waterproofing balsa.

[Dave43Participant @dave43]

hi all

never built a boat with balsa wood before so I have decided to have a go at

H.M.S. sheffield from free plan. got the wood and glue and paint but dont feel too confident, was going to cut it out of 1/8th ply but thought… nothing ventured and all that stuff.so here goes.

just feel if its got to be smothered in fibre glass and stinking resin, then why dont i make a fibre glass hull in the first place.

[Dave43Participant @dave43]

whats the easy way

[LARRY WHETTONParticipant @larrywhetton68737]

Hello Dave ,

You need not use resin to seal balsa, seal with sanding sealer , thined 50/50 ,

sand back a little then cover with tssue aplyed with the 50/50 dope . sand back then dope again ,

sand back ,repeat till you are happy with finish, add final finish ,

on this site there other treatments if its a Glynn Guest plan this his type of finish ,

and it works ……..cheers Larry…

[ashley needhamParticipant @ashleyneedham69188]

Dave. Considering the amount of time spent actually in the water, simply applying several coats of (thinned a bit if you want) ordinary (grey in this case!) household undercoat and then a couple of topcoats of Humbrol or whatever will be quite adequate.

Thinned sanding sealer will obviously penetrate a bit more, and as Larry states, the method is as used by Glynn.

I have been using Eze cote water based resin and fine glass tissue for the last few models and it is the business. Easy clean brushes, no stink..can be applied in the front room. The glass cloth is like silk, and conforms very well to curves, will give a much tougher finish than dope/paper.

Up to you, everyone has their own method. They all work, you could pick any of them and be quite satisfied.

Ashley

[Colin BishopModerator @colinbishop34627]

I agree wih Ashley that Eze Cote resin is nice stuff to use, water clean up and no smell.

Colin

[HowardParticipant @howard79726]

I also agree with Ashley and Colin that Eze Cote is an excellent finishing product. I have used it on a couple of models now. I'm in the final stages of building a Higgins PT boat from a Model Boats plan, with ply formers and a sheet and plank balsa hull, and I'm very pleased with the results using this product in conjunction with fine glass cloth – simply follow the instructions on the bottle!

[Dave43Participant @dave43]

I remember cascamite from years ago this was a water based resin glue comes in powder form and mixes with water to make a stiff or sloppy glue, economical in the way you mix just the right ammount for what you are doing. stiff for skins and stringers, sloppy for waterproofing. so would like to find something that works the same as this

also shelf not cluttered up with loads of bottles and containers …..sorry but im a bit of a dinosaur and takes me a bit to change direction

dave

[Dave MilbournParticipant @davemilbourn48782]

sorry but im a bit of a dinosaur and takes me a bit to change direction

dave

I could have written that, too. I have also been persuaded to try Eze-Cote and can heartily endorse what's been said. I miss the smell of cellulose but cleaning up is so easy and sanding is a doddle (Tip: Use silicon-carbide paper 320-400 grade). Foiurteen quid seems a lot for a bottle but I've done a whole model with one coat and only just down as far as the shoulder of the bottle. Try it and see.
Dave M

[Keith LongParticipant @keithlong89920]

Dave

Cascamite is still available but under another name – "Polymite" available from Axminster Tools in various sizes from 125gm (£3.67) to 6kg – for models of the Titanic – (£61.75). Also worth looking at "Resintite" from Toolstation another urea-formaldehyde water mixing resin – water resistant to D3 standard so suitable for exterior usage. Tha pack sizes on the latter are larger 1.5kg and 3kg but the prices are not bad at £8.50 and £14.55 respectively.

Axminster also sell "Aerolite 306" which is similar but has a hardener as well as using the water/powder mix. That is used for building light aircraft as well as boats. A 375gm "glue pack" of that is listed at £11.19.

Quite a few options as well as the newer products to the market.

I've no connections with any of the companies above except as a customer,or experience of the products mentioned, I just looked in their catalogues.

