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Schooner Altair by KeithAug - Scale 1:32 - 1931 - Finished

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ALTAIR is an auxiliary gaff rigged schooner built by William Fife & Sons at Fairlie as yard number 789. She was launched in May 1931.




The 1.32 scale model plans were created by Sandy Cousins and produce a model 1200mm LOA and 200mm Beam. The plans are on 6 sheets and include building notes by the author. 


The plans can be used to create a sailing model. To achieve this requires the addition of a significant extension to the keel in the form of a metal plate some 100mm deep with a swing keel pivoting below this. As I am building a static display model I don’t need to worry about this.


So to begin………..


I chose this build as as I had really enjoyed building the Amati Endeavour 1:35 kit but wanted to return to scratch building for my next project. My daughter bought me the plans and they were delivered by Santa a couple of weeks ago.


As designed the plans suggest that the main frames are made from 1/8 inch ply stiffened by several 1/8 inch ply “decks” forming a box structure. This felt overly complex and I resolved to make the frames out of ¼ inch ply as I had done on previous models with a ¼ inch ply keel running the length of the model. The plans also suggest that he hull is constructed attached to a building board. The allowance for the upstand from the board seemed excessive and potentially wasteful so I reduced it by about 1 inch at the bow and about 1.75 inch at the stern. I will step the building board to allow all frames to sit correctly relative to one another.


I considered a number of options for marking out the frames. As per normal practice only half frames were drawn. The building notes suggest transferring the outlines to the ply using carbon paper. I didn’t fancy this and decided to cut out the frame outlines from the plan and then mount the half frames on card to create templates. The templates were then used to transfer the outlines onto folded paper.  Once cut out and unfolded I had the frame cutting profiles and these were attached to the ¼ inch ply with Pritt Stick glue. I tried a few arrangements to get the minimum waste. Before cutting out the frames using a jig saw with a fine cut blade. I don’t have a scroll saw and cant justify one for the limited use I would make of it. After a number of hours of careful cutting I finished up with a reasonable set of frames.post-17220-0-78523000-1452459195_thumb.jpost-17220-0-25202900-1452459225_thumb.jpost-17220-0-24002400-1452459254_thumb.jpost-17220-0-20100000-1452459286_thumb.jpost-17220-0-80874800-1452459313_thumb.jpost-17220-0-63430500-1452459370_thumb.j


I have left the frame keel slot and the building board locating slot uncut while I decide how to saw these accurately as this will be key to a successful build.


Well thats enough for now - back to more sawing tomorrow.












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Keel and building board location slots.


The important thing here is that the keel and building board slots are accurately cut to width and that they are in perfect alignment with one another. I did consider cutting them freehand but decided to try and find a way of slotting them out accurately on the mill. The slots needed to be ¼ inch wide to match the ply that I intended using for the keel.


I started by making a jig for drilling - see photo. With this I drilled holes at the inner end of the location slot in all the frames. By drilling trough the frames and the jig I created a position for a location peg (1/4 inch diameter) which meant I could accurately reposition the frames to drill the ¼ inch holes at the end and at interim positions in the keel slot.post-17220-0-94422900-1452535239_thumb.jpost-17220-0-15557800-1452535280_thumb.jpost-17220-0-21745700-1452535303_thumb.j


I should explain that I am drilling using a mill with an x/y table. I am keeping the y setting locked and only varying the x setting to accommodate the different positions of the keel slot. I am therefor ensuring that all the drilled holes are in alignment and at right angles to the building board edge of the frame.


To cut the slots accurately I decided to use a slitting saw mounted in the mill. My first operation was to mount a piece of wood vertically in the mill vice. I then locked the mill spindle and machined off the upper edge of the wood using the slitting saw, thus ensuring that the saw cut relative to the wood was the same for all subsequent cuts. See Photo.post-17220-0-84916700-1452535468_thumb.j


Using the ¼ inch holes in the frames with a pair of location pegs I then clamped the frames to the wood with the pegs tight against previously cut surface. Once clamped the pegs were removed. With the slitting saw (still locked in its preset vertical position) I then cut one side of the keel and location slots (obviously two cuts from opposite ends). See Photo. I then unclamped the frame reinserted the dowel pegs flipped it over re-clamped and repeated the cuts as before. Result! – accurate ¼ inch keel and location slots perfectly aligned.post-17220-0-24903200-1452535492_thumb.jpost-17220-0-42731700-1452535519_thumb.jpost-17220-0-06933600-1452535715_thumb.jpost-17220-0-44520400-1452535732_thumb.j









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A dilemma for the future?


Bulwarks extend above deck on all sides. So the dilemma is do I do the deck and deck planking before the hull planking. The advantage of this sequence is that I get unrestricted access for fitting the sub deck and sanding the deck planks. The building notes suggest hull planking first!!! All this is made a bit more complicated by the sculpturing of the upper section of the hull. See Photo. 


