple times. It may still be off by a gram, but that small of a possible error isn't an issue.

Testing strength:

I cut out 10" x 20" pieces of foam board. Then I placed them on the seats of two chairs. I kept the chairs at the same distance apart and I put the foam board pieces on the chair in the same direction. I will note that I am unsure if foam board has a grain to it. (More detail on possible grain at the end of this article.)

I added bottles of water to the center of the foam board until the foam board crumpled in the middle, causing the foam board to fail. I tried to keep the weight in the center and not distributed, but it is kind of hard to properly do that when dealing with 8 or 9 bottles of water.

Results:

Adams brand

Bought at Dollar Tree

Price: $1.00 (not including tax)

Sheet size: 20" x 30" x 3/16" measurements were double checked and are true.

Total weight of sheet: 115grams

Weight per one square inch: 0.191666grams

Test 1: 10" x 20" piece weighing 38grams, broke right away when third bottle of water was added.

Test 2: 10" x 20" piece weighing 38grams, broke a few seconds after third bottle of water was added.

Each bottle of water weighs about 525 grams.

Test 1: Broke with 1575grams of weight.

Test 2: Broke with 1575grams of weight.

**********************************************

Elmer's brand

Bought at Target

Price: $2.99 (not including tax)

Sheet size: 20" x 28" x 3/16" measurements were double checked and are true. note that this sheet is smaller than the other two.

Total weight of sheet: 224grams

Weight per one square inch: 0.4grams

Test 1: 10" x 20" piece weighing 80grams, broke when tenth bottle of water was added. Plenty of time was given between when bottles were added.

Test 2: 10" x 20" piece weighing 80grams, broke before tenth bottle was fully put on.

Each bottle of water weighs about 525grams.

Test 1: Broke with 5250grams.

Test 2: Broke with 5250grams.

***********************************************

Flip Side brand

Bought at World of Variety (local craft shop)

Price: $3.99 (not including tax)

Sheet size: 20" x 30" x 3/16" measurements were double checked and are true.

Total weight of sheet: 249grams

Weight per one square inch: 0.415grams

Test 1: 10" x 20" piece weighing 83grams, broke a few seconds after the eighth bottle was added.

Test 2: 10" x 20" piece weighing 83grams, broke shortly after the eighth bottle was added.

Each bottle of water weights about 525grams.

Test 1: Broke with 4200grams.

Test 2: Broke with 4200grams.

Notes:

I noticed that the paper on the Adam (Dollar Tree) brand is a lot thinner and is easy to peel off. Elmer's and Flip Side are about the same and it is hard to peel off the paper. It is to the point where foam goes with the paper when you peel it off of Elmer's and Flip Side; But with Adam, you can easily remove the paper without affecting the foam.

The Adam (Dollar Tree) brand foam board is a lot easier to cut. Almost no resistance at all where as the Elmer's and Flip Side brand it can be more difficult and is common to have to cut twice to actually get the paper cut that is against the cutting surface. Elmer's and Flip Side also dull blades quicker because of this.

Conclusions:

I want to keep this up to you. There is a clear difference between Adam and the other two, but the other two really aren't that different. That doesn't mean any of them are better than the others. A lighter plane can mean that you don't crash as hard, so you don't need the strength. You may know you're going to break it regardless and you'd rather go cheap. Maybe you don't mind the extra cost or extra weight because you want the strength. It's just up to you.

The point I really wanted to get at is that there is a difference between foam boards.

Now I'm left with a pile of broken foam board.

Important Update (foam board grain):

Today I cut out a 20" x 10" piece of Adams (Dollar Tree) foam board, from a new sheet, so that any possible grain in the foam would be going the other way. This piece weighted 39 grams, instead of the 38 I got from the other two tests. This is probably from the other two pieces weighing close to 39, but this one was probably cut a little bigger. This piece handled having three water bottles on it just fine. But it broke right away once a fourth one was added. I'm not sure if this even means that the foam it's self has a grain to it. With the first tests, it could handle having three water bottles for a second, then it broke. With this test it broke right away. Clearly a fourth bottle was way too much. I think the darker streaks in the Adams foam, when you hold it up to a light, is from the glue used to hold on the paper.

