Topic: Models by Design Mersey Class Lifeboat. [1/12th] (Read 112273 times)

gregk9 · « **Reply #75 on:** November 18, 2011, 06:22:02 pm »

Now that the internal hull cross bracing has fully dried. I have now cut the centre sections out of 2 braces, this is to allow the cabin interior to drop below the deck level, as it will be attached [not permanently] to the upper cabin. I have also added some wooden braces in the forward section, these will allow me to secure the access panel for the electrical kit. This lot does not need total access once setup, so best to hide it away from falling screwdrivers and sticky fingers. the main batteries will be accessable as you lift the cabin up for simplicity.

As you can see from this last image. Once the cover plate is secure "over" the main electrical kit, it then permits the top of the cover to carry the main swich gear, which can be accessed through the 2 forward access covers, so there is no need to then keep having to lift off/back on, the main cabin assembly everytime you want to go sailing.

"IF" I was going to use ordinary nimh batteries, this is also where I would locate a charging point, so you can charge the batteries whilst still in the hull, but being as they will be Lipo's, I much prefer to remove and charge in a safer loaction.

gregk9 · « **Reply #76 on:** November 19, 2011, 05:25:07 pm »

I have now made up a hull cross brace, from which teh electrical panel tray is supported. This tray will hold all the electrical items for the boat.
So the "Action Electronics", ie, P94 dual Esc, P102 Power board, P95/2 motor fuse panel, P103 dual battery panel, " P100 noisey thing & P101 amplifier" will be sited. The majority of items are held within black protective boxes, those that are not are held clear of the wooden panel by plastic spacer bushes, this ensures no electrical shorting underneath the panel if any water or buildup of damp occurs.

To also add a little more protection to the electrics, I have also retained part of the deck I cut away to enable the interior to sit inside. This will then be screwed down for normal use, but easily removed, should the need arise to access the electrical panel items. The pic below shows the panel "in place" but not as yet secured, just to show what I mean.

gregk9 · « **Reply #77 on:** November 21, 2011, 12:26:38 am »

Not much free time today, so i decided to have a look at the engine exhausts. Firstly, I "naturally presumed" there were going to be some white metal ones supplied in the metcalf fittings kit .....WRONG! None whatsoever. So I ordered some resin cast ones from MAc's Mouldings,along with a few other items mentioned earlier, but after looking at these resin ones, i decided they were too large in diameter for this hull, with the original moulded detents in the glass fibre.

So time to make my own. I used some 7/16th plastruct tube for simplicity and lightness, plus its easier to bond other items to them. I cut a couple of discs to create the flaps from some plastic sheet, then cut out some hinges. I filed a small detent in the tops of the tubes, to allow a small piece of smaller plastruct tube in, to act as the pivot.
So, once assembled, the exhaust flaps are full hinged, as I intend to pass some "cooling water" out of these pipes as the boat is in motion.
I did however save the outer circular resin discs from the mac's ones, drilled out the centres to leave a flat disc with a ring of bolt heads. This then had the back face sanded down to a more realistic thickness, so it looks like a piece of stainless plate, not armour plate, so these will be fitted as the surrounds, around the exhaust outlets on the stern.

Number 6 · « **Reply #78 on:** November 21, 2011, 02:49:02 pm »

Looking good, I made working exhaust fittings on mine. They're deffinitely worth doing and look the part once in place. It's coming along very nicely, look forward to seeing it. Maybe at Wicksteed, or one of the Lifeboat days maybe?? Dave.

returnee · « **Reply #79 on:** November 21, 2011, 04:03:56 pm »

What a great build, I keep checking daily to check your progress.

Where do you get your small springs for use on your hatch covers.

G.B.

gregk9 · « **Reply #80 on:** November 21, 2011, 07:15:32 pm »

Thanks for your comments, much appreciated.
the hatch springs are "self made". I followed a "trick" I read in the original build in Model Boats, back in 2004.

They simply coiled a piece of brass wire around a suitably sized rod, alllowing sufficient brass wire at each end to create the lever arms. then cut the spring in half. Then slide both pieces on to the hatch pivot rod. press closely together, so the spring looks complete, but in fact its not, as brass wire would not bend many times before breaking, plus trying to purchase and bend spring wire is fairly difficult, but this little trick suffices.
What I also did, was to cut a slot in to the glass fibre, below the spring arm boxes on the foredeck, so I could bond them in more securely from underneath, rather than rely on a simply weak dab of glue from above. id rather do these sorst of bonding jobs now, than have to keep applying glue over the top of the finished paintwork several times afterwardas, or each time someone "test fits" the fittings for you whilst on display somewhere. Afterall, you cant be standing by it every miinute its away from your home base.

