Model Boat Mayhem

Mess Deck: General Section => Beginners start here...! => Topic started by: Paul1 on May 03, 2021, 11:37:16 am

Title: Fibreglass tissue hull
Post by: Paul1 on May 03, 2021, 11:37:16 am
Hi just finished the hull of a slec police launch which is a lot stronger construction than the Aeronaut classic i built and didn’t fibreglass the hull, can I just sand seal prime and paint or do you recommend I fibreglass the hull ,I’ve never done it before and a bit worried about making a mess of the hull thanks

Title: Re: Fibreglass tissue hull
Post by: Stan on May 03, 2021, 12:15:39 pm
PM sent .


Stan
Title: Re: Fibreglass tissue hull
Post by: Paul1 on May 03, 2021, 12:56:30 pm
Hi Stan once again thank you for good advice and help you have given me it’s much appreciated
Regards Paul
Title: Re: Fibreglass tissue hull
Post by: Stan on May 03, 2021, 08:14:11 pm
I have been asked why my answer to Paul 1 was by pm?  The answer was quite simple leave well alone he was not confident in carrying out this operation. For any one in the same position if your are not confident at carrying out this type of work leave well alone. I do share any information on this and other sites to help others but sometimes a pm is more personal than wading through oceans of answers that a newbie may not understand




Stan. :(( :(( :(( :(( [size=78%]   [/size]
Title: Re: Fibreglass tissue hull
Post by: Martin (Admin) on May 03, 2021, 08:54:17 pm
 
You could always do a couple of practice runs on something else first....  :-)
Title: Re: Fibreglass tissue hull
Post by: dougal99 on May 03, 2021, 09:15:30 pm
I agree with Martin (well there's s first  ;D ). Have a go on a practice piece. If you don't try you'll never know what you can do. I  have used fibreglass tissue on several of my boats but there was a first time, so give it a go.  :-))
Title: Re: Fibreglass tissue hull
Post by: Stan on May 03, 2021, 09:29:22 pm
Thank you all for the replies but Paul1 is not confident at this stage to have a go.
Title: Re: Fibreglass tissue hull
Post by: dougal99 on May 03, 2021, 09:38:25 pm
That's why I said use a practice piece. Nothing ventured nothing gained.
Title: Re: Fibreglass tissue hull
Post by: Martin (Admin) on May 03, 2021, 10:08:10 pm
That's why I said use a practice piece. Nothing ventured nothing gained.

    :-)) :-))

         First time for everything!   ok2
Title: Re: Fibreglass tissue hull
Post by: Andyn on May 03, 2021, 11:12:51 pm
You learn nothing by giving up %)
Title: Re: Fibreglass tissue hull
Post by: Stan on May 03, 2021, 11:38:46 pm
You could go on about this forever. You are either confident at carrying out this operation our not. Not everybody is confident especially a novice builder who is concerned over making a mess of his project. The model is a very strong construction and should not need fibreglass applying. There is a small amount of balsa on the bow which should pose no problems.
Title: Re: Fibreglass tissue hull
Post by: John W E on May 04, 2021, 09:46:29 am
Interesting subject this is.   Especially today when we have several variants of resins such as polyester, epoxy resins, then Eze-Kote resin which is water soluble and the two previous ones are not.


First of all, I think we have to decide why we are actually coating the hull?  It depends what the hull is actually made from; under normal circumstances the softer the material that the hull exterior is made from and the more water absorbent it is.  The greater the need to put a barrier on the exterior of the hull - so basically the hull itself should be strong enough and not need any re-enforcement of fibre glass material.  We should only use it as a barrier.  Having said that, there are many balsa wood hulls and brown gum-stripped hulls which have had a paint & sand n sealer coating and sometimes a shellac coating to protect the exterior - and they are still around today from many years ago - a tribute to the build.


So, if the hull is made from a good strong birch ply in theory we should only be required to fill the gaps where mistakes were made in the joints of the hull skin with some form of filler and then fill the grain of the plywood with some recommended filler and then carry on finishing the hull with the paint or varnish.   No need to try and add extra strength with tissue mat or woven roving and resins.


