Large picture, acrylic, Newton's rings problem?

[bang]

I'm framing a large picture which is becoming a bit of a 'mare.

Help/suggestions appreciated!

I've taped the hell out of the edges, 4mm in to try and relieve any pressure on the white wood slip/fillet, but I am still getting Newton's rings or little dark marks that disappear with pressure. The marks are along the top and bottom lip of the bevel on the slip.

Am I going to have to glue or tape strips of mount card to the edge as a spacer between the acrylic and the slip?

The image size is 1230mm x 860mm, I couldn't get a paper covered slip at the width the customer wanted without bare wood showing beyond the rebate, I ordered a length of 'coastal woods' and colour matched it, painting it the 'soft white' colour of Lion's mount board. The coastal woods bevelled slip is 69mm. I've got 3mm cast acrylic on it. Fluted correx backing and Brompton black frame with a wooden frame glued, screwed and painted black to increase the rebate at the back.

I've got a couple of wooden lengths cut to reinforce the back and corner L plates to put on after I've fitted it all together.

Thanks!

[Justintime]

Simple answer yes.

[JFeig]

When you do the final assembly of the frame do you compress the contents when inserting the nails/tabs that holds everything in? If so, this might be the cause of deflection that is causing the components to press together. A "looser" assemble will correct this most of the time.

[Justintime]

The last time this happened to me, I think it was pramsay who advised using thin strips of gummed tape or frame sealing tape on the outside edge of the slip, hidden by the rebate to just slightly lift the glazing off the painted slip. From memory I think it took two layers for sufficient space.

[bang]

The last time this happened to me, I think it was pramsay who advised using thin strips of gummed tape or frame sealing tape on the outside edge of the slip, hidden by the rebate to just slightly lift the glazing off the painted slip. From memory I think it took two layers for sufficient space.

I'm on four or five layers now.

I'll try not compressing the contents as much... thanks! I'll also go get some thin wooden strips just in case!

I think my hourly rate on this frame has dropped to 22p an hour!

[Justintime]

Damn..maybe strips of 1.4 board?? You can't put a price on learning or experience!

[bang]

Damn..maybe strips of 1.4 board?? You can't put a price on learning or experience!

Damn..maybe strips of 1.4 board?? You can't put a price on learning or experience!

I've bitten the bullet and I'm going to try 6mm wooden strips as spacers, painted black to match the frame.

Thanks!! You're right. I can only chalk this up to a learning experience! Of which there seem to be a growing number in my life