Again, this second test showed that cutting the Adams foam board so any possible grain is running in another direction did improve strength. But it wasn't a significant amount. I don't think it is necessary to do the same test to the other brands because they are clearly so different from the Dollar Tree (Adams) foam board.

I don't think the foam part of foam board has any grain to it. The paper will, but that shouldn't effect the strength very much. And it may have been the paper and/or the way the paper was glued that changed the foam board's strength (a little bit). (To me it looks like long streaks of glue was applied at the factory, then the paper was added to the foam. This could cause a grain in the glue.)

I do also want to mention that with the Elmer's and Flip Side brands, the weight was spread out due to the number of water bottles used. If the same weight had been centered better, they would have broken sooner. Meaning that those two brands may not be as much stronger as they appear from my data. I think Elmer's and Flip Side are about twice the weight of Adams, and have 2-3 times the strength. Which makes sense.

COMMENTS

rcspaceflight on June 15, 2013
I was debating whether or not I wanted to publish this today. I want to double check that foam board doesn't have a grain to it and that Adam doesn't have their grain in the opposite direction as Elmer's and Flip Side. However, it does make sense that foam board that weighs twice as much could be three times as strong. So I am trusting that my data is accurate. (But I will still double check the possible grain issue.)
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zev on June 15, 2013
awesome article! very scientific. only thing I would change is smaller weight increments (maybe use those mini water bottles?) so that you could get a more accurate number.

still 5 stars though!
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rcspaceflight on June 16, 2013
The problem with that is that the more bottles I added, the more spread out the weight is. The first piece I tested (a piece of the Flip Side), I had the bottles too spread out and it could handle 10 without a problem. The bottles weigh over a pound each so I took a 10 pound dumbbell and the piece of foam board had no chance. It broke instantly. And I could tell it needed less weight to do so. The measurements are actually a little off due to the more weight being more spread out. But it still shows the difference.

I considered using cans of soda because I can stack them. But I was worried that they would land on the floor and bust open making a horrible mess. I didn't want to risk that.
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danield on June 15, 2013
Should have tried cutting board the other direction to see if grain is an issue. Holding up to bright light says there might be. Definite variance in density.
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rcspaceflight on June 16, 2013
I may have to try that with a piece of the Dollar Tree. I played around with a small piece and it feels like there isn't a grain to it. But that isn't very scientific.
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rcspaceflight on June 16, 2013
I tried it and there is a small difference. Unfortunately with the way I tested it it is hard to tell for sure how small, or big, the difference truly is. But for comparing the brands, the first results I got should properly show the differences between them.
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johanjonker on June 15, 2013
We dont have doller tree board here in South Africa.. And i have always wondered what those foam weight, compared to the 2 we get here..

Thanks..


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sailorJohn on June 15, 2013
The strength is in the manner of construction of an build ,try to break up a scratch build to stuff it into a trash can and you will learn more of its strenght
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Ivanlopezvergara on June 15, 2013
Excellent information! Here in Mexico we can get something like Elmer's and I have built different models following Flite Test plans. I have seen a heavier tail final plane and more final weight, so we are forced to use a larger and more powerful motor to compensate the extra weight. We also have to cut a little wider for the A and B folds, and folding the wings is a little thoughter but possible. We have purchased the kits form Flite Test and they are very good, lighter and easier to work, so whenever is possible we get the kit from Flite Test. At the end, with the extra cost of the foam board and the printing, cuttting and invested time it is better to get the kit. It will be excellent if we could get the lighter Dollar Tree. Your article help me to understand clearly the differences. Thank you.

Regards
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rcspaceflight on June 16, 2013
Try going to dollartree.com Search: "foam board" Avoid the black foam board. That is supposed to be crap (according to Josh Bixler). You may be able to get that stuff shipped to you. I have no idea how bad the shipping would be. And I have to thank Tekgeek for pointing out that you can get it from their website.
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Battershell on June 17, 2013
I have purchased new black sheets from dollar tree recently and see no difference is in weight or strength compared to white. I recently built a 52" wing from all black and it went together wonderfully. Maybe they changed something.

