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Plywood in Australia


Quiet

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The Ravenswood plans and manual arrived last week. Very high quality. I was impressed. The manual looks very comprehensive as well.

 

I have been doing some searching for ply, trying to follow Jeff’s instructions as closely as I can. When searching for Baltic Birch here in the SE of Australia I came up with this: http://dmkforestproducts.com.au/wisa-birch/

 

Going by what’s on their web page it looks to be the right stuff, however I wouldn’t mind a second opinion before purchasing.

 

In the event that folks don’t think it’s suitable, or it’s unavailable for some reason, I am wondering if any of the Australian contingent or others on the forum have any experience with Hoop Pine Marine ply: http://boatcraft.com.au/Shop/index.php?main_page=index&cPath=56_60 .  A local product and they certainly talk it up, however do people feel it would be as strong as the Birch? Not as many ply’s and Hoop Pine as a timber is not rated as strong as Birch in the Wood Database.

 

Many thanks for any ideas and input.

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Last year i bought some marine plywood from Bunnings for a skin on frame canoe i was building, it was ok but the top and bottom veneer seemed little brittle and splintered a bit perhaps my jig saw blades were not sharp enough.

So far it has been OK.

https://www.bunnings.com.au/2440-x-1220-x-12mm-aa-grade-mixed-hardwood-marine-plywood_p0320024 

Its a lot less expensive than some but that is not the final consideration

I too am looking at a Ravenswood just making the final decision and considering the timber for the stringers etc thinking about paulownia at the moment nice and light as that is important to me, guess i will just have to step off the deep end ( look out for an order Jeff) and get going. As TV watching is not worth the wasted time. 

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Hard for me to say since I don't know anything about what you have available.  Here, US made plywood is garbage when it comes to boat building.  Baltic Birch is imported from Russia made from birch from the Baltic region, It has even thickness in all the layers and is made from a very weatherproof glue that doesn't fall apart when wet. Even after months outside.

 

US made birch plywood has a thin veneer Birch face only. Who knows what the cores are and they are not durable at all.  The exterior grades of plywood are used on house and covered up so the finish is horrible. Plus it warps and is full of voids inside. So it i poor choice.

 

Main thing is the glue used, will it stand up to being wet. Secondly is the wood it is made from. If you keep it dry most of time rot shouldn't be an issue but I prefer a wood with some rot resistance. Good luck on your search.

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You can always look for BS 1088 standard plywood.  This is available over the world, though it is pricey.  Like I have said in other threads we are using plywood for a design it was not intended for.  So some of the characteristics of plywood are totally irrelevant.  The characteristics of plywood that best support what we use it for are numerious layers with no gaps or repairs and top shelf waterproof adhesive.  Boil proof marine standards are not necessary.  Baltic Birch is probably the least expensive of true integrity in plywood, at least in the Americas and probably Europe.  BS 6566 plywood would be good for kayaks as well.  Less pricey probably than 1088 but still not cheap.  Australia has some of its own standards as well and it might be useful to do a little homework on that.

 

key characteristics:

1. 7 layers in 1/2" 12mm.

2. gapless laminations with no repairs or knots

3. exterior glue at minimum,

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If you search this forum you will find numerous discussions of Baltic birch.  It has become the gold standard, so to speak.  Personally, I think that is primarily due to the structural integrity (number of plies, quality of wood used in the plies and no voids or plugs).  I have seen some descriptions of it that specify water proof glue(type 1 phenolic) and others that specify water resistant glue(type 2).  I believe that some in this forum have used the water resistant and not had any problems.  In reality, the frames seldom spend any time submersed in water and if they are they dry out relatively quickly after the event.   In my mind the structural integrity is the more important characteristic.  Good luck in your search.

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Thank you for the replies, (and for being patient with a newcomer and their questions). On looking back through the forum topics, I can see plywood features regularly. I suppose it can be a bit of a challenge to find in some parts, especially if you are starting out, know little, and can’t locate the recommended type. As others have said, it all becomes a bit of a compromise, trying get the “best” for the project. “Best” meaning many things from cost to glue type, moisture resistance, strength, veneer thickness and quality, etc., etc……  Big danger, for me anyway, is overthinking things and going round in ever decreasing circles. So, I am following up one more lead and then will make a decision over the weekend and order the timber. Now that I have finally finished my workbench and stands, I’m looking forward to actually starting. 

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One thing Jeff touched on but has not been emphasised is that the outer plies should be the same thickness as the others in marine ply. There has been ply sold as BS1088 in Aus for a long time now and I believe it's not genuine due to having thin outer plies. I saw some like this only a couple of months ago. The people retailing it don't seem to realise it is not the real thing - they think that if the glue is waterproof then it is marine grade.

