Model Boat Mayhem
Mess Deck: General Section => Model Boating => Topic started by: Neil on December 18, 2017, 10:42:58 pm
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In the new year I intend starting a new build of the only class of lifeboat that I have wanted to build, but haven't done so yet.
it will be a big one at 60" long and to keep the weight of the plug down, because it will be again plug, moulds and grp moulded hull, my usual standard build, I am contemplating using foam in between frames and skimming with polyester resin.
so before I start, I would like to ask, what foam should I use , where do I buy it from, and what barrier do I use to protect the foam from the polyester filler when skimming it all.
please, I don't want to deviate from polyester resin, because it is easy to sand, and don't want to go down the route of epoxy resins..........I want to keep it as simple and as quick as can be and products that I am used to, as the finishing surface....... a simple question, so please keep the answer simple.........foam and barrier will do just fine, for a quick plug build, with no complications.
cheers, neil.
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Perhaps consider expanding foam? easy to trim and cut when set.
I'm sure you will trial anything before committing.
A trade can goes a very long way if used with an application gun which gives excellent control and you leave it on the can until its empty therefore not needing replacement nozzles or cleaning.
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it's susceptible to the resins of polyester, Andy and melts once in contact with the filler leaving huge hollows behind the skims............I could use it but need a barrier between the two.....there is a dense foam around that saws well, but haven't a clue what its name is or who supplies it.
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If its the stuff im thinking of its called chem wood. It cuts with a saw, knife etc, can be drilled and carved easily. I use it at work all the time.
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Dense foam sounds more like linkspan board
Used for insulation and in a variety of thicknesses
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My current build was done like this. Check the early photo's on stril barents. I built a part frame from plywood and then filled the voids with squirty builders foam. Once it sets up, you can carve it to the shape of the plywood frames with a handsaw and then a coat of plaster of paris over the top of that. The plaster of paris seals the foam from the resin. You sand back the PoP to fair in the shape and then give it a good coat of paint, this is then waxed with whatever you use as a release agent.
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"If its the stuff im thinking of its called chem wood. It cuts with a saw, knife etc, can be drilled and carved easily. I use it at work all the time."
Thank you Klunk, now we know why Luton made cars don't rust!
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The reason no cars made in luton dont rust is no cars are made in luton. Only vans!
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If you're after quick and simple - and if you don't mind sanding the polyester outer for a smooth finish - then I'd possibly not bother with the plaster over the foam core technique. Just cover the (well-finished) core with tinfoil or clingfilm. Check the film to ensure it doesn't react with polyester resin!
Andy
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cheers guys...........I shall google a source. :-))
thanks.
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If you're after quick and simple - and if you don't mind sanding the polyester outer for a smooth finish - then I'd possibly not bother with the plaster over the foam core technique. Just cover the (well-finished) core with tinfoil or clingfilm. Check the film to ensure it doesn't react with polyester resin!
Andy
Tried that method once Andy.....and it turned out disastrous for me..........if the resin had been red It would have looked like the Texas Chainsaw Massacre, lol.........thanks but never again lol.
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I've seen foam cores made 'resin-proof' with 2" Aluminium sticky tape carefully applied to leave no gaps. It can be rubbed smooth & buffed up to a good clean shiny finish.
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Hello,
I built the hull for my Bluenose Schooner filled with Foam.
The foam was being used to make Office rooms within a large warehouse.
The foam was about 6 inches thick, with a paper covering on both sides.
Took some offcuts home and cut them into small cubes, then placed them in a jar of Resin.
Left them in the jar for about a week, to test if the resin would melt them - - it didn't !!.
I was given loads of scrap pieces of foam to take home.
Full details of the Schooner build are on my website.
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thanks guys for all the replies, but instead of allaying my fears I am becoming more confused by the hour..............think I'll go back to good old plank on frame, but again cheers for all your replies............just thought it would be easier.............but become a nightmare............POF and plenty of filler now the route.
cheers.
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Neil, I thought you had had enough of Big boats after doing the Clyde for the Loch Lomond run. Double glazing firms use a blue foam for glass packing also Florists use green foam similar to Oasis. best wishes, nemesis
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I just can't resist the pain and suffering plus the self harm I do to myself, building a big boat................and when I look at it, nemesis............it's only an inch longer than the Jupiter ferry................plus its a lifeboat {-) {-) {-)
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http://trawlerphotos.co.uk/gallery/showphoto.php?photo=96170&title=framing-1&cat=1101
Start there and click right , thats Bill Wood from Aberdeen and he uses this method for all his plugs Neil
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THAT is an excellent how-to!
