Resin or not to resin, that is the question?

[Chris FellowsParticipant @chrisfellows72943]

Now that I'm starting to make some decent progress on my builds I'll soon be at the stage where I skin the transoms.

I'm going to resin the inside of the hull but what are the thoughts on doing the area enclosed by the last frame (solid) and the skin?

I'm doing the Swordsman as I cut a hole in the last frame to give the rudder arms sufficient movement but with the others it will be a sealed space.

Cheers, Chris

[Chris FellowsParticipant @chrisfellows72943]

[Ray Wood 3Participant @raywood3]

Hi Chris,

I'd say not worth the bother , the water should be on the outside, and it's sealed so you'll never know

Regards Ray

[Paul TParticipant @pault84577]

Hi Chris

Fill the void with polystyrene then if you do spring a leak the water can't get in.

Paul

[Charles OatesParticipant @charlesoates31738]

The approach to this varies, unless weight is a critical factor, I always seal the wood in spaces before enclosing them. Sometimes with resin, sometimes with old gloss paint. If there is any chance of moisture getting to an area, you can get warping so for the tiny effort involved I take extra care.

Chas

[Paul FreshneyParticipant @paulfreshney24971]

Chris

Personally I don't like any totally sealed compartment, be it in a hull or superstructure unit. You can guarantee that sooner or later damp or even oil will get into it, even though it is 'sealed' from the outside. Then you have the annoying 'slosh' of liquid inside and no obvious way out. Therefore, there are no totally sealed compartments anywhere on my models, and if of wood, the interior is painted or 'resined'. Having said that, Glynn Guest always leaves his balsa hulls unpainted on their insides, but leaves the hulls 'open' with the superstructures off after a sailing session to dry out if needs be.

Even full-size ships can have problem. Do you remember when HMS illustrious had to be emergency dry-docked because the sealed chamber that allowed filtered seawater into the hull for drawing up into the cooling system was itself leaking into the engine room because the welds had failed. This was a 'sealed' chamber working in reverse.

Buoyancy? Yes polystyrene foam within a hull is a good idea, or even balloons and cut-up swimming floats, if you sail on rough water or there are kamikaze skippers also sailing on your lake! On the other hand, if you build hulls from foam covered resin as does Ron Rees, then the model will float regardless of which way up it is!

Paul.

[Dave MilbournParticipant @davemilbourn48782]

Chris

Do it.

Dave M

[Chris FellowsParticipant @chrisfellows72943]

Thanks for the replies. As said it's no great effort (apart from me having to order the resin (plus cloth etc. for the exterior) first which I'm going to have to do at some point anyway so I may as well do it, though I was thinking along Ray's lines initially.

Dave – I shall refer to your build articles and finishing guides again before ordering anything!

I shall be careful not to get it where I need to glue but does aliphatic resin stick to resin OK?

Cheers, Chris

Edited By Chris Fellows on 29/11/2018 19:14:41

[Dave MilbournParticipant @davemilbourn48782]

does aliphatic resin stick to resin OK?

No. The resin will act as a very effective barrier to the glue penetrating the wood. If you intend to use epoxy resin before gluing up the parts then you'll be restricted to using epoxy adhesive on those parts afterwards.

DM

[Chris FellowsParticipant @chrisfellows72943]

Thanks Dave.

Don't laugh, but what do you think about actually using the aliphatic resin to coat the transom space, it's not that big? I can do it at the same time as gluing the transom skin on then.

Chris

[Ray Wood 3Participant @raywood3]

Hi Chris,

Managed 63 years on the planet and never used aliphatic glue! I'm a fan of Gorilla wood glue water resistant, cheap in Wilkinson's, you only need to varnish the inside of a ply boat really Ronseal does the job. I bow to Dave as he has built loads of Fairy's but I'd glue the spray rails on the ply hull then West resin the whole thing.

Regards Ray

[Dave MilbournParticipant @davemilbourn48782]

I'd glue the spray rails on the ply hull then West resin the whole thing.

Makes it a bit of a bar-steward to sand the hull smooth with the spray rails in the way, but if that's OK with you then why not?

what do you think about actually using the aliphatic resin to coat the transom space,

It's a plan….but not one I'd adopt. Aliphatic resin glue is water-based and so I'm always a bit wary of exposing it directly to the wet stuff. I'd epoxy the transom to the hull after coating all with Z-Poxy. Like Ray, I've also used thinned Polyurethane varnish to coat the inside of of a hull. Works fine. I've never used Gorilla wood glue so I can't comment on it.

Dave M

[Colin BishopModerator @colinbishop34627]

There are always different ways to skin a cat and many of them are equally effective but I would agree with Dave that it's best to get a smooth hull first and then fit the spray rails otherwise the resin will blur them into the hull instead of giving the crisp effect that you see in photos. Resin is difficult to rub down, especially in areas where there are corners.

As for sealing off enclosed areas then just use sanding sealer or some other thin sealant which will soak into the wood and protect against any water ingress. Aliphatic resin will probably do the job as long as you allow it to dry properly but something a bit thinner, even varnish, might be better as it will penetrate more.

It's all proably a bit academic since as long as the external surface is properly sealed you don't need to worry about what is going on underneath.

Colin

 

Edited By Colin Bishop on 01/12/2018 09:40:06

[ashley needhamParticipant @ashleyneedham69188]

I have always used sanding sealer to seal these inside areas as Colin says, it soaks into the wood.

Resin is a bu##er to get smooth, and my preferred method is to wet`n`dry to get the highlights off and then smooth over with P38 car filler (or similar) and smooth that over. HOWEVER you would be adding extra weight by doing that.

Eze Kote and fine glass cloth does it for me nowadays unless the boat is large. Easy to sand and quick drying (but not in the shed in this weather).

Ashley

[Dave MilbournParticipant @davemilbourn48782]

Ashley

The Z-Poxy Finishing Resin which I always use isn't at all difficult to sand, unlike polyester resins and earlier brands of epoxy. Those all seemed to retain a slight degree of stickiness and clogged the abrasive paper very quickly whereas the Z-Poxy has some sort of filler medium which sands off as a white powder. The advent of silicon-carbide abrasive papers has also made the task a lot easier.
As you say, though, this isn't the right sort of weather for any type of painting.

Dave M

Edited By Dave Milbourn on 01/12/2018 09:49:42

[ashley needhamParticipant @ashleyneedham69188]

Dave. I must try z-poxy when I next resin something.

The slow cure epoxy resin I used on a project this summer dried hard and without tack, a novel experience I must say. Still difficult to sand mind you.

Ashley

[Tim CooperParticipant @timcooper90034]

Ashley

I have used Z Poxy a couple of times now. No real problems. I use DM advice and thin slightly with rubbing alcohol.

I have bought a small set of electronic scales from Amazon which makes it easier to mix the two components accurately. Have also used the scales to mix paint to get the same shade each time.

Tim

[Chris FellowsParticipant @chrisfellows72943]

Thanks for all the further replies, plenty of food for thought.

Fortunately I'm doing my building in the smallest bedroom, which is nice and warm, too warm sometimes if I'm doing a lot of sanding!

Applying resin and paint will have to wait until it's warmer and dryer so that it can be done in the garage. Hopefully the hulls and superstructures should be completed by then.

Chris

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