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Author Topic: 3 Lifeboat builds, What goes into a model kit.  (Read 322713 times)

nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #75 on: December 22, 2011, 12:52:28 pm »

So, what's the first stage.
Take the plans, and from them trace a centre backbone following the sheer of the boat and the inside shape of the bow and stern piece onto some stiff paper and cut out.
Tape some cereal boxsides together the length of the sheet of paper and cut the same shape out..........then try to fit into the hull..hopefully it will, probably it won't, lol
however, make sure that the sheer line of the boat does exactly follow the sheer line of the card cut out by placeing a 600 mm steel rule or similar straight edge across the boat hull, whilst the hull is supported squarely on the bench.
If it fits correctly and looks level, you can transfer this template onto a sheet of 6mm birch faced ply, making sure that the outer grain of the wood is longitudinal to the backbone, and not cross grained( as that would weaken the structure.
Cut out the longitudinal beam and then fit to the boat.
Note at this point there will be ABSOLUTELY NO notches slots or any other recess cut into it (as shown on the photo..this beam was cut some time ago before I ever thought of doing a build log).

and the picture below these two of the main back bone shows the approximate position of the cabins to the hull.


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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #76 on: December 22, 2011, 03:44:28 pm »

Once the main back bone fits in snugly the next job is to make the bow and stern gussets that will fasten  onto the top of the backbone. The bow one is made from 6mm ply as a good strengthener piece and the stern one although bigger is from 3mm ply and  both will then hold the back bone straight and in the correct possition. At this point the first cuts into the backbone will be made to remove the section that is now taken by the thickness of each gusset. as these gussets need to fit flush with the original line of the beam and flush with the deck, the cuts will be 6mm and 3mm respectively, and can be seen on the back bone beam.

Also whilst at this point the flat plate for the Servo for the external rudder bar on the Mary Stanford will be made ( using a card template to get the shape and then transfered to 3mm ply. it can then be fitted to the back bone by ise of a slotted joint. AT NO STAGE IS ANYTHING CLUED IN PLACE at this moment.
see photos for the various additions.

the strange cut out in the stern gusset is for the rudder stering block on the Mary Stanford only, which will allow the servo arm to pass through and operate the rudder linkage arm.
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Rottweiler

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #77 on: December 22, 2011, 05:47:13 pm »

     I thought the man in the white coat was waiting to take Neil away,and the rubber gloves were to stop contamination from any dangerous  substances in the shed?

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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #78 on: December 22, 2011, 07:54:37 pm »

Next, is to make the cross beams that attach to the main back bone.

These are supporting the deck at vital positions and have to be measured acurately in order to co incide with the positions of the cabins.
You'll see from the beams that they have a camber on them to begin with and when the notches are cut out to take the cabin supports later they (the notches)  are cut parallel to the camber so that when it is all assembled finally the deck will still retain the camber from the centre to the side gunwails.

They are not cut tightly to fit the beam of the boat as they need to be taken in and out of the boat several times to line things up, cut joints and generally make sure things fit, but all have to be centred up together to make sure that the next set of cuts are parallel to the centre line of the boat.

These cuts are to take the next two sets of longitudinal beams that give side support to the cabins and the deck.

The longitudinal beams are exact copies of the main back bone, except for the gusseted areas at bow and stern and are cut to length once the cross cuts for the  cross beams are marked up exactly to give a perfect square ladder frame that will eventually support the cabin base and the decks.

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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #79 on: December 22, 2011, 08:04:15 pm »

The final cross beams are then made to support the rear larger well deck of the rear cabin, before a piece of 3mm ply is cut roughly as a base for the cabin.

this will eventually sit into all the beams and so they ( the beams ) will have to be recessed down by 3mm to allow the base to fit in and fit flush to the original deck level of the beams.
ONLY when all this cutting, recessing and jointing is done, and all  the structure has been dry fitted with spring clamps both inside and out of the boat will it be ready for fitting, but ven then it is not glued and fitted into the boat.

Other parts have to be designed first befor some construction takes place.
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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #80 on: December 22, 2011, 08:30:22 pm »

The final part of this long process is ( once they are all cut and shaped to the shape needed ) to alphabetically mark these pieces in order of their constructional priority and then they are all taken apart again and drawn around on draughting sheet, firstly in pencil and then drawing ink. They are drawn on this draughting sheet in their own seperate thicknesses, so that once all pieces of the same thickness can be then made into a screen print to be printed into parts for the "box".

