Canvas and fibreglass deck

[Chris Pink]

I'm about to embark on covering a wooden deck in canvas.

 

Would it be worth considering fibreglass. Would I get in right as a first attempt? Is it easy? Would the wood die?

 

I'm 99% for canvas. Ive bern reading about bedding compounds and most of the recipes call for mixing a couple of bedding compounds with fungicide and linseed oil and paint. But the bedding compounds are only available in the US and sikaflex 291 doesn't look like a great mixer.

 

So I'm thinking a slushy mixture of cuprinol, linseed oil, putty mastic and masonry paint with the canvas rolled on after filling the worst voids with graving pieces and P38.

 

Any suggestions from someone who's done it?

 

Incidentally there is bulk sikaflex at it's sell by date. 12 x 400ml for £50 floating around the net I cant use 5 litres that quickly but If anyond down this way wanted to split a case?

[Teadaemon]

If you were replacing the decks with plywood, I'd strongly recommend covering with a couple of layers of glass cloth and epoxy, followed by non-skid deck paint. That's a very common thing to do on old wooden boats and has a good track record of success.

 

Glass and epoxy on to old wooden decks has more pitfalls (getting the decks dry enough and making sure you're not sealing in rot are the two biggest issues), and anything involving polyester resin is far more trouble than it's worth.

 

Since you're planning to keep the old wooden decks, then painted canvas is probably the easiest way to go. It sounds like you've done your research, and your suggested method sounds about as good as any I've read.

[Chris Pink]

I have been further researching and find that a traditional bedding compound is a mixture of white lead and linseed oil.

 

You can buy lead carbonate fairly cheaply.

 

So, adding it to paint? Any ideas? How much, what difference does it make?

 

I used to use red lead primer when i could get it easily and it is the mutt's danglies.

 

Assuming I can avoid poisoning myself and any creatures in the vicinity. Do you think I could make a lead primer easily?

 

They are available around £35 a kilo.

[RLWP]

As it is a bedding compound, does it have to be white lead paint? I guess (WARNING) that they would have used white lead because it was cheap and easily available.

 

Richard

 

I'm surprised Carl hasn't contributed to this yet

 

MORE:

 

White lead is a pigment composed of Lead carbonate and Lead hydroxide. It is used as a rust preventive and it used to be used in house paint until it was recognized that exposure to the old powdering paint and chips created a lead poisoning hazard to people.

 

Read more: http://wiki.answers.com/Q/What_is_white_lead#ixzz1tpdeZ4oP

 

I assume (WARNING) more linseed just adds to the linseed already in the paint, making it runnier

 

AND:

 

In the 17th century the Dutch greatly increased availability of white lead and lowered cost by invention of the Stack Process. All white lead paints included chalk in their undercoats, reserving purer white lead for finish coats.

 

White lead paint was just cheap primer

Edited May 3, 2012 by RLWP

[Chris Pink]

White lead is a heavy, white substance, poisonous, insoluble in water, extensively used as a white pigment and as a base in paints. It is one of the oldest paint pigments used by humans. Chemically, it is basic lead carbonate, a mixture of lead carbonate and lead hydroxide. It is prepared in various ways. When used in paints, it is first ground into a fine powder and mixed with linseed oil. Its covering power is greater than that of most other white pigments, but its use has certain disadvantages. It reacts with hydrogen sulfide and some other sulfur compounds in the atmosphere, the lead combining with the sulfur to form lead sulfide, a dark substance. In paints made with white lead a chalky film is formed after some time.

[RLWP]

Thinking laterally, our flat roof is made of plywood faced Kingspan foam sheets, with a rubberised covering glued onto it. Like this stuff:

 

http://www.permaroofstore.co.uk/products/flat-roof-kits/garage-roof-kits/garage-roof-kits-standard-grade-1-14mm

 

Ours is light grey

 

Richard

[Chris Pink]

yes, I was wondering about a rubber compound for bedding.

 

Like this; http://www.permaroofstore.co.uk/product/48/permaroof-deck-adhesive

[RLWP]

This one is called a roofing and waterproofing membrane. I think ours id Alwitra

 

http://www.flatroofs.co.uk/#/evalonpolymermembrane/4529942003

 

Richard

[RLWP]

I knew I had something on this somewhere. From British Railway Carriages 1901-1922 (D Jenkinson 1988), it would seem you need a bit more than lead carbonate in linseed oil

 

You would need boiled linseed oil and litharge (lead oxide) to ensure a reasonable drying time.

 

The canvas was impregnated with a messy mix of linseed oil, white lead and putty, which would ooze into cracks in the roof. It seems there was more than one layer of canvas too. This was then finished with several layers of grey or white lead paint, the final coat being mixed with varnish

 

All good fun!

 

Richard

Edited May 3, 2012 by RLWP

[Chris Pink]

This one is called a roofing and waterproofing membrane. I think ours id Alwitra

 

http://www.flatroofs.co.uk/#/evalonpolymermembrane/4529942003

 

Richard

 

 

There may be the same problem as using epoxy on laid deck. It has to cope with the movement.

