Laminating Frames - on the bench or on the ribbands

[Sayla]

It's something I've been pondering

- effort of bevel and material loss
- the extent of ribband strength/warping in regard to holding cold-bent laminations
- any steaming effort requiring redrying laminations for glue
- cleaning up frames insitu
- any size issues?
- reduction in output - ? less laminations at one time insitu

etc

opinions welcomed please

sayla

[Gib Etheridge]

It seems that on the ribbands would save having to make a mold for each set of frames?

People are going to want a lot more info., like pictures of the forms/ribbands, net frame scantlings, wood species...

[Peerie Maa]

When laminating on ribbands the bevels will be very difficult to achieve, especially where they are more acute than can be accommodated in one lamination. You might be able to get away with it if you offset the position of the frame by one siding width. Cramping with a bevel in the boats ends will still be difficult, as the lamination will only be touching on one edge.
All in all it will be easier to pick up the frame shape from the ribbands with a template or a chain, and then laminate on the bench to that shape.

[Sayla]

I thought that the bench was the go, but comments I have read have led me to rethink - my question was more generic than specific, but the frames I am looking at are 60mm square, celery top pine aft, new guinea rosewood midships and sawn frames in the bow - 13.78m x 4.22m hull

[JoshuaIII]

Wiz would be the perfect guy to answer about clamping on the ribband as he did it...
From the bench this is the same way as I did mine for cutting them + pattern... it IS labor intensive, but work well once in the routine & pattern of doing it.

[wizbang 13]

Peerie Maa, I think you have that backwards. Or maybe you are trying to laminate square to the molds?
Laminating in place, on the ribbands is self beveling.
Station molds set up on one side of the floor timber, accurately, (the EDGE of the mold needs to be in the correct spot.set the mold up behind the skinny part of the boat).
The laminated frames do not go square to the molds/stations. They run, forward frames run forward and after frames run aft.
It is very simple, There is no need for the frames to be squared up.
Laminating frames on a bench seems ridiculus to me. So much waste, materials and time.here is my old bomb, 34'er framed in 5 days. 2" by3" , 7 laminations of yellow cedar

[Peerie Maa]

Peerie Maa, I think you have that backwards. Or maybe you are trying to laminate square to the molds?
Laminating in place, on the ribbands is self beveling.
Station molds set up on one side of the floor timber, accurately, (the EDGE of the mold needs to be in the correct spot.set the mold up behind the skinny part of the boat).
The laminated frames do not go square to the molds/stations. They run, forward frames run forward and after frames run aft.
It is very simple, There is no need for the frames to be squared up.
Laminating frames on a bench seems ridiculus to me. So much waste, materials and time.here is my old bomb, 34'er framed in 5 days. 2" by3" , 7 laminations of yellow cedar

However, if your bevels change from keel to shear, and it will be very few boats where this does not happen, you will have to edge set your laminations, which will be nigh on impossible when they are lubricated with glue. Either that or use over wide laminations, and then clean up the sideing of the mess afterwards. Remember if you were steaming in timbers, you would have to twist them to accommodate varying bevels, can't do that with slippery laminations.

[Sayla]

Laminating in place, on the ribbands is self beveling.
Station molds set up on one side of the floor timber, accurately, (the EDGE of the mold needs to be in the correct spot.set the mold up behind the skinny part of the boat).
The laminated frames do not go square to the molds/stations. They run, forward frames run forward and after frames run aft.
It is very simple, There is no need for the frames to be squared up.
Laminating frames on a bench seems ridiculus to me. So much waste, materials and time.here is my old bomb, 34'er framed in 5 days. 2" by3" , 7 laminations of yellow cedar

When you say they run, do they essentially equate the positions that steam bent frames would, or is there a difference, and do you steam bend the laminations, or use really strong ribbands etc - I presume they always set tangential to the hull, and twist to achieve relatively equitable positioning.

