I'm looking for information on the weight of canvas that should be used on a wood car roof. I've heard of both #10, about 12 to 14 ounce, and 22 ounce being used.

Also looking for the methods on finishing the roof such as paint, rubber coating, etc.

Thanks for the help.

Richard

> Also looking for the methods on finishing
> the roof such as paint, rubber coating, etc.

A few years back, Mid-Continent Railway Museum recieved a grant to experiment with different types of roofing materials for railroad cars, and they applied a variety of different types of materials to some of their cars. You may want to contact them, and find out which type(s) worked out best.

Allan

Mid-Continent Railway Museum Contacts
ddg14@msn.com

You might contact Frank Sirinek at the Illinois Railway Museum. Frank has done a number of canvas roofs and can certainly advise on material, preparation and installation. The Museum number is 815-923-4391; leave a message on the answering machine or with the business office.

beast@mc.net

I matched a sample of old canvas with new duck at a sailmakers recently, and used an elastomeric sort of latex based really gloppy roof coating to glue it down (with staples around the edges) followed by 3 cover coats over staples and all. This was a partial roof repair on a T&G decked arched streetcar roof. The coating comes in a 5 gallon bucket in white or gray, I reckon you could tint it with cal tint or colored latex paints mixed in. Given the heat reflection factor in south Georgia, we went white. It seems to be working well after two years and some months.

Dave

irondave@bellsouth.net

At the San Francisco maritime Park we use a sybthetic canvas that looks quite real. The product name is Duradon. Can be worked with either latex or oil base paint.

For a slightly less authentic but still effective
coating there are roofing coatings that they call
"air ball" basicly a synthetic that is good on decks for us. It may be to rigid for rail car roofs though.

ted_miles@nps.gov

At the San Francisco Maritime Park we use a sybthetic canvas that looks quite real. The product name is Duradon. Can be worked with either latex or oil base paint.

For a slightly less authentic but still effective
coating there are roofing coatings that they call
"air ball" basicly a synthetic that is good on decks for us. It may be to rigid for rail car roofs though.

ted_miles@nps.gov

> For a slightly less authentic but still
> effective
> coating there are roofing coatings that they
> call
> "air ball" basicly a synthetic
> that is good on decks for us. It may be to
> rigid for rail car roofs though.

Never tried this Ted but I have had good luck with seamless rubber roofing for less authentic but more practical applications.

Dave

irondave@bellsouth.net

This is interesting stuff for our Restoration Department.

dan

svry@attbi.com

> I'm looking for information on the weight of
> canvas that should be used on a wood car
> roof. I've heard of both #10, about 12 to 14
> ounce, and 22 ounce being used.

8# or #10 duck canvas, no lighter, although on one occasion I did see #6 duck used (not recommended for amateurs). 8 is heavier than 10.

> Also looking for the methods on finishing
> the roof such as paint, rubber coating, etc.

Originally canvas roofs were painted with 2-3 coats of raw linseed oil tinted with pigment (usually black). If you do this, Sirinek says to use a canvas preservative paint first--he claims linseed oil rots canvas, although I've not seen this myself.

Porch and floor acrylic latex works well (apply with paint roller). Use two coats right off the bat and be prepared to recoat periodically. The roof will last for decades. Don't waste your time with these expensive rubbber coatings.

Canvas roofs are not used on cars operated behind coal burning steam engines.

For what it's worth. It is my understanding that a thin layer of white lead was applied to the wooden car roof and the damp canvas stretched over it, tacked down and allowed to shrink. This was then rollered to force the white lead through the canvas from the bottom and then the roof was painted. In this neck of the woods (LSE & CSW&C) you could have a grey or black roof. White lead like raw linseed oil took many years before it hardened providing a flexible base for the roof paint.

> Originally canvas roofs were painted with
> 2-3 coats of raw linseed oil tinted with
> pigment (usually black).


lamontdc@adelphia.net

There are a lot of different methods out there for canvas roofs. One question worthy of consideration is how well the paint or stain penetrates the canvas. Latex paint has a hard time penetrating all the way through heavy canvas. If water gets in, or wicks up from the edges, the canvas may fail. Apco Paint Co. in Illinois is manufacturing a real canvas stain, based on an old formula. Also, Don Curry at Seashore (a former latex paint advocate) got Cabots to select one of their current stains for working with canvas. The stains soak all the way through the canvas, offering added protection from moisture.

As noted in Dave's post, elastomerics will adhere extraordinarily well to canvas- this method is used by Seattle Trolley, for example. Elastomerics will not, however, soak through the canvas, the underside remains untreated.

In any of the above methods, periodic re-coating is required.

Rubber roofing is not a first choice for museum work, but it does hold promise for turning a wooden roof into a low maintenance item. Follow the link below for photos of a Tremco rubber roofing system being applied to one of the replica Pacific Electric 500s being completed at the Port of Los Angeles.

> 8# or #10 duck canvas, no lighter, although
> on one occasion I did see #6 duck used (not
> recommended for amateurs). 8 is heavier than
> 10.

> Originally canvas roofs were painted with
> 2-3 coats of raw linseed oil tinted with
> pigment (usually black). If you do this,
> Sirinek says to use a canvas preservative
> paint first--he claims linseed oil rots
> canvas, although I've not seen this myself.

> Porch and floor acrylic latex works well
> (apply with paint roller). Use two coats
> right off the bat and be prepared to recoat
> periodically. The roof will last for
> decades. Don't waste your time with these
> expensive rubbber coatings.

> Canvas roofs are not used on cars operated
> behind coal burning steam engines.


Railway Preservation Resources
jsmatlak@earthlink.net

> As noted in Dave's post, elastomerics will
> adhere extraordinarily well to canvas- this
> method is used by Seattle Trolley, for
> example. Elastomerics will not, however,
> soak through the canvas, the underside
> remains untreated.

John - you bed the canvas in a thick gloppy coat of elastomeric to glue it down. Staple or tack around the edges then seal with 2 or 3 coats brushed in to the weave. I get pretty good penetration.

Dave

irondave@bellsouth.net

Apco Paint Co. in Illinois is manufacturing a
real canvas stain, based on an old formula.
"Also, Don Curry at Seashore (a former latex
paint advocate) got Cabots to select one of
their current stains for working with
canvas. The stains soak all the way through
the canvas, offering added protection from
moisture. "

John, correct me if I am wrong but are not most stains are pigmented linseed oil thinned with mineral spirits? This takes us back to a linseed oil treatment. It's much cheaper to buy your linseed oil and mix it yourself. Daves's method sounds great ... what is the working time to apply the roof coat and play with the canvas, rolling it to insure penetration from the back?

lamontdc@adelphia.net

It worked for me. I would like to try some of these other techniques sometime to see how they compare.

We generally coated about 2 feet of roof and immediately rolled and smoothed and stapled. As the undercoat dried, it sized the canvas and shrunk it a little to fit tightly. The first overcoat went on as soon as we could get it on.

I used this same elastomeric gunk as 3 final cover coats (tinted) on a flat soldered seam metal roof which had split at some seams and had many holes in it from subsequent layers of roll roofing. We used latex and silicon caulks and fillers, some Bondo included, to fix the cracks and divots before covering.

Time will tell if this technique will work on sheet iron. It hasn't seemed to want to peel in a year so far.

Dave

irondave@bellsouth.net