Best way to scribe to ceiling approx 120cm width.

[Northbeach]

Hi all,

I've just studded out a frame on the wall (3x2) to hang a piece of MDF onto (with a hole cut out in the middle for a TV bracket). The 12mm MDF will overhang the frame slightly so I can hide LED strip lighting behind.
The piece is mainly square (1200mm width x 1650 mm height) but the top section is straight for 570mm before the ceiling slants down (740mm slant) till it meets the right hand side of the frame which will now be 1290mm (instead of 1650mm).

I have to offer up the MDF so I can work out the scribe but given the weight of the MDF this won't be possible. If it was small I could use card (folded into the curve/incline of the ceiling) but given the length of the slant/curve, this might prove difficult.
I don't own an awful amount of tools (I do have a adjustable bevel) and don't really want to purchase something for this ...but I'm all ears!

Once the scribe is marked I'll use my jigsaw to cut and eventually caulk and paint (it's at the top).

Many thanks.

 

[foxhole]

Fix it to Stud short of final position so you can scribe .

 

[Northbeach]

Fix it to Stud short of final position so you can scribe .

Thought of that foxhole but there's a height difference of 36cm...if I can do an 'approximate scribe' first so the MDF is offered up much more closely then that's the solution right? I've left a little on the length just in case I 'over scribe'. So...If I measure the ceiling width until it starts to slant (570mm) then measure the right hand side height (1290mm) then do a rough guideline and cut - then fit up temporarily and then do the refined scribe. That sound about right?

Cheers.

 

[foxhole]

Thought of that foxhole but there's a height difference of 36cm...if I can do an 'approximate scribe' first so the MDF is offered up much more closely then that's the solution right? I've left a little on the length just in case I 'over scribe'. So...If I measure the ceiling width until it starts to slant (570mm) then measure the right hand side height (1290mm) then do a rough guideline and cut - then fit up temporarily and then do the refined scribe. That sound about right?

Cheers.

Yup

 

[Northbeach]

...

Yup

...Well would be. I've completely lost my knack for scribing (this is a little more difficult due to the position and weight of the MDF board. I drew (and I did this a number of times) what I thought was the perfect scribe line only to find out on the cut that the slanted bit has a huge gap between the board and ceiling (huge as in around 7mm). I'm going to place a long batten on the frame at the bottom so the MDF can sit on that as I scribe as it;'s been tricky to get the board level then screw into the studs. Then I'll tape a piece of wood to a pen/pencil and scribe again - I think my last method (using first a cotton bobbin then my fingers to follow the line) didn't work

Cheers.

 

[opps]

The piece of MDF to be scribed- clamp/pin it/whatever to the studding or mdf. You want it to be perfectly level horizontally (as per Foxhole's suggestion). Your batton will work but then you need to try to hold the MDF and scribing block.

Once level, measure the maximum gap up to the ceiling. If, for example it is 100mm, accurately cut a block of wood at 100mm. Run the block along the ceiling (ensuring that it is vertical as you go. You don't want the block to be too wide though. If it is too wide and your pencil isn't right at the edge you will suffer parallax.

Adjust the length of the block depending on what the final required size of the MDF will be (ie. max gap plus excess on the MDF).

If it helps draw some vertical pencil lines on the MDF to make sure that your block stays vertical.

36cm is quite a lot so perhaps do it in stages if you are worried about your scribing block being too long and running off vertical.

 

[lostinthelight]

Can't you template first with thinner material , divided into sections if necessary?

 

[Northbeach]

The piece of MDF to be scribed- clamp/pin it/whatever to the studding or mdf. You want it to be perfectly level horizontally (as per Foxhole's suggestion). Your batton will work but then you need to try to hold the MDF and scribing block.

Once level, measure the maximum gap up to the ceiling. If, for example it is 100mm, accurately cut a block of wood at 100mm. Run the block along the ceiling (ensuring that it is vertical as you go. You don't want the block to be too wide though. If it is too wide and your pencil isn't right at the edge you will suffer parallax.

Adjust the length of the block depending on what the final required size of the MDF will be (ie. max gap plus excess on the MDF).

If it helps draw some vertical pencil lines on the MDF to make sure that your block stays vertical.

36cm is quite a lot so perhaps do it in stages if you are worried about your scribing block being too long and running off vertical.

Hi opps - I probably wasn't clear.
The 36cm is the difference between the highest point of the ceiling and the lower bit of ceiling where the it slants/curves down (might be best if I stick a pic up). It drops like this on the front and back of the house.
I'm also struggling to visualise your block method...maybe because (and again I should've clarified more) the MDF piece is going right up to the ceiling so no gap. I was contemplating a shadow gap but the ceiling itself isn't particular uniform. Any examples of
I just about managed it in the end (having to lug that huge piece of MDF up and downstairs to cut outdoors) and any discrepancies will be caulked, sanded and painted when I do the finish on the board.

...actually, reading your post again I think I understand now. The gap you refer to is the temporary 'in situ' of the board I've sat on the temp sill and fasted onto the studs. The largest gap being the size of the cut block and then just following the line of the ceiling as it 'undulates'.
Any pics/examples would be great however....

Thanks very much.

 

[Northbeach]

Can't you template first with thinner material , divided into sections if necessary?

That would have been a great idea too - will do that next time.
Cheers.

 

[big-all]

your 7mm problem would probably be -----
what you need to do is work out what direction the timber needs to move from the tempory marking position till its in place when scribe lets assume thats strait up parralel to the wall and squaure to the ceiling
to mark the intersection on the top off the board along the line the board will travel in this instant you could use an offcut off board on the ceiling with the corner at the transition point and transfer that point down and when scribing the slope you need start the scribe at that point you also need the carry on scribing with the space at the same angle as the level bit
in other words the top off the scribe bit will have an angle on the top the same as the angle on the ceiling
if you rotate the scribing at all you will have an arc causing the cut line to move off line

 

[Northbeach]

your 7mm problem would probably be -----
what you need to do is work out what direction the timber needs to move from the tempory marking position till its in place when scribe lets assume thats strait up parralel to the wall and squaure to the ceiling
to mark the intersection on the top off the board along the line the board will travel in this instant you could use an offcut off board on the ceiling with the corner at the transition point and transfer that point down and when scribing the slope you need start the scribe at that point you also need the carry on scribing with the space at the same angle as the level bit
in other words the top off the scribe bit will have an angle on the top the same as the angle on the ceiling
if you rotate the scribing at all you will have an arc causing the cut line to move off line

Thanks Big-all.

If there are also any videos demonstrating the correct method that would be handy along with your advice (I bet if I saw you do it I'd get it a lot easier). Tough when you've no real experience in the finer points of carpentry (and want to do a good job).

As it stands, it's not too bad but wish I'd used an off cut and used the methods described above.

Cheers!