As an update on the exhausts, heres a few pictures of the painted items, prior to a test fit to check where I can locate the water pipes to them.

gregk9 · « **Reply #81 on:** November 21, 2011, 09:18:02 pm »

And exhausts in situ...........

the internal ends of the pipes were blanked off and some adaptors bonded in to accept the silicone water pipe from the water scoop intake [yet to be fitted].

6705russell · « **Reply #82 on:** November 21, 2011, 09:58:08 pm »

Hi Greg

How do you plan to fit/seal the deck now that you have sprayed the hull and fitted the fendering?

Russ

gregk9 · « **Reply #83 on:** November 21, 2011, 10:54:59 pm »

I still have the main electrical panel to finish wiring up, plus make some bases up for the battery packs, all of which are better/easier done whilst the deck is still not fully fixed down.
Same goes for the mounting for the rudder servo and water pickup for the engine exhausts.

But, being as I have a full wooden frame around the hull edge, it will be easy enough to bond down with cascamite and give a virtually "guaranteed 100% bond".

I will however be bonding on a sheet of styrene over the wooden deck, as this will allow me to use styrene to make up the toe boards. These will be stronger made from this, as using such a small size of wood strip, the slightest knock to the railings would cause the tow board to snap. So me thinks styrene would be better, but to get a good strong bond, rather than trying to bond plastic to wood, on such a thin base, its easier to bond the plastic to the wood over a much larger area, spreading the bonding surface and loading, then the plastic simply welds to itself on the toe boards [and other deck fittings too].

Call it "belt n braces" again, I'm full of it [ha ha].
With this build, Im looking for the thing to "last" and be able to take the odd knock with some flexibility, So I'd rather build it with the long term in mind.
Same goes for the hull, now that the decals have had time to dry off, along with the red/yellow stripes, I will be giving the hull a good coat of laquer to finish it off, rather than risk scratching the paintwork on that if it comes against something floating semi surface in the water somewhere, Well, "you never know" and having to repair/paint 2 tone paintwork aint easy or nice to do. Whereas a scratch in the laquer is easily touched in and repolished.

But word of warning, be careful with overdoing the number of coats you apply. the thinners in each coat can "reactivate" the layer below and cause the psint to "move" which in turn causes the paint to crack and seperate. Several layers is normally applied over many days/weeks if not using a bake oven. I used to work in the car repair trade so know this only too well. I know you "know" what you are doing Dave, but for the sake of others seeing all the paint going on our boats of late. using aerosols in a "home" situation needs time for the thinners to evaporate, even with "gentle warming" of the room you are spraying in. Easy rule. 1 coat = 2 days to fully dry. 2nd coat = 3 days to dry. Each further coat will take longer to "fully" dry due to the "soak" effect in through the under layers, so beware folks.

Rush the spraying [thinking it is touch dry and ok for the next] and you can risk severe damage. maybe not immediately, but give it a couple of months and the cracks will appear and by then it will be a lot harder to rectify as all the paint will have to come off and start all over again.

gregk9 · « **Reply #84 on:** November 21, 2011, 11:21:33 pm »

"Anti Slip" surface on roof and foredeck on the mersey. I looked at using a commercial "anti stone chip" type paint, but the finish is too "smooth", plus no where near to scale, So I have tried another source. "wet & dry" sandpaper! Well it accapts being put in water for sanding purposes, so it should recieve a coat or three of paint too. [Fingers crossed].But heres a pic or two of the sections Ive attached to my mersey. Waht grade? ..........................120 grit. Too fine and the paint will simply fill all the grit up, too coarse and it will look like a gravel driveway.

Tug-Kenny RIP · « **Reply #85 on:** November 22, 2011, 03:57:44 pm »

Thanks for the painting 'tip' Greg. I didn't know that information. I shall relax between spraying in future.

ken

stuarts2 · « **Reply #86 on:** November 22, 2011, 05:53:07 pm »

Hi. I am building the 16TH Severn and for the anti slip deck I used Aluminium Oxide Powder mixed into the paint and them with a small varnish brush DABB it on to the service keep stirring the mixture at all times, just one coat was needed and then dilute 50/50 the colour and DABB that on too till you are happy with the colour I put on three coats, NEVER brush it on then the same with varnish 50/50 Satin with Matt,

worked for me.

gregk9 · « **Reply #87 on:** November 22, 2011, 11:43:15 pm »

Paint, especially any that is "thinners based" can be nasty stuff when over applied. BUT it takes time for it to all "react" underneath. Once the resultant "crazing" appears on the surface, its too late, the damage is done and nothing except total removal to base material and start again, will ever do it justice again.
Water based paint these days are more safer to use and don't suffer from this internal reaction, but more expensive to purchase. But I dare say the regulations that hit the motor trade and commercial painting trades will hit the hobby end eventually, but thats another story and full of "mines" currently, so we won't "go there".

