Gluing curved sheets of plywood

[Nacimroc]

I'm in the process of making a jukebox and need to bend a sheet of plywood to make the shape! Because I have to bend it so much, I have to use 3mm ply and use a few layers to make up thickness to hold speakers. I was planning on screwing these sheets together and gluing. The sheets are about 4 ft high x 2 ft wide and curve about 6 inches in the middle.

Question is do i just tack the sheets together, screw them together in loads of places or glue them or a combination of all. If gluing what glue should i use?

Also, would 4 sheets of 3mm hardboard together be sufficient to hold a sub woofer in place or should i use 3 x 3mm plywood?

Thanks

[Kman-Sweden]

You might consider bendable MDF... I don't know the name of it in Enlish but here's a bad picture of it. 


You just put glue on it and bend it to the shape you need.


You end up with someting that looks like this.


Or this...


Try googleling bendable or grooved MDF.

[Nacimroc]

That looks ideal! Will try have a look for some of that! Thanks

[EightBySix]

If you cant find any, you can still get your effect. You'll need to make a 'former' which is just something solid of the same shape you can bend it around. Clamp each layer to the former, and spread the whole surface with glue before adding the next layer and so on. When the glue is dry it will hold it's shape.

[Knave Jack]

You can also cut a bunch of slots on the inside of the plywood before you put it on a form. Makes it much easier. There is also a form of bendable plywood that the cabinet and trade show booth guys use. If I can find the link I will post it.

[SavannahLion]

Once you bend the er... bendable ply/mdf/whatever, don't you need to back it with something or fill in the gaps or something?

My office (work) used a bendable laminate (redwood I suppose) on a staircase and it receives regular damage from careless customers. From the looks of it, if they filled in the gaps with a putty or glue, it probably wouldn't so easy to damage.

[Nacimroc]

I thought the same thing! The problem with that wood is I didn't think it would be strong enough to hold 2 speakers and a sub-woofer and the major problem of I couldn't find it anywhere local. So instead I used 3.5mm sheets of plywood and hardboard. I glued and screwed the sheets together and its rock solid now.

(Side note: One of the sheets wouldn't bond as I reckon it was too cold -1 C that night)

This is the finished product as of 2 days ago.


Mountain used that bendable mdf stuff and it looks like he filled the grooves with glue to help firm it up

[ami-man]

Hi,

That bendable MDF looks great but to finish it off I would glue a sheet of very thin ply or thin MDF to the grooved side once the shape is formed so none of the grooves can be seen.

Regards
Alan Hood
ami-man
UK

[javeryh]

Did you try using band clamps though to hold everything in place?  They work great and the joint between the layers will be nice and tight.

[ami-man]

Hi,

Here are some details of suppliers of bendable MDF sheets in the USA and the UK.

Regards
Alan Hood
ami-man
UK


http://www.mobilesolutions-usa.com/smartparts/bendablemdf.htm
http://www.bendymdf.co.uk/

[mountain]

Bendy MDF is expensive so I machined the slots on my CNC machine. In the past, when I wanted to bend a panel, I would cut the grooves on a table saw. Fill in the grooves after bending with Bondo if you are looking for a lot of strength.

[Epyx]

@ Mountain

I was going to try this on my table saw but realized as I was about to cut the slot that my table saw doesn't let you pass through unless you are splitting the wood.  Did you remove the cover and top of your table saw to do this?

[mountain]

@ Mountain

I was going to try this on my table saw but realized as I was about to cut the slot that my table saw doesn't let you pass through unless you are splitting the wood.  Did you remove the cover and top of your table saw to do this?

-Insert disclaimer here-

Yeah, I never use them. It really limits what can be done with the saw.

[Epyx]

-Insert disclaimer here-

Understood 

[javeryh]

Norm doesn't use the cover either.  Just remember, before we use any power tools, let's take a moment to talk about shop safety. Be sure to read, understand, and follow all the safety rules that come with your power tools.  Knowing how to use your power tools properly will greatly reduce the risk of personal injury.  And remember this: there is no more important safety rule than to wear these — safety glasses.

[fixedpigs]

And remember this: there is no more important safety rule than to wear these — safety glasses.

i would say respect & fear for the tool should be number one...

safety glasses...while very important...aren't going to prevent kickback if you're not paying attention to what's going on...

 

[Epyx]

there is no more important safety rule than to wear these — safety glasses.

Agreed and for me that is habit...although a mask for *cough* mdf dust is a good idea as well

Which is one I don't always make habit...