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I keep seeing comments in articles and in discussions about always using a sharp #11 Exacto (tm) blade while working. My other hobby is woodworking (I should take up something cheap like yachts and sports cars!) and I do a lot of woodcarving. I beg to differ about the definition of sharp when it applies to cutting edges. If you want to learn some fast secrets to sharp edges, read on, otherwise scroll past this message.
I have the same 5 pk of Exacto blades that I bought many years ago....and haven't used them all up yet. This is not to slam Exacto or put them out of business, but there is sharp as delivered by Exacto and other hobby knife suppliers, and there is sharp as I work. I promise you that once you try my methods, you will be happier with the quality of the cutting edge you get. Exacto makes an excellent, affordable product that you can sharpen to exquisite sharpness in a few minutes.
Good news is, you probably have everything you need around the house or can get it at the local hardware store. And you won't spend more $$$ on this than you would a couple of packs of new blades. Still interested? Lets get started.....
What you need to get:
When you get fancy and want to start modifiying blades to suit yourself, get a diamond sharpening stone from DMT. Your hardware store will probably carry those. the mail order tool shops mostly have them also. the small stones in a leather case is about 1" x 5" and costs about $20. I recommend the red, fine grit stone for most work.
What a sharp edge looks like..... 8^)
If you magnify the cutting edge of a blade, you will see the blade is a
flat piece of metal with one or both edges ground at an angle until they
intersect at the cutting edge. The grinding process leaves a series of
very fine ridges and valleys parallel to each other and perpendicular to
the blade usually.
The idea is to reduce these ridges and valleys until the blade is super smooth along this ground area leading up to the edge. Start with a blade in the handle and the 320 grit paper supported on a board or other flat raised surface. Hold the blade at an angle so the ground edge to be flattened is flat on the paper. You then stroke this blade, EDGE TRAILING along the paper several times. It may take 10-30 strokes to get the edge uniformly smooth and dull. Do both sides of the #11 blade, or the single edge of other blades as needed until smooth and dull. DO NOT ROCK THE BLADE as you do this. You don't want to round this flat edge, just smooth it out.
Once done with this grit paper, go to a finer grit, either 400 or 600 grit. Do the same for each grit, getting finer and finer until you have a very smooth dull finish on the two flat surfaces you have been working on. Once you get a blade polished like this, you can use the 1000 or 1500 grit to touch it up when needed. Mostly I just touch up a blade with the next step, leather stropping.
BTW....at this point, if you are sharpening a blade with one ground edge only, turn the blade over onto the side that was flat metal, and give it a couple of swipes on the finer grits of paper. This will remove any raised "wire" edge that develops when using this technique. You will want to polish this side as well.
Ideally you should glue the leather down to a piece of wood. This keeps it from slipping around and if you leave extra wood, you have a place to hold onto when stropping. Open the tube of red rouge and use course sandpaper to scratch off some sprinkles onto the leather. As you use the leather over the years, it will get darker and smoother. when you have a dusting of rouge on the leather, strop the blade the same as you did for the wet/dry paper, that is, EDGE TRAILING. I strop 10 times for one side, then 10 for the other edge. Then 5 times and 5, then 2-3 each and I am done.
Again, if the blade has only one side that you have been honing, hone the flat side as well with a few strokes when done to insure a smooth finish on that edge.
When you get thru, don't try shaving the hair off your arm, try looking at the blade with the edge toward a light where the light could reflect off of any dull spots on the cutting edge. If you see a dull spot, you will need to go back to the w/d paper to get rid of it. Rightfully, you will see NO reflection back off the cutting edge. If you see no reflection, you are probably sharp and ready to use. Try cutting a bit of lightweight paper. If it cuts with no snags, you are sharp!
Always use a cutting mat (quilting section of any store that sells crafts or quilting material) or a piece of masonite to cut on. The blade will last longer and not run away on you like it could when cutting on a wooden surface.
Now, why did I go thru all this with you and what does it buy us as narrow guage modellers????
I _know_ it is easier to cut any modelling material with a really sharp blade than a new hobby knife blade right out of the package. A properly sharpened blade does not drag and catch like even a fresh blade sometimes can. The smoother the finish on the 2 edges that make up the cutting edge, the better the cut will be. We tend to only use the very tip end of the #11 blade, maybe a bit more with other blades. These will all last longer for you with an initial honing and regular sharpening. As I said before, I find I can work for days with just touching up the knife blade on the leather strop on a regular basis. Once the stop has some rouge working into it, you don't even need to add rouge everytime.
I hope this helps with your modelling! If you are unclear about this, let me know....
Vic H
PS: Next installment, modifying blades and making permanent handles for them.