[wizbang 13]

PM, I do not know what you mean by "edge setting". Yes, I grind the sides of the frames . I buzz them a foot or two at a time as the ribbands come off.
I have retro fitted frames in boats too, and the grinding has to be more precise, but with modern slow speed polishers with the correct backing pads , it is a lot easier than it was 25/30 years ago. The material removed from the frame side ,( not so messy for me, I am not messy with epoxy), is much less than post beveling would be. I use clamps sideways too. And on my own boat, I nailed the lams with small galv nails. Sometimes I put them on one at a time, sometimes 3 or 4 at a time.
And of course, this would only work with epoxy, non gap filling glues would fail.
Sayla, yes, exactly the way a steamed frame runs. The ribbands are only normal strength. I framed the whole boat , each frame with only 2 laminations the first day,. Not a lot of strain in 2 lams, and the first lams may have been only a quarter inch thick. On the second day, the "cage" was much stronger because now the boat had half inch thick frames in addition to station molds and ribbands.
No, no steam bending, no soaking, no water. If the lams cannot bend, mill them thinner.

[Jim Ledger]

Laying out the curve from a tick-stick pattern...




Running a batten around the curve...



Screwing down some angle iron brackets...



A glued-up stack of laminates ready to clamp on...



Clamped on...



Finished, and cleaned up...

[wizbang 13]

But it is not finished, unless it goes exactly in the middle of the boat.

[Jim Ledger]

But it is not finished, unless it goes exactly in the middle of the boat.

No, but I can put it where I want it, not where it wishes to go.

[Sayla]

No, but I can put it where I want it, not where it wishes to go.

Jim is that oak + resorcinol, and what sort of resorcinol is that?

------------------------------------------------------------

I also wondered if internal fitout is easier with tangential frames - maintaining consistent curvature, but more fitting for floors or bulkheads

sayla

[wizbang 13]

here's a better pic. Molds are still in place,( 2 layers of 3/8ths cdx) and the frames are started. Nothing special about the ribbands.

[Sailor]

Bruce, I saw your "build history" thread. I think you should keep at it. I have enjoyed it and will likely be using a few of your ideas in my build. Not sure yet though because you haven't finished your thread.

[wizbang 13]

Thanks Sailor, "woody "is only 28 years old, not 100% finished yet !
B

[Jim Ledger]

Jim is that oak + resorcinol, and what sort of resorcinol is that?

------------------------------------------------------------

I also wondered if internal fitout is easier with tangential frames - maintaining consistent curvature, but more fitting for floors or bulkheads

sayla

The wood is locust and the glue is Cascophen, available here...

http://www.aircraftspruce.com/catalo.../cascophen.php

The resoucinol glue gives a longer opening time than epoxy, which is needed when you are laminating a large number of thin pieces. It takes time to both spread the glue and work it into position on the mold. The glue is not so forgiving as epoxy. It needs a lot of clamping pressure, low moisture content in the wood and sixty-plus degree temperatures while curing.

I'll be dealing with the fitting of the frames in the catboat build shortly. I expect it to be a lot of work beveling the inside and outside faces, but it will become pretty routine long before the end.

[RFNK]

I'm going to laminate around 30 or so frames for the Twister I'm restoring (Restoration of a Twister in B & R). I'll leave the planking in place while I do it and I too have been wondering about the best method. I've made up this jig and, like Jim, I'll cut templates using sheets of mdf and a tick stick (joggle stick). I'll start in the middle of the boat so that I can keep reusing the mdf.





I'll use epoxy rather than resorcinol. I'll glue up the laminations then wrap it in plastic tightly before clamping it to the jig. Like Jim, I'll be using plenty of clamps in between the jig blocks. And, like Jim, I'll cut the bevel to fit. I like vertical frames!

Having said all that, I haven't tried it yet so, if there's anything wrong with this grand plan, I'm happy to hear about it!

Rick

[RFNK]

Just a note to add to Jim's comment re gluing up time. I've used West epoxy and an Australian product called Bote-Cote. I found the West difficult to use due to short working time. I think the Bote-Cote is formulated better for the warmer Australian climate - I've rarely run into strife with Bote-Cote going off in the middle of a job, and I've used it frequently in high 30s (C). I'd talk to the guys at Boatcraft Pacific about this if I were you Sayla.


Rick

[Quest]

I have had a similar experience with botecote, am using it now to laminate up curved shape for the tops of my frames. Lasts plenty of time for this amateur to get everything lined up and clamped.

[wizbang 13]

WEST has about 4 or 5 hardeners, doncha know.

