Canvas over ply application.

[Deleted]

Yo Vanvestites

I am at a point on the resto of dear old Mildred.Plyvan where i am ready to start slopping paint around the outside.
I have mentioned on the "Mildred" thread that the timber on the van is very dry and "grainy"and asked what is the best way to fill the grain .

People have replied with ....Just keep painting and sanding, painting and sanding until i fill it up.
I have decided to leave as is and just paint the sides as they are.
I have been considering doing a "canvas over ply roof" the same as many old vans ( including Matilda.D.Plyvan) has.

I can get the plain canvas from a local dude that does annexes etc. Probably going to need about 4 metres X 2 metres so i can roll it down over the front to the top of the window and down the back to "waistline."
Shouldnt be a problem cutting to fit around the roof hatch and working in all 4 directions from there. Once i have "dry fitted" it i can then go about "fixing " it in place.

Heres where i sort of wander which is the best way to attack it.
The topic has been breached before on the forum and i have always thought about rolling a good wet layer of paint on the roof then roll the canvas into it working my way out from the roof hatch to iron out any wrinkles etc.

So i thought i would ask you guys if you can think of any better medium for glueing the canvas down in a way that will make it stay put and waterproof. I intend to apply a couple of coats of paint over it once i have it fixed in place. but i want to make sure it doesnt bubble up or lift with temperature or come away from the ply due to flexing and movement from roaduse.

Maybe i can buy an el-cheapo spray gun and use some of that upholsterers glue or roll the glue on somehow. it would need to be even and consistent and i would have to work fast ??
:oWork fast me not bloody likely ;D

Whats this.. Surely the shed of invention would have the answer.
Sorry folks there has been another explosion and the shed is shut for roof replacement ( again)

Reddonthaveananswer

[minicamper]

Reddo,

You can't use paint as any sort of adhesive medium. Your idea about rolling it in is a good way of bonding to the canvas but not both to the timber.

If it helps, when I stripped the roof of my 1910 Tait train (yes the big bloody red first electric, all timber trains), the roof was sealed as follows:

Timber substructure, coated with glue, hessian laid over the glue.
This was covered in a medium to light weight canvas which was tacked down absolutely everywhere! Then the painting began over the top.

Ironically, there is a vehicle upholsterer doing a presentation at my car clubs meeting tonight AND there will be another working where i'm going tomorrow, so I'll ask both. I've seen one spray a blue glue that you could stick a bondy to the roof with so will ask both of them for you..

Cheers
Chris

[scootman]

REddo .
Re the canvas , I have a mate who was a shipbuilder and he tells me that he rolling canvas onto boats used to be a common thing they did, if you can hang of for a couple of days then I will find him and ask him what he used to do/use
Cheers Scoot

[cobber]

I don't know much but, I thought calico was the go.
Enamel paint first then the calico which would be more absorbant & easier to work than canvas, then enamel paint over that.

Chris,
Ask the eggspurts if they think that would work.

Cobber.

[Deleted]

Thanks scoot , MC and Cobber

I will wait for yours .. and anyone elses replys before deciding to use the canvas or just paint the roof and be done with it.
I might be creating more problems for the timber than i would be curing.

I have an inkling that the membrane paint that Will uses on the roofs of houses might be the go. Trouble is i want a semi gloss or gloss type finish over the top of the canvas when i paint it. Not sure if the stuff that Will uses is waterbased or oil based. This creates other problems when ya go to put a top coat over it. would prefer oil based and flexible .
I use to build train carriages for the NSW tangara project. When building the seats we use to glue the sponge for the seat cushions to the ply with a red glue which was sprayed on like spider web . The stuff was like bear glue but in a "gossimer" form.
When i demolished the old tin van to build the TD replica it had like a red oxide type paint ( probably red lead) that held the canvas on to the ply roof.
If the canvas can be glued on tidy then i will just buy light green canvas. Glue it on , and its all done finished. It can then fade like an old pair of Levis.

Reddo

[Deleted]

Slow down you buggers i cant keep up with the replys.. ;D

That'd be great Kaybee. May as well stick it up here so others that havent got the van builders bibles on the shelf can reference it later on.
I have just got off the dog and bone to Charlestown canvas.
The stuff they suggested is called

"8oz Loom state canvas".. in other words "Artists canvas"
It comes in 191cm width and is $15.95 per metre. They have it in stock. .... CCCCooooooLL Mildred measures 1850mm across her butt ;D so no joins down the middle.
Kaybee.. Silver frost enamel would probably be the old "silvo roofing paint " that everyone use to use to freshen up the corrugated iron roofs with. .. again lead based enamel..

