sealing the inside of the hull

[dave garrettParticipant @davegarrett24229]

how did you go about sealing the hull when it was all closed up and what did you use to seal it with please ?

[dave garrettParticipant @davegarrett24229]

[Richard SimpsonModerator @richardsimpson88330]

Hi Dave and welcome to the forum. I think most people who would be better qualified to answer you than I am would probably want to know a little bit more about the hull you are referring to. Specifically what it is made of, coated with etc..etc..

Just as a general approach from my own point of view I have never put a great deal of emphasis on sealing the inside of the hull. I only coat it internally if it needs greater strength or for protection from steam plants etc. When it comes to sealing though the effort all needs to be put into the outside. If you imagine a perfectly internally sealed hull made of wood that has not been properly treated on the outside there will be a possibility of the wood getting wet and either rotting or delaminating with paint peeling etc. Water might not get through to the inside of the boat but the hull can still deteriorate.

My personal take is that sealing the hull completely should be done from the outside. As regards what you use that is very much dependent on what the hull is made of but either two part epoxy coating, such as David's, or water based coating, such as deluxe Materials Eze Kote, with or without glass cloth are all popular. Probably the toughest epoxy is the West system but that is pretty expensive stuff and difficult to sand afterwards.

[ashley needhamParticipant @ashleyneedham69188]

Hi Dave. I used to use varnish, or paint, but nowadays I use EzeKote…or acrylic varnish!

Some prefer NOT to seal the inside, so water that gets into the interior wood can dry out.

I go with Richard with sealing the outside, but a few of mine are unable to be made watertight for one reason or another, so I splash on the varnish.

its up to you really, there is no right or wrong.

Ashley.

Snap. Example of a boat I am unable to seal up..look how much water is sitting on the exterior.ior!

[Colin BishopModerator @colinbishop34627]

Generally I use EzeKote to seal the inside and then overpaint with white primer/undercoat. A white interior makes it easy to find things that have dropped off when they shouldn't and looks smart in my view. It's all down to personal preferences though.

Colin

[neil hpParticipant @neilhp]

There is also the point of the material that the hull is made of!.

If the model is made from Hips [High Impact Polystyrene Sheet ] then you must NOT use any form of polyester resin [that used in glass fibre construction and moulding] to seal your hull, prop shafts and such, as polyester resin will melt polystyrene plastics…….i.e. plasticard.

That is all I can add to this thread, as I have only built models from grp hulls for over 30 years, sorry.

[ashley needhamParticipant @ashleyneedham69188]

Neil, no need to be sorry…that’s a pretty serious tip you have added to this thread! Ashley

[Richard SimpsonModerator @richardsimpson88330]

The first thing I said in my post above was we need to know the material it is made of.  There could be a few challenges if the wrong coating is put over certain building materials, although Neil mentions probably one of the more disastrous.

Edited By Richard Simpson on 05/12/2022 09:55:34

[Colin BishopModerator @colinbishop34627]

A number of contact adhesive glues also attack and soften moulded plastic hulls.

Colin

[Andy Stone 1Participant @andystone1]

In my current build I am not sure weather to seal the inside or outside the hull, I have usually sealed inside with an epoxy coat and a tin fibreglass mesh. After reading the comments made which made good sense, I should probably use the epoxy resin on the outside of the hull,

Way back I think I remember reading on Model boats some builders used tissue paper and epoxy creating a smoother and quite strong surface, Would it be easy to rub down afterwards when the epoxy is dry if I use this method ? does the hull need to be blemish free and a smooth surface prior to the epoxy treatment ?

Andy

[ashley needhamParticipant @ashleyneedham69188]

Andy. The smoother the hull is before applying epoxy, the better the finish will be.

Sealing the outside of the hull is a must.

Paper tissue and dope was the long-standing combination to finish the outsides of models as it is cheap and what was available at the time.

Glass tissue or cloth is now available. This is very thin, and would add much more strength to the outside rather than paper tissue if using epoxy.

Easy to smooth epoxy using wet’n’dry paper (wet)

Ashley.

[Andy Stone 1Participant @andystone1]

Thanks Ashley, for some reason I thought that Tissue was preferred as it doesn't have any of those nasty fibres that stick into you or hang around the workspace. Maybe my age is begining to show up.

One other question I have to ask, If the hull your working on after the epoxy has dried, rubbed down and still got holes or dents in it, can you fill those holes or dents with resin or can any other filler be used ?

Andy

[ashley needhamParticipant @ashleyneedham69188]

Epoxy will take almost any filler. P38 car filler is one of the best in my opinion. Easy to sand, smooth, and can be used as an adhesive…it’s very sticky.

Halfords do a tube of filler paste, acrylic, made for filling fine cracks and dents. Takes a while to set (in this cold).

Ashley

[Ray Wood 3Participant @raywood3]

Hi Andy,

What are you building this time down under ?? and please no more text pictures of you jumping in the pool on Christmas day

Kind Regards from the UK

Ray

[Andy Stone 1Participant @andystone1]

It would be nice to get hold of the filler you mentioned Ashley, Ive found a tube of plaster flier which is pretty handy and sands easily too, It only takes an hour to harden off to sand lightly so its just the ticket for me, ( my shed is 34c-36c at the moment ) so I don't really want to hang around in it for too long.

Ray, it ws supposed to be a pilot cutter, Ive often admired the look of them So i decided this year with this build to buy a fibreglass hull from -? in UK, Easy build I thought, It was expensive but I thought id treat myself, they first quoted 40 pound freight, then sent me a message after i had paid that they couldn't get anyone to deliver at that price but can do for 80 pounds if that's ok, A bit disgusted i cancelled and thought to try an Australian supplier only to find they went out of business. So no plans Ray but loads of pics, So thought why not give it a bash.

Stay warm, best wishes from Queensland

Andy

[ashley needhamParticipant @ashleyneedham69188]

Oops! Forgot you were not near a Halfords! Knifing filler is what the generic name for tube car scratch fillers was called.

Humbrol and others do the same thing.

Yes, don’t do a Harry and post pictures of you and yours round a BBQ while we sit here in the snow at -4 degrees!

Ashley

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