 

Looking into it , it may be flexible enough but a quote for a coach roof?

[PhilR]

I have been further researching and find that a traditional bedding compound is a mixture of white lead and linseed oil.

 

You can buy lead carbonate fairly cheaply.

 

So, adding it to paint? Any ideas? How much, what difference does it make?

 

I used to use red lead primer when i could get it easily and it is the mutt's danglies.

 

Assuming I can avoid poisoning myself and any creatures in the vicinity. Do you think I could make a lead primer easily?

 

They are available around £35 a kilo.

 

In 1970, I used a mixture of white lead and yacht varnish to stick down and seal canvas onto a new T & G cabin roof.

This was 100% successful and fully waterproof. After several coats of this I used a few coats of oil based gloss paint

and added dry sharp sand to the penultimate coat for a non slip finish.

 

This was the method recommended to me by a firm of local coach builders. I think they called the mixture *smudge*.

 

I'm sure there will be lead free primers that will do the job just as well. Make sure you stretch the canvas and tack it

down at the edges until the 2nd coat is dry.

 

 

Good luck!

Edited May 3, 2012 by PhilR

[RLWP]

 

Looking into it , it may be flexible enough but a quote for a coach roof?

 

Come on, you'll love to make that 'phone call. "Hello, I'd like someone come and quote on putting a membrane on a boat"

 

Richard

[Chris Pink]

I had a think about the rubberised compound route and whereas it might be a good idea as a substrate, the canvas will need something that will soak in and provide a bond for the paint.

 

The main problem I'm going to have is that with the width of the roof, about 8 foot is to get the gloop spread and the canvas rolled into in without covering myself. To get access equally to both sides might be an issue. Not for the first time I wish there was a work flat in the family.

[RLWP]

Don't you spread the gloop and roll the canvas at the same time? That way, when you reach the edge you don't have to stand on fresh air to gloop, you can stand on the canvas

 

Richard

[Chris Pink]

Don't you spread the gloop and roll the canvas at the same time? That way, when you reach the edge you don't have to stand on fresh air to gloop, you can stand on the canvas

 

Richard

 

....you can stand on the (very messy gloop soaked) canvas.

 

Duck boards I think are the way to go.

 

it's the old painting into the corner of the room problem.

 

Though it will be easier when the boat's in front of me (and the rain stops!!!) because even visualising it now I can see how it might be possible from one side (ie doing it sideways)

 

though the ideal is to work from the centre out as I believe it's going to wide enough to need a seam in the canvas.

[RLWP]

Do you need to sew a seam? I would have thought making sufficient overlap would be enough

 

Richard

[Chris Pink]

Do you need to sew a seam? I would have thought making sufficient overlap would be enough

 

Richard

 

My experience with canvas is that if it's not held down by something (a moulding -not sure of the nautical term, strip of wood on the side, cabin frame or coaming or something) it will peel. Also an overlap would need hemming) It would be favourite to put a piece of wood over the seam too which, if I get right down the centreline would look OK.

[smileypete]

I'm about to embark on covering a wooden deck in canvas.

 

Would it be worth considering fibreglass. Would I get in right as a first attempt? Is it easy? Would the wood die?

 

What sort of boat and what's the existing deck, ply, planked? Also what's the condition, and is it curved or flat?

 

cheers,

Pete.

[Chris Pink]

It's planked in mahogany (possibly) curved abeam, flat fore and aft. Not bad condition. Looks like it was canvassed once now scrappy roof felt which is coming off. It's unlikely I'll be able to completely remove the bitumous underneath so that also needs to be taken into account.

 

There's a fair amount of deck fittings I can remove. 2 hatches and a section of coaming I can't. Not sure whether to remove the mast, deck stepped. I probably will.

[smileypete]

It's planked in mahogany (possibly) curved abeam, flat fore and aft. Not bad condition. Looks like it was canvassed once now scrappy roof felt which is coming off. It's unlikely I'll be able to completely remove the bitumous underneath so that also needs to be taken into account.

 

There's a fair amount of deck fittings I can remove. 2 hatches and a section of coaming I can't. Not sure whether to remove the mast, deck stepped. I probably will.

Seems good old google comes up with some links to forums worth reading: (linky). Following the above results also came across a canvas supplier (linky), a local decorators merchant may have off-mixed gloss at a good discount if you explain.

 

Don't think I'd bother with white lead and stuff, maybe just try painting the canvas with spirit-based Cuprinol wood preserver or similar then let it dry. With these things I usually try a sample first (what I call the 'here be dragons' phase ) instead of going all-in from the start.

 

Edit:

 

To get the paint nice and thick you could try a little 'colloidal silica' eg. from Ebay or here, stuff like talc will just absorb water. And work some wood preserver into the joints while the deck is off. Any remaining patches of bitumen on should be overcoated with 'aluminum wood primer' to stop it bleeding through.

 

If the deck is really lumpy, covered in bitumen, and the boat won't be used off-shore maybe consider 'skinning' it in 1/4" decent ply first.

 

cheers,

Pete.

Edited May 5, 2012 by smileypete