[PeterSibley]

A long while ago Covery Island Boatworks had a series of process photos up on their website showing something very similar to Wiz's process .The over wide laminates were bundled up in plastic film then clamped or screwed to the ribbands. After the epoxy had gone off the plastic was removed and the lot was run through a thicknesser to clean them up.

[Sayla]

Just a note to add to Jim's comment re gluing up time. I've used West epoxy and an Australian product called Bote-Cote. I found the West difficult to use due to short working time. I think the Bote-Cote is formulated better for the warmer Australian climate - I've rarely run into strife with Bote-Cote going off in the middle of a job, and I've used it frequently in high 30s (C). I'd talk to the guys at Boatcraft Pacific about this if I were you Sayla.
Rick

Yeah, I generally get about a 1/2 hour with the West - hey, that jig looks like the one Larry Pardey wrote about - I was thinking of making one of those myself.

sayla

[PeterSibley]

Um... Wiz did it .

[chuckt]

I wonder if anyone has tried to make an adjustable bench dog that you could change the angle on so that your lamination came out approximating the curve of the hull. I'm trying to picture how that might work.

[Peerie Maa]

A long while ago Covery Island Boatworks had a series of process photos up on their website showing something very similar to Wiz's process .The over wide laminates were bundled up in plastic film then clamped or screwed to the ribbands. After the epoxy had gone off the plastic was removed and the lot was run through a thicknesser to clean them up.

That is pretty well what I was talking about. The lamina will not lie in a flat plane, nor will the edges of the inner ones line up with the outer lamina. So there will be a stepped and wavy surface on both sides that will need to be cleaned up. So that there is enough wood left for the dsigned scantling of the frame after clean up the individual laminates must be over wide.

Wiz, edge setting is bending across the width, rather than across the thickness. You sometimes do it when hanging plank so as to save on plank stock. In effect all strip planks are ege set, but as they are narrow it is easy to do.

[Sayla]

That is pretty well what I was talking about. The lamina will not lie in a flat plane, nor will the edges of the inner ones line up with the outer lamina. So there will be a stepped and wavy surface on both sides that will need to be cleaned up. So that there is enough wood left for the dsigned scantling of the frame after clean up the individual laminates must be over wide.

Wiz, edge setting is bending across the width, rather than across the thickness. You sometimes do it when hanging plank so as to save on plank stock. In effect all strip planks are ege set, but as they are narrow it is easy to do.

So, is removing the frame to plane a jaggered edge, as below, a bit of a balance between both worlds - not much loss of meat, lamination in-situ to shape without bevelling, squared to centreline frames, inner and outer edges already tangential -



Can it be done as per this drawing - do the curvature changes around the hull allow the for concentricity to be maintained and laminations kept aligned?

[wizbang 13]

Ah Ha, I never really thought about the "edge set" . I try to line them up, clamping sideways . gap filling 403 !!

[Sailor]

If you clamp to a jig, you'll have all the laminations square to the jig. I can't see how they would come out like your picture Sayla. What I do see is that you'd be laminating them square to the centerline then removing the outer face on an angle in order to ensure the frame is flush with the inner face of the planking. Beveling the outside and inside I guess. I think it would already be square to the CL of the boat. Or am I seeing this wrong somehow?

[Sailor]

Unless you're talking of clamping it in place to ribbands as you build...... Never mind, that must be what you meant.

[Sayla]

If you laminate as above, on the ribbands, you could then remove the frame and send it through a thicknesser - I presume that's what Covey Island boatworks did? Which seems like not a bad idea, but it looks like epoxy only, due to the less controlled nature of the clamping, and maybe a bit more fiddly to do (less laminations per glue up), but all in all I think I'm liking the idea - What say yee?

[Jim Ledger]

A stack of laminates clamped up to ribands and allowed to lie in a natural position will only be close to straight near midships where there is little bevel. The closer you get to the ends of the boat, the more curve, and sometimes recurve will occur, depending on the hull form.

There's nothing inherently wrong with this with regards to strength, but putting a compound curved frame through a thickness planer presents its own set of problems.