Hello Michael - my jigsaw work is flattered by my camera, its ok but not as good as I would like. I really need to bite the bullet and buy a scroll saw. However I have so many saws and I'm worried that my wife will think I am developing a saw fetish.


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Frames finished (23 in all)


Having cut out the frames I stacked them and did an eyeball check on how well they nested. All seemed to be sensible with the exception of frame 8 which was noticeably too narrow by about 3/16 of an inch. I assumed that I  had marked it out incorrectly so rechecked it against the plans. It turned out that I had marked it out correctly and the frame drawn on the plan was incorrect. The frames on the plan are all individually drawn rather than the normal convention of overlaying all hull lines on a single image. The latter approach would of course have revealed the error during the draughting of the plans. I corrected the problem by widening frame 8 with strips of wood on either edge and then sanded by eye using frames 7 and 9 as guides. See Photo.post-17220-0-55358700-1452709705_thumb.j


I used the jigsaw to cut through about 80% of each frame at deck level to ease removal of the building board up-stand later in the build.


I then stacked all frames to satisfy myself that the transitions between frames seemed logical. 







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Keel and building board


A bit more progress fitted in around various DIY jobs. I transferred the keel shape to card that I the stuck to the ¼ inch ply before more jigsaw work. See Photos.post-17220-0-83908400-1453142653_thumb.jpost-17220-0-28967500-1453142685_thumb.jpost-17220-0-52691300-1453142703_thumb.j


I made the building board from ¾ inch thick 6 inch wide MDF. For about 2/3 of the length of the hull the building board is double thickness with the stand off for the frames reduced in height to compensate (reducing plywood wastage). Using my router table I machined slots along the length of the MDF to facilitate:-


1.   accurate alignment of the 2 boards

2.   location of the frames along the center line

3.   location of the board on the milling machine to cut slots for the frames at right angles to the center line.


The frame spacing was accurately measured from the plan and I used the digital read out on the mill to accurately set the positions for the frame sots. None of the frames were equally spaced which was a bit of a bind.

The photos should illustrate the process.


Finally I did a test assembly of the frames to give myself a feeling of progress.post-17220-0-54697900-1453143180_thumb.jpost-17220-0-12157400-1453143209_thumb.jpost-17220-0-78158600-1453143234_thumb.j

Everything fitting together well and all right angles accurately made .......... feeling very content!











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Frame Adjustment & Fairing


Having done the test assembly I did the usual plank check by laying a .040” by .200” plank along the length of the hull and looking for high and low spots. The significantly oversized frames were marked with a green felt tip and the significantly undersized frames were marked in pink. By significant I mean a deviation of between .040 and .080 inches. See Photos.post-17220-0-82044400-1453400021_thumb.jpost-17220-0-82044400-1453400021_thumb.j


The oversized frames were easily adjusted using disc sander while the undersized frames had to be built up by bending and gluing .040 strips of wood around the frame edges.


Having got the frames about right I then glued up the skeleton of the yacht. Only 4 of the frames were glued to the building board to ease removal at a later date. Because all frames were positively located in building board the gluing of 4 frames proved sufficient to create a very rigid assembly.


After gluing I used a felt tip pen to colour the edges of all the frames. I do this as I find it gives a very good guide when sanding to fair the frames. By watching where the felt pen is removed during sanding I am able to duplicated the fairing on both sides of the hull and ensure that that the blending of the hull lines is uniform.  I take my time while sanding and frequently check the form of the hull using the previously mentioned flexible plank. See photos.post-17220-0-83356700-1453400074_thumb.jpost-17220-0-68808600-1453400103_thumb.j





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Michael / John 


The lines are looking good - nice rounded form, not a sleek racer but nice never the less. I need to think about what's next. I filled between the frames with balsa on my last model and then double planked and it worked so well I think I might repeat it again although I may just single plank. Decisions decisions!!



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Balsa Infill Prior to Planking


I find infilling between frames with balsa eases the planking operation. Also I quite enjoy the process as it’s a bit of a challenge creating the 3 dimensional shapes necessary to nest between frames while conforming to the profile of adjacent infill pieces. All the balsa is ½ inch plank 3 inches wide by 18 inches long. I needed 12 planks to complete the hull – cost me £12 on ebay.

I use a disc sander for shaping – mine has been modified to take the miter gauge from my Byrnes saw. A simple and cheap way of getting an acceptably accurate disc sander.


Having completed the rough fairing of the frames I re-marked the edges of the frames with the felt tip pen. This would give me the guide for final sanding once the balsa infill was complete.


