Hi Roy
Thanks for your reply, glad I didn't offend you.
As far as cleaning brass goes I use this on my classic Rover car on the chrome and it works wonders on all types of metals like brass, copper, aluminium and even stainless steel.
The price on this box is a bit out of date now I think as when I buy it I usually buy two at a time.
You can get it at Halfords and most good car accessory shops.

Hi Boatshed no offence taken and I agree it is dodgy stuff. We used to have a club member who used it regularly and we were amazed how pliable the wood became.

Now with H & S being at the forefront,💡 nobody gets to handle even relatively harmless chemicals, but most man made compounds and liquids harm the environment so just as well. The nastiest thing we have in the house is the oven cleaning kit and I am very careful handling that, gloves on all the time.

I wish I had an effective way of cleaning brass. Tamarind as found in sauces works a bit but is slow and vinegar and lemon juice hardly get going.

regards
Roy

Hi RoyCV,
Yes I did see your comment on the window cleaner solution. But not everyone would take that into consideration. I was not criticising your comment intentionally, I was just try to make a friendly warning to those who may not have ever handled this liquid before. If they could get hold of Ammonia they may just try using it as it is. It is also not a good liquid to keep in the house if there is children in the house and as you know it's an evil substance if NOT handled properly. I spent 26 years working in dry cleaning using this product in a solution of 70% neat along with Peroxide and several other acids for removing stains on clothing and knowing just how lethal they can be. It was a job I enjoyed and the pressing of the clothing once I had cleaned it. I was saddened when I had to pack the job in. Then a follow up of 17 yeas of bus driving was an awful job, it was heaven when it came to retirement day.

I do apologise if it came over if I was being critical of your post. I wasn't.

The quality of the plywood is also important.
Back in the day the British Standard was BS1088 WBP - the latter initials standing for "Water and Boil Proof." With this stuff, there should be no delamination using water or normal steam.
The modern European standard is now EN 636-3, EN 314-2, Class 3. although I don't see it used as often in the thinner sections used by modellers. However, my advice would be to avoid most "Construction plywood" as the surface timbers are often coarse grained and the adhesive is not always water resistant.
Plywood has had a resurgence thanks to it being used as a substrate in some decorative veneer timber floors and in caravan/RV furniture - but wow hasn't the price gone up!

Here are some easy suggestions, it shouldn't be a problem at all.

First, plywood generally bends easier in one direction than another, choose the easier one.

For difficult small radius bends, bend it gradually. Wrap plywood around a form and let it stay for a day, You can use straps and/or clamps to help. Start with a larger diameter and each day make it smaller. Keep going till you get it smaller than the final shape. Then it will easily yield to the shape you need.

For thicker material laminate several thin sheets.

Hot water can help, you don't need anything special hot tap water is fine.

For my last build I needed a round gun tub. It is made from three layers of 1/32" plywood wrapped gradually around a tuna can and then let out to final sizes. Stagger the joints for added strength.

Hi Boatshed you are right about the danger of ammonia. If you read my post you will see that I said what it did, not recommending using it. And as I said it is weakly in solution in window cleaner fluid.

To another post, the hot water applied just enough to soak it does not delaminate the ply.
regards
Roy

Hi, I suppose it all depends on the radius. I suggest you build a former that simulate the deck and lay up a few thinner sections and laminate. That way it will fit well on the boat once glue is dried. Hope this helps. Cheers Ian👍

What depth of bend are you trying to achieve?

In the past I have always steamed or dampened the ply but on very tight bends I have had to resort to scoring the underside to remove some of the material or using double layers of thinner material with epoxy glues and laminating.

NB Plywood has an odd number of layers and hence has a "grain" and is easier to bend in one direction. Also beware that if it is building grade ply it may have some internal voids that can ruin your bend.

I would be careful on using steam or any solution with the plywood as it may warp the outer layer or affect the glue. It also depends on the type of plywood as there is a softwood type and an aircraft type that is hard. I had a springer tug where there is plywood on the bottom of the keel. I used a water proof wood glue that I picked up at a hardware store and used a lot of 1inch rubber bands tho hold it in place. I picked up the rubber bands in a store called Staples👍

On thin ply, such as hull skins. Have found using a heat gun quite adequate. Heat bend, clamp then reheat😌 l

BEWARE WITH AMMONIA, when you are using it it will hut your eyes and your lungs when you are breathing it in. It also burns your skin. I used to use it when I worked in a dry cleaners for removing blood stains. I always keep some at home, but I never let my wife use it, it is lethal stuff.
I thought that there is now laws on being able to buy it due to these idiots that throw it to burn peoples faces.

But getting back to bending plywood I have only ever dampened it and steamed it into shape then let it dry. That is how my father showed me when we used to build model boats together, even done that to form the side stringers.

Hi I use boiling water on the outer side to loosen the wood and for this job I would use a length of timber along its length on the underside with lots of insulating tape to keep it in place. Over bend rather than under as it will relax after release.

Also Ammonia will allow wood to be bent/formed easily. For thin ply try a spray of window cleaner as this contains ammonia as well. But I mainly use hot water and let it dry before glueing.
Good luck
Roy

Fred

Plywood can be bent though it will be more difficult than other material as it is created by gluing thin sections of wood in opposite directions which gives it stability.

Please provide a photo of the plywood in question.

The bending process should be done according to the grain of the wood. Birch will be different than Mahogany.

Is this for a deck?

Hi Raggie
You could try a wet towel and a steam iron over some formers.
Soak it in the bath then try bending it around an old paint tin.
Try a hot air gun again around an old paint tin.
Fred