[boattruck]

Gents, We wrestle with this challenge a lot in our repair work, we have the planks, most of them, in place, assorted bilge stringers, I have had some luck with cutting up a few wedge shaped lams, inserted in the outboard side of the stack till it lays more or less fair. As others have mentioned, the ends of the boat are where this really shows up, near mid ships the thick glue etc nearly eliminates the problem.
If there were no planks or bilge stringers in your way, I think you could do nice frames as shown on the flat table, then rough on your bevels, inside and out.
I have fantasized ( sad, eh...it has come to this...) about trying the edge setting type jig, where you rough out your bevel on your fence posts, and with the strength of lots of clamps simply force/torture the lams into the intended shape. Advantage being it would be able to be built correct from the git go, rather than 'whittled' individually to fit. Frames built on the flat table are real nice and easy to run through the thickness planer to clean up for a good looking job.
Cheers, Steve/BT

[wizbang 13]

One could put waxed paper against the ribbands /floors, etc, and remove to clean them with a power plane and sander, and it WOULD make a cleaner job.
In my case, I followed with strip planking of course, so the frames would have , and did, get a bit messy again, in the gluing of the strips to the frames.
It is how I learned, and have done the same with 2 other vessels, from new. I never thought I was doing anything special. Doing more thinking on it now than then.
The importance of a good disc sanding technique is paramount!

[JoshuaIII]

Just throwing a idea out loud here....
If you clamp on the ribband, then take a long piece of wood as long as the width to rest on the pair of the frames(both side), on this you add a router on one end... Resting on both frames and working it up and down along the frame it should (In my head) make a perfect 90 degres bevel with the center... or really close to it without too much effort.

[Sailor]

That's a good idea.... What about when you're down low where both parts are really close together...... you'll have quite a long unwieldy batten to support. I guess you could always rest it against the matching frame on the upper ribband, stringer, sheerstrake etc. and just pivot around that radius from there. I like it. I wonder how well it would work. Anybody see any problems with that plan? As you shorten the radius of the batten you'll need to ensure you have room in the shop, shed etc for the extra length of batten on the outboard side of your ribband. Don't want to go poking holes in your bowshed.

[JoshuaIII]

It may be long to do a entire set of frames this way, but you can always just make a few pass every foot or so to give you a "guideline" and cut with a faster tool in between...

[Gib Etheridge]

Hope I'm not repeating something someone else already suggested, I only skimmed.

If you want the forward and after faces of the laminated frames to be perpendicular to the centerline and the frames to be in planes parallel to the forms you might try this. Fasten cross pieces on top of each set of ribbands to act as guides and to provide something to edge clamp each lamination to. Once the glue has cured remove the frame, belt sand the squeezeout and steps of of one face, hand plane that face to a flatter surface then run it through the thickness planer, both faces. It's going to spring back edgewise some, especially on the frames towards the ends of the hull, you may not be able to run them through the planer, but the belt (or disc) sander and hand plane will make short work of it. Then clamp the frame back into the boat, fasten to the ribbands, floors and keel with screws and/or bolts and move your cross pieces to the next frame. I guess you'll need to dry fit each one first in order to fit the heel to the keel.

[RFNK]

Anyway, it's academic for me as, with the planking already in place, there's nothing to clamp the laminations to so I think i have no choice other than the jig first, and then cutting the bevels. I'm pretty confident it'll work.

Rick

[Jay Greer]

Here is a little more info on the subject. Two of the shops I worked in had tilting bandsaws made by Tanenhauser. These were driven by rack and pinion and required two or more men to make a running bevel cut. Lacking one of these monsters most of us resort to having a lever bar attached to the band saw table and a pointer rigged to a large degree scale. For a laminated frame it is a simple matter to mark the bevel degrees along a piece of frame stock which will become the first laminate. This allows the sawyer to call out the degrees as his helper watches the pointer and levers the table as the cut is made. Once the full running bevel has been cut, it can be planed to remove any unfair bumps and then returned to the resaw where, with no bevel, it is sawn out as the first laminate. All other laminates should then require no coaxing or difficult twisting. Once glued, the sides can then surfaced clean. This approach will work on the bench or against the ribbands as the frames will fay against the ribbands or bending dogs, wedges may be needed here, with a fair running bevel. Now that West System has given us G/flex the job should be a snap for you.
Jay

[PeterSibley]

There are other ways of acquiring a tilting bandsaw .