I find filling alternate frame gaps with balsa has the benefit of allowing me to progress while the previously completed and glued balsa infill dries (I use a PVA wood glue). Also at this stage I roughly shape the infill using a rasp leaving about 1/16 inch of balsa proud of the adjacent frames – for final finishing with sandpaper.


I then infill the remaining frame gaps before finishing the rough shaping with the rasp.







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Much sanding - but now complete. It took about half a day per side using 60 grit emery cloth attached to my home made sanding block - in one of the pictures. The reshaping of some of the frames (mentioned earlier) proved to be necessary. Marking the edges of the frames was very helpful as a sanding guide and the sanded hull passed the "hand undulation check". The frames in the area of the hull at the top of the rudder proved to be incorrectly shaped and i will sort this out prior to 1st planking. I have attached a photo of the real thing to show what I need to reproduce.post-17220-0-29123000-1454444352_thumb.jpost-17220-0-89075100-1454444332_thumb.jpost-17220-0-21406500-1454444248_thumb.jpost-17220-0-80309600-1454444227_thumb.jpost-17220-0-55299900-1454444202_thumb.jpost-17220-0-04601100-1454444172_thumb.j







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I thought it would be interesting to compare the hull with what Endeavour looked like at this stage. I have done a better job with balsa backing Altair. Endeavours frames however show the greater uniformity of shape. Laser cutting of frames on a mass produced kit clearly has advantages over not so well drawn jigsaw cut frames.post-17220-0-62321200-1454444898_thumb.j


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Experiments with Planks.


For a while I have been thinking about planking the hull. In particular I have been considering how to go about creating the sculptured lines on the bulwarks. See Photopost-17220-0-83115100-1454606655_thumb.j

I think I am going to overlay 3 layers of 1/32 (.031) inch ply to create the effect and this means the planking thickness will need to total 3/32 (.094) inch (to avoid a step where the ply meets the planks).


The outer mahogany planking on Endeavour was .020 inch thick by .160 inch wide  - basically a veneer. It had the advantage of shaping easily but I was very nervous that I would rub through when finish sanding. In the event I din't rub through but I can't help thinking I was lucky. For Altair I thought I needed to go thicker.


Mulling things over I decided to 1st plank with bass or obechi planks .060 inch thick and .200 inch wide and 2nd plank in mahogany .031 inch thick and .200 inch wide. 


The challenge of accurately cutting the mahogany second planks (which I haven't done before) prompted a bit of experimentation. The mahogany I am using is about 100 years old, beautiful stuff but a bit brittle. I ripped the 1 inch thick plank down to .200 inch thick using the carbide blade supplied with my Byrnes saw. I then switched to a 1/32 (.031) slitting saw blade to cut the .031 inch thick planks. The set up of my saw (which is a bit unusual) is covered in the attached series of photos.post-17220-0-19542900-1454609828_thumb.jpost-17220-0-33979900-1454609855_thumb.jpost-17220-0-89518600-1454609876_thumb.j


The experiment was a success. I cut 3 test planks and all were .031 +/- .001 inch. I am now feeling confident about going into mass production.post-17220-0-04858000-1454609921_thumb.jpost-17220-0-65394600-1454609941_thumb.jpost-17220-0-02775600-1454609979_thumb.j








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The deck (and hence the hull top line) has a significant bow from stem to stern. I therefore decided not to try and follow the deck to hull intersection with the 1st plank. Also the first plank was being laid at a small distance from the hull / deck intersection to take the later installation of the bulwark.


The line of the 1st plank was marked using a flexible straight edge which I made from .060 inch plastic.post-17220-0-61026000-1455048916_thumb.jpg



Having marked the line I placed a number of pins along it to act as stops against which to accurately locate the 1st plank. The first plank was then installed using PVA wood glue and held in place by notice board pins while drying.



At .060 inch thick the first plank wasn't as flexible as I would have liked and so I decided to thin down succeeding planks progressively thinning each plank by .002 inch (reducing the planking thickness .050 inch by the 6th plank). Another departure from a previous post is that I found that I only had .250 inch x 3 inch x 48 inch obechi. I ordered up some .200 inch but decided to progress the planking using what I had. I will revert to the narrower planks where the hull curvature becomes more pronounced.



The first 5 rows of planking have gone on well and I haven't felt the need to do any tapering thus far.post-17220-0-40280700-1455049786_thumb.jpg


The natural flow of the 1st plank left the stern in need of additional planks and before proceeding with the stern I marked a straight edge for the uppermost (nearest the deck) plank. I checked that the line for the upper plank was identical on both sided of the hull using my improvised height gauge (on the right of the picture)



I then installed the top plank on each side.



I then infilled the remainder of the stern using tapered planks.post-17220-0-10277900-1455050491_thumb.jpgpost-17220-0-91353800-1455050522_thumb.jpg

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