Reddo

[scootman]

ok redoo here are your instructions from the shipwright

airmen says:
paint it down
airmen says:
then paint again
airmen says:
paint
airmen says:
with a special paint
airmen says:
called emaclad , will last forever

[trodler]

Hi Reddo.
Yep you have to use unbleached calico, and yes the roof canvas can be stuck down with enamel paint, and I wouldnt use emerclad, only because you cant paint over it with enamel paint sush as silvasheen.
If you want more info let me know.

Cheers.
Trodler.

[humpty2]

The good old roofing silver paint was tar based........Don't know if you can get the good stuff anymore.

[Deleted]

I used emaclad by the 25 litre drum full everyday when we worked on the train seats... yup. we used it to cover the sponge and spring steel mesh before applying the material.
Reason?? .. Its flame proof. stopped the mindless vandals from setting fire to the seat. the spring steel mesh stopped em stabbing and ripping the seats.

Emaclad is water based and stinks of ammonia. i used to wear a paper mask and still go home with an inflamed throat.

Can see why you cant paint over it with oil based enamel . enamel would "fish eye" or "fry".

Thanks for the headsup everyone. looks like calico is the go and i figure a thick coat of silver roof paint applied with a long napped roller to give a nice thick bed to smooth the calico into. Then a couple of top coats in the finish colour.

Trodler can you flick me your contact details. we can yarn.
Reddo

[Don Ricardo]

Hi Reddo,

For what it's worth, some caravan builders may have used silver frost paint as has been said (and I'm not at all questionning that), but others used an earlier version of Dulux Silvasheen enamel, as Trodler has suggested. So the Silvasheen is the modern equivalent. It gives a distinctively different look and finish to the silver frost, so I guess it depends in part on the look you want to achieve. One may last better than the other, but that's not something I can comment on.

Regarding the tar based silver paint - there is a tar based paint which is used on boat trailers, etc. It was recommended to me by an 'expert' at my local big green shed. I painted the roof of our van with it, and within 12 months it had turned from a slightly bronzed silver colour to a dirty brown. I then repainted the roof with a couple of coats of Silvasheen (ie on top of the tar based paint) and it has worked really well. My assessment is that the paint on the roof has cracked much less than has been the case in the past. I put it down to having the tar based paint as a base.

As I say for what it's worth...

Don Ricardo

[Franklin1]

Hey reddo, here's some more info to cram inta ya brain!! Ya can get unbleached calico from Spotlight stores in widths of 900mm, 1200, 1500, 1800 and 2400mm. I bought some 2400 wide stuff about a year ago for I think about $7 per metre. Was gonna use it on the Franklin, but then lost it in the garage fire. Some time later, was snoopin' around Bunnings paint department one day and saw this item, and thought "Ooh...wonder if this would do the trick?"...



Ya can get different sizes up to 12ft x 18ft, which sells for about $56 from memory. Bought two different sizes for half price from the local Mitre10 store when it closed recently.

Figured it could be a goer, because:
1. it soaks up paint
2. it's cotton
3. it's thicker than calico
4. it's roughly the same price per square metre as calico
5. in my case, the price was right! ;D

cheers,
Al.

STOP PRESS!! Scratch my idea! After posting this reply I had this horrible thought: "What if the dropsheet is not one piece?!" Opened up the 12ft x 18ft sheet and it is lengths of 4ft wide strips sewn together to make the 12ft width. D'oh! Anybody want some cheap dropsheets?
Orrrrrr...you could make your van 4ft wide, and this idea would still be a goer!
No?? Not an option? Bugger!

[minicamper]

Reddo, I've asked the "eggsperts".

Both were of the same opinion. Doesn't matter whether its calico or canvas (getting canvas that's not too heavy may pose a problem)

They said that in their opinion, use a contact adhesive, whether you spread it by hand or use the thinner trimmers stuff that can be sprayed doesn't matter.
Attach, rolling it out (and use a roller as you go to press it in and exclude bubbles). But, and there's always a but... Canvas can shrink A LOT unless you weather it for months, so either allow for that shrinkage, or go for the calico.
Paint as you wish.

Don't worry about the enamel vs water based. Use the primer sealer i spoke about in another thread. Mind you, enamel is not flexible and is liable to crack, they thought acrylic would be better..