Providing sufficient time is allowed to elapse for the thinners in the paint that is applied to fully evaporate and this does go beyond it being actually "touch dry". PLEASE remember that that is only on the surface, it takes many hours for the paint to fully "cure" in a natural envioronment. Thats why car repair shops run cars and panels through an "oven" to "bake" the paint, this get the paint that hot the thinners is evaporated out and bakes the paint layer nice and evenly. Be wary of applying direct heat to a sprayed item. Alwasy heat the "ambient air" and get the room to an even temperature, normally about half an hour before you begine to spray is best, as it also then gives the item to be painted time to come up to the same temperature too, making the paint easier to apply as the panel is warm and the paint "flows" readily.

DON'T use a hot air gun or a heater with an electrical element in, as both have very hot filaments in and if the "overspray" gets too dense, it could ignite against the element and cause a flash fire.

Call me over cautious, but ive done enough "risk assessments" on stuff like this to write my own safety manuals [ha ha].

Right, sermon over for today, I just hope that the above helps to explain a bit better to all of you about the insider info on spraying paint. its not just a case of shaking ***t out of your wrist till the rattle of the can drives everyone mad, then going for broke and seeing how quickly you can empty the can and then counting all the "runs", til they merge.

The white primer has been applied over the superstructure, now that the glue has dried overnight on the anti slip deck sections. A light first/dust coat was applied and allowed to dry for an hour before a heavier second coat was sprayed on.

The paint was then left for 24hrs before a second primer coat was applied, just before the paint was left to dry,a slight dust of "top colour" was drifted on, as this allows me to check all the panels for smoothness and any problem areas, as white primer is difficult to see faults in.

The painting will now halt for 2 days to allow the paint to harden and the thinners evaporate off, but the build will continue with "other items".

gregk9 · « **Reply #88 on:** November 23, 2011, 10:02:03 pm »

Whilst the primer is still drying on the cabin, work has recommenced inside the hull.
I have now installed the water pickup for the engine exhaust outlets. the pickup itself ive mounted high up on the inside of one of the prop tunnels, so its not too obtrusive or likely to be snagged on anything.
I then ran the hose to a "T" piece before routing the hoses round to the 2 exhausts, making sure the hoses will not foul the rudder operation at the same time, so allowing plenty of "flex" in the hoses.

I have also now added the rudder servo mount. As you can see from the above pics, this was mounted on 2 runners, bonded to the tops of both prop tunnels, using a under braced ply sheet across the top.
The try was made sufficiently wider to enable me to add a couple of cable clips, which secure the water hoses and prevent then fouling the servo link arms to the rudders.

gregk9 · « **Reply #89 on:** November 24, 2011, 10:06:19 pm »

The upper cabin primer coat has now fully dried and been wet sanded with 800 grade paper. it has also been remasked and the top orange coat applied. i have to admit that the sand paper I used for the anti slip deck areas has come out really well. it has given a nice uniform covering and not as potentially "hit and miss" when using the "add loose grit" to the paint prior to painting option. By simply cutting the sand sheet to size, glue bonding it down, then overpainting is far the easiest and achieves a good result, which i have tried to capture in the pictures, but as always, its far better seen "in the flesh".

gregk9 · « **Reply #90 on:** November 26, 2011, 12:50:58 am »

gregk9 · « **Reply #91 on:** November 27, 2011, 05:11:14 pm »

I have finally managed to glue down the main deck of the hull, now that the cross deck formers are sanded and shaped to suit the angles of the walkways. I have temporarily drilled and screwed the outer edge to teh wooden hull edge bearers, to enable me to get a clean bonded edge, plus hold the damm thuing down whilst the glue dries. The inner edge is simply clamped down with croc clamps.

The Action Electronics sound system is all working ok, as a temporary measure I connected up to a seperate 11.1 lipo stick battery, untill a 12v one arrives in the post. I wanted to keep the battery supplies for motors and sound seperate, so the sound system does not flatten the drive batteries whilst out having too much fun.

http://youtu.be/mx9WmVVoeMY

The bonding agent Ive used for this is Cascamite, having found it to be so super strong once fully dried, plus its waterproof and Id hate to risk the deck coming off in a couple of months time!
the hull/deck assembly will now be left to allow the glue to dry, so its back on to the upper cabin again for a while, but at least i still have loads of things to build yet.

