Problems with combining stabilized and non-stabilized woods?

[greasedbullet]

I recently got some stabilized woods and I am relatively new to working with them. I have a plan to make a western handle with some stabilized wood and a non-stabilized ferrule. Would there be problems due to the natural wood shrinking more than the stabilized or is this a negligible detail? The natural wood is kiln dried for what that is worth.

Thanks,
Mike

[Dream Burls]

If it's a natural hardwood like African Blackwood there shouldn't be any problems. But if you use a soft wood that's not stabilized it will move differently which could cause gaps and cracks. The wood being kilned dried really doesn't matter because over time it will absorb moisture and expand, then contract under dryer conditions. I'd stick with a hard wood or a stabilized piece for your ferrule.

[CPD]

I've combined stabilized and non stabilized materials in Wa handles a bunch of times and never had any problems from inconsistent movement/shrinking. I won't say it's a negligible detail - the type of unstabilized wood you are using , how dry the wood is, and how humid an environment you're in could be factors that make a difference. That said, though, if you're careful about your techniques and how you join the two materials, you should be fine unless your pieces are especially thin. I'd recommend using a good epoxy that has some light flex at the joint to help keep things in check if there is any subtle movement. (I personally use G-Flex)

I'm by no means an expert on stabilized woods, but couple other points others have shared with me over the years --- If you're working from a block of stabilized wood, I've been told it's generally a good idea to trim the outer 1/8 inch off and consider that scrap. The outer edges being most prone to warping as a byproduct of the chemical reactions and forces put on the material in the stabilizing process (vacuum, heat etc). Precut scale blanks, obviously that advice is irrelevant.

The other general tip that applies to any thin woodworking project (Stabilized or not) is to try to treat both sides of your material as consistently as possible. As an unrelated illustrative example -- when working with veneer....when you glue it down to a substrate, it wants to curl and the power of that warping force is surprisingly strong. By wetting the visible face with water or softener, it helps prevent the veneer from cupping or pulling on the other material. Sort of the equal and opposite forces rules of physics. Where possible, the same principle is usually good to follow and helps prevent problems here too.

Other info, though I'd guess overkill:
flatsawn wood will move far more than quartersawn.

You can find tables that show formulas to calculate wood movement based on species. Dense hardwoods properly dried are going to be more stable in general.....

In dry woods, most movement is going to be across grain - side to side - rather than end to end. Because of that, the stress on your glue joint between materials is lateral. That kind of movement is unlikely to shear your joint, and since you will have glued your blanks to your tang this being a Western handle, you'll have a lot of surface area preventing that kind of lateral movement in your woods. More reason not to worry.

an oil finish that provides a moisture barrier will help prevent problems down the road too

[Burl Source]

Good advice from both of you guys.

What is the natural wood you will be using Mike?

[greasedbullet]

Sorry I have been at work. I am planning on using bloodwood. I have some stabilized redwood that I can use instead, but it wont be as vibrant as I would like.

Also thanks everyone for the info, it is very helpful.

[JohnnyChance]

ALL of my handles that have multiple materials in them, be it stabilized wood, unstabilized wood, synthetics, horn, metal, etc, have some degree of movement, regardless of how they are made or who made them.

[apicius9]

ALL of my handles that have multiple materials in them, be it stabilized wood, unstabilized wood, synthetics, horn, metal, etc, have some degree of movement, regardless of how they are made or who made them.

I wish I could say otherwise, but I have seen a few of those changes also. Just got one back for repair where the premium grade aged ebony cracked, and the horn had shrunk enough that the transition to the metal spacer was noticable. I am usually overpaying on my materials to get the best quality, and I always let them sit for longer periods of time to adjust, but it just happens when they get shipped into a different climate and environment. I would expect that the movement would be minimal if the wood had time to sit for a few months before you use it and if you keep the handle in your climate zone (I am assuming you make it for yourself?). I also tried at least a dozen different epoxies, and I agree with CPD that the West System G-flex is probably the best option to join pieces out there. I may be off on the bloodwood because I have not used it much, but IIRC it can be a bit oily, so it is important to really clean the gluing surfaces well and get any oil off before you put epoxy on it.

Stefan

[Dream Burls]

Bloodwood is pretty hard and dense so your expansion should be minimal. However, the wood tends to be brittle and can splinter easily while being worked so be careful.

[greasedbullet]

I am pretty used to working with bloodwood because I got a large amount at one time and am kind of trying to use it up. This is not for me and will be moving to a completely different climate. I guess I will just make it entirely with stabilized woods to be safe.

Thanks for the help everyone.
-Mike

[CPD]

ALL of my handles that have multiple materials in them, be it stabilized wood, unstabilized wood, synthetics, horn, metal, etc, have some degree of movement.

When you factor in other materials like metal or synthetics that don't move, I think it can magnify the potential problems. A wood to wood joint is easier to predict and manage because you create opposing forces with grain alignment and joinery. In other words, while the wood will expand and contract - you can insure pieces move somewhat together so they don't pull apart a joint or create a visual or tactile change that stands out. Plywood is a basic example - the grain direction is varied from layer to layer so that as they move, the forces offset each other. With handles, when we have elements that don't move (metal), or pieces that respond to the environment differently (horn), the combination of moving and non moving parts makes things ...um, more challenging.

Treating both sides of your material the same, or not, is also (I think) a big factor in noticeable movement when it comes to handles. In a western, for example, if we glue up parts to the tang with epoxy - one side of handle has had it's ability to move seriously restricted. A light oil coating on the exposed side, in contrast, is going to provide nowhere near the same kind of restrictive force. So, when the wood wants to move, one side can and one side can't..... that leads to more cupping or creates the potential for cracks. That's especially true in really dense, rigid hardwoods like ebony that are somewhat prone to cracking to begin with.

There's not a ton that can be done to prevent this short of epoxying both sides of material which is aesthetically not an option. Somewhat flexible glues like g-flex does help as does trying to make sure your final finish is as moisture proof as possible to limit the environmental exposure that will fuel the woods movement.