"What is the difference between birch and polypropylene?" 

We get asked this a lot so we put together some specifications, applications and pro's/con's for each. Other companies call the polypropylene "XLT", "flight panel", "the board", and several other names. We didn't feel like coming up with some catchy new name so we just call it what it is. Polypropylene has a fluted core laminated to an ABS top skin. ABS is the sheet that is laminated to our birch wood. We also carry different types of wood upon request. 

Polypropylene's greatest feature is the weight. We typically recommend it for lightweight applications, especially when flying or just trying to shave off some weight. Most common uses are guitar cases, pedal boards, amp cases, keyboard cases, etc. Both have their pro's and con's but both are very good materials. On larger cases, we typically recommend birch and usually 3/8" or 1/2" if it is large or bearing high weight loads. 

On pedal boards, guitar cases, etc - we would expect to see about 5-8 lbs off, sometimes more depending on the size of the case, with the polypropylene versus the wood. On amp and cab cases, it's often a good bit more. We have a calculator that we input the dimensions and hardware and we can usually get you a figure to the nearest pound of what a case will weigh if you have certain requirements.

Below are some basic comparisons, things we've (and our customers) have noticed. With airline prices, polypropylene and T-Kore can pay themselves off pretty quick. If you have any questions, don't hesitate to contact us!

Pictures:

1/4" Birch	1/4" Polypropylene
3/8" Birch	3/8" Polypropylene
1/2" Birch	3/8" Stucco

Basic Comparisons:

	1/4" Birch	1/4" Polypropylene	1/4" T-Kore
Weight	Wood is the heaviest	30-40% lighter than wood	Lighter than poly
Cost	Most economical	Typically $35-50 more than wood	Most expensive
Flexing	The firmest material	Flexes more than wood	Firmer than polypropylene
Warping	Possible warping in high heat	Will not warp	Will not warp
Impact	Crack before puncture	Will not break but can puncture	Will not break but can puncture
Cosmetics	Best over time	Can dent in	Can dent some

Technical Comparisons:

	1/4" Birch	1/4" Polypropylene	1/4" T-Kore
Weight/Sheet	27	22.2	20
Sheet Size	48" x 96"	59" x 90"	48" x 96"
Lbs per/sq. in.	0.00585	0.00418	0.00434
Thickness	.25"	.28"	.25
Tensile Strength	21,022	8,373	8,009
Flexural Strength at Yield	24,572	21,068	20,612
Impact Strength Falling Iron Dart	96.4 in/lbf-break	288 in/lbf-no break	288 in/lbf-no break