DickyD · « **Reply #92 on:** November 27, 2011, 10:04:29 pm »

I'd just like to ask a question.

Why did you not cut the shafts back nearer the tube, thereby moving the motors back to where they ought to be. Or am I missing something here ?

gregk9 · « **Reply #93 on:** November 28, 2011, 12:00:39 am »

The motors had to be placed where they are simply due to the angle of the shafts coming through the tunnels, in to the inside of the hull. if i had of wanted to mount the motors closer to the tunnels, I would of had to angle the prop shafts even steeper, thus reducing prop thrust as they would be pushing down at a steeper angle, rather than simply pushing water backwards.
Afterall, the idea is to get as much propulsion force in one direction, so best to puch backwards, rather than have the shafts angled too steeply so it tries to lift the stern of the boat as its driven forwards.

But, dont forget, there is no golden rule as to where anyone should or should not mount stuff, its still basically down to personal taste and ideas, everyone should be encouraged to try ideas out, as afterall, thats how we all learn different things and not be forced in to strict guideleines. If someone wants guidelines, then they simply go buy a kit build with numbered instructions.

if you would like to check back through the earlier posts, this question was asked before and pictures were posted which highlighted the motor mount positions, so you can clearly see whay the motors are mounted where they are.

To be honest, after doing an initial water test in the most conveniently sized tank, namely the "bath", this motor position gives the hull a nice even balance and allows for the weight of the batteries in the larger/flatter stern area, rather than trying to cramp them in towards the bows.

gregk9 · « **Reply #94 on:** November 28, 2011, 07:33:40 pm »

I am still waiting for the hull to deck "bond" to fully cure, so i have started the build of the radar and navigation light assembly.
this is easy to construct the basic shape, the lower panels will be added later, but just to give you an idea, plus show the geared motor I have locate which fits in to the radar motor pod and wil rotate the radar head at approximately 60 rpm.

The wiring will be routed down the cable trunks as per lifesize version, no problem.

gregk9 · « **Reply #95 on:** November 29, 2011, 04:52:41 pm »

If anyone is waiting for a set of windows for a "Trent" from Speedline Models. I HAVE BEEN SENT THEM ! By Mistake.

So you will have to wait a short while for them to be returned, once Speedline finally get my order right.

heres a link to a short video clip of the radar motor. http://youtu.be/P4lxKDWobJE

running a 3v battery, this motor give 60rpm, which looks as near as I can match to correct rotation speed. Obviously if not, i can always add another cell to the pack and quicken it up, but the references I can get to seem to suggest this is near enough.

CF-FZG · « **Reply #96 on:** November 29, 2011, 06:28:11 pm »

Quote from: DickyD on November 27, 2011, 10:04:29 pm

I'd just like to ask a question.

Why did you not cut the shafts back nearer the tube, thereby moving the motors back to where they ought to be. Or am I missing something here ?

Dicky, it looks like the shaft outers have been installed butting up to the A-bracket instead of just a small amount protruding from the hull into the tunnel and more running inside the hull with a supporting 'wedge' - which causes the inners to look way too long

Mark.

DickyD · « **Reply #97 on:** November 29, 2011, 06:37:02 pm »

Quote from: CF-FZG on November 29, 2011, 06:28:11 pm

Dicky, it looks like the shaft outers have been installed butting up to the A-bracket instead of just a small amount protruding from the hull into the tunnel and more running inside the hull with a supporting 'wedge' - which causes the inners to look way too long

Mark.

Oh, right, so in effect the shafts should be exposed on the outside and the tube should be inside the hull.

They've been put in the wrong way round then, I thought that might be the case.

17-21 · « **Reply #98 on:** November 29, 2011, 06:41:39 pm »

running a 3v battery, this motor give 60rpm, which looks as near as I can match to correct rotation speed. Obviously if not, i can always add another cell to the pack and quicken it up, but the references I can get to seem to suggest this is near enough.

[ if you want the right speed it should be only 26 RPM just in case you wish to change it before you go to far

Phil.]

Netleyned · « **Reply #99 on:** November 29, 2011, 06:49:01 pm »

Most nav radars run at around 24-28 RPM
This is something that if scaled down would not
look right
At 1:12 that would be 2 RPM which would look wrong

Ned

News:

Author Topic: Models by Design Mersey Class Lifeboat. [1/12th] (Read 112273 times)

returnee

stuarts2

CF-FZG