Bending ply?

[Terra]

Hello everyone!

I am new at this forum stuff, so I hope this works....here goes.

I have to do a repair on an old ply van for a friend and have been chasing around all over the place for information on plywood.

Yes, I have been through all the threads and read what everyone has said about marine ply etc, but that's not what I want to know.

My question is what radius can I bend ply around? I know this will depend on it's thickness, which I think is about 4mm.

I have been trying to find answers for about 4 weeks now and no one seems to be able to help me with an actual radius, all I can get out of suppliers is "sick it and see" which isn't what I'd call technical.

Hope someone out there can help me!

Thanks.

[Franklin1]

Hi Terra,
Make contact with EWPAA (Engineered Wood Products Association of Australasia) via their website at www.paa.asn.au/

From the Austral Plywoods website ( www.australply.com.au/ti_fixing.html ) comes this information...
"Bending plywood is relatively simple. Plywoods with Type A bond phenolic glue lines can be soaked or steamed to assist bending. Minimum safe bending radii are obtainable from the EWPAA technical literature. It is not possible to obtain a compound curve when bending flat plywood panels."

Let your fingers do the walking...

cheers,
Al.

[cobber]

G'day Terra,

That Austral Plywoods link Al has given you has a lot of good info on it if you browse through it.

If you want a tight bend have a look at their “bendy ply”.....I used it on Ol'36.
www.australply.com.au/pr_bendy.html

They also give some info regarding painting of ply wood at
www.australply.com.au/ti_exterior.html

Cobber.

[cobber]

G'day again Terra,

I just got a phone call from George so now I know what you are talking about specifically .
If you give Austral ply a phone call on 73426866 they will let you know who supplies their product closest to you.

There are a few blokes on this forum who have restored Properts and would be able to give you advice as to what ply you could use to go up the front and over the top of a Propert.... originally it was joined just before the bend over the roof and I suspect wetting the ply was how the bend was achieved, but people like Trodler and Roehm3108 will be able to give you first hand experience.

Cobber.

[tearterra]

Thanks for all the good info.

I'll have a look at those web sites right now and let you know how I go.

Cobber,
good, you've been talking to George, I haven't heard from him yet. I didn't even know the name of the van, so it's a Propert!

I was thinking at one stage about scarfing the sheets and doing away with the join at the front all together, but there is nothing wrong with the lower sheet, so as they say "if it aint broke don't fix it".

Thanks for the help everyone

Terra!

[Roehm3108]

Don't shout so loud, Cobber, ain't deaf yet!! Just cos you still walk around with a pipe stuck in your ear, thinking it's as good as a gramophone speaker to hear with!!!! ;D ;D ;D

Seriously though, I have only had to reskin the inner shell, and that was on my first Propert. On this one, the ply was about the only thing I didn't replace, so really can't give any constructive (get it) opinion. I reckon though that the skin on the outer shell, which has the tight bend, may be thinner than 4mmm. You want to be careful with that bendy ply, as to my knowledge that is an interior use ply. Perhaps if you used the bendy ply and used two layers, you would get a strong finish - a bit like laminating.

Am thinking of re-doing the outer skin on my Propert somewhere W A Y in the future, as it has a lot of sanding scuff marks on it. Was thinking of covering it with a sheet of flat aluminium like the first one, but am watching Jailbar's project with interest to see how his work comes up in the final wash.

Ray

[retro1]

I have bent ply as thin as 1.5 mm.
Once bent it gains a hell of a lot of strength.
The cupboards in the link below are 1.5 mm ply.
Bending ply is great to get the form but needs to be laminated to another surface. The radius of the cupboards is about 50mm.

vintagecaravans.proboards30.com/index.cgi?board=photo&action=display&thread=1140&page=1

[tearterra]

G'day again,
ordered some bendy ply the other day to do the job, hope it'll be by next weekend. I don't think I'll have any trouble with the strength (fingers crossed).

