ACX vs. CDX?

[fornesto]

I would like to be able to use CDX on my tear due to the cost and availablity. Most instructions say ACX, but that's double the price. I will be skinning in aluminum and want it to stick. I've heard that the aluminum is actualy held in place by the trim anyway.

Is there any problem using CDX instead of ACX?

[Steve Frederick]

Cdx is, at least where I live, very rough stuff to work with in a project like a Teardrop Trailer. It's hard to get/keep straight. It has voids, and is usually only three ply...the reason it's hard to keep flat. Acx is flatter, has any voids filled, and is more plys. I used cdx when I built my house. I used it in the roof. I recently built my garage/shop. I used waferboard everywhere. It's more stable and is flat when you lay it out. For a Teardrop, it would be way too heavy.

[Ron Dickey]

Cdx Acx ??

is this a glue or a siding (feel like I am eves dropping)

Time like this make me wish we had a glossery

Any one have a glossery of terms on their site?

Ron D.

[SteveH]

The first two letters are the grade or quality of finish. A being the best, on down to D being the worst on each side, I think. So, AB would be a very finished grade of plywood. I believe the X is weather resistant glue, but not shure, so someone else with more knowledge will have to chime in here.

[mikeschn]

Here's some information on Plywood...

Veneer Grades

Veneer is made by placing a cut log on a giant lathe and then rotating it against a cutter. As the log rotates, the cutter peels off a thin, continuous strip of wood that is then cut into pieces, graded, dried, and eventually made up into plywood sheets.

The veneers are given a grade based on the allowable number of defects and repairs and range from A (best) to D (worst). Under the rules of the American Plywood Association (APA), here is an abbreviated look at what is permitted under each grade:

A: No more than 18 neatly made repairs are permitted, parallel with the grain.

B: Repairs and tight knots up to 1-inch in size are permitted across the grain. Some minor splits are permitted.

C: Tight knots up to 1 ½-inch in size and knotholes up to 1-inch across the grain are permitted. Limited splits are permitted, as well as sanding defects that do not impair strength. Stitching (a type of rough veneer repair) is also permitted.

C-Plugged: This is an improved version of the C veneer. Splits are limited to 1/8-inch. Knotholes and other defects are limited to ¼-inch by ½-inch.

D: Allows knots and knotholes up to 2 ½-inch wide across the grain. Limited splits are allowed, as is stitching.

Exposure Ratings

Construction plywood is also rated by the APA according to one of four weather durability classifications. These include:

Exterior: These sheets have a fully waterproof glue joint and are designed for use in areas that are permanently exposed to moisture or weather. LI> Exposure 1: These also have a fully waterproof bond and are designed for use where the construction process will subject them to long periods of weather exposure before they are fully protected.
Exposure 2: This grade is intended for use in protected construction areas where they will only be exposed to moderate moisture or weather conditions.
Interior: These sheets are limited strictly to use in protected interior environments.
Understanding the Designation

A finished plywood sheet is designated by the grades of its face and back veneers respectively. For construction projects, some of the typical grade combinations include:

A-C: With an A face and a C back, this is a common plywood for use where one smooth, solid face is required, such as cabinet making, signs and some types of painted paneling applications.
C-C Plugged: This is a good plywood for use where one smooth, paintable surface is needed. Perhaps the most common construction application is roof overhangs on porches and exposed soffits.
C-D-X: A common panel for use on roof and wall sheathing where strength and moisture durability are important, but because the panel will be covered, appearance is not a big factor.


Mike...

[Ranger Rod]

While we're having this plywood discussion, has anyone tried using MDO (Medium Density Overlay) it is used for signs, etc. and is resin impregnated to stand up to exterior use. I have been thinking of using it on my trailer since I'll be using epoxy paint. I don't want to worry about checking as you have to with fir ply (even marine grade)

[Chuck Craven]

While we're having this plywood discussion, has anyone tried using MDO (Medium Density Overlay) it is used for signs, etc. and is resin impregnated to stand up to exterior use. I have been thinking of using it on my trailer since I'll be using epoxy paint. I don't want to worry about checking as you have to with fir ply (even marine grade)

My experience with MDO is it is 1: it’s heavy, 2: does not hold up to vibration very good.
It works for small sings but for lager signs it has to be edge and cross braced.
Chuck[/quote]

[Larry Messaros]

While we're having this plywood discussion, has anyone tried using MDO (Medium Density Overlay) it is used for signs, etc. and is resin impregnated to stand up to exterior use. I have been thinking of using it on my trailer since I'll be using epoxy paint. I don't want to worry about checking as you have to with fir ply (even marine grade)

My experience with MDO is it is 1: it’s heavy, 2: does not hold up to vibration very good.
It works for small sings but for lager signs it has to be edge and cross braced.
Chuck

Chuck, are you not thinking of MDF?

MDO is basically a waterproof plywood with a craft paper type face that is very smooth and weathers like iron when painted. Sign makers use this for long lasting signs. If I was to use any plywood with a painted surface, it would be MDO. Using it for the sides would be ok, but trying to bend it around a curved surface would be a real challenge. I couldn't find anything thinner than 5/16".


Here's one west coast manufacturer of MDO.

[norm perkiss]

I've done some sign work using MDO. It is very stable. To help weather proof the MDO or any plywood, apply some quality caulking to the edges before you paint or install. Run a bead and force it in to the fibers and any voids along the edges. I use my fingers to smooth the caulking. Can you say splinter...

Norm

[Chip]

Let me put one more kink in the question,, In building a trailer with luan interior plywood and metal or some other outside covering, could ya use 3/4" OSB as the core material and glue and screw the coating materials to it, Is it stable enough or will the warp factor be too great for a satisfactory end result...any body tried this and how did it turn out??

If this works it sure would shave a few bucks off but if its gonna be a nightmare then I just as soon pass,,

chip

[Ranger Rod]

(snip), apply some quality caulking to the edges before you paint or install. Run a bead and force it in to the fibers and any voids along the edges. (snip)
Norm

I was thinking of using CPES on the edges and either 1/8 or 1/4 Luan for the roof (CPES treated) then applying epoxy paint.

I think I'd stay clear of OSB.
Rod

[Chuck Craven]

I've done some sign work using MDO. It is very stable. To help weather proof the MDO or any plywood, apply some quality caulking to the edges before you paint or install. Run a bead and force it in to the fibers and any voids along the edges. I use my fingers to smooth the caulking. Can you say splinter...

Norm

Norm is right I was thinking of MDF fiber board with a water resistant glue.
Comes in 3/4" and is very heavy.

[asianflava]

Norm is right I was thinking of MDF fiber board with a water resistant glue.
Comes in 3/4" and is very heavy.

That is what makes it good for speaker enclosures.

[Chuck Craven]

I work on audio amplifiers that are 3 channel 60,000 watts each channel.
They don’t make speakers big enough that I can’t blow up, including the enclosure, in a micro second or less.
Our voice coils weigh 3000 lbs and the magnet 8 tons. Not meant for a teardrop sound system.
Chuck

[fornesto]

I got a message from the lumber yard and he said they have my "AC". I wanted ACX for the X (exterior grade). What will be the ill effects of using AC instead of ACX?....I'm not cladding in aluminum!