creating a curved panel

[mseries]

I might need to create a quarter round curved panel soon, approximately 6" radius and 6" high. The panel needs to be about 3/8" thick, I could possibly get away with 1/4". I appreciate that I'd need to create a former/press to clamp some laminations and this is no problem. I am hoping someone can accelerate my trials and advise what material will be best. External finish will be painted, I'd like to think 3 layers of 1/8" hardboard would work ? Maybe with kerfs on the back ? What do you think ? Would soaking/steam improve it's flexibility before it tears ? (My fall back will be more laminations of 1/16" or 1/32" ply from the model shop though this will be more expensive that hardboard - and I'd have to make a trip to get some)

 

[marcros]

bendy ply?

 

[Paul Chapman]

You can buy MDF that's already grooved on one side for bending.

Cheers :wink:

Paul

 

[Rob Platt]

You can buy MDF that's already grooved on one side for bending.
+1
does the job perfectly
all the best
rob

 

[Steve Maskery]

2mm MDF is used as backing board for picture frames. As 6" s quite a tight radius, I'd go for 5 layers of that. It would also be a lot stiffer than 3x3mm because there are 4 layers of glue rather than just 2.

S

 

[neilyweely]

Sir
When you say the external finish will be painted I guess you mean the outside of the curve? To the bst of my knowledge there is no MDF/Hardboard on the market that is suitable for exterior use. I think I have seen some bold claims but am still yet to see anything convincing.

Otherwise I watch with interest

Neil

 

[xy mosian]

If you are going to paint the finished object. Build it up in the manner of bricks around a well. Then do a final shaping. If you cut the 'bricks' as small sections of the curve then that final finishing should not be too tricky.
xy

 

[johnwc812]

Hi
Just one panel? I would cut 6"+ by 1" by 1/2" strips of timber plane slight angles along the edges and glue, similar to a straight sided barrel (or a tambour lid). Using a 12" diameter tin as a former.
Then finish off with hand tools.
Cheers John

 

[mseries]

some food for thought thanks. One panel, inside use, painted MDF will be fine,

 

[mseries]

OK resurrecting an old thread because I still haven't done this !. My curve is 4" radius and the height of the panel is about 4" also. Right, that said do we think 2mm MDF will bend to that radius ? What about 1/16th ply ? I shall build it up to maybe 1/2" thickness. I would prefer not to make a kerfed bend* because the top edge will be visible and I'll then need to mess about with filler once it's fitted. The piece in question is going to form skirting around a bottom stair to cover the edge/expansion gap of laminated flooring.

*Part of me would like to mess around with kerfing but I don't think the top edge will work out too well

 

[Jacob]

Kerfing works really well, especially if you have a table saw. Couldn't you plant something on to cover the end? A bit of thin board cut to the shape?

post779166.html?hilit=kerfing#p779166

 

[xy mosian]

If the curved panel is not too long, how about cutting it from the solid? Bandsaw or turning saw would do it quite well. As the outside is the 'seen' side you are in luck, that is the easy one to finish.
xy

 

[mseries]

I had a bit of a play with kerfing today. I am thinking of covering the full face of the bottom step not just create a skirting. Not successful I tried with 3mm hard board,kerfing to leave about 1mm left, kerfs centred 4mm apart. It was still too stiff. Next I tried some ply, 4mm apart kerfs leaving the last ply in tact. I think I left the last ply with the grain going the wrong way as it creased on some of the kefs and didn't flex enough. I curved along the grain so my short side is along the grain. Looking at Jacobs and others pictures I think maybe this was wrong and I should have curved against the grain on the last lamination. My prototype was using 6mm MDF and this seemed to be positive, maybe I'll try again with that tomorrow if I get a chance.