:-)) Andy
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Bills been making models this way for years , its the blue extruded insulation board you need
https://www.ebay.co.uk/itm/EXTRUDED-STYROFOAM-FOAM-FOR-MODEL-MAKING-SCULPTING-FREE-POSTAGE-/282593175331
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Bills been making models this way for years , its the blue extruded insulation board you need
https://www.ebay.co.uk/itm/EXTRUDED-STYROFOAM-FOAM-FOR-MODEL-MAKING-SCULPTING-FREE-POSTAGE-/282593175331 (https://www.ebay.co.uk/itm/EXTRUDED-STYROFOAM-FOAM-FOR-MODEL-MAKING-SCULPTING-FREE-POSTAGE-/282593175331)
cheers Davie........I'll track some down.
neil.
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Hi Neil,
Hope this may be of interest, I have recently watched my cousin (a retired expert pattern/model maker
specialising in car prototypes for the likes of - Jaguar, Bentley, BMW, Volvo etc working all around the world)
produce his first model boat - a 28 inch scale round bilge model of his own full size 28 foot yacht,
by his preferred method of polyester glass over foam and I found it a revelation !
The ease of construction and speed the hull went together was amazing, bread & buttered from 2'' thick layers,
and I (traditional ply bulkheads & skins man) will be using his method wherever possible in the future,
I'm the one thinking about a huge 1/6 Atlantic 75/85 on FaceAcheBook,
and will be going down this route if I build the model.
I don't know the brand name but it's bright pink or bright blue builder's insulation foam, very dense 'closed cell'
foam that carves beautifully with a brand new Stanley Snap-Off knife blade protruding 4 inches out of its handle,
or easily sawn with a decent household bread knife ! (2 inch thick 8x4 sheets).
For the barrier layer he uses, what is industry standard in his profession - 2 layers of glossy 2'' brown parcel tape,
covering the entire up-turned hull and leaving an inch of excess tape overhanging to prevent any resin creeping up
attacking the foam.
Then he layers up in Polyester and matting, much sanding and P38, and on to paint - no need for moulds etc,
fastest boat building I've seen to date, saves all the hours of wood working/mould production for one off's.
When discussing how to build a large model tug hull, he suggested cutting bulkheads out of thin ply or
possibly 1/4'' Depron foam (as used by Aeromodellers for small profile R/C model wings etc),
and infilling between with pink/blue foam blocks.
When asked how to make the foam blocks the correct size to fit between the bulkheads,
he showed me his bench pillar drill with a lashed up with a horizontal sanding disc mounted in the chuck
used to machine the foam sheet to thickness, then laminated to form blocks etc,
or length ways bread and buttering with 2'' sheet laminated onto a full depth solid ply keel.
A different way of thinking ! and I think someones just posted a similar reply while I been typing this.
cheers Paul
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Hi Neil,
Hope this may be of interest, I have recently watched my cousin (a retired expert pattern/model maker
specialising in car prototypes for the likes of - Jaguar, Bentley, BMW, Volvo etc working all around the world)
produce his first model boat - a 28 inch scale round bilge model of his own full size 28 foot yacht,
by his preferred method of polyester glass over foam and I found it a revelation !
A different way of thinking ! and I think someones just posted a similar reply while I been typing this.
cheers Paul
Thanks for that Paul, and I found it very interesting indeed.........have sourced local some high density board, and shall be making a start in the new year..........
again, thanks to you all for replying.........and yes farewell POF .......a new excursion for me, I think.
cheers. neil
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Hello Neil.
I think I have seen the pink foam in wicks.
Regards Howard.
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cheers Howard..........there's one close to me in Blackpool..............off to Preston tomorrow so will call in on the way back.
thanks
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Try your local branch of Sheffield Insulations for foam sheets. If using the blue foam you must put a barrier between the foam and polyester resin. Brown wrapping paper soaked in diluted waterproof wood glue (15% water) three coats ,allow to dry between coats. this will give an eggshell type skin that you can apply the resin/body-filler to.
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thanks Arrow but just looked and Sheffield insulations nearest is 70 miles away......think I'll stick to wicks 5 miles down the road.
cheers for the other info.
neil.
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I believe Ron Horabin perfected a similar build process 25years ago using foam between each frame and coating the foam with plaster , sanding down and casting in GRP .
Bowwave
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:-)) :-))
thanks dave.
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Hi Neil,
I too am an exponent of the 'Foam' building method as can be seen from some of my articles in MB mag. The best foam I have found is Blue Polyurethane foam and I order this from Balsa Cabin or Technology supplies. It is a very stable closed cell structure and originally used for insulating commercial freezers and fridge units in large supermarkets like Lidl, Sainsburys etc.
I use single part foaming Polyurethane glue from Screwfix (same as Gorilla but cheaper) to build up layers of foam.
