Underpinning mount slips

Not your average framer · Tue 18 Mar, 2008 6:39 pm

I thought that sealing wooden slips with acrylic paint was a sound practice, but I've just had to repair a frame for a customer who has just moved house and had the frame wrecked by the removal people. I was suprised to find that the wedges in a 10mm deep hand-finished mount slip had gone rusty and inspite of a good thick coating of acrylic paint the rust had broken through the paint.

There was no signs of any rusting of the wedges in the actual frame at all and no suggestion that any of the rest of the framed package had ever been subjected to any dampness problem. I wonder if the application of the acrylic paint might have something to do with the rust forming.

Any comments?

JFeig · Post by **JFeig** » Tue 18 Mar, 2008 7:03 pm

Acrylic paint is porous. The only proper barrier would be an approved metallic tape or equiv.

In the US we have Lineco http://www.lineco.com/item.cfm?itemnum=L387-0151

and Marvelseal® a metal coated polyester used to package food products.
http://www.archivalsuppliers.com/prodin ... r=974-MARV

Paul Hardy · Post by **Paul Hardy** » Tue 18 Mar, 2008 7:28 pm

Acrylic paint is waterbased, which is what will have started the rust. You'd need to seal the wedges with an oil primer before applying the acrylic paint to prevent rusting. As for being acceptable practice, it depends on what level of conservation you want to achieve.

Paul Hardy
www.sudbury-picture-frames.co.uk

Roboframer · Post by **Roboframer** » Tue 18 Mar, 2008 7:48 pm

I've never underpinned a mount slip.

Wedges ('V' nails) rust - or can. they are not stainless steel and even if galvanised, the cut ends are not - Gummed tape can rust them (not talking about mount slips there)

Not your average framer · Tue 18 Mar, 2008 8:15 pm

JFeig wrote:Acrylic paint is porous.

Thanks Jerry,

That's what I was wondering.

Bill Henry · Post by **Bill Henry** » Tue 18 Mar, 2008 8:55 pm

Again, I am slightly confused with the difference between Yank and Brit terminology. When you speak of a “slip” are you referring to what we barbarians call a “fillet”?

If so, like John, I don’t see the need to under pin them. The ones I deal with are so narrow and shallow that they would take only one nail and that is likely to split them.

Once they are mitered, glued, and fit inside the mount or frame, they ain’t goin’ nowhere. With a “slip” inside a window mount opening, since the “fillet” is generally deeper than the mount, we build up the area between the outside edge of the mount and the interior edge of the “slip” with 3 mm strips of foam board. If the foam board strips are glued or adhered snugly against the slip, it cannot move once the frame package is fit.

Like Jerome, we use the Lineco foil tape to keep the nasty stuff in the wood fillets from migrating to the art. It is a little difficult to work with, though.

We also use this foil tape to line the interior rebate of frames for art mounted on stretcher/strainer bars for the same reason.

If “slips” are not the same thing as “fillets”, well, … never mind!

Not your average framer · Tue 18 Mar, 2008 9:04 pm

I was told during some training I received, that acrylic paint could be used to seal wood as an acid barrier. I suspect I may have read something to that effect too, but until I saw that rust can penetrate the acrylic, I had not questioned this at all.

Roboframer · Post by **Roboframer** » Tue 18 Mar, 2008 9:11 pm

Bill Henry wrote:
If “slips” are not the same thing as “fillets”, well, … never mind!

You're OK Bill - same horse, different jockey - I've taken to calling them 'fillips' or 'slippets' here from time to time.

Our suppliers call them slips too.

Not your average framer · Tue 18 Mar, 2008 9:22 pm

It's amazing how a common language gets so confused. I know that in the U.S. fillets and liners are very different, but over here they are both called slips. So when I see the word fillet or liner, I still find myself doing a quick mental check to remember which is which.

Post by **prospero** » Wed 19 Mar, 2008 3:39 am

On my planet, a slip is a flat section with a flat/bevelled/coved edge. A fillet is basically the same but with a raised lip on the top edge.
A liner has a rebate/rabbet.

Framer Dave · Post by **Framer Dave** » Wed 19 Mar, 2008 4:38 pm

Not your average framer wrote:I was told during some training I received, that acrylic paint could be used to seal wood as an acid barrier. I suspect I may have read something to that effect too, but until I saw that rust can penetrate the acrylic, I had not questioned this at all.

Acrylic paint is porous. It might be better than nothing, but only metal or glass are considered impermeable for the purposes of framing. The easiest and most practical application would be the Lineco tape Bill and Jfeig mentioned.

bexwell · Post by **bexwell** » Wed 19 Mar, 2008 5:02 pm

Not your average framer wrote:It's amazing how a common language gets so confused. I know that in the U.S. fillets and liners are very different, but over here they are both called slips. So when I see the word fillet or liner, I still find myself doing a quick mental check to remember which is which.

Slightly off topic but a friend who is a teacher once askked an american child she was teaching to bring a rubber to school - ( eraser to those in the USA) - there was quite a lot of confusion on the part of the parents!

fionnuala · Post by **fionnuala** » Wed 19 Mar, 2008 11:05 pm

is anyone sourcing this 'lineco foil tape' in Uk or Ireland at the moment? if so, from where?

if not, do u use some other product to do same job?

Roboframer · Post by **Roboframer** » Wed 19 Mar, 2008 11:59 pm

PEL do one and Lion do the Lineco one

fionnuala · Post by **fionnuala** » Thu 20 Mar, 2008 1:48 pm

thanks john!

should have looked at lion brochure before i posted!

fionnuala · Post by **fionnuala** » Thu 20 Mar, 2008 2:28 pm

back again!!!

i looked up lion to see this tape. am i right in thinking that this tape can be used to protect artwork from a gold slip for example that would touch the artwork.

if this is the case why does it say in the lion brochure: do not apply this tape directly to the artwork? do they mean the self adhesive side? because the backing of the tape will touch the artwork wont it?

also lion sells a self adhesive conservation "fillet tape" page 59. is this the same thing?

Framer Dave · Post by **Framer Dave** » Thu 20 Mar, 2008 5:23 pm

Yes, the Lineco frame sealing tape is perfect for sealing the back of a fillet/slip in direct contact with the artwork. The note about not applying it directly to the artwork is simply to make sure nobody gets the silly idea of using it to mount artwork. That would not be good.

The fillet tape is meant as a high-strength tape to attach the fillet/slip to the mount or inside the rebate of a frame.

fionnuala · Post by **fionnuala** » Thu 20 Mar, 2008 6:26 pm

Crystal clear now!

thanks for taking time out to answer!