I have also recently found heavier day-glo colors available in an assortment pack from a CVS. . Quite a bit more expensive! After looking at it more carefully I realized there is only paper on one side. This makes it almost useless to make a complete kit able to fly. But if you needed some color in small areas it would be fine. Just be warned and look thru the plastic bag an note that it is more for signs and only single sided.
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EwanP on October 23, 2015
Hey Ivan where did you find the board. Im in DF
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ProjectFlightDesign on June 17, 2013
Good work! Though I used to be of the mentality that "stronger is better", now I want to go light! I basically used 100% dollar tree Adams board now
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rcspaceflight on June 17, 2013
Yeah. I used to only use the Flip Side brand that I tested because I had easy access to it. A Dollar Tree just opened near me less than a month ago. Now that I compared them, I think I have to switch to the Dollar Tree stuff. I want strong planes, but then I have to fly fast. I'd rather fly slow and light.

I makes a lot more sense now why the FT Delta I made needed so much power to fly. It was about twice the weight of the one Flite Test reviewed.
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rickitee on June 17, 2013
If you are looking for anything related to rc aircraft and home built and how to do articles and videos I collected over 70 posts so that I could refer to, when building my rc planes.

rcflying.rickitee.ws
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hotwax on June 19, 2013
I repeated the test for the european readers with foamboard I purchased at modulor.de (Foamboard weiss, weisser Rand) .
Fibers are running all in one direction. weight of the 10 x 20 piece is 63 gr.
Lenghwise 3724 gr hold, 4250 gr fail after 10 sec
otherwise 2127 gr hold, 2500 gr instant fail
Werner
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BrownEyedFool on September 5, 2013
Adams dollar tree foam board the paper is not glued on. It is pressed into the surface of the foam while it is still hot from being extruded.
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rcspaceflight on September 5, 2013
I did not know that. But it explains why the paper can so easily be removed from Adams foam board and is impossible to do with Elmer's or Flip Side. Probably also explains why Adams is lighter and weaker.

Thanks for the information, it explains so much. :)
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Lenny on February 13, 2014
I'm in Canada and there are two varieties of Elmer's foam board here. One is sold at Dollarama Dollar stores and is similar to the Dollar Tree Adam's foam board and I actually like it better than Adams, the paper is whiter and maybe a hair thicker and the factory cut edges are much cleaner. I have also found some of the Adams to be wavy on one side. Dollarama sells their Elmers for $1.25/sheet (30x20"). Dollar Tree Canada sells Adam's for the same price. The other Elmer's is around $3.99 for the same size sheet and I think it is probably the same stuff you tested above. Has anyone else used the lighter weight Elmers stuff? Again, I like it better than Adams and where I live, it is the same price.
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Voombaloo on October 6, 2014
I have used the cheaper Elmers board from Dollarama. Compared to DTF, the paper doesn't come off as easily and it's bit thicker but it seems stronger and resists warping better. I've had good success and built a Delta and Flyer out of it. The Flyer was pretty underpowered with the 24gram motor from HK on 2S. It flew, but probably would be better on 3S.
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gtrguy on January 9, 2015
Word of caution for the Elmers stuff, it does look better but if you're cutting it on the laser cutter, it'll flame up much easier than the adams stuff...
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Kendrick57 on April 14, 2014
Hi
I am in the UK. I have tried 2 types of foam:-
The first from eBay it stated it was 5 mm thick A1 sheets, it was thicker than stated and the paper covering is more like thin card. The "glue" used to stick the paper to the foam was strong enough that removing from a channel to make an a or b fold was imposable I had to cut the foam off the paper.
The second was sold as 20" x 30" x 3/16 on getting it out I found the measurements to be true I will be testing the paper and glue when I can get it on the building board if it proves to be the same as Adams foam board I will disclose the price and web site I for the foam from, it is the cheapest source to my knowledge in the UK.

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Christopherspeir on May 2, 2014
question of the day, that im not sure has been answered or not; what kind of foam board is used in the speed build kits?

I have not purchased one yet, but plan to in the near future regardless of what kind is used. I think all brands have pro's and con's. I would think that for more aggressive flying, a foam board with glued paper would allow for a higher g loading.
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rcspaceflight on May 2, 2014
Flite Test uses Dollar Tree / Adams brand / Readi-Board with their speed build kits. Yes, it's known by those three names, but it's the same thing. (Technically some Dollar Tree's sell a foam board similar to Elmer's, or is Elmer's. Which is why some people call it Adam's brand or Readi-Board.)