Cheers
Chris

[JBJ]

Hi All,


I cant see why a properly sealed & gloss painted ply roof would react any different to weather than the sides, back or front would.
When I restored Groovin, the bum of it had been in the western sun for 20 plus years. Sure the paint had cracked, & the oregon window framing had actually burnt inside the cracks in the paint.
But it didnt take a lot to sand & repaint, & the ply showed no sign of long term damage

But a van thats used regularly , & stored under a carport except for when its on the road ( maybe max 2 months a year, or 16% of its life), surely would survive if it had decent paint on it.

The van I'm currently rebuilding,Lucille, has rot in several places in the ply from being unpainted & stored in various places for 50 years. There was a real problem with the canvas over the ply lifting, & trapping moisture, thus causing rot in a few spots.

But I'm finding that by painting primer, letting it dry over a week or so, then sanding & re priming, & going through that cycle for 3 or 4 times, that the ply is ending up with a glass like surface.

Surely when I put the final primer, then several coats of gloss enamel, the paint will provide a totally weatherproof surface.

I dont believe that panels flex enough to cause any cracking. The nature of ply is that it will not move around, so shouldnt crack.

After all, paints have improved immensly over the last 50 years, or so the manufacturers tell us.

Can anyone tell me definitely, based on real experience not hearsay, that I'm doing it wrong?

Jailbarjuice

[Deleted]

Hi dudes.
The canvas i intended to use and got a price on is 8oz . same as the white sides on the old tents that had 15oz roofs .
If i used the silver sheen it would onl;y be to "bed" the canvas into. The top coat would be Eau - de-nil ( light green) like the colours on Matilda and my ex TD. os no worrys about the silver turning bronze or brown.

The way i see it if i cut the canvas so that it wrsaps over the edge of the roof and tucks in behind the 'J" or "L" mould it can shrink a bit and it wouldnt matter too much .. in fact if it does shrink it would close the weave of the canvas and probably give a better watertight seal with 2 top coats over it..

Just gotta decide whether to glue it down or bed it in a thick coat of paint so the paint adheres to the pink primer and soaks through the canvas to form a bond.

The worst i can do is stuff up..... something that happens quite frequently in the shed of invention. At least the police and firebrigade wont be involved.

Thanks for the info guys.
Reddo

[Deleted]

Hi Dennis.
We must have been typing at the same time.

Not saying paint doesnt seal proprely.
Its just that i have had a few vans with canvas over the roof .
Matildas roof has the canvas on it and i figure it was done for a reason back in the old days.

Sure paints have improved and they expand and contract much better than some of the old enamels etc. but i thought i would give canvas a go as i havent tried using it before. I am not trying to achieve a gloss finish . just playing with an idea that was used in the past and see how i go. Hopefully it will give a flat consistent surface that protects the old grainy ply. as i said it already has 2 coats or pink primer and being only three ply i dont wont to keep sanding it and risk going through a "soft spot"

years ago a local radio station ran a competition . first prize was a VW superbug that had been covered in denim. you could see the bog repairs ( bulges) underneath the denim, but the denim held it all together and it looked cool.

Reddo

Reddo

[smiles]

An old trick to estimate how much shrinkage there'll be with any fabric ,with either calico or canvas, is to cut an exact 6" square of fabric then soak it in lukewarm water before drying flat. Canvas & even calico can have a lot of sizing in it that keeps it nice & flat for putting on the roof, so I would actually think that either a lightweight canvas or a heavy weight calico would be best such as a 10oz canvas or lighter, especially if it wasn't going to shrink too much. I got 20 yds of old fashioned woven ticking to make cushion covers for the van, and washed my 6" sq before cutting the 20 yds into pieces the washing machine could handle.
Our Overlander has canvas on the roof, but it is pretty light weight stuff, more like heavy calico.

[Deleted]

Hi Smiles

I will probably go with the 8oz artists canvas. Do as you say and "pre shrink it" by throwing the lot in a bathtub full of water for a day and then letting it dry by laying it out somewhere in the sun . I wouldnt peg it up becuase it would probably stretch and sag unevenly causing problems before i even start.

I have Trodlers number but havent had a chance to yarn with him yet. He does a brilliant job on van restorations and i feel i am 75% right in what i plan to do. I would imagine He will set me straight on the finer points of applying the canvas and painting.

As i said in one of my earlier posts . I could probably get away with just doing as JBJ has suggested and keep preping and painting but i have the opportunity to try this old technique out . If i stuff up i can always tear it off and paint finish the roof.
Other option would be to "reskin " the roof with ply or masonite or apply/glue sheets of masonite over the ply to give it a really smooth finish

Its only going to cost me my, time, patience and money.. of which i am short of on all 3 counts

Reddo