Problem gilding deep crevices

[Charles Plumber]

I am attempting to gild routed clear acrylic but am having trouble getting into the very deepest part of the rout. The rout is made with a 90 degree 'V' router bit and is approx. 1/2 inch (11mm) deep. I have tried: cutting transfer paper into strips and applying to oil size, floating leaf onto a gelatin size -have even tried painting the deepest gaps with mica and shell-gold but the effect is not up to the perfect standard required. Interestingly the imperfections are most obvious from the un-routed side (I guess because the glitter of the 23.5K gold is reduced.) The hardest part comes in getting into a flowing curve's bottom e.g. an 'S'.

I would be very grateful for help from anyone who has "been there done that."

Thank You

Charles
Melbourne, Australia

[Mike Jackson]

Charles,
I can throw out a few tips. First, get a shallower router bit...12 to 15 degrees. The one you have is actually called a 45 degree bit. Your gold will reflect back to the viewer at shallower angles, where it gets very dark at 45 degrees.

Second, you mentioned gelatin. You shouldn't need any sort of gelatin for a surface gilded letter. Are you cutting in reverse and then wanting to view the piece from the flat side? You might have other "issues" if this is the case.

Third, if surface gilding, you can use either patent or loose leaf. You must be very careful when applying the oil size so you don't get a lot of puddles in the bottom of the letters. Otherwise, your sides will dry to the correct tack for gilding, but the puddles will cause problems. They would take a lot longer to dry. If done correctly, you should be able to get about 95% of the gild with the patent leaf or loose leaf applied with a gilders tip. Before blowing out the skewings, use a soft nylon "artists" brush to tamp the excess gold into the deeper crevices. Our brush has soft white bristles about 3/4" long and roughly 3/4" wide...sold at any art supply store. We've used the same one for years.

Again, if water gilding over a deep carved plex, you have a different set of problems to solve.

Good luck,
Mike Jackson

[John Studden]

Charles, Is it viewed from the front or the back? What size are you using? 12 hour LeFranc would be best, & after sizing turn the piece upside down overnight to prevent "pooling" at the bottom. As Mike said a 15 degree bit would probably look better... Sometimes at the bottom of a v-cut there will be a rough edge, this could be eliminated by polishing with a flame, as in flame polishing a plexi edge. I would always use loose leaf in this application, I use an old water size brush to press down & burnish. Hope some of these tips will help.

[Charles Plumber]

Mike and John, thanks for replying with those great tips.

To answer your questions:
-I was hoping to view the letters from the un-routed side but the diminished reflection and unfilled grooves (ridges to the viewer) may force me to change the viewing direction.
-I am indeed having problems getting the size not to 'puddle' and in fact using even the thickest size it seems to still run into the valleys -as suggested I will try inverting the piece and allowing to dry.
-Flame polishing does seem to make the valley floor smoother but I guess I will have to be careful not to use a size that accentuates any resultant stress fractures and opens up/fills into those fractures.

Am I right in assuming that you would tell me to change the router angle depending on which side you are viewing the letters from?

Thanks again

Charles
Melbourne, Australia

[Doug Bernhardt]

I guild carved letters all the time and would agree with all that has been said. Both Studdley and Mike have experience with computers and Plexi as I have not but, keeping a tin even layer of size is the key. It also may require giving the letters a priming with "maybe" a spray balm primer which precludes guilding the inside. The fat soft brush is also good sound advice as is the idea of a change from 45 degree router bit...very deep.

[Danny Baronian]

As others have mentioned, you need a bit with a shallower angle. What is the dimension of the piece, how thick is it? You may not want to waste the material, but by the sound of it, the best job will be accomplished by doing it over.

Flame polishing the letters will help with clarity and smooth the acrylic, but take care not to warp areas that get more heat than others, or round over delicate areas.

I'd suggest masking the acrylic, using a new or very sharp bit with a shallower angle, route through the mask - like Gerber Mask II. Run in two passes, one to hog out, the second or possibly a third as a finishing pass.

Leaving the mask on, roll the mask with a brayer to ensure the mask is well adhered. Clean, taking care not to not disturb the mask. Spray on size and gild. In reverse gilding on acrylic, the best results I've had are masking as above then spraying a mixture of varnish and gold mica.

Reverse gold on acrylic never looks as nice compared to glass unless it's surface gilded.

Rather than route a whole new panel, first take a scrap of acrylic, set a line of text and duplicate 3-4 times. Then route with the mask, without, and try various methods to apply the finish and you'll have a visual sample to choose the best from.

[Charles Plumber]

Doug and Danny,

Thank you as well for the advice.

I haven't tried a different angle router bit or masking yet but I have had success getting into the bottom of the valleys by:
(1) Oil size and leave upside down to tack
(2) Tear the leaf into 1/2inch strips (pull page cover back 1/2inch and hold taut with spread fingers off the gold stack then apply tip and tear gently along cover page edge)
(3) Place a vertical edge on side of 'V' and gently blow the gold off the tip from one end to the other.
(4) Use soft large brush to tamp into place remainder and distribute flakes to the very bottom and un-covered areas.

The effect is a nice satin.

Will now go on to test router angles and masking.

Mike, I think you alluded to water gilding over deeply carved acrylic (presumably giving a near mirror finish); is the technique in this case to 1/3rd flood the bottom of the valley then gild allow to dry, then flood to the 2/3 mark and guild allow to dry then flood to the top and guild?

Thank you all for the great advice -I couldn't have got there without your help.

Best Regards

Charles
Melbourne, Australia

[Mike Jackson]

Charles,
Actually YOU mentioned gelatin in your first post, or I wouldn't have even thought to discuss it.

As far as the 1/3, 2/3 and final zones go, I'd question if that is a good way of going (if trying to water gild over plex from the back side). Without trying it, my concern would be a large build up of gelatin by the time you get to the final gild at the top. Cleaning off excess gold is already a bit tricky on plex because you can't use bon-ami (or you can scratch the plex). Before I did a real project, I'd do as always and make a few test pieces and solve all the issues before going to the real panel.

Good luck,
Mike Jackson

[John Studden]

Charles, The best way to water gild a depression like a v-carve or chip area I have found is to lay the piece flat, fill one letter at a time with the water size, float enogh loose gold onto the area, then slowly raise the workpiece from one side, so the water starts to run out of the groove, in doing so the loose leaf will be drawn down into the depression. Let dry, burnish & repeat, this works well & saves a lot of gold. Then back up the letter & clean of an excess with Splash or an equivalent product that will not scratch the plex like bon-ami would. I have done this successfully a number of times.....Also in the case of plexi it would be good to add a little Ivory washing up liquid (1 drop per pint) to the size to help with adhesion.