How many sheets in a ply

I was looking at the 1/4 plywood they have here at work.
I dont like it.
I call what they have here LUAN.
It has 2 thin sheets of veneer over junk wood. Its very warpy and flimsy.
So, yous guys that use plywood for fins,what do you use and how many ply/layers/sheets is it made up of.
3/16,1/4, whatever.
Thanks
Scotty the wonder Dog

1/4" should be at least 5-ply.

dixontj93060 said:

1/4" should be at least 5-ply.

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Is that something you would find at Home depot or the like?

No. Home centers aren't normally gonna carry it. For thin plywood you need the check craft or hobby stores. You may get lucky, but my experience has been that the home centers all have either the luan veneer stuff or dimensional ply for home building.

Typically 1/4" at Home Depot is three ply. You would need to go to a hobby store to get aircraft or Birch plywood.

Baltic Birch or aircraft grade plywood is great stuff ,made of hardwood (Birch usually) more plies and no voids ,surface quality is near cabinet grade.I buy mine in 5 x 5 foot sheets (I know ,weird size) at a local specialty wood chain ,but some hobby shops/RC shops may have it as does Lee Valley and even Michaels (but in smaller sizes and not usually over an 1/8" thick)

Of course ,I live in Canada in a bigger city ,but you should be able to score something in your area or near a bigger center.it might be worth the gas driving to get it as opposed to getting it shipped.

The 1/4 " thick Baltic Birch I use has 5 plies.Very nice to work with and machines well.Also great for shop jigs and fixtures (very stable)

Lee Valley has a 1/8" Finish Baltic Birch that has 6 plies ,pretty much aircraft grade.

See yah

Paul T

1/4 aircraft or baltic birch is 3-5 usually. Mostly, I have seen mostly 5 use din rockets. It bevels better than than the 3 ply home depot stuff.

Anyone Google?

https://www.google.com/search?q=air...&rls=com.microsoft:en-us:IE-SearchBox&ie=&oe=

shreadvector said:

Anyone Google?

https://www.google.com/search?q=air...&rls=com.microsoft:en-us:IE-SearchBox&ie=&oe=

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Well yes, the first two listings are Aircraft Spruce and Wicks which both supply aircraft grade birch ply in their product line. This is overkill for rocketry at 12-ply and over $100 for a 4'x4' sheet. Stick with the non-aircraft grade birch 5-ply and you will be fine.

shreadvector said:

Anyone Google?

https://www.google.com/search?q=air...&rls=com.microsoft:en-us:IE-SearchBox&ie=&oe=

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Nah...too impersonal ,we are afterall social animals :wink:

I think I spend 90% of my time on google to tell the truth !

Paul T

My 1/4 birch aircraft has 5 layers

pay no attention to that lower board, It's a trick!

Scotty Dog said:

Is that something you would find at Home depot or the like?

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If you're looking for good quality 1/4" plywood, if you have a Menard's nearby, grab a sheet of their 1/4" floor underlayment -- it's good quality wood, and what we use when we need 1/4" on our big projects.

The 1/4" floor underlayment from Lowe's and Home Depot, on the other hand, is junk for our uses.

-Kevin

You can also get the Baltic birch plywood at fine wo odworking stores that sell dimensional lumber, veneers and fine and exotic hardwoods, or you can go to a fine cabinetry shop. The one I go to uses Baltic birch for drawer sides. I have also made my own plywood in themselves past and it has worked great.

You can get good birch plywood from vendors that cater to the RC airplane crowd. Balsa USA is one of the biggest. There are a ton of others as well.

Scotty Dog said:

I was looking at the 1/4 plywood they have here at work.
I dont like it.
I call what they have here LUAN.
It has 2 thin sheets of veneer over junk wood. Its very warpy and flimsy.
So, yous guys that use plywood for fins,what do you use and how many ply/layers/sheets is it made up of.
3/16,1/4, whatever.
Thanks
Scotty the wonder Dog

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It's Phillipean Mahogany. I use it all the time on high power rockets. It's very porosity is why I use it. When painted with thinned epoxy the epoxy soaks into the pores and when it sets up it becomes very strong. The thinnest, 3mm I think it is, penetration is to the center. I had a 4 pound 3" x 4' PVC rocket fall horizontal from over 3000 ft and all it did was chip the tip off one fin. I spliced in a piece and it's good to go.

I've used ultra-lite spackleing to fill the porus surface then painted with epoxy. Not as good of penetration but still good enough for a fin.

This procedure is best done outside

I've made fins that had a core of basswood and outer birch plywood. 7 layers total for 3.0mm thick fins.

Michaels crafts sells 12x24 sheets of 5 ply 1/4" at a reasonable price. Their 1/8" is 3-ply - ok, but not great.

Try this guy:
https://www.woodnshop.com/hardwood/Baltic_Birch_Plywood.htm
All the thicknesses that you can possibly want for rocketry.
I buy 1/4" and 3/8" for my fins and CR's.
I get the 30 x 30" sheets..... You can cut it smaller once you get it.


JD

Scotty Dog said:

I was looking at the 1/4 plywood they have here at work.





I dont like it.
I call what they have here LUAN.
It has 2 thin sheets of veneer over junk wood. Its very warpy and flimsy.
So, yous guys that use plywood for fins,what do you use and how many ply/layers/sheets is it made up of.
3/16,1/4, whatever.
Thanks
Scotty the wonder Dog

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I have had success ordering from eBay. But I tend to buy in bulk and look forward to the next "half-dozen" projects or so to get the right common denominator on size across all the projects and get the best deal on shipping. Just make sure you contact the seller to verify the quality/ply/flatness of the pieces before purchasing--99% of the time I have been happy.

I've made fins with a luan plywood core and Formica skins. They're solid and you don't have to paint them.

WOW, thanks for the info people.
One ethign nbui 76vc8 Hgeti o anin hte rca shtfer hg asenve?

Scotty Dog said:

WOW, thanks for the info people.
One ethign nbui 76vc8 Hgeti o anin hte rca shtfer hg asenve?

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No !! my 76 Pacer is not stuck in reverse!

qquake2k said:

I've used 1/8" and 1/4" birch plywood from Michael's a lot. I've been able to get some really nice pieces there. Plus the 40% off coupons are nice. I ordered some 3/16" from BalsaUSA, but wasn't impressed with the quality.

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I would think you have stock in plywood.

Scotty Dog said:

I would think you have stock in plywood.

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I probably should, considering haw many rockets I build. I'm obsessed.

Have you tried here? https://www.micromark.com/plywood.html

SteveA said:

Have you tried here? https://www.micromark.com/plywood.html

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I've only ordered 3/16" plywood from BalsaUSA.

I just bought a 5' x 5' sheet of 3/8" ,7 ply Baltic Birch Plywood today for some upcomming projects.Cost was $ 35.00 at my local specialty wood store (Windsor Plywood)

Paul T

Not too many specialty wood outlets in this part of the world (which is the height of irony), so I get my plywood from here and from occasional pilgrimmages to a Michael's. Michael's is good for 1/64" and 1/32" plywood. For some odd reason they don't carry 1/16" plywood, so their next size up is 1/8" which is not quite as high grade at the two smaller sizes. So for sizes other than the two smallest sizes, I get my plywood from National Balsa.

National Balsa: https://www.nationalbalsa.com

I have also purchased plywood from BMS: https://www.balsamachining.com/

michaels here carries it, as does Ace hardware of all places. i have a stock pile. everytime i go in there ill but a sheet or two for future projects