 

I used the same stuff that Teasea mentioned earlier from the big green shed and while it was not great to work with it will be OK with a little care. I have a vague recollection of doing a water resistance test over some days before using it and it passed.

 

If I was doing another SOF and had spare cash then I'd use the expensive ply - either gaboon or hoop pine - but if not then the Bunnings stuff would get another go.

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I used Douglas Fir for a long time but the quality of the face(s) kept getting worse and worse. Plus it splintered really bad but I could deal with that. I went over one day and when they brought out the stack on the forklift I took one look and said that is it! That is when I found Baltic Birch.  The plywood worked fine, but cosmetically it looked terrible and I just could not sell kits that looked like that.  But keep in mind all but 3or 4 frames are totally hidden, do cosmetics might be acceptable to you.

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Over the weekend I digested the information  folks have given and weighed up as best I could all of the pro’s & con’s of the different types of ply available to me. Ended up going with the AS2272 Hoop Pine marine ply. Order has been placed, so hopefully will see it in the next few days. Thank you again to all for your input.  

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  • 2 weeks later...

The Hoop Pine plywood arrived this week. First impressions are very positive. An even, creamy smooth surface, 7 plies, no visible voids in any of the edges and no visible knots to speak of. Unfortunately, life is getting in the way at the moment so it may be a week or two before I can start to cut out the frames, however will post impressions when I do.

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  • 4 weeks later...

Well it took more than the 2 weeks I had intended, however I was finally able to start cutting out the frames on the weekend. For those that are interested, the Hoop Pine ply cuts quite well with almost no splintering. I have found 2 internal voids, 1 about 1 mm wide (say, 1/32”) and the other about 6-7mm (say about 1/4”) wide. They are each near the end of a frame and should be easy to completely fill with a syringe filled with thickened epoxy so I don’t think I will need to cut new pieces. Of course if anybody thinks differently, this newbie would be very happy to hear.

 

I also gave the plywood a highly scientific strength test by bouncing up and down on a 50mm (2") wide offcut supported on 2 blocks. I am around 87kg (say 185lb) and it seemed to hold up just fine.

 

At this rate it looks like it may take a while to get the Ravenswood done, however that’s not too bad as I am really enjoying the process.

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9 hours ago, Quiet said:

 I have found 2 internal voids, 1 about 1 mm wide (say, 1/32”) and the other about 6-7mm (say about 1/4”) wide. They are each near the end of a frame and should be easy to completely fill with a syringe filled with thickened epoxy so I don’t think I will need to cut new pieces. Of course if anybody thinks differently, this newbie would be very happy to hear.

 

Not sure what you mean by "end", a picture would help a lot.  But that being said, the plywood you are using exceeds any standards Baltic Birch meets and your remedy should prove sufficient for our application of plywood.

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You are right, a picture would help. Here is a shot of the end of the bow piece. It is the one that contains the larger void. As you can see, the void is right towards the pointy end. As such I don’t think there is much load on the ply at that point. Pity I couldn’t see it until the piece was cut or I would simply have moved the pattern along a small amount. Should be easy enough to epoxy fill.

This is the plywood straight off the jig saw. No sanding has been done. As you can see, it cuts quite well

Ply Void.jpg

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It is hard to tell from the picture, but can you find the end of the void?  Or does is continue through the whole sheet?  Basically there are 2 kinds of voids in plywood.  One is a damaged spot or missing knot leaving a hole in the layer.  The other is when there is a seam in the layer and the 2 pieces of veneer did not meet. In some US junk plywood I have found the meeting edges of one veneer overlap the other creating a bump in the product.   

 

In either case this doesn't seem like an issue, but I would fill it like you suggested just because too much work goes into boats to leave it to chance.  Your corner might be more prone to damage without the repair.

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The plywood part of the kayak build turned out for me to be a pleasant surprise. I actually struggled to trust it in the beginning, so I left a little more meat on the frames than the templates showed. By the end of the build though, I could tell it was a quality material. And I like the way it smells like Tinker-Toys! ?

20170412_220208.jpg

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Looking at the offcuts, the void appears to close up again. In the only other frame affected the void is down to about 1 mm wide, so not an issue, although I will fill that with epoxy as well just the same. All other pieces look fine so onwards to the sanding. Thank you for the input. Lets see how many months it will take me before I can supply the mandatory FROG shot.

 

Benhardt57, what's your ply? The Baltic Birch?

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