Model Boat Mayhem
Mess Deck: General Section => Model Boating => Topic started by: Pointy on May 31, 2007, 07:40:56 pm
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Okay, here is the deal, my tools and expertise are....limited but not my single mindedness (cant' believe spell check let me get away with that one)
What would I need?
I'm thinking a model saw, one of those right angle things, thick plasticard, fibreglass type car body repair stuff and epoxy?
PS
If I don't get it right and the bow kind of points off centre- will the boat go round in a circle?
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Measure twice cut once.
Slap forehead, measure again and cut properly. That's my normal method. ::)
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Tempted to vote for idiot, but it can be done.
You will obviously need to cut the hull, if it is a plated hull cut on plate edges.
If it isn't don't cut a straight line right round the hull, stagger it like bricks.
you will need to fit an internal keel and doubler plates inside the hull made of marine ply.
Glass everything in.
On the curves of the hull when the resin is FULLY cured epoxy plasticard internally over the gap.
Before you go any further treat the hull roughly when all is fully cured.
There is no point fairing in the join in the hull if it isn't strong enough.
If it isn't start all over again :)
If it is fair in with car Body filler eg Davids P38 and rub down wet and dry on a block.
It should be OK, I have seen a few done this way.
Bob
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What hull is it though?
Bob
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Why do you want to do this Pointy? and by how much longer do you need?
chromedome
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Model Slipway 10 hatch coaster.
I have completed one but I'm watching it die gradually due to a reaction of the varnish and paint- it looks like a mosaic in some areas. So thinking of getting another kit, sawing new hull in half- then adding a middle section of the old one. Its a kind of recycling as I just don't know what to do with my poor coaster. :'( Sanding it down is just not practical- would have to dismantle most of it.
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oh yes i remember you post of a few days ago about you paint dissaster :-\
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Pointy, I cant see how adding a new section of hull solves the problem. I thought your "mosaic" problem was all over the hull - so what about the bow and stern.
You could try applying paint stripper to the very bottom of the hull - dont leave it on too long then scrape and wash down. I reckon you might be able to shift most of the paint before the stripper attacks the gel coat. Doing it on the bottom means that if it is too aggressive a process then it will be out of sight. If, as i hope this will work for you you'll then have the confidence to try it on the hull sides. Even if you only remove the plasticote varnish you could sand down,repaint then recoat with a compatible clear coat. I really sympathize with your problems here but I don't think "piecing in" a new section would work
Best Wishes
Douglas
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Pointy,
Just bite the bullet, get a bowl of water with washing up liquid in it, lots of wet and dry and start rubbing.
Honestly it wont take that long.
yes it is a complete pain in the proverbial, but it will be OK with just a bit of patience and a lot of elbow grease.
I quite often refurbish hulls with all sorts of problems and it doesn't take long.
She did look good, and do know how you feel, but she can look at least as good again and with the knowledge with all that rubbing down a superb key for the new topcoat :)
Bob
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Pointy
How much are you looking to add into the middle of a hull? If its less than the length that is the same shape in section you have a couple of options 1 make a mould of the section you want to add in and then take a molding from it or ask model slipway if they can do it in the hull mould. Then just cut your hull in half and fix in the new section with glass tape. I would use epoxy, as it will bond better to the cured fiberglass. Once that is cured fill the outside with gel coat filler and flat down.
As with any GRP molding once it cured the only bond is a mechanical bond and not a chemical one.
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hi there Pointy
If I were in your position, I would sit back and have a look at what everybody has posted and weigh up the pros and cons of cutting the hull in half. The way I perceive it is, you are going to take the hull that has the damaged paintwork on, cut it in half and enlarge it with a new centre section - to gain what? A larger hull, where you have to rebuild all the deck fittings.?
Personally, I would go the way Shipmates60 is suggesting; strip the paint off the existing hull and repaint it.
You will have to start removing paintwork (if you enlarge the hull) to get a mechanical bond on the outside.
Also, you have to take into account, that you must make the hull fair and true, with the new section added in. I can guarantee that will require the same amount of effort, as stripping the paint off, of the untouched hull. I should imagine you would encounter other problems with enlarging a 'ready-built hull' which nobody can foresee.
