separating etched metal parts fr. fret

Here are two more: sprue or parts tree.

Ray Austin, TX ===

To re-post myself...:

I've been cutting and bending etched parts for years, and I find my most useful tools for working with etched parts to be needle files, two single edged razor blades, a #17 X-Acto blade, an X-Acto hobby hammer, and a scrap of 1/4" plexiglass sheet.

The plexiglass sheet is a good, flat, hard surface for bending and striking against. The "striking" I refer to is where the hammer and the #17 blade come in - a metalsmithing technique. You can squarely align the chisel shaped blade at the very edge of the metal "sprue" and give it a tap or two with the hammer - you can make very precise cuts this way to seperate parts from the fret, and also trim parts after they are free. The plexi is just hard enough to back the strike, but flexible enough not to shatter under it.

As for bending, I use the "two razor blade method" for even the smallest of parts. Once the part is free and trimmed, on that same flat plexi surface - hold the part down along the desired fold line with one razor blade. Then slip a second razor blade under the part to raise it to the desired angle. Done...cheap. Another way is to look around your bench until you find an object which will make a good form for the bend - as an example, the cap from the bottle of CA I use is the perfect radius for forming the backs of 1/48 Eduard etched WWII cockpit seats.

For adhesives, I use both thick CA glue and watch crystal cement. I find that watch crystal cement works well for small parts there a thicker glue with a bit more working time is required. It also works well on larger flat joins. The black thick CA "tire cement" also works well with etched parts - I presume because it has a flexing agent in it...but I won't swear to that.

I paint my etched parts just like any plastic part - I use enamels exclusively. One thing to note is that you will need to attach the etched parts directly to the bare plastic for best result...if you attach them over a painted surface they will merely peel off with the paint. So you need to plan them into your assembly and then paint the assembly in accordance. Some people also wash and/or prime thier etched parts - I do niether and that works fine for me with enamels.

Hope all that helps ya...

For me, it depends on the material. If using regular brass photo-etch, I use a round blade scalpel (#10) on a teflon pad. I cut as close as I can to the part itself with a forward-back rocking motion. For smaller parts, it's smart to tape it down so that it doesn't ping off into never-never land. With tougher material, such as DML/Dragon's nickel plated brass or whatever it is they used in their early stuff, I cut with Xuron micro-shears, leaving a good nub that has to be filed off. Don't cut too close with the shears; you can screw up the part badly. Also, with that tool, you don't have much of an opportunity to tape the part down, so try working inside a plastic bag. Then when it pings off, it doesn't go far.

And yes, the waste is called a "fret". One more word about PE... don't think you have to use all of it, just because it's furnished. Frequently it includes a) parts that are never seen b) bits that are no better than the kit part and c) parts that are better fabricated with round stock.

--- Tontoni

Rufus covered the subject very well. I only add the following:

I use double sided tape to place on top of my cutting surface, a piece of glazed ceramic tile. I then stick the PE fret onto the tape. This does two things: (1) prevents the dreaded "part launcher effect" that often occurs when cutting on a hard surface endangering your eyes (wear eye protection anyway). (2) gives a bit of cushion for the cutting edge of whatever instrument you use thus prolonging the useful life of it.

Art

Yes - that's a handy trick...though I find I end up bending the part more often than not trying to get it off the tape. Probably because I should try a different brand of tape with lower tack...

What I end up doing is to hold the #17 blade (blade only, no handle) between my thumb and forefinger - which allows me to rest my thumb on the part. I'll add that I always place the non-ground side of the blade toward the part, and the ground side of the edge toward the fret...thus my thumb on the part keeps it from launching, and the fret side is usually large enough that if it does travel, it doesn't move very far.

Bending can be a problem. I use an X-acto blade and slide it under the part. The tack problem can be mostly overcome by using loops of 1" Tamiya masking tape.

I forgot to add that I use sandpaper to remove rough edges or barbs after the cut, which I seldom attempt to make flush with the part.. *Gentle* sanding with little pressure will quickly remove the barbs/rough edges.

Art

I continue the tap-cutting process once the part is free - as I've mentioned, you can get very close to the partline if you hold the blade as I describe. I find I can "nibble" away the edges with the blade fairly quickly. Then I resort to the needle file if I feel it's required.

Occasionally it may also be easier (and/or produce a better fit) if the etched part is glued in place to the plastic part first, and then filed flush.

I use piece of 1/16" aluminum for my cutting surface. It is hard enough to support all PE materials (even stainless steel) but is is soft enough not to destroy the edge of the X-acto knife blade.

To prevent launching I hold the parts with my finger. I don't hit the blade to separate the part - I just put pressure on the knife and rock the blade from side to side until it goes all the way through the "fret".

Peteski

Thank you all for your contributions. I will try some of the described techniques and see which appeal to me. The "two razor blades" bending technique sounds good to me... Ingo

Now I *know* I'm in the presence of a master! The thought of my gluing a PE part to a plastic part (or model) and then attempting to sand conjures up all sorts of memories of past disasters. I lack the delicate touch necessary as I subscribe to the "bull in a china shop" method of dealing with small PE parts. :-)

Art

Yes.

I use a piece of 1/2" thick acrylic scrap as a cutting surface and a #17 X-acto blade like a guillotine to cut the pieces free. I find it best to leave as much tab as possible on the part and go back later a chop it off flush.

It's all in the wrist...;)