Wood types for compression block

[Ryan]

I am replacing a sizable block of wood that sits at the forward end of the bilge and extends up to the bottom of the cabin sole under the compression post. Originally it was teak plywood and globs of resin/sawdust. I'd like to use something like G10 or GP03 fiberglass, but the size of the block (approximately wedge shaped with a 8" square base and 9" high) make this a pretty expensive proposition. Given that whatever wood is chosen will be well sealed with epoxy and a couple of layers of glass to seal it from the bilge proper, can anyone recommend an easily available hardwood? I have white oak and ipe on my short list, but I am not much in the way of wood knowledge, so any suggestions are appreciated.

Ryan

[Case]

I don't personally have any wood recommendations... But I have to say something about the compression block:

Some people buy fiberglass sheets between 1/2" to 1" thick then cut them up, then... epoxy them together to reach the desired size. Good old boring cheap fiberglass is sufficient for this, no need to spend $ for fancy G10 fiberglass or the like. I used electrical fiberglass panels for use as backing for my seacocks. They were red colored and were among the very cheapest fiberglass I could find. And they were most definitely harder than the hardest oak wood...

Just a thought. Try pricing out fiberglass sheets and some epoxy and I think you will find the price to be not that bad at all. I use McMaster Carr as my supplier.

- Case

[Ryan]

Case

I have also used the GP03 sheets (3/4") for seacock backing plates, it is great stuff. Using it was my original plan, but given the size of the block it is still pretty darn steep. I even have a large supply of GP03 in 1/4" thickness, but that is a LOT of laminating to get a 8" block. I may still go that route, but wondered what the wood consensus may say. Thanks!

Ryan

[Hirilondë]

Originally it was teak plywood and globs of resin/sawdust.

If it really was teak veneer plywood then it was an extremely poor choice. The core layers for most teak veneer plywood is poplar, one of the most rot prone woods known to man. Ipe is an excellent choice for this application, so is teak Glue up as many layers as it takes to make the size and shape you need using epoxy and move on. Glassing over it will do nothing to make it more waterproof and add nothing to its compression strength. If the need to fabricate it out of an inert material like fiberglass board is too great to resist then go ahead, it will certainly work. But I think you are over-engineering it. In the end you are the one who has to get to sleep at night after the project is done, give yourself what ever it takes to do so.

[okawbow]

Osage orange, sometimes called hedge apple, is the strongest, and most rot resistant american wood. You can get it from most hardwood suppliers, and maybe from your local sawmill. I hve seen it for sale on online auction sites.

[Hirilondë]

Osage orange, sometimes called hedge apple, is the strongest........american wood

No it isn't. First of all there are 3 basic types of strength for wood. Tensil, compression and deflective, so using the term strong is misleading. A general description of Osage Orange is certainly rot resistant, very dense and quite strong. But let's please be careful with definitive statements that just aren't true. .

[Ryan]

Originally it was teak plywood and globs of resin/sawdust.

If it really was teak veneer plywood then it was an extremely poor choice. The core layers for most teak veneer plywood is poplar, one of the most rot prone woods known to man. Ipe is an excellent choice for this application, so is teak Glue up as many layers as it takes to make the size and shape you need using epoxy and move on. Glassing over it will do nothing to make it more waterproof and add nothing to its compression strength. If the need to fabricate it out of an inert material like fiberglass board is too great to resist then go ahead, it will certainly work. But I think you are over-engineering it. In the end you are the one who has to get to sleep at night after the project is done, give yourself what ever it takes to do so.

Obviously the original choice poor proven by the fact that it was rotten I have had to spend too much time upside down cleaning out the remnants. Since the block makes up the forward wall of the bilge, glassing over it cheap insurance against any bilge liquids spending all its time against the wood.

Thank you for the confirmation about ipe.

Ryan

[Hirilondë]

Since the block makes up the forward wall of the bilge, glassing over it cheap insurance against any bilge liquids spending all its time against the wood.

Thank you for the confirmation about ipe.

Ryan

The glass does nothing to make it more waterproof, the resin does. Glass cloth/mat/etc is used for adding different types of strength characteristics to different applications. Ipe is incredibly rot resistant by itselft, but coating the finished block in epoxy certainly won't hurt.

[okawbow]

Osage orange, sometimes called hedge apple, is the strongest........american wood

No it isn't. First of all there are 3 basic types of strength for wood. Tensil, compression and deflective, so using the term strong is misleading. A general description of Osage Orange is certainly rot resistant, very dense and quite strong. But let's please be careful with definitive statements that just aren't true. .

I've worked with osage orange for over 30 years. I've never found another american hardwood that can match it in overall strength and durability. I've made archery bows, violin bows, tillers, winch blocks, hand rails, and even halyard pulleys from osage. Those items have out performed any other wood I've tried. Farmers in my area use it for machinery bearings, drift punches, and mallets. I've seen osage fence posts that were in the ground for over 75 years, and still solid. In bow making osage is in a class by itself in it's ability to withstand both compression and bending tension, better than other woods.

Name any other available native hardwood that is stronger and more rot resistant in all those areas.

[Hirilondë]

I've worked with osage orange for over 30 years. I've never found another american hardwood that can match it in overall strength and durability.

This qualifies you to make definitive statements that the rest of us are expected to take as fact? I will not debate with you which wood is the best. My point is that there is no definitive statement that can be made, and in doing so you are professing a fallacy. It is your opinion, and you should preface any statements as such.

[okawbow]

I've worked with osage orange for over 30 years. I've never found another american hardwood that can match it in overall strength and durability.

This qualifies you to make definitive statements that the rest of us are expected to take as fact? I will not debate with you which wood is the best. My point is that there is no definitive statement that can be made, and in doing so you are professing a fallacy. It is your opinion, and you should preface any statements as such.

Virtually evey statement is an opinion. It's a waste of time to preface them as such. I personally don't accept anything I read on the internet as fact. However; I listen to advice. 30 years of personal experience carries more weight than " someone said, or I read it once" advice. My opinion of osage happens to be shared by most of the wood bow makers in North america.

Back to the original question..........I can't think of a better American wood than osage for a mast support block.

[cantstopnow]

Locust, Robinia pseudoacacia

[cantstopnow]

A quick Google search brought this link for more info on wood strengths.
http://www.woodbin.com/ref/wood/strength_table.htm

[okawbow]

Here's an interesting test that includes osage.

http://chestofbooks.com/home-improvemen ... ength.html

[Figment]

ok, I'll join in:

MRREEOOOOOOWR!
HISSSSSSSSSSSSSSSSSSSSSS!

[Rachel]

All joking aside (nice hiss there, Figment), I can see where Hirilonde is coming from.

I do get a bit uncomfortable when opinions are stated as facts (or could clearly be interpreted as facts by the original poster or by future searchers). In this case, I believe I now understand that osage orange is a great wood, and very strong and very rot resistant. However that's not the same as being THE hardest and most rot resistant American wood. It really wasn't stated as an opinion (in the first mention of it), but as a fact.

On the other hand, I also don't agree that everything is an opinion. There are facts, and I don't think there's anything wrong with stating them as such. Certain principles of physics; where a particular metal stands on the scale of nobility; the LOA of a given boat, etc.

One thing I'm very grateful for is the breadth and depth of experience and expertise we have on this board; thanks to everyone who takes the time to chip in with their knowledge.

Rachel