So, its up to you my friend, you know your skills and limitations.
Best of luck.
aye
john e
bluebird
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Hi guys, thanks for the imput but some of you seem a bit confused by it?
I think my post was not that clear so here is what I have in mind.
Have built a coaster but am not happy with it for many reasons, not just the paint. My plan was to recycle it- in effect break it up for parts as I don't want to waste the material and it took me a long time to build.
So I was going to get a brand new kit- the same one. Was going to lenghten the new hull by cutting it in half and inserting the centre section of the old boat in there (after I'd sanded the wretched paint off it). This would also allow me to recycle other parts such as deck details, railings etc.
Depressing number of you have gone for the "idiot" option, hope its just in relation to this post!?
Strange, makes me even more determined to try it......
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Pointy,
One thing to remember when adding a section to a grp moulding.
The original moulding uses cut strand matting.
This is what gives the moulding its "strength" when the resin is added.
If you cut the moulding then you produce in effect a fault line in the new section.
Glassing over the inside and filling the exterior will not supply the original strength to the hull.
You have to use some form of mechanical strengthening to hold the parts together.
My preferred way would to use an internal keel fixed with epoxy and screwed from the outside into the keel.
Then glassed in.
This will of course need careful lining up.
This is best marked inside and out while the hull is in one piece, then you do have the markings to use to line everything up.
Hope this helps
Bob
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There is some misinformation flying around in this thread. It is possible to mould a new section into a hull, I've done it many times, but it isn't all that easy. There's more than one way of doing it, which I'll describe in a moment, but first you need a bare hull, and that means removing anything you want to re-use from the model, then stripping off the paint. I haven't tried it myself, but the car brake fluid method that was discussed here a couple of weeks ago sounds like the best method. Otherwise, it's wet & dry and a lot of patience.
First the best, but more difficult hull-lengthening method. Make a mould, preferably in GRP, though plaster of Paris also works, from the mid-section of the hull. I'm leaving out any advice on waxing and release agents here, if you don't know a fair bit about this kind of thing, then this technique may be beyond you. Then cut the hull in two using a hacksaw blade. With the two hull halves in the new mould, slide them apart to the length you want, and laminate the new section. I use double-sided tape between mould and the old hull sections to hold everything firmly in place, but you'll also need some clamps. Then you have to apply a gelcoat, a bit of extra thickness for rubbing down if the old hull isn't seating perfectly into the mould, then the usual glass mat and resin, forget epoxy, use the material that the hull was made from originally. Avoiding shipmate's 'fault lines' is easy, you have to chamfer the edges of the old hull on the inside, so that all the real strength is in the new fibreglass, but don't thin down to much less than 1mm, or the edges may start to curl, slightly. If you take your time and do it right, there won't be any weak spots, and the join should be completely undetectable under a few coats of paint. You can't fill a tight butt joint, cracks will always appear eventually, so use a Dremel to cut a shallow groove a few mm wide on the outside, and fill this with P38 before rubbing the whole thing down.
Next the slightly easier method. Prepare three lengths of straight timber about a foot long, using something like half inch ply. Ideally you should have a helper for the next bit, but tape fairly thick flexible polythene over the gap between the two hull halves, apply double-sided tape to the wood and the hull and stick everything together applying one piece of wood to the hull bottom and one to each side. If you don't get it right first time, pull it off and try again, but this should result in a pretty solid assembly eventually. Then with the hull edges chamfered as described before, apply gelcoat, glass mat & polyester resin to the inside, going at least an inch over the joint either side with the mat & resin. Once this is hard, remove the wood and peel off the polythene. Clean off any traces of tape adhesive with thinners, and fill & sand the outside until you're happy with it. There will be a lot more sanding & filling with this method, but it avoids all the hassle of making a mould that you'll probably only ever use one time.
You'll probably get some alternative advice about 'easier' methods, same as with that recent thread on the distorted Bluebird hull, but there are no easy fixes for difficult problems. I do this kind of thing for a living, these are the methods I use, and either method will work OK if done properly
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I've just been having fun and games with Kayem.... for sum unknown reason the word "c u r l" with a space after it - causes the forum software to crash! ??? :o ???
Martin.
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Kayem,
Glad you came in with your experience.