The bendy ply is 5mm thick, this is as close as I could get to the original, and as for making it waterproof I was going to try painting the outside with the stuff that they put on bathroom walls and floors to waterproof them........then just paint over that.

Well that's the theory behind it at the moment...........I'll let you know how the practice goes when the ply arrives.

Thanks for the advise!
Terra

[JBJ]

Hi teartera,


Before you seal ply with anything, have a check of the sealer manufacturers instructions as to the type of paint you can use to finish over the sealer.

Some will only work under Acrylic (water based) paint, & some will only work under enamel paint ( oil based), & even less will be OK under anything.


Dependent on the gloss you want on your finished van, you may have to reconsider your choice of sealer.


I'm only using an oil based primer/sealer on Lucille, my ply van I'm rebuilding, this time around, because I want to finish with full gloss enamel.

I used Gripset waterproofer/sealer when I restored Groovin' a couple of years back. It did a good job, but I could only use Acrylic Gloss external paint. I believe Enamel gives a shinier surface.



Jailbarjuice

[tearterra]

G'day retro1,
I have just had a look at the restoration you did on diner2.

It does the old ticker the world of good to see that you have used all that timber, I could almost smell the stuff through the computer.

Congratulations on a great restoration! They don't make em like that any more................well, no one but retro1 anyway!

Terra!

[tearterra]

Good point Jailbarjuice,

I hadn't thought of that one. I'll check with the paint suppliers as soon as I can......Thanks!

Terra!

[Deleted]

Terra wrote:
"It does the old ticker the world of good to see that you have used all that timber, I could almost smell the stuff through the computer"

Good onya mate. Another forum member to recieve a years free membership in the "Royal Society for Preservation of Bondwood Caravans of Australia"

You must promise to keep the bondwood faith and fight the good fight against the evils of fobbergross caravans ( and thier owners)

All tongue in cheek stuff Terra.


Good luck with the repair job.
My two bobs worth:.......
I bent "normal "5mm ply to a 350mm radius when i built that Teardrop van. I use oil based primers , undercoats and gloss enamel top coats on any of the vans i restore or repair.
Solarguard is good.. it expands and contracts just that bit better than the average enamels.

Reddo

[scootman]

Hey Reddo, that interests me, When I built PH I painted her with a weather/water proofing substance, but the instructions were, must be painted over with a water based paint. As a result I dont have the glossy shine that I deserve. Tell me , what sort of water proofer do you use? or dont you?
Cheers scoot

[Deleted]

;D ;D ;D
Hi Scoot.
Anyone that has hung around this site for a few years will tell ya i have always harped on about OIL BASED PAINTS.... thats what i use to make things water proof. If i could get hold of the old red lead paint i would be using it today.

I have a picture somewhere of "Just croozn" when i had my first attempt at painting it ( sky Blue ) i done it with water based acrylic gloss .. I made sure i done it on a warm day in full sunshine so it would have plenty of time to dry.
it came out looking like chalk .
totally peed off i rubbed the whole thing down again and done it with oil based gloss enamel in the Reddotel fleet colours.
Birdseed cream
Eau-de-nil pale green
and sherwood dark green
Not only did it look better than blue it actually had a shine to it.

So to answer your question.. Start out with an oil based pink primer. might take 2 or 3 coats on raw ply before it stops swallowing it in the grain.
at least one coat of oil based undercoat and then 2 top coats on a warm sunny day or in a heated spray booth if you are spraying it and your van should come up a million bucks... oh.. another tip.
If you are brushing the paint on ...boil a saucepan full of hot water and sit the paint tin in it. the warmer the paint the better it flows and drys with less brush marks..
Oil based paint also comes up good after a wash .. i wash the van the same as i do the cars. soapy water and a sponge.. it doesnt hurt timber with a good coat of paint on it.
Jeez i wish i had listen to myself when i prepped and painted Rosie... she looks like a slab hut up close... but... she probably had that sort of finish when she was new back in the fiftys anyway......

Reddo.


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