The main thing people seem to fall down on is whether to coat the inside of a hull as well the exterior and the answer I think should be yes - as wooden material when damp tends to swell and if a plastic material has been used to coat the exterior to form a barrier - it will not expand when it's damp.   Therefore the wood may have a tendency to break away from this exterior barrier.   If we coat the interior of the hull as well as the exterior we are preventing any dampness entering the timber, therefore preventing any swelling/movement of the wood.


Regarding confidence and working with resins - confidence is only gained by trying as everyone knows - so therefore as has been suggested it does pay you to practice on a scrap bit of wood.   Especially today with the water soluble resins, if it is going wrong we can always quickly wash it off with warm water and soap - as I have done myself in the past.


That's my thoughts :-)


John
Title: Re: Fibreglass tissue hull
Post by: JimG on May 04, 2021, 12:45:06 pm
With a ply hull there is no real need to fiberglass the hull as the surface is quite strong. However I would coat it with epoxy surfacing resin (I use Deluxe Materials Aeropoxy) this will soak into the wood surface and harden it and give a good surface to sand down. I also add some microballons (tiny glass or resin bubbles), just enough to thicken it slightly, better less than too much. This makes it easier to sand and fills the grain so that one coat of epoxy does the job to give a smooth surface, it can then be easily painted. Using paint to fill the grain needs several coats wet sanded between each to properly fill the grain. The epoxy should also be applied to the inside to waterproof the wood. Aeropoxy is mixed by volume so a medicine measuring cup does the job.  The measurement does not need to be exact it will still harden although it might take longer.Some epoxies need to be mixed by weight so accurate scales are needed.If you are confident enough to use paint then you can use epoxy, it goes on in the same way using a brush.
Jim
Title: Re: Fibreglass tissue hull
Post by: RST on May 04, 2021, 10:21:57 pm
Would I skin a hull with fibreglass tissue -absolutely not. Would I do it with a skin of cloth and resin, absolutely!  It's such a very easy thing to do.  It takes very little skill at all. It's not essential but given what's offered in terms of coatings theses days hard not to do it, certainly and absolutely not hard at all for a beginner!! More work in building the thing than trying it as a final layer or painting it. And as a belt and braces it should never go wrong.
Title: Re: Fibreglass tissue hull
Post by: Martin (Admin) on May 05, 2021, 03:36:58 am
 
Anyone found a decent instructional video yet?     :-))

Title: Re: Fibreglass / glasscloth / tissue hull covering
Post by: Martin (Admin) on May 06, 2021, 12:01:14 pm
 
Someone found these for us....



 
 
 
 


 
 
 
 
 
Title: Re: Fibreglass tissue hull
Post by: Martin (Admin) on May 09, 2021, 07:01:28 pm
 
Another video....

https://youtu.be/XQJ-mkoYQIo
Title: Re: Fibreglass tissue hull
Post by: Subculture on May 10, 2021, 09:20:12 am
You can just use epoxy resin on its own. A ply hull has a lot of strength, adding glass fibre is more applicable if you're coating a balsa hull, which is inherently soft and very 'dingable', or are repairing a hull which is past its best.
Title: Re: Fibreglass tissue hull
Post by: Paul1 on May 10, 2021, 07:00:14 pm
Thank you for you help/advice on this matter
Regards Paul
Title: Re: Fibreglass / glasscloth / tissue hull covering
Post by: Martin (Admin) on May 10, 2021, 11:31:43 pm
 
I've seen various picture of using tights material, is there any advantage / disadvantage is using ladies stockings / tights instead of glass-cloth?
Title: Re: Fibreglass tissue hull
Post by: derekwarner on May 11, 2021, 12:20:12 am
Martin..


The beauty is in the beholding  %) .....so assuming the stockings were from a Lady, the strands of the synthetic material has elastic properties and when woven is designed to provide a smooth and creasless surface over hills & hollows, whereas the strands of the glass fibre sheet [tissue] has near zero elasticity and is woven in such a manner that cannot necessarily conform to the same hills & hollows without creating a crease line


We know that the cured epoxy resin itself whilst hard and tough, however is extremely brittle so by having layers of glass fibre sheet interleaved within the epoxy resin provides the higher strength + impact resistance of the final product


The synthetic stocking woven material has far lower strength with the individual strands of the stocking material retaining their elasticity, however simply encased in the epoxy fluid & hence the final resin + synthetic cloth retains a higher brittleness and has a lower impact resistance over the product with the glass reinforcement