All the parts for construction. be they hatch covers, seats inside the cabin, navigation light boxes.........will all be given this treatment and all, once made into the relative knock down parts, be transcribed onto sheets pf paper in order to make a screen print off, and all with their own seperate sheets for material and thickness.....it's all fun.
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furball

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #81 on: December 22, 2011, 10:24:12 pm »

Neil,

Out of curiosity, why did you pick Field Marshall & Mrs Smuts, rather than Henry Blogg?

Then you'd have two Cromer boats.


Lance
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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #82 on: December 22, 2011, 10:46:40 pm »

I think that was exactly the reason, Lance...............rather than build two Cromer boats, I thought I'd share the station names around..........and also I like the name. FM and Mrs S...got a certain ring to it, lol
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furball

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #83 on: December 22, 2011, 11:18:58 pm »

Ah...

And there was I thinking all you need is a 45 footer single screw and you'd have the full set!   :}

Lance
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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #84 on: December 22, 2011, 11:27:59 pm »

yer forgettin' the single screw Liverpool Harriet Dixon,  {:-{ {:-{
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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #85 on: December 23, 2011, 03:51:37 pm »

The frames for both H F Bailey and Field Marshal and Mrs Smuts have now also been constructed and all items transfered to draughting paper ready for screen printing. the models can be seen below with both framework in place and the cabins and their bases in place, but not glued.

there are slight subtle diferences between the two.
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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #86 on: December 23, 2011, 03:52:33 pm »

It's now time to put the frames aside and start working on the running gear which is supplied with the kit.
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RaaArtyGunner

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #87 on: December 23, 2011, 09:17:28 pm »

Yes, see that they are similar but not the same.

Very very informative  O0 O0 O0
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furball

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #88 on: December 23, 2011, 09:36:40 pm »

yer forgettin' the single screw Liverpool Harriet Dixon,  {:-{ {:-{

Yeah, yeah... I forgot about the No. 2 boats...They also had a single engined Norfolk & Suffolk as well.

Are you using the same hull moulding for both the 46s?

Lance
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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #89 on: December 23, 2011, 10:18:37 pm »

Yes Lance, as they had the same dims and were more or less the same boat, all taken from the same builders plans. It was only the two from Gorleston and Lowestoft boats, the Michael stevens and the Louise Stevens that had shallower drafts that would be a little off scale.

This is going to be my last set of postings until after Christmas as I've been banned from going in the workshop tomorrow, Christmas day and Boxing day, so won't be able to find my moulds, masters or fittings that I have done over the past 4 - 5 years until 27th December.

All the work that I have shown you so far has been done in stages over the past few years, because other work has come along that I have had to do for others, including a lot of charity work. As you can see it's not all plain sailing and hands on 8 hours a day, and it is the same with most of those who are one man bands.

Developement of new models takes second place to moulding, casting packaging of fittings , timbers, plastics..taking moulds to the moulders for new mouldings for customers, and a hundred and one other jobs that come first before the new development of forthcoming models, and as such with constant interuptions, the flow of work suffers, and a certain percentage of the time spent in the workshop on a new developement is in the thinking stage of what you were going to do next on your new model.............and then just as you are going to get on with the next part, the next piece of turning to produce that new fitting......someone will ring up with good news.....they want a new kit off you........or someine will ring up telling you your kit is a load of C*** because they haven't followed the instructions and the part won't fit correctly because they have cut it wrongly.............so you have to sort that one out as well, and the thread is again lost.........

It is no bed of roses, and not fun half the time, but the rewards of seeing people who have made a lovely job of one of your kits, sometimes just makes up for it, and that is probably why manufacturers keep on doing it......all they ask for is a little understanding and good will, without the jibes that they get.

So picking up the thread that I left before. I have now put the deck support frames to one side to now concentrate on the running gear.

Most classes of the old double ender motor lifeboats had different rudder set ups to each other class and so most models that are being developed have to have a different set of "fittings" to make them work, and my three models are no exception.