[Sayla]

Here is a little more info on the subject. Two of the shops I worked in had tilting bandsaws made by Tanenhauser. These were driven by rack and pinion and required two or more men to make a running bevel cut. Lacking one of these monsters most of us resort to having a lever bar attached to the band saw table and a pointer rigged to a large degree scale. For a laminated frame it is a simple matter to mark the bevel degrees along a piece of frame stock which will become the first laminate. This allows the sawyer to call out the degrees as his helper watches the pointer and levers the table as the cut is made. Once the full running bevel has been cut, it can be planed to remove any unfair bumps and then returned to the resaw where, with no bevel, it is sawn out as the first laminate. All other laminates should then require no coaxing or difficult twisting. Once glued, the sides can then surfaced clean. This approach will work on the bench or against the ribbands as the frames will fay against the ribbands or bending dogs, wedges may be needed here, with a fair running bevel. Now that West System has given us G/flex the job should be a snap for you.
Jay

Now that's food for thought.
If the lamination is ripped carefully to bevel, prior to assembly, the only waste should be the thickness of the sawcut and cleaning - the offcut could even be used for the internal face - it will take some figuring (though my own job is computer digitised), but should work


As you stated, on the bench or on the ribbands, the job is done, and squared to the centreline (hopefully)

sayla

[JoshuaIII]

How I cut mine. The futtock are roughly cut at first, then riveted and this is the bevel being cut.

[JoshuaIII]

Close up show the angle marked on the side, the person tilting the sawn adjust accordling to that.

[Jay Greer]

[QUOTE=PeterSibley;3379141]There are other ways of acquiring a tilting bandsaw .

[
I am really impressed. Wow, a plywood framed Tannenhauser!
Bravo!
Jay

[Jay Greer]

Now that's food for thought.
If the lamination is ripped carefully to bevel, prior to assembly, the only waste should be the thickness of the sawcut and cleaning - the offcut could even be used for the internal face - it will take some figuring (though my own job is computer digitised), but should work


As you stated, on the bench or on the ribbands, the job is done, and squared to the centreline (hopefully)

sayla

Actually, there is no real need to bevel the inboard laminate.
Jay

[boattruck]

Gents, Sayla's sketch with bevel in and out is much like what we end up doing if we have to meet up with bilge stringers etc.( also have resorted to localized wedge shaped 'packers' at the stringers....) if there are none, then the net angle of the inboard surface is less important, except perhaps ascetically. As ours are repair work, they are done 'in situ', often using selective though bolt fastenings as the 'clamps'. Read with interest your 'running bevel lam' description Jay, as the single bevel first lamination is at best a crude approximation... will experiment with this approach next time...Cheers, Steve/BT

[Jay Greer]

It is not a crude aproximation in my shop.
Jay

[Sayla]

Gents, Sayla's sketch with bevel in and out is much like what we end up doing if we have to meet up with bilge stringers etc.( also have resorted to localized wedge shaped 'packers' at the stringers....) if there are none, then the net angle of the inboard surface is less important, except perhaps ascetically. As ours are repair work, they are done 'in situ', often using selective though bolt fastenings as the 'clamps'. Read with interest your 'running bevel lam' description Jay, as the single bevel first lamination is at best a crude approximation... will experiment with this approach next time...Cheers, Steve/BT

Milling the whole inside face seems like an effort for bilge stringers, aesthetics and, perhaps, easier cabinetry - but utilising an off-cut doesn't seems like a big effort, even if some cleaning up is involved (bit of a beltsand etc).

"It is not a crude aproximation in my shop."

sounds very do-able

sayla

[PeterSibley]

[QUOTE=Jay Greer;3379811]

There are other ways of acquiring a tilting bandsaw .

[
I am really impressed. Wow, a plywood framed Tannenhauser!
Bravo!
Jay

Thanks Jay. I went little over board with that one and built the bandsaw as well . I should have been smart enough to just build the pivoting base and install a cheap 14" bandsaw. It would have worked just as well .

I recommend this idea to people, it is really very simple and the flat table makes the cutting of changing bevels quite easy . The angle is adjusted with battery drill driving a threaded bar(unithread?)through a pivoting nut.The protractor overhead gives an easy visual.