Keith

Edited By Keith Long on 11/03/2013 13:55:51

[Dave43Participant @dave43]

thanks all,

very helpfull and plenty of info… got a couple on the go so will try the differant glues and finnishes on each one. allthough I still like the idea of water based resin glues, seems the way to go, easy clean and all that.

dave

[michael howarth 1Participant @michaelhowarth1]

I am a complete newcomer to boats although I am a builder of Gauge 1 live steam locomotives and similar scale traction engines. It was at a steam rally that I picked up what appears to be a well made RAF Crash Tender for a ridiculous £7. It is, I estimate, about 80% complete, requiring two cabin covers and deck fittings and then some type of radio control. I think that my first job will be to ensure a watertight hull and from what I have read above, Eze Kote is the way to go. If I use this in conjunction with glass fibre matting what thickness should the matting be? Is tissue just as good? Can I use any tissue or does it have to be of a certain specification?

Mick

[Mark Jarvis 2Participant @markjarvis2]

HI Mick

The site you need to look at is http://www.easycomposites.co.uk they are specialists in epoxy, glass cloth etc, the epoxy can be thinned with meths to make it runny, also try using your wifes tights to cover your hull, to seal the inside pour thin epoxy into each compartment and role the hull to speed it round, what doesn't soak in brush it into the next compartment.

Regards

Mark

[michael howarth 1Participant @michaelhowarth1]

Thanks Mark. The thing that I love about these forums is that there is always someone who knows which direction to go.

Mick

[Dave MilbournParticipant @davemilbourn48782]

Eze-Cote isn't intended to add strength like, for example, chopped-strand matting or heavyweight woven cloth used in conjunction with epoxy or polyester resin. Its use is to give the outer surface a smooth durable base for a paint finish. I use 0.6gm cloth from DeLuxe Materials. Use one coat of Eze-Cote to apply the cloth, allow to dry for at least 20 minutes then sand off the excess from round the edges. Apply another coat of Eze-Cote, allow to dry then attack it with 180, 240 and 320 silicon-carbide finishing paper. Give it a thorough dusting off before priming etc.

If you want to waterproof the inside of the hull then you would best use polyester or epoxy resin. Depending on the strength of the existing hull you might not need any matting or cloth at all – just slop in a good thick coat of resin and let it set for at least 48 hours. It will slowly run into all the cracks and gaps and set up hard.

Bluebird swears by glassfibre tissue but I've only ever used it as part of the hull laminating process i.e. between the gelcoat and the matting/ lay-up resin.

DM

[michael howarth 1Participant @michaelhowarth1]

Thanks Dave. The hull seems to be well made, well braced and strong enough. My main concern is to make it watertight not only for now but looking to the future. Is Eze-Kote on its own on the exterior of the hull a good waterproofer? I note your comments on using epoxy or polyester resin on the inside. What is the fundamental difference between polyester resin and epoxy resin?

Mick

[Dave MilbournParticipant @davemilbourn48782]

Mick
Is there any sort of finish on there at the moment? If so then Eze-Cote, being water-based, probably won't stick to it. If not then it would be a sound BASE for a waterproof finish e.g. add primer and topcoats from aerosol spray cans. Epoxy and polyester are both used as laminating resins but polyester is much cheaper and much, much smellier. Epoxy sands much better. I use polyester for waterproofing inside the hull and epoxy finishing resin (Z-Poxy) in conjunction with glassfibre cloth to form a base for the outside finish. Eze-Cote is an alternative to the epoxy finishing resin. It's easier to apply and clean up but not as good a finish as epoxy IMHO.

Dave M

[Tony HadleyParticipant @tonyhadley]

A good item was written in the September 2014 Model Boats magazine by Ron Rees about the products manufactured by Deluxe Materials, who are the manufacturers of Eze-Cote.

The product which is worth mentioning for balsa sealing is Sand 'n' Seal. The paragraph covering this product reads – "Another discovery, because it takes a while to fill the weave of a nylon stocking was Sand 'n' Seal, which works really well on balsa as a sealer, once again fast drying and with no smell , unlike Shellac sanding sealer or thinned dope. This product seems to be similar to EZE-KOTE but has a much thicker texture."

Never tried the product, but I think it will be worth a trial in the future.

Tony.

 

 

Edited By Tony Hadley on 15/09/2014 14:04:14

[michael howarth 1Participant @michaelhowarth1]

Dave M…..thanks for the post. The hull is unpainted, rubbed down very smooth and I would guess that it is plywood. When I think of "epoxy resin", a thick syrupy liquid comes to mind. Is this the stuff that I would be using, albeit watered down with meths? Is epoxy resin essentially the same as glassfibre resin?