For those of you who enjoyed and tried my method of sharpening hobby knife blades, here is the second part of the series as promised.
Once you have become proficient at sharpening the blades, there is no reason to use only the metal handles. Having 3-4 different blades in front of you already sharpened and mounted in handles makes your modelling easier and faster. The hobby knives available have a good selection of shapes, but there are several more you may find useful as well.
First shaping the blades. A Dremel tool with a cutoff wheel is fine for changing the shape of a blade. USE A FULL FACE MASK while cutting these blades. When, not if, the cutting wheel breaks up, you want all the protection you can get. Full plastic shields are cheap insurance for your face and especially eyes. These thin cutoff wheels do a nice job but don't force them, let them cut through the blades at their own speed.
One shape I find useful is the small, narrow blade that is a flat chisel shape with the edge 90 degrees to the length of the blade. I have narrowed this blade down from about 1/4" to 1/16" wide. This is useful for neatly chiseling off rivet heads, grab irons, etc from tight spots. Hold the blade in a vise and use the Dremel with cutoff wheel to slowly and gently cut a slot down the blade to leave the width you desire. Don't let the blade get too hot. take breaks every so often to keep the blade cool. Once you have cut a slot the length of the blade, cut across the blade to remove the waste.
Once you have cut the blade, you can use a Dremel grinding point to smooth the cut side. A final polishing on the flat sides of the blade on the fine grit sandpapers will remove burrs and make them safe to handle.
A second blade shape that I have not made yet myself but I have been thinking about is to take a #11 pointed blade and trim back the point with an angled cut. This should still leave a fine point but with a bit more metal behind it for strength. If you hold the blade in front of you with the top, non-sharp edge horizontal and the blade pointing to the right, then think of trimming the blade tip back like this '\' with the cutting edge extending all the way to the right but some of the pointed tip now gone. The leaves the cutting edge with the double bevel but a bit more metal behind it for strength.
To cut this one, use the cutoff wheel again with the blade in the vise. It should be a quick and easy cut, just don't let the wheel hit the cutting edge. Come in from the back side to cut it off. About 1/16" should be enough to cut off to give you the shape we are looking for. All you want to clip off is the bit of the tip where the two bevels are coming together.
Use your imagination and modelling skills to "design" other blades you need for your work.
To create permanent handles for these, use 3/8" dowels. Use a course sander or hand plane or similar device to flatten three sides on the dowel to form an equilateral triangle cross section. You can leave some roundness between the 3 flat sides and then sand smooth. Cut the dowel to 6" lengths and smooth the cut ends.
Saw a fine slot into one end, starting on the peak of one angle and going straight across to the middle of the opposite flat side. Keep this slot as thin as you can while still allowing a blade to be fitted into the slot. Mix a 5 minute epoxy (couple of drops each will do!) and fill the slot you just cut. Fit the blade with the cutting side DOWN toward the flat part of the handle. For a blade like the #11, this means the blade will rest with the cutting edge down and be ready to cut when you pick it up. When the epoxy hardens, finish sanding the handle, paint it if you so desire with some bright color so you can always find the particular knife you want with just a glance.
And you are done! Sharpen your blades once, keep them sharp by stropping them frequently and you will find your modelling goes more easily.
One last word on stropping.....the more you strop, the smoother the blade becomes until it reaches an optimum smoothness. You may have to strop a blade several hundred times on each side to get to that point but once you are there, 5-10 licks on each side of the blade will keep you sharper that you ever thought possible.
PLEASE, keep your fingers away from in front of the blade and don't let little fingers try to cut with these! ALWAYS be safe when using these knives, they will cut clear to the bone if you get a finger in front of them.
Let me know if you have questions or to share useful blade shapes that you create!
Vic H
Found this stuff, hope it helps someone, not edited Reg Barron
>Subject: RSM
> (Vance Bass) says:
> I have heard that it is possible to build a resistance soldering rig
> using, among other things, an automobile battery charger and carbon rods
> from flashlight batteries.
>
> Has anyone ever done this? Do you have or know of plans which detail
> how to accomplish this? (I have more money than time, but the amount which
> is allocated to my hobby prevents me from spending $300 on a resistance
> solderer.)
> Thanks for any help!
>--
I have just completed building such a rig.
My carbon rod came from the brushgear of a large electric motor,
although I beleive that from a flash light baterry should work.
The motor brush carbon is formulated to withstand arcing and may
last longer.
I mounted the rod in an old soldering iron handle (heat resistant
plastic) using telescoping brass tubing to match the diameters
of various components.