As Josh Bixler proved with the Kraken, when used correctly, Dollar Tree foam board can be very strong.
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haygood on June 11, 2014
Great info. I wonder what the weight is when you remove the paper. As an example, you could consider removing the paper from one or two sheets of Adams and sticking them together to make something twice as thick, less than twice the weight, and at least 4 times as strong. That all assumes you find a reasonable way to adhere the sheets to each other without adding much weight. Super 77 spray, perhaps?
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rcspaceflight on June 11, 2014
Adam's foam board actually weighs half as much when you remove the paper. I don't know about the other brands because it is so difficult to remove the paper. So much so that you pretty much can't remove it.

I don't know if you ever removed the paper from foam board, but the foam it's self is very weak and brittle. The paper is actually the majority of it's strength. But I don't know what would happen if you left the paper on the outside, removed it on the inside, when sandwhiching two sheets together. I doubt it would be 4 times as strong. Maybe twice as strong, but not quite.
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Gelisob on October 26, 2014
I have information on weight of Kapa and Artfoam, those are available for me here in europe/Estonia.
------------------
Kapa-line 5mm - (1sq inch 0.41g) - 6.4x6.4cm 40.96 cm2 - 2.65g

1 paper layer less on one side - (1sq inch 0.38g) (easy to peel) - leaving matte (hairy?) nonslippery paper on foam
2.45g

1 paper layer less on both sides - (1sq inch 0.35g) -(easy to peel) - leaving matte (hairy?) nonslippery paper on foam
2.25g

1 side completely paperless - (1sq inch 0.23g) - easy to peel - panel very flexible after this
1.50g
------------------
Artfoam 5mm - (1sq inch 0.37g) - 6.4x6.4cm - 40.96 cm2 - 2.35g

paper teared partially off one side - very hard to remove, forget it.
1.95g (1sq inch 0.30g)
------------------
1 square inch is 6.45cm2
40.96 / 6.45 = 6.35

So we divide all results by 6.35 to get 1sq inch gram value.
------------------
Dollar tree is 0.19g per 1sq inch.
Information on the net also says that foam-x (Kapa) also has a weight of 0.37g per sq/inch. Maybe it has easyer to peel paper, will try in the future
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Gelisob on October 26, 2014
So if you build your plane out of kapa line foamboard - expect it to fall like a rock with entry level motors that are usually recommended on flitetest builds :) Needs serious overpowering on the motor and battery side to get them weighties to fly AND balance properly.. this is my noob experience atleast.
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AERODROME on February 10, 2015
I LIKE THE ELMERS BOARD. I GET IT FROM WALMART. LAST TIME I PAID $1.89. THE BOARD PAINTS NICELY. IT IS TOUGH. THE PAPER HINGES HOLD UP . IT DOES WEIGHT TWICE AS MUCH BUT ONLY THE AIRFRAME. THE OVERALL AIRCRAFT DOES NOT DOUBLE IN WEIGHT. JUST ADD A BIT MORE POWER IF FOLLOWING A PLAN FOR ADAMS BOARD.
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xmw on July 5, 2017
Additional data on KAPAgraph board (available via boesner.com online and in retail store in Munich):
whole board 70cm x 100cm weights around 574g equals 0.53g per square inch or 820g per square meter.

Note: The foam is very stiff, I had to cut a shallow 30deg double bevel at the wing-tip and reinforce with grip tape. There is no chance to not tear the paper apart.
Note(2): The foam is heat resistant, you can mould the hot glue into the hinges with the tip of the gun.

My attempt on FT Tiny Trainer already weighs 340g for board, hot glue -- way above the specified 193g w/o batteries. Maybe no trainer at all? I need to get hold of "Depafit" or choose bigger models, maybe the regular Guinea Pig.

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xmw on July 5, 2017
Depafit 5mm and local german "foamboard" weigh around 340g per 70cm x 100cm (0.31g per square in). I think I build another trainer for the best experience.
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junwoo091400 on September 12, 2018
Awesome indeed. Very scientific approach, thanks for sharing.
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UKPete on June 18, 2019
The heavier 240+ grams per sheet have a massive impact on the CoG, just built the FT Edge and will need the weight of a 220 and a 1300 3 cell lipo's to get it right and that's without mounting the elevator and ruder servos, which to be honest will make it barely flyable, I will have to move the wing back 2-3 inches I think.

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Comparing Foam Board (updated)