I am wanting to re saw some Ash lumber and laminate the pieces together to create an arc of about 6″ in height and about 4-5′ in length and about 4″ in width and 1″ in thickness. Realistically, what dimension to re saw the lumber, what thickness to mill down that re sawn material to and any other info I might need to create this monster.
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Replies
That would depend on whether it was captive or restrained by another part, and the type of glue.
I am thinking that if it was restrained, maybe six plys just over 3/16". But if it needs to stand alone, I would want at least eight plys.
The amount of waste probably depends on what tools you have, and how well you use them.
You should be able to get them out of two 3/4" thick boards, or one 10/4.
When you say restrained or captive, I am assuming you mean glued,screwed,nailed or some fashion to another piece/pieces of wood, either above, below,or both to the laminated piece I want to do. Is my assumption correct? The answer is yes,there will be a solid piece of lumber below this laminated arc. This solid piece will be cut from one board (maybe 2 edge glued) on the band saw. Item #2--what is your suggestion on the glue type? Thanks for you help----WW57
Yes, that is what I meant. You still are not giving me or anyone else for that mater enough information to be as helpful as I could be. What are you making? What are the dimensions of the solid piece? Is it a bed, Door opening? crown of a cabinet? Why keep it a secret, if you want real help? One thing to remember, whenever bending, is that you can not bend a board or laminate down all of its length, whether solid or laminates. Eight times the thickness will be straight on the end. Even if you have extra length at the time of glue-up, then cut off later, you will likely get some spring-back on the ends. This is a fairly easy bend. I use curves quite often in my work, and the best advice I can give it to dimension one ply, and bend it to the curve, then you can anticipate how much pressure it takes times the number of plys. The most common mistake that newer woodworkers make is to go with fewer, and or a glue which creeps. So don't think about trying to make it easier on the front end to only trade the heartbreak of trouble forever after. Flat sawn lumber will be rift on the edge, which doesn't show glue lines as much as a QS face with a plain sawn edge.::
I wasn't keeping it a secret, did not realize that piece of info would be beneficial. It is going to be the very top of a bed head board for our newest grand daughter. The board below it is not completely determined yet and it will not be a consistant arc, but at its highest point ,it will also be 6". Part of this bed is still on the drawing board, which adds to the uncertaintity of stuff. As I draw, sometimes I start to decide how to do this step or that, and that is where I am at right now. Thanks for your help---------WW57
One other thing, I was thinkig that after I made the top laminate and let it spring back to whatever, I would use this laminated arc to scribe the supporting piece below it. Is that out of the question? Just brainstorming here-------WW57
Given the additional info you provided I can offer up this picture of a similar bead I made a few years ago. The top rail was made from three pieces of white oak that were about 1/4 in thick. That is thicker than others have recommended but the curve is gentile enough that I still only got about an inch of spring back. I laminated the top rail first and then cut the piece underneath to match. I also used regular white glue - there are other types that are less subject to creep and would probably produce less spring back.Hope that helps.
Chris
Not related to this post but I have no pride so I'll ask.
I liked the style of your bed. It 'may' fit for my new project. I will be making two canopy beds for my granddaughters. The woods will be a combination of Panga-Panga and Jatoba for contrast wood.
They will be 'my' interpretation of Chinese style. No expert on design or Chinese style but I looked a MANY pieces of very old furniture the two times I was in China. Mostly the southern part of china. I do not recall many curves (circles, yes) but maybe I can come up with something 'fitting'.
Is it OK to 'steal' you basic design idea?
Please feel free to copy any parts of the design that fit your project. I would be glad if someone else found any of the ideas useful and if you want any measurements or construction details please let me know. I also made some matching bedside tables that may spur some more ideas for you. Here are a couple of pics.
Chris
Thanks for the pictures.. I like the bedroom set.
The fancy dovetails. Hand cut or one of the Leigh templates?
The dovetails are hand cut. My results are far from perfect but it seems like a lot more fun to cut them by hand. If you look at the ones in the picture sideways they actually spell out my wife's initials - BHW. The ones on the drawer on my side are the regular type. Trying to do a C seemed like too much work and I got anxious to get on with things.
Chris
The more plys you use, the stiffer the arch will be. I would go no more than 1/8" - but try to see if you can bend that thickness around your form. (I have bent ash around a 60" diam form. You will need PLENTY of clamps.)
Frosty
"I sometimes think we consider the good fortune of the early bird and overlook the bad fortune of the early worm." FDR - 1922
I would go no more than 1/8"..
I would agree. I have never made an arch with Ash but I have made more than several archery bows with Ash and Hickory (mixed laminations).
For the bows, the final size of the built up laminations are about 2 inches wide by 1.5 inches thick by 70 inches long. Even with 1/8 inch thick laminations you may need a block and tackle to bend a tight curve. I use poly sometimes but usually DAP WELDWOOD Resorcinol Waterproof Glue (two component adhesive).
I 'think' the poly makes the bow more flexible. I understand many long bows with 70 lb pull are made using DAP WELDWOOD Resorcinol Waterproof Glue. At least, I have seen it posted often.
I guess what I am leading up to is the old boy scout motto.. 'Be Prepared' when doing the glue up on something that large.
Edit: I would never do it with a bow, but for a permanent structure I would 'think' you could do it stages and not try to bend all the wood at the same time. Somebody correct me if you feel otherwise.
