Jen Jackson 7/8/09

Anybody out there actually flame polished acrylic before? Seeing as how I am always looking for ways to speed up production time (slightly lazy), it seems like this technique would save tons of sanding work- however I found this crazy video on you tube: http://www.youtube.com/watch?v=w8MEhbH6DK4 It seems like flame polishing would make it impossible to use weld-on after words. It would be pointless having a nice pretty edge if the structural integrity of the mount was compromised. Anyone?

Philip Brutz 7/8/09

Cool video!  That crazing effect happens on any polished edge.  The main lesson is don't use denatured alcohol on acrylic.  We flame polish as the very last step after we do any welding.

Philip Brutz Mountmaker Cleveland Museum of Art 11150 East Blvd. Cleveland, OH 44106-1797 216-707-2617

Suzi McG 7/8/09

Good video.  I knew heat and certain alcohols can do some funky stuff to acrylic.  It's nice that his video really showed it well.  (And his lovely bandage - ouch! I'll bet that hurt.)

I have done some flame polishing before and it does save time if you do it like he did in the video and keep the flame moving quickly.  I made the mistake of doing it when I was a bit tired and found out that acrylic was indeed flammable.  After throwing it in the water bucket I called it a day.  Flame polishing will give a slightly rounded edge to the acrylic, but I think a little less so than the standard polishing does.

Thanks for sharing the video!

Suzi

trebletomb 7/9/09

Hello All,

I am just beginning an installation of musical instruments, mostly woodwinds. Does anyone know of any brilliant installations out there I might want to have a look at for inspiration? The cabinetry has already been built and designed, and there is a glass deck. Naturally! So I am mounting into the back of the case, projecting reeds and sundry forward.

Thanks Brian Gravestock

trebletomb 7/9/09

Re: [mountmaking-forum] Re: Flame polishing acrylic? I have done a tonne of flame polishing acrylic. The trick is to to move steadily while keeping only the tip of the flame in contact with the material. I also found the realtionship to heat varied dependant sometimes on the manufacturer and their product. Some acrylics are more brittle and some softer. There was another video in the side bar where someone is flaming an edge with an oxy-acetylene set up. He moves steady. You can always go back if you under flame it. Overheating or dragging in one spot, inevitably causes blistering. A small propane tank, like one used for copper pipes, provides good heat. Its pretty difficult to flame anything over 3/8". The acrylic tends to fog up.  Residue from scratch remover on the acrylic will give similar distortion.

Brian

Howard 7/9/09

The plastics guys here use oxygen/hydrogen for flaming the edges. They take them down to 250 grit after the table saw.

Bradley Sanders 7/10/09

Re: [mountmaking-forum] Re: Flame polishing acrylic? Brian, I have something that might help you. We have developed a series of bronze cast swivel sockets graduated from 1/8" to 5/8". They have proved very successful for us in mounting things such as musical instruments. They solder to the back of the mount, and lock the mount in any position from 90 degrees to 180 degrees, as well as turn on a socket, so compound positioning is easy. They're not cheap, but they save major labor time, and they give the job a totally finished look. We also cast bronze floor and wall socket flanges from 1/8" to 1". We haven't marketed them yet, but have used them successfully in exhibits (Most recently National Infantry Museum) for years. Good luck in your installation! Bradley Sanders Sanders Museum Services

Jamie Hascall

7/10/09

RE:Musical Instrument mounting [mountmaking-forum] was Flame polishing acrylic?

Hi Brian,

The glass deck quandary is definitely a pain, but I found an interesting work-around on one project. A client wanted a polished plex base placed on the existing glass deck and it needed to be stable enough for Seattle area seismic stabilization needs. The piece was fairly tall 16” and the footprint of the base block small (4”x8”). I used pieces of clear 3M VHB tape diagonally across the corners of the block to adhere it to the glass. The result was visually very clean, firmly held, and I think it would survive quite a shake. In this instance, all forces were pretty static, with no cantilevered weight acting on the mounting. I don’t know if this may help in your situation. It’s just another good trick to have in the kit.

Jamie Hascall

Chief Preparator

Museums of New Mexico

Santa Fe

trebletomb 7/10/09

Re: [mountmaking-forum] Re: Flame polishing acrylic? Hi Bradley, Thanks for the speedy response. Could you be so kind as to send me an image of the hardware? Or is there one online somewhere? There are some time constraints so I would be interested in saving some.

Thanks Brian

trebletomb 7/10/09

Re: Musical Instrument mounting [mountmaking-forum] was Flame polishing acrylic? Hi Jamie, That's a great idea! I'll suggest that to the architects. The case is also bottom lit. The project was very developed before they hired a mountmaker, so the challenges are many. The tape that you used, do you think that would show up if it were lit from beneath?

I will source some anyway. Thanks so much.

Brian

steve 7/13/09

I flame polish edges at times but they still need good sanding first. They will also distort visibility through the plex near the edge.

Jamie Hascall

7/13/09

RE: Musical Instrument mounting [mountmaking-forum] was Flame polishing acrylic?

Hi Brian,

The case I used it on was also bottom lit and it worked quite well. The secret is to lay it on so that you get as few bubbles as possible. By placing it diagonally across the corners, I got only one short straight line to pick up the light. By being such a regular form and placement, it was unremarkable to the eye and drew little notice. I think a piece place in the center of a visual zone would be much more obvious and bothersome. I’d recommend doing some test blocks to get your application technique down and find the look you want. If you leave a small tab sticking out that you can grab with pliers and pull sideways, you may be able to get it to release for test purposes. However, once installed, I’d bet that is going to be a bugger to de-install. I was told by the rep that this tape’s bond gets stronger as it is in place.

Just so you know, I have never Oddy tested this tape, so if this is being used in an enclosed case with sensitive metals, you might want to get that done. If you do, please let us know here. I think it should be OK, but I just wanted to put out that disclaimer. If anyone else out there has done testing on 3M VHB tape, please post your findings.

I’ve generally sourced the VHB tape from R.S.Hughes. What you want is the 3M 4910 tape. It says that it is a foam tape on their web site, but it actually appears to be a clear flexible solid. It comes in different thicknesses and widths. This link should get you there. http://www.rshughes.com/catalog/351890.html

Good luck and let us know how this works for you.

Jamie