Strapping plank

[adam_86]

Hi everyone

 

I'm pretty new to milling and I'm wondering what the best way is to strap planks to reduce them bowing.

 

I've milled a small bit of oak a couple of months ago and it's warped even though it has been strapped.

 

Thanks

 

Adam

[Big J]

The sticks you have between the planks are much too think. They are allowing too much air flow, which will cause movement. Restack with sticks of 12-18mm thick. As it's summer and it's Oak, I'd be inclined to go 12mm. 

[Squaredy]

I agree with what Big J says, but would also add that a lot depends on the log and how it is cut so to an extent if a board wants to twist or warp it will.  To avoid movement you need to quarter-saw logs, or at the very least saw into narrower boards.  Also straps don't really help as they will loosen as the timber dries and shrinks.  I guess they may help if you keep tightening them.

 

Also think about where you are storing the boards - out of sun and rain, but with good airflow.

 

But to a large extent a good straight grained log without knots will stay much straighter than a knarly old knotty bendy log when milled.

[CDMR]

Just for the sake of debate rather than offering a hugely informed perspective, I reckon that any given plank has a shape that it wants to be at any given moisture content. Slowing the drying, allowing the wood to ease its way to a shape by gradually losing the tensions within it is probably the only way to permanently change this shape. Straps and weights ultimately seem to just be temporary measures to affect the shape at a given time. If you don't give the wood time to ease into being that flat it will just go back to being the shape it wanted to be in the first place, usually at an inconvenient moment such as when impersonating a table top. So the recipe for flat plank has to be slow drying, with weight ideally that moves with the wood. The more the wood is likely to move the slower you dry rather than the more weight you use. Alternatively, cut it thick, dry it fast, let it be whatever shape it fancies and be prepared to cut off a lot of wood to make some flat bits, though it will probably bend some more.

 

In summary, what they said. 

[adam_86]

The sticks you have between the planks are much too think. They are allowing too much air flow, which will cause movement. Restack with sticks of 12-18mm thick. As it's summer and it's Oak, I'd be inclined to go 12mm. 

Thanks I'll change them out for some smaller ones.

[adam_86]

Thanks guys. They are milled to 2 inch and stored under my garden work bench which is out of the sun and covered.

[Forest2Furniture]

I'd go with what Big J said too but add that you tend to get more movement on shorter lengths then you do on boards 8'-12'.

 

[Rob D]

Weight is prob best over strapping as it gives a continued force but certainly some dry B&Q plain sawn battons 38mm by 50mm I find work really well.