[Woodcarver] Need adviced on relief carving panel construction

[Bill Judt]

Alex:

Adding cambre to a relief panel ONLY controls the tendency of the  
wood to cup as a result of the carving process. It will not control  
the effects of expansion, contraction a moisture changes on carving  
when exposed to the outdoor elements.

If the carving were hanging from a chain, rather than being mounted  
on a plywood backing, there would be less stress on it. A small roof  
over the church sign would also moderate the effects of the elements  
on the carved panel.

Having said that, it is also true that some woods are better suited  
for use as outdoor signs. Mahogany is excellent, and so is cedar.  
Don't use birch or maple, for example.

About casting... remember that the BACK of the duplicated carving  
will be level regardless of the cambre in the master carving. This is  
because when you pour the moulding material into the mould, the face  
of the carving is facing down, and the back of the carving is facing  
up. The moulding material finds its own level like water in a bucket.

If you wish to make a casting of the warped carving, simple build the  
sides of the mould with plywood to compensated for the deflection of  
the back edges of the carving.

If the original carving is cupped (warped) to the carved side, don't  
be concerned. When the reproduction is finished, it will make little  
difference, since the reproduction will have a smooth and flat back.

If you wish to make a second carving 24" wide by 26" tall, used  
boards that are 5" wide, for a total of 25" width. This will allow  
for applying cambre at four joints, and will also allow and extra  
inch width for the jointing process. Set your jointer fence to 91°,  
as this will give you 2° cambre at each joint for a total of 8°  
cambre over the width of the carving. Hopefully this will give you  
about 5/16" cambre or more.

Hope this helps. If you have any more questions, email me off-list, OK?

Blessings and Peace,

Bill
List Owner

My books are for sale at: http://wwwoodcarver.com/Books/index.html
W.F. Judt,
46 Harvard Cres,
Saskatoon, Saskatchewan,
S7H3R1
PH: 306-373-6649
Email: bjudt at sasktel.net
Website: http://www.wwwoodcarver.com


On 3-Aug-06, at 9:20 AM, Alex Bisso wrote:


> At one time I carved a sign - sort of a cut out relief - of an  

> elevated lighthouse.  I did not  but any initial cambre into the  

> the pieces of basswood that were glued up for the piece (the center  

> piece with the lighthouse and the two wings - see photos named  

> Summit Lighthouse and Summit Lighthouse Painted  in carving album  

> at http://www.picturetrail.com/gallery/view? 

> username=abisso&x=19&y=15 ) and the wings have badly warped  

> outwardly.  I also did not seal the back which I think also  

> contributed to the bad warping.

>     Now I plan to recarve the sign, this time as a complete relief  

> carved panel that will be approximately 24" wide and 26" tall and I  

> have conflicting thoughts about how to glue up the panels.   

> Although I would like to be able to use the original wood carving  

> for the outdoor sign, I am thinking that even with building in  

> cambre, sealing, etc. there will still be some warping and  

> weathering of the wood (sign is exposed to harsh weather and  

> afternoon/evening sun).  Therefore I am thinking about keeping the  

> carved sign for inside use and doing a mold and cast of it for the  

> outdoor sign.  Here are my questions:

> 1.  If gluing up the panel with the boards running the long way,  

> how many boards/joints are recommended and what degree of cambre  

> should be put it each?

> 2.  If I build in the cambre, will this make doing a mold and  

> casting more difficult because the panel might not be flat upon  

> completion?

>     Discussion:  My original sign was nice and flat after carving  

> and only warped after exposure to the elements.  It would have been  

> easy to make a cast of it.  Since I have almost no experience with  

> relief-carved panels, I am concerned that after initial carving, a  

> panel with cambre might arc up some in the middle causing some  

> difficult in the molding and casting.

> If you have any experience with doing something like this I would  

> like to consider any advice that you might have to offer.  Thanks.

> ALEX


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