Its good to hear the "correct" way to do it from someone who has more experience.
I have done it and it was OK, but I left the strengthening wood in as I didn't trust MY glassing.
Bob
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I've just been having fun and games with Kayem.... for sum unknown reason the word " c u r l" with a space after it - causes the forum software to crash! ??? :o ???
Martin.
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The lengths some of us go to for you lot, I seem to have spent a good part of this afternoon swapping e-mails with Martin or chatting to him on the phone, all in an attempt to find out why the forum was refusing to accept one of my posts. We were both mystified, not too surprising in my case, as I quite often sit in front of my computer being mystified, but isn't Martin supposed to be some kind of 'expert' with these things? In his last call, he could hardly talk for laughing, apparently I'd found a word, possibly the only word in existence, that screws up the forum software. He started spelling it out to me on the phone, and as he read out 'C', 'U'... etc, I feared the worst, had I been in one of those moods when I wrote my post? If I'd really used that four letter word, surely a lifetime ban was on its way, but no, the word was c.u.r.l, nothing more offensive than that. I suppose that's what is meant by the phrase, 'had him by the short and curlies'.
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So the site "CURL-ed up its toes" for a while :)
Bob
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I'm very grateful to all you who have helped and given me advice on this thread- and other threads, you have given me alot to think about.
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In my humble opinion, why not make a new hull completely from scratch like we do from drawings instead of 'language' (dont need it thanks bradders) about with something that is almost 100% CORRECT IN THE FIRST PLACE?
C'mon guys, get a grip?
Naff paintwork is easy to fix, if you use modelling paints in the first place for a model.
What's wrong with a bit of elbow grease and gritted paper etc.
To me this is going beyond a joke!
I just thought I would add my two P worth.
Paul...
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Humble.. :-\......... ;)
chromedome
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Paul, you seem to be missing the point here. Some of us modellers don't always want to do things the easy way, we do things that may seem illogical to someone like you, because we enjoy a challenge, to most non-professionals, that's what modelling is all about. It's a bit like someone who likes climbing mountains "Because they are there", especially if they could take a chairlift to the top instead. If pointy wants to cut a perfectly good hull in two to lengthen it, that's a good example. If he gets it right and no-one can see the join, then no-one will ever know, unless he tells them of course, but he'll have something that's unique, he'll have done something clever, and nobody else will have a model exactly like it. I think it's great that professionals like kayem take the time to post helpful advice on this forum to help us less gifted mortals, and there are several others just like him. If kayem and other experts come across as nice helpful people with a genuine interest in our problems, that's great, and I hope they get more business from other forum members on the strength of it.
Moderated
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That last post looks a bit odd now, I posted it in response to a bad tempered midnight rant from one of Mayhem's 'characters', more or less along the lines of ".... you're all a bit sad to even think of doing something like this, what's the point?" The original post was removed by Mayhem pretty quickly, and the last bit of mine suggesting that the individual concerned should take more water with it was also moderated. No real harm done, but I'll try to remember to take a bit more water with mine as well in future.
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Good man splodger ;D
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Having just read through this thread I am put in mind of the story about the government inspector who was visiting a secure mental hospital.
Inspector, "How can you be sure that a patient is cured and ready for the outside world?"
Governor, "We have an infallible method of ensuring someone is sane, Come to the bathroom and I will show you"
The two men go to the bathroom and are confronted by a bath full to the brim with water. On the floor are a bucket, a teacup and an egg cup.
Governor, " Right then, the question is - how would you empty the bath?"
Inspector, " Obviously I would use the bucket because of its greater capacity"
Governor, " Actually we just pull the plug out. Now we happen to have a vacant bed on E wing....."
The answer is staring you in the face, REPAINT THE MODEL!!!!!!
Good luck and best regards
Tom
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Cheer's Tom, this site is getting too PC! That was my point"!, Why go to the expense and trouble?
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Cos he feels like it!
It's what he wants to do
Why not?
He who dares wins (Maybe ;D )
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OK, what ever floats the boat and all that!
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One for Splodger though, if sailing on a lake while I am sailing my 12 footer, you will need to put plenty of water between your boat and my SHIP! >:( ::)
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I do not have the skill or tools, space etc to build a hull from scratch- this is something I'd like to learn in the future.