The Mary Stanford has a rudder attatched to an external rudder bar on the stern post, and the two Watson's although similar have different skegs to protect them and are set into the "deadwood" of the rear keel, and as such these skegs have to be built up from a sturdy material once the hulls have been moulded.

Leaveing the mary Stanford till last, I'll deal with the two Watson's first.

First job is to take a template in card of the recess that has been taken out of the rear of the hull ( and as both hulls are exactly the same) the one template will do.

You can see the area vaguely that has been cut out in the first photo.

Once the template has been drawn out on card, but not cut,  and the piece doubled up to two templates it can be placed against the plans of the two boats, and the rudder skegs can be drawn onto the card so that it will sit in place into the apperture made when moulding the hull and then transposed onto a singe piece (each) of 6mm birch faced ply.

Also whilst drawing these skegs  out, the shapes of the two rudders ( as, on the two different boats, they are  both different ) can be traced onto paper and then transposed onto two different thicknesses of ply wood. The rudders are made of three layers of wood for the kit maker which will give then a rudder that once made will not twist on it's own rudder bar once it gets older or knocked from time to time, in a way shown.

The centre core is made from 3mm ply, the same thickness as the diameter of the rudder bar, withan outer skin on both sides of 1.8 mm ply. The rudder bar is set into a channel cut into the centre core with a right angled bend so that it cannot possibly twist once all glued together.

The other pictures show the different rudder skegs and rudders, cut out in ply and not yet glued together with water resistant aliphatic resin. The skeg with the two outer skins is from the Field Marshal and Mrs Smuts, and requered this to give the effect of a trailing edge for the skeg to which securing lines could be passed through hols in the skeg when hauling back up the slip......these are not the "Ruffle" holes, which will be put into the skegs later, but just securing areas for rope ties

All of these pieces are then transfered onto the relevent draughting sheets associated with each particular boat and particular sheet of the same timber thickness to be used for screen printing, after they are dry fit to see that they actually do fit.

Finally the rudder for the mary Stanford can be made.

This is actually a straight forward transfer of a tracing of the rudder from the plans to 4mm birch faced ply, but the fitting is totally different with no less that ten white metal and resin fittings (some of these can be seen in the last photo) being used to make the assembly work......and these fittings all have to be made from masters first, and then set into moulds, and cast before you end up with a product that will make the whole assembly operational, but that's another story.

And that is where I stop until after Christmas........that process will be discussed once I can find my moulds for the stuff shown here and made some time ago.
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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #90 on: December 28, 2011, 10:54:52 pm »

The whole process from start to final dry fitting of those frame works can take anything from 3 to 15 hours depending on how complicated the construction is, and also not forgetting that some of the beams and timbers may be cut wrongly or not fitting when put together and so new pieces have to be made.

It's not a case of at this or any stage that "Oh I'll correct it at the build stage"..by then it is too late as the pieces which have been screen printed will be ready for production run, and will be wrong.

So now it's onto the process of making the parts that go to build the kit....the white metal and resin fittings, and without them there wouldn't be a kit.

and just a note before a salutary thought to put to you.........each one of the ten + white metal and resin fittings that can be seen in the last posting picture above, took on average 1 - 2 hours to make, as the master for a mould..........and all were made in plasticard, not brass. If I had made them in brass, it would have probably taken twice the time to make each fitting.

But why do I make them in plasticard, myself............. reasons.....1) as stated it probably takes half the time, and 2) I can use plasticard masters with the technique of mouldning that I use...........but here's the real reason for all those who curse the cost of a kit.

The "big boys" in kit manufacturing use a different technique for making their moulds for centifugal casting.....on an industrial scale.

Whereas I can use RTV ( room temperature vulcanising) rubber for my moulds which will give me limited numbers of castings before they wear out, and because they are room temperature vulcanising ( setting and hardening) and as such I can put plastics that are succeptable to heat and high temperatures anfd therefore would melt and distort if put through a high heat process, the kit manufacturers such as Metcalt Mouldings and Model Slipway use a much harder and firmer rubber to make their moulds for industrial usage, and multi castings with hot (250 - 300 degree) liquid white metal.

This needs a rubber that will withstand such temperatures time and time again. And the only way is for them to use vulcanised rubber to make their moulds.

Where as I can place my masters into plastecine and mould one half at a time ( see my pics), those using vulcanised circular rubber blanks have to make their moulds in one shot.

