Replies

1. 
   mufti | Oct 10, 2006 10:49pm | #1

              The easiest option is available at B & Q in the form of small sheets of Bendiply, two or three laminations of which bonded over a former should give the required result. Good luck, post how you get on!

1. 
   GOBEEN | Oct 10, 2006 11:12pm | #2

   Hi MUFTI,thanks for the info,I should have thought it out a bit more,I was thinking along the lines of 1/2" ply,but I can see now it would probably split along the seams with bending,I will give the thin stuff a go,I don't have a mould or former as you call it,I think that's right,so I will try to construct one,any idea's would be appreciated,happy chippin, MAC <(:-)>Gobeen <!----><!---->

1. 
   KeithNewton | Oct 11, 2006 05:09am | #3

   I am not so sure about using bending ply outside. You can use epoxy for your part, but I don't know if the glue that they use is exterior or not. I would lean toward re-sawing, and gluing thin layers up with epoxy. although, I don't recall what the part is that you mentioned, so I might be off due to that small technicality.

2. 
   mufti | Oct 11, 2006 05:12pm | #4

               In the past I have got by curving laminations around plastic dustbins or anything to hand and holding them in place with string, straps or whatever until the adhesive is set. Keith is correct in that anything left outside is difficult to waterproof and ply (or mdf ) is very difficult. However I have had success by bonding laminates with West system epoxy and then covering the outside surfaces with the same epoxy thinned to brushing consistency by the addition of thinners meant for Rustins Plastic coating, giving three coats.

   No one will recommend the above but for me it worked and I tried it because I had the materials. It does not work on thick timber since normal movement results in surface cracks.

1. 
   GOBEEN | Oct 11, 2006 11:26pm | #5

   Hi Mufti & Keith,thanks for your time,that is a very good tip about bending round common h/hold gear,why is it so dif.to waterproof the ply.can I just seal it and then varnish ,which I did on the bench and table I've made,I'm making a gateway arch type pergola, the arches I've cut from 1/2"ply. so that exposes the laminates,I'm kind of concerened now,if I seal them and then varnish them with Antique pine varnish will that stop rain getting into the seams,do you think,have you had occasion to try this method,I'm open to any sugestions, keep chipin, MAC <(:-)>Gobeen <!----><!---->

1. 
   Patto | Oct 12, 2006 06:43am | #6

   Construction ply generally does not have waterproof glue between the sheets. So if you are laminating several sheets of (say 3 ply) your joint might hold but the original joins are prone to water failure. As the wood moves in temerature changes the finish wil get small cracks trying to keep up. this really obvious on old peeling paint. Where these cracks are on the edges of your work, then moisture will get into the glue layers.

   Might not happens for perhaps two seasons, but will happen. Most of the woodworkers here don't see their work as temporary (anthing less than 50 years without repair on indoor work - 5-10 years between refinishing outside) so their advice will usually reflect that sort of time scale.

   dave

2. 
   GOBEEN | Oct 12, 2006 11:07pm | #7

   Hi Patto,thanks for the note,5-10 yrs,that will do me I don't think I'll be around that long,but,if I am I will find it a bonus and redo the arch,bye the way this is from a plan bought on the "Woodworker" site,you would think they would raise that point,still thats commerce I suppose,I'm doing a "wishing well" and square planter boxes to go either side of the aforementioned,whapping word,pergola gateway,I'm using waterproof glue and hoping for the best, keep chipin, MAC<(:-)>Gobeen <!----><!---->