This foam sands very easily to a nice fine finish by hand, do not try power sanders at the latter stages of shaping as the surface can get hot and it will tear patches out of the carving or leave darker, rock hard streaks.
This foam will also react with Fiberglass resins so some protection from the car body filler is essential. Epoxy resins are fine. I have used the PVA soaked paper tape method several times but now give the plug a few coats of Dulux Vinyl Matt emulsion which is easier and cheap. It can also be rubbed down carefully if you leave the emulsion to dry thoroughly, you can then go over it with car body filler to get your glass smooth finish before laying up the Master mould as normal.
Some of the yellowish roofing panels from builders merchants are OK but are more crumbly, though you can often find sizeable offcuts in skips. The Pink foam is OK too but not as dense as the blue which is now used a lot for CAD/CAM prototype product modelling and so on. (This was the subject I taught Engineering and Design students at Degree level before I retired)
I actually make the whole hulls out of the foam now, finishing them initially with nylon cloth or ladies tights and Epoxy resin or Ronseal Floor Varnish (PVA based). They are very light and unsinkable and will take quite a knock with little or no damage. Just carve out the locations for fixing the hardware.
I do not recommend foam masters for Vacuum forming though as the resins used for the finish coats will come away from the foam sub base if any excess heat, like in Vac forming is used.
Average time to carve a 30 inch hull is about an hour or so, so it is a very quick method.
Hope this helps..........Happy boating.
RON.
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Ron...........that is a very concise and superb description and probably the best I have heard from anyone, and many thanks for your input and your superb knowledge.
I appreciate it very much and all the downfalls that one might encounter on the way. I shall now google these two suppliers and get something going for the new year.............
I thought my luck was in the other day when I passed a spot coming out of Fleetwood where someone had flytipped a load of blue foam, so like the womble I am, I turned back and went to load it into my car..............sadly only to find that it was about 25mm thick but glued to 20mm ply wood, so abandoned the thought.
thanks again Ron, for taking the time to give a blow by blow of the stuff......greatly appreciated.....blue foam it is.
neil.
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When I was building my 19 foot long Big Boat I used Blue foam to float the centre sections on, I got it from Travis Perkins the Builders Merchants, The bloke in the Yard said there were some packing pieces around the back and to help myself, just the job. :-))
Len.
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Neil find a local commercial builder , they use this foam in industrial units for insulation and most of these companies will happily let you take all the offcuts you can carry as it costs them money to have them disposed of
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cheers guys...........i'll go on the hunt. after the new year....everyone has packed up now.
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New years Resolution = Never pass a Skip without checking for Stuff.
And be nice and ask if you can take, before you take it.
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Hopefully you can see this.
https://www.facebook.com/photo.php?fbid=2206511616033019&set=pcb.1567192376669244&type=3&theater
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Hopefully you can see this.
https://www.facebook.com/photo.php?fbid=2206511616033019&set=pcb.1567192376669244&type=3&theater (https://www.facebook.com/photo.php?fbid=2206511616033019&set=pcb.1567192376669244&type=3&theater)
:-))
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having looked at that aberration, %% .I think that method would take more time in cleaning up the expanding ffoam than it would a plank on frame build...........not for me am glad to say..........couldn't stand the mess it causes to begin with..........my work shop in in a big enough mess as it is, lol.
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Back when I was doing fast electric and gas racing models we experimented with the expanding foam. Found out that you can not pour it into a restricted space, as once it expands to fill that space any extra liquid gets trapped in it and with applied heat (hot summer day) start to expand again, forcing the original foam as well as the hull sides out of its way. I have found that the blue builders insolation foam works good.
Gerald.
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I agree about pink and blue foam. I have a Pre dreadnought on the go with the hull built in pink foam which I intend to hollow out and furnish. Ron gave me many tips about the tecnhiques in using insulation foams.
You do make a lot of shavings and some dust, but a sharp carving knife and fully extended snap-off craft knives keep dust to a minimum especialy once you get your 'Carving mojo' on.
I have coated my hull in a mix of Blue emulsion and PVA. The former shows where the latter has not covered fully. I will then try the tights and EZEkote method also shown by Ron to clad it in before hollowing and detailing.
Good luck with your build Nick, I look forward to seeing your progress :O)
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cheers, neil.
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Sorry :embarrassed:
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as mentioned, depron is a close cell foam, cuts with a sharp knife, sands very easy. You can use epoxy resin, uhu por, or foam friendly cyno. You can paint it etc.
American variation is blue dollar tree foam, I understand this is all floor insulation. We use this in aero modelling as its light, and can be covered, and cheap. Its waterproof, we use it for water-planes to great effect. I know a few people who have constructed boats from this.
hope that helps!
Paul
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cheers all that have contributed...........shall go in search for some in the new year. :-))