And to do this they need a special machine.....a vulcanising machine at my last research was anything from £1500 for a well used second hand one to about £4 k for a new one.
This works on heat transferance through the hard solid rubber which is placed under a press with two parts, top and bottom, and the masters are placed inbetween these two blanks, along with a number of locating studs.
The machine is thermocontrolled to a temperature set, and once the temp inside the rubber is achieved, the press is wound down, thus imprinting the master into the two halves of the rubber, and then it's all left to cool. That is now why all the masters for such a process have to be made in brass and therefore much longer to make the masters.
I haven't counted the masters on any of the three boats I am building, but quite a few are generic with the other two boats that I have done and so will not need to be re made for a new boat.

However, the single master count ( not the actual number of white metal fittings in the kit) for the Anne Lettitia Russell is 182 seperate masters that had to be made. If each took an average of 1.5 hours ( and that is a very conservative cost of time) that is still 273 hours of solid time spent on developing the masters alone.

Then you have to "cut the rubbers"....make groves into them for the molten metal to run to the imprints of the masters before you can start casting.
Finally you have to work out how many of a certain fitting is needed for that boat/model and run a series of casts with the master mould to build up a set for a production mould. Say a set of stanchion is needed, at say 24 stanchions per boat..then you have to run that master mould at least 24 times to get out that number of single stanchions for a mould and then, after cleaning them all up, put them into a new set of moulding blanks, set the vulcvaniser to heat, and mould a set of moulds with 24 stanchions in them, not forgetting that you have to cut the moulds after cooling, yet again in order to take the white metal.

Oh but I forget..........where do you do the casting................well a centrifugal caster  of course, but not a little piddly thing like mine.......No, one that has counter ballance weights and the full jobbie........an indistial scale machine  and the last time I enquired about one of those, it was going to cost me, either second hand for yet again a well worn one, to the latest in machines that could take upto 12 inch moulds............errrhhh, between £3000 - £6500....and I'm now talkiing 20 years ago.

And that, my friends is just the start of it all for the "Big boys"..........so in just two moulding machines, not counting the cost of the rubber blanks which although initial outlay!!!

next time I'll take a look at making a few masters myself.

But just to start off with, the picture below shows a finished mould with a set of fittings which make up into the hand windless on the RNLB Mary Stanford...the masters for this took 42 hours to make from start to finish. All time, and it's amazing where tiome goes whin you don't have to think about it.
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Norseman

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #91 on: December 28, 2011, 11:41:24 pm »

Although I do now feel a bit guilty for moaning about the cost of a kit
I was just wondering Neil ..............



Could I have a piece of that nice chocolate cake please  :D

Dave
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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #92 on: December 29, 2011, 08:36:02 am »

Could I have a piece of that nice chocolate cake please  :D
Dave

Are you in delerium with pain Dave............I can't for the life of me see any chocolate cake.......but if I've missed it, it'll be my younger daughter, the one with the model building skills , that made it..........unlike me, she's definately multi tallented,  O0 O0 O0
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Netleyned

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #93 on: December 29, 2011, 08:38:56 am »

The icing style is definitely different  %% %%

Ned
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RaaArtyGunner

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #94 on: December 29, 2011, 09:50:51 pm »

The icing style is definitely different  %% %%

Ned

Flashy to say the least  %) %) %)
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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #95 on: December 29, 2011, 10:57:30 pm »

c'mon guys..gizza clooo.where's this b***** cake %% %% %% %%
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Rottweiler

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #96 on: December 29, 2011, 11:04:41 pm »

I can see the star in the centre of the cake and the two stable doors,but not sure what the other round items are?
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andyn

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #97 on: December 29, 2011, 11:06:02 pm »

Our centrifuge moulds look more like ladyparts than cake {-)
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nhp651

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #98 on: December 29, 2011, 11:17:20 pm »

you lot'll be telling me next that these are ballast.......... rotten sods!
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Rottweiler

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Re: 3 Lifeboat builds, What goes into a model kit.
« Reply #99 on: December 29, 2011, 11:24:29 pm »

 No Neil, I think those are something to do with global warming ? are they not the icebergs that titanic hit? They look a bit too heavy to be asteroids (not the other things that are a pain in the A##e)
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