As for repainting, well its like I wrote a bit earlier- this was my first ever build and I can see so many mistakes in it and things I would like to do in a different way- the failure of the paint is just the icing on the cake for me. In order to repaint it I'd have to dismantle a lot of it anyway- buy new paint etc.... I'm not sure its worth it as I made mistakes of a fundamental nature. For example I've never been able to make it sail straight- I now realize that the rudder is slightly crooked. Yep I can hear the laughter from here. I spent ages detailing the bridge interior which is also waisted effort as the glue I used fogged up the plastic windows which I can't get access to now. I would like to start from scratch again and re-use parts of the old model. By lenghtening the hull of a new one it would let me use quite a lot of material from the old one.
To be honest I'm wondering if I'm better off just picking another boat to build but I love the subject of modern merchant ships. I've been looking at the Deans range but they are unknown quantity to me- the car ferrys interest me alot but both are more expensive than another Slipway kit. I know Model Slipway quality and instructions so trust them. Just don't know if I've got the abilty to pull this off or the spirit to break up something that took me such hard work to build but yet...
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i had a guy build me a smit nederland hull in glass and strech it 7 '' in the middle she now 40''
(http://i136.photobucket.com/albums/q162/bigfordf550/smitfranken1.jpg)
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Q. Is this possible?
A. Yes, I guess so.
Q. Is it a good idea?
A. No, I dont think so.
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I just don't believe this forum on times, Pointy asked a question, what he got was a lot of WHY's and some nasty insinuations. It's none of our business why he wants to do it, if he wants to do something then, as most of you said, " Good luck and here is my advice etc;. you never know but he may come up with an answer to other problems which will help all of us. I think Martin was right in moderating this thread. bigH
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http://www.rcgroups.com/forums/showthread.php?p=6955357#post6955357
pointy read this post from rc group about streching my smit nederland
boatfox did a super job with the hull
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I am not a skilled modeller as you chaps, but as a seaman who has seen real ships increased in length, beam and height. I would say some worked BUT I know some which became cranky for stability reasons, stretch a hull etc beyond it's design specs and well ? usually a lot of reseach work go's on before a hull is altered. But it has been very interesting reading your comments from which novices like me learn from.
David
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Where can I get fibreglass/resin and gel coat from?
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The two usual suspects are
Glasplies and Polyfibre - both do mail order.
Danny1
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Hi there, the Royal navy cut submarines in half and added another 20ft seemed to work out ok, The S/M Andrew was one of them.
:D :D ::)
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Well guys I'm going to go for it, new kit on order......
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Okay, I now have two halves of a coaster. At least the cut was dead straight in the middle and what a feeling doing that was!. :o
I'm going to make the new section from fibre glass and want to use the method suggested by Kaymen.
I do have a question- If I use polythene or sheet styrene etc on the outside of the hull gap in order to give the fibreglass the shape I want- how on earth do I then get the polythene/styrene off once the fibre glass has set?
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I do have a question- If I use polythene or sheet styrene etc on the outside of the hull gap in order to give the fibreglass the shape I want- how on earth do I then get the polythene/styrene off once the fibre glass has set?
That won't be a problem, at least as long as you've used polythene and not some other kind of plastic, definitely not styrene, as the resin will attack it. Very few materials will stick to polythene, so once the resin has hardened, it will just peel off. Don't try to rush what you're doing, allow plenty on time for everything to harden properly, and let us know how it goes. PSSHIPS and probably a few others seem to think you're mad for even thinking about this, and I think you're quite brave, but as long as you take it one step at the time and don't try to rush things, you should be OK.
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Kayem
Lawrie has used styrene without any problems. This hull is quite easy to lengthen.
Jackie
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Pointy
I Admire you for having a go, we all had to learn in this hobby, we only learn through trying.
My advise is just this:
You will have 2 weak points in your hull once you have finished, what I have done when I did this some years ago was to add strength to the keel by fitting a steel U channel bolted and resined to the keel, this will help stop the hull from hogging or sagging.
Keep us posted on your progress.
Well done for trying.