Mick

[Dave MilbournParticipant @davemilbourn48782]

Posted by michael howarth 1 on 15/09/2014 16:16:52:

Is this the stuff that I would be using, albeit watered down with meths? Is epoxy resin essentially the same as glassfibre resin?

Mick

"Glassfibre" is the term for the mat or cloth. You can use either epoxy or polyester resin to laminate it. Most hulls are done with polyester resin because it's much cheaper, so I suppose that's the stuff you would know as glassfibre resin. Proper epoxy finishing resin is less viscous than epoxy adhesive, and I thin it down further with isopropyl (rubbing) alcohol – about three parts resin/hardener mix to one part IPA. Once set it is very easy to rub down as there is no inherent stickiness left to it. I wouldn't use standard polyester resin as a finishing coat.
DM

[John W EParticipant @johnwe]

hello Mr M see you have dragged me into this topic – as if I need dragging into anything about using fibre glass resin and tissue, saying I swear by it – I don't know about swear by the method but I have sworn at it a few times – especially when the resin hasn't gone off. & left with a gooey mess to try and clean up

Mick, there is a vast difference between polyester resin and epoxy resin; just to give you a broad outline; polyester resin is very temperamental in many ways and to being with :

 

1. you have to get the mixture between hardener and resin spot on, if you don't add enough hardener the mix sometimes doesn't go off and can stay tacky for weeks on end. If you mix too much hardener in – it can go off rapidly generating great amounts of heat which can sometimes ignite. Or if it doesn't ignite it starts smoking and turns the mixture into a form of cinder toffee which unfortunately you cant eat.
2. you have to have a reasonable temperature, no lower than 15 degrees and it has to be a dry area where you are working, this again can upset polyester resin. If the temperature is too low or too damp the resin wont go off.

That's just a couple of the downsides of polyester resin. The good side is its a lot cheaper than epoxy.

 

Now, for epoxy resins, one of the downsides is you have to be very careful while handling this because some people are very allergic to it, if it gets on the skin – it can cause some nasty rashes. It doesn't smell as strong as polyester resin, but it does have an odour. The good side of it is the mixing – one portion of hardener to an equal amount of resin. That is 1:1 ratio, on the majority of epoxy resins.

 

The next good thing about epoxy is that its not so temperamental to temperature – it will set at a lower temperature than polyester.

 

Now, we have been speaking about tissue matts – one has to remember this:

fibre glass tissue matt or heavier gauge matting cannot be used with epoxy resins. This is because the fibre glass matting has a bonding agent, which bonds the strands of glass together in the makeup and this bonding agent dissolves when polyester resin is mixed with it, but, it will not dissolve with epoxy and you just end up with a mess. Make sure you sue the correct materials for the epoxy.

 

Hope this is of some help.

 

aye

I am finished editing now by the way

John

Edited By bluebird on 15/09/2014 17:29:05

Edited By bluebird on 15/09/2014 17:29:44

Edited By bluebird on 15/09/2014 17:30:51

Edited By bluebird on 15/09/2014 17:31:31

[Dave MilbournParticipant @davemilbourn48782]

Sorry all – I'd forgotten about the bonding agent in chopped strand and glass tissue. BTW John, do you still have the photo of your 12"=1ft scale model being craned over the garage?
Tony
I spotted that new Deluxe stuff on their website but having just bought a shed-load of other finishing materials I never got round to trying it. I have to say how impressed I've been with Z-Poxy Finishing Resin and lightweight glass cloth. I can't see me straying from that except maybe for a quick thrown-together model for one of the kids.
DM

[Mark Jarvis 2Participant @markjarvis2]

Hi Fellas

Can i bring you back to the company i mentioned. http://www.easycomposites.co.uk they supply all the glass cloth, chopped mat, epoxy resin.

All mail order unless you are in Stoke on Trent.

Someone mentioned Deluxe Materials, fantastic products at a price. Eazycote brilliant £13 a bottle, Epoxy £8, Glass cloth .6oz is half the price.

I have no interest in the company other than great stock at superb prices, reasonable mail-order cost.

Mark

[Dave MilbournParticipant @davemilbourn48782]

Nice to find lightweight glass cloth at a sensible price. Thanks for that link, Mark.
DM

[michael howarth 1Participant @michaelhowarth1]

Thank you all for the wealth of information that you have provided.

Mick

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