Thread: Bending MDF - curved sides cabinet construction

I think you'll have trouble bending MDF to that radius. You'd be better off using bendy ply. Available from most suppliers.

Possibly doable with bendable mdf. You can buy it at Mr Plywood. It may also be called 'easycurve'.
You may need to laminate several sheets together as its only 9mm thick.
Cheers
Arron

Thanks Alex and AAron for your professional comments. That person used 3mm MDF and knife + damping mop to bend the MDF layers. Do you think common MDF will do the job?

If the common MDF will crack (according to your previous experience) , I will certianly buy bendply or bendable MDF sheets. Thanks.

Cheers.


Edward.

Originally Posted by edward13c

Hello Everyone,


I am quite a newbie to this forum, and I don't have much woodwork experience.


I am now planning to build a pair of homemade DIY speaker cabinet with MDF boards. With some past build threads on internet forums, those step would be valuable instructions to me. One of them is the curved canibet build as here: Clearwave RBR curved cabinet build - diyAudio. Just in case if the above hyplerlink is invalid, I attach some photos from above webpage.


Here I would like to consult you guys experts here for some professional comments. Since I have little experience dealing with wood, any comments would be appreciate.


My question is "is it difficult to reporduce this technique / skill" to build a similar curved sides cabinet? How does it work with 3mm thickness MDF? Any unexpected difficulties will happen?





Thanks in advance for your comments and expertise. Cheers.


Edward.

The poster of that speaker build has pretty much answered most of your questions - laminated kerfed 3mm mdf assisted with lots of straps and cauls.

I wouldn't use bending ply as it this application with a 60mm radius is too tight even for bendy ply (I've had bendy ply crack at 150mm radius - but maybe I have been unlucky).

Where I would differ with the builder of that speaker, is that I would use epoxy rather than pva. A good pva like AV180 might be good for this application but I find it cures too quickly which would make bending an absolute PITA as you would be racing against time. Epoxy (I'm thinking Techniglue) on the other hand will give you ample time to laminate, bend and correct any mistakes you might make and when cured will be rock solid. I would be interested in how that builder's speaker holds up in the long term as he has bent the laminated mdf at a very tight radius using pva as the glue.

Hope that helps.

Bill.

Originally Posted by bill2016

The poster of that speaker build has pretty much answered most of your questions - laminated kerfed 3mm mdf assisted with lots of straps and cauls.

I wouldn't use bending ply as it this application with a 60mm radius is too tight even for bendy ply (I've had bendy ply crack at 150mm radius - but maybe I have been unlucky).

Epoxy (I'm thinking Techniglue) on the other hand will give you ample time to laminate, bend and correct any mistakes you might make and when cured will be rock solid.

Bill.

Thanks Bill for your precious experience. My speaker will have about 130mm radius, I will try damp the MDF first with a small piece of sample.

As to the glue, I have bought TiteBond Ultimate III, do you think it will do the job from long term perspective? Should I buy the epoxy for this project particularly? Thanks.

Edward.

Titebond III is still a PVC based adhesive, and all PVA adhesives are subject to creep under load. Its good for flat lamination, but for that sort of curve I'd really suggest an epoxy such as Botecote or West. Plus the epoxy will give you about double the working time of the Titebond...which you'll appreciate if this is a first time lamination!

Originally Posted by edward13c

Thanks Bill for your precious experience. My speaker will have about 130mm radius, I will try damp the MDF first with a small piece of sample.

As to the glue, I have bought TiteBond Ultimate III, do you think it will do the job from long term perspective? Should I buy the epoxy for this project particularly? Thanks.

Edward.

Echoing what Master Splinter has stated, PVA will creep and I don't think it is the suitable glue for your application. I regularly use AV180 which is a PVA that has tries to emulate epoxy in that it cures very hard - but even then will creep under load. I have no experience with titebond but I would go for epoxy - Techniglue would be fine, West System would be perfect (I've never used West but from what I've read in technical manuals and seen what others have said, it cures much harder than Techniglue and they have a proper dispensing system which would make it more convenient and easier to use)

Thanks Bill and Master Splinter,


I found the products of West System here , WEST SYSTEM epoxy| Products | Resins and Hardeners - WEST SYSTEM by ATL Composites .


Do you recommend 105 Resin + 206 Slow Hardener ? BTW, are those 105 + 206 also work for fiberglass moulding?

Fortunately, there is one retailer near my place.


Cheers.


Edward.

206 slow hardener would give you a good amount of time to do the lamination.

Read the instructions carefully, with particular attention to accuracy of amounts (near enough is not good enough) and not mixing too much at once.

And yes, it's also for fiberglass.

Read the full documents here - Epoxy by the Leading Epoxy Manufacturer | WEST SYSTEM Epoxy

Originally Posted by edward13c

Thanks Bill and Master Splinter,


I found the products of West System here , WEST SYSTEM epoxy| Products | Resins and Hardeners - WEST SYSTEM by ATL Composites .


Do you recommend 105 Resin + 206 Slow Hardener ? BTW, are those 105 + 206 also work for fiberglass moulding?

Fortunately, there is one retailer near my place.


Cheers.


Edward.

Cheers, mate. I will certainly go with that West epoxy, so that I can build the curved cabinet properly. Thanks.