Very Large Cornice

[Eldodgerino]

Have some very large cornice to put up for my mother in law.

Its proper plaster moulding and I have to say it intimidates me.

The wall drop is just under 6" but the ceiling section is 13.5".

Several issues arise from this size.

I've built the mitre box to fit the cornice but at its current size a 22" saw barely crosses the 45 degree angle. I'd rather use a saw with a high tpi(teeth per inch) than a wood saw which are about 7/8. Is there such a saw out there at about 28" long?

THe cornice seems is flimsy aswell. Is there a better way to brace it?
I made the box from 18mm ply - may upgrade to a more robust 25mm MDF

All help appreciated

 

[1john]

perhaps you could run a temporary supporting batten around the wall to hold the bottom of the cornice and then find the joists and countersink screws through the cornice up into them. these could be filled and sanded afterwards, it seems like alot of weight for adhesive to hold until set.
The flimsyness will help you share out discrepencies in the ceiling and wall where they are not 100% true.

 

[trowelmonkey1]

hmmm interesting problem dodge! not sure how to help with the 'special' saw mate, maybe one of the experienced fellas on here can help.

RC? Rich C? Roy C?

 

[1john]

perhaps you would make a mitre box which enables you to make a bevel cut if you get what i mean, so it is narrower and you have the cornice on edge so to speak?

 

[Eldodgerino]

Cheers Monkey.

Yes John - I think I get you - do you mean stand it upright so the cross section would be smaller? It did cross my mind but its just not strong enough really

 

[Micilin]

Have the mitre box a bit different -

You need to have the mitre at the end of the box, rather than the middle so that you can cut down thru the cornice rather than across the top.

You can have a guide across the top of the box, a piece of 2 x 1 (or two pieces with a slot for the saw)

You could also have a bottom guide - but it has to be wider than the box so that you can get the saw into it before you get to the cornice.

Use this on a bench, so that you are cutting down rather thanacross.

Not a very good explanation - I know!

Edit - Your mitre box will now look like a 'T', with the top of the T being the guide, and you will still be able to use a fine toothed saw, cutting into the face at an angle to make it neater

 

[1john]

I think micilin is on a similat page to me.

You have constructed a box that will cut through the cornice at it;s widest point with the area that will touch the ceiling at the bottom of the box, if that is correct then I am suggesting that you build another box where the cornice sits in it with the area that would touch the wall sitting at the bottom. the cuttin guide would then be straight across the top of the box and at 40 degrees down the sides of it.

 

[trowelmonkey1]

ah! i see! now i'm on the same page as both of you! Dodge?

 

[roy c]

Can you post some pictures of the cornice?

 

[joe-90]

If it's anything like cutting coving it'll be a right pig as you need it in just the right position or it doesn't butt up.

 

[roy c]

Quote..

Several issues arise from this size.

I've built the mitre box to fit the cornice but at its current size a 22" saw barely crosses the 45 degree angle. I'd rather use a saw with a high tpi(teeth per inch) than a wood saw which are about 7/8. Is there such a saw out there at about 28" long?

THe cornice seems is flimsy aswell. Is there a better way to brace it?
I made the box from 18mm ply - may upgrade to a more robust 25mm MDF

Can you not cut through as far as you can from the front, then go to the other side of the mitre box and finish your cut off from that side? Another thing is when you are putting up coving that big/wide you really need one or two more pairs of hands to help support it when you put it up....

 

[Micilin]

I think micilin is on a similat page to me.

You have constructed a box that will cut through the cornice at it;s widest point with the area that will touch the ceiling at the bottom of the box, if that is correct then I am suggesting that you build another box where the cornice sits in it with the area that would touch the wall sitting at the bottom. the cuttin guide would then be straight across the top of the box and at 40 degrees down the sides of it.

Same principle, just that I would have the cornice flat to make it easy to handle and cut - also should be easier to get the orientation right to match where the cornice goes on the wall. The guide at the end of the box will let you use the saw without it having to be longer than the width of cornice.

As joe says above, just as you need to remember with ordinary coving that the wall edge is uppermost in the box when cutting, this cornice will have to be cut in the same way.

 

[Eldodgerino]

Thanks for all your advice on this lads - much appreciated

Got too much on for the head scratch so have out sourced to another firm who do this sort of thing every day.

Will post pics when done

 

[1john]

please do, it sounds very interesting.