The connection to the rod from the battery charger is about #8 flex cable,
again connected to the nested brass tubing. (I crimped it all with an
industrial strength crimping tool).
I modified the battery charger by putting a normally on push button
switch in the primary circuit (mains side of the transformer) to allow
me to postion the rod, brass components etc. before applying
the current. If you don't do this you will ruin small components with
burns from the arcing.
Does it work? yes, but my 6 amp battery charger is not strong
enough for my needs, also keeping my foot on the push switch
and releasing to turn on the current is not natural and akward.
Modifications for the future:
A larger battery charger of transformer/rectifier.(a friend uses a 15 amp
lashup with no problem)
A better and independant control for foot operation. Probably a dimmer
switch mounted in a box with a plug, this should also work for my
dremel motor tool and setting the temperature of my soldering irons.
Ian Simpson (ian.simpson@ualberta.ca) wrote:
etc-rification
: I mounted the rod in an old soldering iron handle (heat resistant
: plastic) using telescoping brass tubing to match the diameters
: of various components.
: The connection to the rod from the battery charger is about #8 flex cable,
: again connected to the nested brass tubing. (I crimped it all with an
: industrial strength crimping tool).
: I modified the battery charger by putting a normally on push button
: switch in the primary circuit (mains side of the transformer) to allow
: me to postion the rod, brass components etc. before applying
: the current. If you don't do this you will ruin small components with
: burns from the arcing.
: Does it work? yes, but my 6 amp battery charger is not strong
: enough for my needs, also keeping my foot on the push switch
: and releasing to turn on the current is not natural and akward.
: Modifications for the future:
: A larger battery charger of transformer/rectifier.(a friend uses a 15 amp
: lashup with no problem)
: A better and independant control for foot operation. Probably a dimmer
: switch mounted in a box with a plug, this should also work for my
: dremel motor tool and setting the temperature of my soldering irons.
Watch out!!!! A triac-type dimmer may either blow itself into the next
county with such an inductive load, and Dremel does NOT endorse the idea.
Most of their tools now use a permag motor with a bridge rectifier inside
the case. Use of half-wave rectified scr controls can destroy the tool,
but a full wave control works fine. I use a variac with a resistive foot
control for my small power tools- Dremel, Unimat, Sherline, etc. I also
picked up a small adjustable xformer which was made by Ungar for my soldering
pencil- type iron.
Sears has a foot switch in their tool catalog which is heavy enough for
larger tools like a drill press, table saw, etc. In my shop, every thing
is controlled by a foot control. It makes life a lot easier.
See if you can find a catalog by a company that supplies tools for
jewelers- Vigor used to be such a company. After you quit salivating all
over the pages, you might find a resistance unit or just the tool for
with your own transformer for a more rational price than PBL wants.
Or not- I haven't priced one in decades. I bought mine from a company called
"Brookstone" which used to offer a great line of precision tools, but they
went yuppie with exotic garden and kitchen tools and I haven't heard from
them in many years. Pity.
Again, I'd suggest a Variac feeding a husky fixed xformer via a foot
switch for the current source. These beasts can be found in surplus
places sometimes for a good price. Five amp minimum, I'd say for the
input into a step-down xformer. Mine is not metered- I adjust for smoke
as the expression goes so can't give you any idea of what I'm using.
I'll look into it and try to post some numbers later.
Fred D.
In article <3ce8h1$pos@dns1.NMSU.Edu>, fdabney@nmsu.edu (Fredric W.
Dabney)
writes:
[...]
>
>See if you can find a catalog by a company that supplies tools for
>jewelers- Vigor used to be such a company. After you quit salivating all
>over the pages, you might find a resistance unit or just the tool for use
>with your own transformer for a more rational price than PBL wants. Or
>not- I haven't priced one in decades. I bought mine from a company called
[...]
The latest Vigor catalog has a soldering machine that includes several
carbons and claims to be a 1320 watt unit (intermittent use), if you
have $188 you want to spend on it...
...when I sit down to write
Don Holly my intentions are always blameless however
deplorable the ultimate effect of the act may turn out to be.
--Joseph Conrad
dholly@psl.wisc.edu wrote:
: In article <3ce8h1$pos@dns1.NMSU.Edu>, fdabney@nmsu.edu (Fredric W.Dabney) writes:
: The latest Vigor catalog has a soldering machine that includes several
: carbons and claims to be a 1320 watt unit (intermittent use), if you
: have $188 you want to spend on it...
That is less than some models of the unit PBL sells. If it is the same
unit I bought from Brookstone many years ago, at max it'll vaporize a
piece of .25" brazing rod.