Pretty sure sheets of glass tissue would be preferable in building a swimming pool over lots & lots & lots of box's of pairs of tights  {-)


Derek


Title: Re: Fibreglass tissue hull
Post by: SailorGreg on May 11, 2021, 09:04:14 am
I'm with Derek - never understood why you would want to use tights to sheath a hull.  Although I have sheathed a few of my hulls, it is usually the icing on the cake rather than an essential structural element for a model boat.  A ply or non-balsa planked hull is plenty strong enough for most model applications.  But if it is being done for strength (such as over a soft balsa hull) or to ensure no leaks, don't bother with tights, use the proper stuff (glass cloth, not tissue).  I reckon the only reason the tights seem to work is that they weren't really needed in the first place.  Stick to wearing them!  %%

Greg
Title: Re: Fibreglass tissue hull
Post by: Subculture on May 11, 2021, 11:28:17 am
Tights are nylon. Plenty of laminates use kevlar, and that has lot in common with Nylon. You won't get the rigidity with nylon that you will with glass, but it's a lot lighter and a perfectly acceptable reinforcement for use with resin for this type of application.

I've found epoxy resin ion it's own to be very tough. Polyester resin is another kettle of fish- very brittle without reinforcement. Bear in mind once you coat wood with resin it's forming a composite of its own.
Title: Re: Fibreglass tissue hull
Post by: JimG on May 11, 2021, 11:47:09 am
Martin..

The beauty is in the beholding  %) .....so assuming the stockings were from a Lady, the strands of the synthetic material has elastic properties and when woven is designed to provide a smooth and creasless surface over hills & hollows, whereas the strands of the glass fibre sheet [tissue] has near zero elasticity and is woven in such a manner that cannot necessarily conform to the same hills & hollows without creating a crease line
Derek

Tissue is non woven and is basically a fine version of chopped strand mat so will not conform to hulls in the same way as a woven cloth. As the tissue is made up of short sections of glass fibres held together by a bonding agent which dissolves in the resin there are no continuous fibres to follow the curves. (It is generally intended for use with polyester resin not epoxy) Proper low weight glass cloth will follow the curves as the strands don't fall apart when resin is added. Cloth is really intended for epoxy use and is the best choice when glassing. Tissue is really intended to smooth the surface when using chopped strand mat and polyester resin.
Jim
Title: Re: Fibreglass tissue hull
Post by: spearfish99 on May 11, 2021, 07:55:44 pm
Hi just finished the hull of a slec police launch which is a lot stronger construction than the Aeronaut classic i built and didn’t fibreglass the hull, can I just sand seal prime and paint or do you recommend I fibreglass the hull ,I’ve never done it before and a bit worried about making a mess of the hull thanks


  This may help.   https://www.youtube.com/watch?v=stefVW2Zx5A
Title: Re: Fibreglass tissue hull
Post by: ballastanksian on May 11, 2021, 08:59:39 pm
The idea to use tights stems at least from a splendid modeller who wrote an article about it in Model Boats some years back. I think tights work well on smaller hulls made of styrofoam and possibly balsa where the model will be lighter than say a plank on frame or larger hull. Also, tights can be bought reasonably (so I have been told).


I reckon that if someone has built multiple hull using the technique successfully (well good enough to risk their reputation in print) then it cannot be that bad.


To quote a popular car restorer on Youtube: 'If it worked, was it such a bad idea?'
Title: Re: Fibreglass tissue hull
Post by: JimG on May 12, 2021, 12:35:33 pm
While not using tights the Dundee Club had several 36r yacht hulls made by a friend whose job was making prosthetic limbs. The hulls were made for the clubs centenary in 1985 to put more yachts on the water (club was formed as a yacht club, a number of 6m yachts were converted to radio as well.) 

A wooden plug was covered by fabric sleeves and resin, this was then removed from the plug after it hardened. I think it may have been under vacuum in an outer sleeve while it hardened. This gave a strong but light shell and the only difference was the outside showed the fabric weave, this could be filled before painting but most didn't bother. ( Some later hulls were made by vacuum forming in plastic but this soon stopped as the plug was being damaged by the heat during moulding.)
We still have a model of the Bell Rock lighthouse produced in the same way for shows and displays.
Jim