depron hull and ‘tights’

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14 January 2021 at 16:33 #93244
Graham Jewitt
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@grahamjewitt47037
I am attempting to build a pilot boat hull using depron foam and then propose covering with tights/epoxy as per Ron Rees article. However i am wondering how to deal with the 10mm deep keel. Would it be OK to attach the keel later or should I use glass cloth instead?
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14 January 2021 at 16:33 #2978
Graham Jewitt
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@grahamjewitt47037
14 January 2021 at 19:09 #93252
Tim Rowe
Participant
@timrowe83142
Hello Graham and welcome.

I would attach the keel later. The tights would not conform around the keel and that would leave you a problem.

Tim R
14 January 2021 at 19:29 #93254
Chris E
Participant
@chrise
I seem to remember that one one of his models Ron pinned the tights into the space that they would otherwise bridge.

It didn't sound very easy to me which is why I remember it. You would need to be sure that there was absolutely no gap anywhere.

I would be interested to know the penetration resistance of this construction method which I suspect isn't very much
15 January 2021 at 10:41 #93261
Colin Bishop
Moderator
@colinbishop34627
To be honest, while tights are better than nothing, it would be more effective to use proper glassfibre cloth with the epoxy. When saturated it will follow the shape of the hull much better and provide a stronger skin to the Depron.

**LINK**

Colin
16 January 2021 at 09:05 #93276
ashley needham
Participant
@ashleyneedham69188
I would imagine that tights were used in the olden days as they were readily available and cheap, however nowadays we have purpose made stuff which does a better job and is not relatively expensive.

Ashley
16 January 2021 at 09:52 #93278
redpmg
Participant
@redpmg
Think Ron Rees would be better at answering this question – believe his article on a multi purpose hull promoted the same method ?

As an aside there are various other things one can use with dope or thinned polyester resin rather than fibreglass as even the fibreglass mats are unpleasant to use. However there is one very thin tissue type fibreglass meant for use on walls to hide small cracks and surface blemishes – lighter than tissue itself . Bought some in UK about 15 years ago – easier to use than the others and provides a strong surface.

The alternatives are the tissue meant for waterproofing roofs , waterproof paper towels (the kind used as washing up cloths usually blue or green which end up quite heavy) and finally nappy liners meant for use with cloth nappies. Used all three with polyester resin thinned about 30% & dope with success . Produced strong hulls with balsa . Paper towels over cardboard were used on a full size Beach Buggy – reluctant to use them on small boats because of the weight.

Have also seen a lightweight cloth tissue in the drapers (thanks to better half) – meant for stiffening light cloth in dressmaking – never got around to testing it – may well work too . All of these are preferable to paper tissue as it tears far too easily when wet.

Never tried epoxy resin as it not easily available in SA – should imagine it would work with any of these over foam . Hard to get anything model boat related here – including the magazine……….

Edited By redpmg on 16/01/2021 09:55:31
16 January 2021 at 10:29 #93280
ashley needham
Participant
@ashleyneedham69188
I am not poo pooing the use of tights as a covering material, no doubt they are quite adequate and Ron no doubt had more than acceptable results.

J-cloths and wet-wipes also do the trick!

However, glass cloth is hard and when rubbed down it is quite smooth.

Ashley
16 January 2021 at 10:59 #93281
Colin Bishop
Moderator
@colinbishop34627
Back in the early 80s I used tissue nappy liners and shellac.. Best if liners were not secondhand of course.. Lovely smooth finish – just like a baby's bottom.

Colin
16 January 2021 at 11:41 #93282
Chris E
Participant
@chrise
I fly models made of Depron (or similar) and cover the high damage areas in packing tape or laminating film. It certainly helps but I would not describe either as very damage resistant.

If I were to make a Depron hull I would in essence want to build a hull around it using the depron as a buck. How far you need to go with this would depend on the type and weight of the model, The ambition would be that whatever I covered the hull with was substantial enough to resist the damage that I inevitably subject my models to.

I don't think that, for me, one layer of tights would be anywhere near enough.
16 January 2021 at 11:47 #93283
Colin Bishop
Moderator
@colinbishop34627
Support tights then Chris?

Colin
16 January 2021 at 13:12 #93284
Chris E
Participant
@chrise
Posted by Colin Bishop on 16/01/2021 11:47:57:

Support tights then Chris?

Colin

………….and a corset
16 January 2021 at 15:15 #93285
Graham Jewitt
Participant
@grahamjewitt47037
Many thanks for replies. I think I will go with the light glass cloth and epoxy as I am used to this material.

Graham
16 January 2021 at 19:17 #93287
Peter Vinton
Participant
@petervinton69315
I used the same on my depron Fairey Swordsman, it’s lasted very well.
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