Michael's plywood

[JeffS]

I was at Michael's the other day and noticed that they had some fairly inexpensive 1/8th plywood. I was about to get some for my first try at cutting out fins on the bandsaw when I noticed that the sticker on the wood said "no aircraft use". Is this stuff ok for fins or do I need the high priced stuff from the RC airplane store?

Thanks,
Jeff

 

[sandman]

LOL!

I think they are trying to cover their legal behinds!

You can use it for a rocket or an aircraft...just not for one you are going to fly in.

 

[powderburner]

Sandman is correct,
These markings are to warn that the plywood has not been 'rated' as suitable/acceptable/safe for use on manned (real) aircraft like homebuilders do in their garages
The manufacturing process for man-rated plywood has to pass much more stringent criteria, and samples of the product have to pass testing (kinda like samples are tested when manufacturing rocket motors?) Consequently, man-rated plywood ends up costing quite a bit more, too
The stuff you found in the store is just fine to use for rocketry (unless you are riding in your rocket?)

 

[Micromeister]

LOL What powder said! not for manned aircraft use!
It's great for anything we'ed like to build! Incidentally 3/64" 3 ply can be rolled into some fairly tight (BT-55 to 80 or BT-60 to 101) transition and boattail cones. Also make a great covering to foam fins like the very large and complex fins and transition on this 3X upscale Laser-X

 

[JeffS]

You know, the thought did occur to me that they meant "real" aircraft, but then I thought" naah, who buys wood for their homebuilt at Michael's?"
Thanks alot guys. I'm off to get some.
Jeff

 

[powderburner]

Originally posted by Micromeister
this 3X upscale Laser-X

Only word of warning that comes to mind is to pay attention to the weight that this adds to the back end.

Fins laminated with plywood will be pretty much bullet-proof, at least compared to the balsa that I usually use.

I know Micromeister already knows this, but many of you guys need to remember to recheck your stability margins if you add this type of construction to your rocket.

 

[rstaff3]

Of course you should always check the stability margins for any scratch or modded rocket...and for some kits too!

 

[JeffS]

pay attention to the weight that this adds to the back end.

Of course you should always check the stability margins for any scratch or modded rocket

Absolutely. Here's a pic of the machine in question. Very plain 3fnc. I had a bt70 tube left over and wanted to try some mid/high power building techniques. It's alot like the 3x24 cluster I built except with a 29mm motor mount, one less fin, and a payload section.

 

[Micromeister]

Originally posted by powderburner
Only word of warning that comes to mind is to pay attention to the weight that this adds to the back end.

Fins laminated with plywood will be pretty much bullet-proof, at least compared to the balsa that I usually use.

I know Micromeister already knows this, but many of you guys need to remember to recheck your stability margins if you add this type of construction to your rocket.

Absolutely Powder.. However the reason for using 3/64" 3 ply laminated over foam is to SAVE weight. those huge fins...1/2" to 1/4" root to tip tapered were amost 20% lighter then Balsa fins of the same size. Believe it or not that entire model with 9volt battery and upper stage ignition wiring weighs 685.4g a little over 24ozs or 1.51lbs Last logged staged LOWt: was 837.1g with 3 D12-3's and a B6-6 sustainer,still a good bit under 2lbs.

My reasoning for using rolled ply on the transition was concern that the sustainer motors exhaust might burn thru a cardstock or other shroud material and turing suchs a huge transition would add a ton of unnecessary weight. a secondary advantage to the rolled ply shroud gave me a perfect place to house the upperstage (encapsulated mercury switch plus) ignition system and battery. Mid-west or however is manufactureing this light plywood is doing a great job. I really like the stuff for most LMR projects. I've also used the 3/64" - 3ply as fins for a couple of my micro models as well

 

[kelltym88]

I purchased and used said "1/8 plywood" from Michaels for my upscale Disruptor (https://www.rocketryforum.com/showthread.php?s=&threadid=10161&highlight=photon)

The link shows a step by step build. I was a little concerned at using that plywood at first 'cause I thought it was a little heavy. But, I loaded up the G64-4 reload and let 'er rip. It was awsome. I don't think you'll have any problem using it.

 

[JeffS]

Wow, great documentation and a great looking rocket!

I cut my fins out yesterday. My band saw blade is a little coarse for this stuff but I sandwiched the fin material between two pieces of scrap and they came out ok.

Jeff

 

[rstaff3]

I've use this stuff many times also...love their coupons. Just have to check that the pieces are not warped.