Big-Geoff
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Go for it pointy - I too only build models that probably won't work as its more fun that way. I built a plastic ORSV when I had a broken leg and basically you just followed the instructions and...... it worked. Yawn. I know a lot of people make very lovely models starting with styrene mouldings and love doing it, so good for them. Whatever floats your boat - even if it sinks! it's all part of the learning process.
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Thanks a lot guys for your support (including PSSHIPS who offered to help me in a PM), its good to know I'm not nuts. Model Slipway have superb customer service and have been very supportive as well.
Will let you know how it goes......
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Hi Pointy
Why dont you use the old model hull as a base to make a mould ,if you cut it in half you can then use them to form the front and back,sorry ,bow and stern ,add a middle bit in timber and then make a mould the length you want ,you then have a mould to make another if you want to ,
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Pointy
I Admire you for having a go, we all had to learn in this hobby, we only learn through trying.
.... you will have 2 weak points in your hull once you have finished .....
I agree with the first line, but not the second. If you bevel the cut edges on the inside, then take the new glass a further inch or so over the original hull, you won't have any weak points. Also, Slipway's Laurie is a very skilled modeller, but I'm not too sure that Mrs Slipway (Jackie) has read back through this thread. All the styrene I've come across is attacked to some degree by polyester resin, so it isn't a suitable material for moulding onto. Lengthening a cut hull by glueing in a styrene section would be quite different of course, though never as strong or easy to finish as an all-fibreglass job.
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Kayem,
Lawrie did read the postings and this is what he says:
You are correct, resin will attack styrene, however this is how he proceeds:
He uses a sheet of styrene as a support for the matting, resin etc. He clamps it to the hull on the OUTSIDE, then applies a release agent to the styrene on the inside of the hull, then gelcoat, then matting, resin etc. When all has hardened he rips off the styrene sheet; the outside surface will be lumpy and horrible, he then uses car body filler and elbow grease to smoothen the area.
As you say there are several ways of lengthening a hull, this is his way and it works.
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Kayem,
Lawrie did read the postings and this is what he says:
You are correct, resin will attack styrene, however this is how he proceeds:
He uses a sheet of styrene as a support for the matting, resin etc. He clamps it to the hull on the OUTSIDE, then applies a release agent to the styrene on the inside of the hull, then gelcoat, then matting, resin etc. When all has hardened he rips off the styrene sheet; the outside surface will be lumpy and horrible, he then uses car body filler and elbow grease to smoothen the area.
As you say there are several ways of lengthening a hull, this is his way and it works.
As you say, there are several ways of doing this, and we all have our favourite methods, so each to his own.
".....the outside surface will be lumpy and horrible....."
Well, certainly no surprises there.
I rest my case.
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Robin, whats your problem?
No need to come over all 'anti', are we not on the same side?
All I said was that I HAVE on several occasions lengthened hulls using styrene sheet as a mould medium, I know full well that its not ideal, but I've done it & it works, of course it comes up 'horrible' , but 'horrible' can be fixed.
Yes, polythene is better, but we don't all have access to it, thin ply, alloy sheet etc. can also be used, but polystyrene does as well. In other words, your particular method isn't necessarily the ONLY way of coming to the same end.
Remember that this isn't a kit that is being 'correctly' (factory) converted, but simply one way of a modeler altering his/her model & thus exploiting his/her skills, Isn't this what its all about???
Lighten up!
Lawrie
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;D ;D ;D ;D ;D ;D ;D ;D ;D Mr Kayem Have you got a new role, working in a clock factory as a winder-upper cos by gum you certainly do some winding up me lad
Pointy, I hope you realise you have 3 of the best model hull manufacturers helping you out here when we can stop the winding up :o ;D ;D ;D
aye
john e
bluebird
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Nice one Lawrie, this £$%t had a go at me, but, "Pointy" being a good lad an all, put him right, but, he hasn't appologised!
We all have our own ways of making and modifying hulls, Kayem's way is just his way.
We all do it differently, like he says, "each to his own"
::)
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Robin, whats your problem?
Lighten up!
Lawrie
Certainly no problem with you Lawrie, never has been and I hope there never will be, and like you say, we're all on the same side. We all have our own specialist knowledge, and I've never said that my way was the only way. Pointy was being given some advice that wasn't the best, so I was just trying to help him, for example advising him to avoid mixing materials that will by your own admission, react with each other, so where's the harm in that? Hope I won't have to duck next time I pass a Model Slipway stand at a show.
