Plywood for bulkheads

[woodartist]

What plywood/ grade is best for bulkheads?

[Mercator]

. I found the high grade sanded 1/4" plywood from Home Depot to be very useful . Not too thick to be cut into shapes with a hobby scroll saw. Also easily available and not too costly.

[Chuck Seiler]

Baltic birch used in model RC aeroplanes.  Michael's used to sell it.  Hobby shops, wood working stores, Amazon.  Great quality.  Various thickness down to 1/16", or less.

[allanyed]

There are four APA grades of plywood, A, B, C, and D.  A is best but it is not cheap.  

Allan

[mtaylor]

Try this.. https://www.nationalbalsa.com/collections/lite-plywood.  I've used their lite ply in my current build and it works very well.   If I remember right, Chuck uses it also in his kits.

[Dr PR]

I have used Sig aircraft plywood and it is very good:

 

https://sigmfg.com/collections/plywood

[allanyed]

11 hours ago, Dr PR said:

I have used Sig aircraft plywood and it is very good

Totally agree with Phil that it is great.  I did a little digging and plywood is an interesting thing.  Aircraft ply has the most stringent criteria in manufacturing for plywoods.  A description from Wicks Aircraft --->  it is made with thermosetting, synthetic resin type glues.  Geniune aircraft plywood meets MIL-P-6070B which requires that the plywood be tested for general condition of boards, deviations of thickness, moisture content, tensile strength of wood, gluing strength, bending test, torsion test, immersion test and boiling test.  (The boiling test is three hours!)    No voids (filled or otherwise) are permitted as is allowed in cabinet grade that is found in the big hardware/lumber stores.    https://www.wicksaircraft.com/c/aircraft-plywood/    They have larger sheets and the prices looks competitive, especially for the thinnest stock.

Allan

[Dr PR]

Here is a bit of trivia for you:

 

In 1980 I started working for a company that had the contract for automating plywood lathes from the company that owned the patent. We supplied the computers and software to peel veneer from logs. By the mid '80s nearly all of the plywood lathes in North America were operated by a small (6" x 6" x 6.5") multiprocessor computer I designed. If you used plywood in North America from 1985 through to about 2000 the veneer was probably produced by that small computer.

 

It was a fun project!

 

https://ao-cs.com/Projects/little computer project.html

[Roger Pellett]

If you have a table saw you could make your own plywood that would be more suitable than anything that you could buy including the high priced stuff.  Cut strips from ordinary lumberyard construction grade pine and laminate them with  PVA glue. Two plies with grain oriented differently and joints staggered Harold Hahn style should work.

 

Roger

[woodartist]

This has been really helpful. I appreciate your input immensely.

[Roger Pellett]

Since you may not be familiar with my reference to  Harold Hahn allow me to elaborate some.

 

Harold Hahn was a prominent model maker back in the ‘70s and ‘80s.  He developed a system for mass producing the two ply blanks for the frames for POF models.  His work did much to encourage others, including me, to dabble in building POF models.  The resulting models resemble the old Admiralty dockyard models but the framing is not the same, nor does it represent full size construction practice.  As a result his work has fallen into some disfavor.

 

His system, would however, be great for making fully planked Plank on Bulkhead models. You should be able to find details here in the forum via the search function.  Volume 1 of the NRG’ Shop Notes available from their store also includes a full description of his system.

 

Roger

[woodartist]

Roger Pellet, thanks for the follow message. I will look into that possibility further now

[Bob Cleek]

On 12/27/2023 at 8:36 AM, Roger Pellett said:

If you have a table saw you could make your own plywood that would be more suitable than anything that you could buy including the high priced stuff.  Cut strips from ordinary lumberyard construction grade pine and laminate them with  PVA glue. Two plies with grain oriented differently and joints staggered Harold Hahn style should work.

 

Roger

Easier still is a method I've used with satisfaction: Laminate "Hahn style" frame shapes (and whatever else desired) with PVA glue using birch tongue depressors sold in quantity dirt cheap at craft supply stores. These can be neatly "chopped" at angles using a standard "classroom" paper cutter, which, BTW, is also a very handy ship modeling tool.

 

 

[woodartist]

Thanks, sounds like a plan.

[Dr PR]

Bob,

 

I discovered this fairly cheap source of good quality wood (along with bamboo barbecue skewers) long ago. Other useful sources of supplies are paint mixer sticks, roofing gutter flashing, jewelry supplies, carpentry wedges and even bundles of fire starters! Walk through a crafts store or hardware store with an open mind and you can find all sorts of materials useful for our hobbies.

Edited January 1 by Dr PR

[Jaager]

On 12/27/2023 at 11:36 AM, Roger Pellett said:

Cut strips from ordinary lumberyard construction grade pine and laminate them with  PVA glue.

My back of the envelope calc has the Home Depot endcap 2x4's coming in at ~ $0.75 per BF.  If you have the tools to cut them, that price is difficult to beat.

[Ikcdab]

On 12/27/2023 at 4:36 PM, Roger Pellett said:

If you have a table saw you could make your own plywood that would be more suitable than anything that you could buy including the high priced stuff.  Cut strips from ordinary lumberyard construction grade pine and laminate them with  PVA glue. Two plies with grain oriented differently and joints staggered Harold Hahn style should work.

 

Roger

I'm not sure that two-ply will work well.  There is no balance of forces.  That is the reason that all commercial ply has an odd number of layers, so that the warping forces are balanced out.  And to make ply you need a suitably flat surface to make it on if you are to avoid warped material.  Ply in the amounts that we use is pretty cheap and it's worth using the best for the foundation of your boat.

[vaddoc]

If I need really flat strong plywood, I make it my self. 

If I need 6 mm, I take two sheets 2.5 mm each on a flat surface. Thicken epoxy with gypsum, spread onto one sheet, cover with the other and put something very heavy on top. 12 h later I get very flat, very rigid 6 mm ply.

[GrandpaPhil]

On 1/1/2024 at 1:28 AM, Dr PR said:

Bob,

 

I discovered this fairly cheap source of good quality wood (along with bamboo barbecue skewers) long ago. Other useful sources of supplies are paint mixer sticks, roofing gutter flashing, jewelry supplies, carpentry wedges and even bundles of fire starters! Walk through a crafts store or hardware store with an open mind and you can find all sorts of materials useful for our hobbies.

Phil,

  I do the exact same thing!  Yard sales are gold mines for hobby supplies too!