Edited 8/29/2008 7:40 am by WillGeorge
Experience is a great teacher - I learned several valuable lessons on the attached project:1. I used Gorilla glue. NEVER again! Talk about a Chinese Fire Drill! I had foam, sticky foam, on my clamps, my tools, myself and the floor. The stuff just went every where. 2. I made the lams too thick to conveniently bend the full set. Conveniently means I needed someone stronger than I am to bend all the plys at once - so I bent them in two stages.3. More plys makes a stiffer arch w/o spring-back. When I took the clamps off the first set of plys I had about 3"-4" of spring-back. I figured I could restrain this with the shelf, so I went ahead, gluing up the rest of the lams. Surprise! There was NO SPRING-BACK and there has been none after a year.A thicker piece places structural material farther from the 'neutral axis' making a stiffer piece.Frosty"I sometimes think we consider the good fortune of the early bird and overlook the bad fortune of the early worm." FDR - 1922
I loved the table but SURE wish you did NOT put those squared off end support blocks next to the curved legs.. Sorry, No hate here... Just me. I had to.
I have used Gorilla glue on laminations. Yes a mess, but that stuff sure holds well!
I have some bows where I used Gorilla glue. They shoot nice and not a whimper from the laminations. The two part glues can be a bigger mess!
Edited 8/29/2008 7:16 pm by WillGeorge
I agree! I had a terrible time "balancing" the top on the crest of the arch. I had plumb bobs hanging on the corners for alignment and no place to clamp while I fashioned a support system. What you see is what I came up with. (At least it IS sturdy.)The rest of the story:The blocks are Walnut. I thought the contrast would be 'interesting'. It was awful - so I took a segment of the laminated Ash to the paint store and had them match the color - a version of 'paint it out'.The idea for the arch came from a bridge we saw outside Osaka, Japan. It was a good idea but it just didn't work out. When I walk by the table I choose a route where I can't see the blocks.Frosty"I sometimes think we consider the good fortune of the early bird and overlook the bad fortune of the early worm." FDR - 1922
Frosty.. I 'think' I now understand the 'blocks'..
Probably not the bridge you are speaking of (I would assume the BIG Arched bridge).
At the Sumiyoshi-taisha Shrine I remember a bridge.. Curves AND Blocks. Japan is full of that style. 'Curves and Blocks' that is.. Thinking back to the bridge at the Shrine, in the link below, your blocks were most fitting. Anyway, I was not really being critical of your work. The blocks just caught my eye in the photo and.. Well, I thought, and that always gets me in trouble.
http://www.tripadvisor.com/LocationPhotos-g298566-d320984-Sumiyoshi_taisha_Shrine-Osaka_Osaka_Prefecture_Kinki.html#17498202
You mentioned you hid the Walnut.. I was thinking again.. You did not like.. BUT I would think if the 'squared off' blocks were conterasting wood in the photo, my eye would have liked it!
Ohhhh.. design problems for the masses....
That is a beautiful bridge but not the one that caught my eye. We were on an expressway (I don't know what they call them in Japan) when we drove over this beautiful arched shape. But - for a table, obviously the 'deck' has to go on top, not suspended from the arch. Ahh! Therein lies the rub! Balancing a flat piece on top an arch is a challenge. And considering the overhang,the issue of structural rigidity is a serious question. I'm not aesthetically satisfied with the solution but I'll live with it. I appreciate your comments.Frosty"I sometimes think we consider the good fortune of the early bird and overlook the bad fortune of the early worm." FDR - 1922
One important rule I think some other contributors are missing:
Always laminate odd number layers for stability.
3,5,7....
Dan,
I believe that the odd number of ply's or lamination refers mainly to alternating grain directions, i.e. plywood.
I worked in a millwork shop that did a lot of radius jambs and window casings, and as long as the grain was all going the same way, we were not concerned with the number of ply's being odd...nor did we have any problems.
More importantly is having all the ply's being the same thickness. An uneven thickness in the ply's will bring some unexpected movement as the piece transitions through the seasons; expanding in the humid summer months and contracting in the drier winter months.
In the end, regardless of the count of the ply's, you want the whole piece balanced, and it should remain as it was intended.
-Kevin-If you didn't learn something new today, you're not looking hard enough!
This bend is not out of the realm of steam bending with a single piece. Ash bends extremely well, and with a rise of 6" over 4-5', I would increase the rise to about 7-8" to account for spring back. Also, you want to add around 6" to each end. Unless you have some insanly large/powerful clamps, you're not going to get an effective bend at the ends.
There is a plethora of steam bending info both here and elsewhere on the net, and making your own steam box is easier than you think!
For some great info on steam bending, check out this site.
If you want more info, just yet me know...
.
Edited 8/27/2008 8:03 pm ET by grainwise
Dear ww57,
If you are not too concerned about the glue line, go ahead and glue up directly from the bandsaw. I run my laminations through a drum sander after resawing for a better looking lam.
I just purchased a new blade from Laguna Tools. It cost about 8 times that of a regular blade but gives a cut smooth enough to lam w/o sanding, and its' carbide teeth can be resharpened.
I use polyurethane glue on lams. It activates with water, so I spray the wood first with water, apply the glue and spread it with a rubber roller, then wrap it all with 6" cellophane packing "flat twine". This contains the nasty glue and retains the moisture, giving more working time. Another advantage is that it dries hard unlike yellow or white glue which can allow "creep".
Good Idea to enable email on your profile for direct messages.
AZChip
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