Still friends?
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Please, please, please don't fall out on this thread I value all advice but now worry about asking :-\
I've never tried to make fibre glass before so forgive me asking what may be silly questions.
I can't find what I need locally so have been looking on the internet at fibre glass suppliers and getting a bit confused as to what I need.
1. Release agent- Needed if I use styrene as a mould?
2. Gel coat- What is this and do I need it? Does it go on then the matting?
3. Matting- Any particular type best for this kind of thing?
4. Resin - What kind? there seems to be an awful lot of choice in the matter!! Does this go on last?
5. P38. For filling then a lot of elbow grease for sanding ;D
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hi pointy
thanks for the pm
the black park warship squadron will be at kingsbury water park this sunday for warship day i think its a good idea for you to join us.
glad PE is working better now he has proper radio gear glad to hear your rudder now does what it says on the tin.
as you say some advice was better than others and i found what came from slipway & psships worth it
& you should find a kit at halfords made by a company called Holt's its about a tenner.
hope to see you sunday pm me if you need direction
cheers
gary
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gel coat does not go on after the matting gary r UK..... it goes on first, you then lay up the matting with resin after an application of gel coat, you fully wet out the matting with resin, the gell coaot goes nearest the mould, its the ' outer surface of the hull as it were.
and pointy, there are plenty of fibre glass places locally, the one i use is in desborough road in high wycombe, there is another i have heard of near uxbbridge/ hayes, but i have not used it, sadly strand supplies in brentford appear to have gone now..... :(
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For a release agent use wax polish, AVOID at all costs anything with silicone's in it.
also cling film works good and just peels off afterwards. [did this with a 14 foot canoo a while back I used timber lathes for added strength glassed in]
spelcheck allowed canoo ButI just know?
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Interesting reading this thread, amusing too. Talking of lengthening ships I thought these pics might be of interest of how the big boys do things. Dan.
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great pictures there !- i wonder if they will re- inforce the joiints with tape and how much GRP will that use up.... and imagine all the rubbing done that is required !!! ::)
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[Even crooked car dealers do it' lets do it, lets all cut and shunt our boats ( with apologies to Cole Porter)
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Pointy,
It is your boat if thats what you want to do then do it, just take note of the advice posted here, it is your boat to do with what you like, I have lengthened two models so far with no problems just take your time and it will work OK mate....
Roy
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This is proving to be bloody difficult for me. :-[
Three failed attempts so far, two failed at the gel-coat stage. Trying a different method of combining styrene outer hull section with a fibreglass interior surface. Going to have to rely on good old P38 and sanding fibreglass for the bilge curves as I just can't get the outer hull shape right by bending styrene alone. Its a big section I'm inserting and I just cannot match the hull curves without making the rest of section inaccurate somewhere while bending. Thats why I'm using this "mishmash" method.
Don't know if it will work but I'm a stubborn "xxxxx". ;D
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Just a thought and I HAVE NOT TRIED THIS but how about spacing the hull with somethink like 20 mm x 20mm deck supports and a keel support and possibly a support in between glass these in so the hull is rigid then try using this product that I have used on decks and other parts of boats sold by http://www.mickreevesmodels.co.uk/ its called pro skin and is only 0.2 or 0.3 or 0.4 and this can be overlapped on to the hull on both sides and as its so thin can be faired in .it can then be glassed on the inside to give it strength and it paints well. Peter
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Think I've pulled it off!! :o
The new section has an outer layer of styrene and an inner layer of fibreglass. I made sure I overlapped the joint and must have used about 3 layers of matting. This has resulted in the section being a lot more ridged than the rest of the hull but don't think its a problem? I used P38 for the bilge curves so I have a lot of sanding to do but figured it gave the whole thing a little extra strenght. Later I plan to put a long bit of strong ply inside the hull using epoxy and P38, this will act as a keel and a bed for the motor etc..
Thank you to everyone who gave advice and encouragement, it all helped and gave me confidence to have a go. Whats even better is that my old coaster is in one piece as using it as I had originally planned, I now realize would have upset me.
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good glad to hear so when you are a bit further on how about a picture
Peter