By the way, if you do decide to try building your own, and if you get the
notion of using arc welding rod, watch out. There are several versions of
the carbon rod, many of which have a soft center (not being a welder,
I don't have the foggiest notion of the purpose of this rod) and it isn't
worth a hoot for a resistance soldering machine. For one thing, you can't
shape it to a point. Someone gave me some years ago, and I still have it
because I can't use it.
I'd like to see some information on this matter since I could use some rod.
I've also given thought to making a very small holder and using
draftsman's pencil graphite sticks. I suspect they are also in short
supply now, CAD being as pervasive as it is.
Fred D.
In article <3cfdec$1c4@news.doit.wisc.edu> dholly@psl.wisc.edu writes:
.
.
.
>The latest Vigor catalog has a soldering machine that includes several
>carbons and claims to be a 1320 watt unit (intermittent use), if you
>have $188 you want to spend on it...
And MicroMark has a 250 watt unit for $330. Address for Vigor please.
--
Bill Ganoe -- U. of Arizona, SIE Dept ** Engineering:
bill@SIE.Arizona.EDU ** The ultimate art
602.621.2528 ** of the human mind.
In article <3c7uucINNsp7@duncan.cs.utk.edu>, bass@cs.utk.edu (Vance
Bass) says:
>I have heard that it is possible to build a resistance soldering rig
>using, among other things, an automobile battery charger and carbon rods
>from flashlight batteries.
>
> Has anyone ever done this? Do you have or know of plans which detail
>how to accomplish this? (I have more money than time, but the amount which
>is allocated to my hobby prevents me from spending $300 on a resistance
>solderer.)
I have built several of these over the years. You will spend $20.00
tops on the thing.
Rather than a battery charger, I would recomend a 6.3V filament
transformer from most any electronics supply house or old TV. These
used to be very common as they provided the juice to heat up all those
old glass glowing things used in electronics before transistors.
The transformer fits into a small box. Wire the Primary to a 110V plug
with an on/off switch. If you use a female plug like on most
computers, you can hook in any line-side controls (such as foot
controls and dimmer switches) at your leisure. Wire the secondary to a
large stereo plug. This allows you to try lots of different carbon rod
combinations easily.
For the rod, cut appart a C-Cell flashlight battery. Wash away the goo
inside being careful not to get too much in your eyes or on the family
dog. You will be left with a carbon rid that can be sharpened to a
point and connected to one of the secondary wires. The second wire
works well with an alligator clip to attach as a ground.
If you use a foot switch on the primary side, you can hold the work in
place with the carbon electrode, hit the switch 'til the solder flows,
and then let up on the switch, holding the work 'til the solder
rehardens. I like these best for trackwork, prefering a torch for most
brass engine jobs.
Enjoy.
Skip Egdorf
hwe@lanl.gov
In article <3c7uucINNsp7@duncan.cs.utk.edu> bass@cs.utk.edu (Vance Bass)
writes:
> I have heard that it is possible to build a resistance soldering rig
>using, among other things, an automobile battery charger and carbon rods from
>flashlight batteries.
>
> Has anyone ever done this? Do you have or know of plans which detail
>how to accomplish this? (I have more money than time, but the amount which
>is allocated to my hobby prevents me from spending $300 on a resistance
>solderer.)
>
> Thanks for any help!
>--
>=-=-=All the above are OFFICIAL POSITIONS and are ABSOLUTELY TRUE!=-=-=
>Vance Bass Reply-to: vrbass@vnet.ibm.com
>"It don't mean a thing if it ain't got that certain je ne sais quoi."
-- Peter Schickele
Yup. Been there, done that. Followed plans in the Narrow Gauge and
Short Line Gazette, a mag for model rr. buffs. You need about 6-8
volts and a bunch of amps, say possibly 10 or more (memory not sure
here), a lamp dimmer on the hi voltage side of the xformer for
control, a ground lead and the lead to the carbon rod. Email me your
snail-mail address and I'll copy the article for you.
___________________________________________________________________
Greg_Lewis@csufresno.edu
Photojournalism sequence, Department of Mass Communication and
Journalism
CSU Fresno, Fresno, CA 93740-0010
In article
gregl@zimmer.CSUFresno.EDU (Greg
Lewis) writes:
>From: gregl@zimmer.CSUFresno.EDU (Greg Lewis)
>Subject: Re: Building a resistance solder machine
>Date: Fri, 9 Dec 1994 01:18:50 GMT
>In article <3c7uucINNsp7@duncan.cs.utk.edu> bass@cs.utk.edu (Vance Bass) writes:
> I have heard that it is possible to build a resistance soldering rig
>>using, among other things, an automobile battery charger and carbon rods from
>>flashlight batteries.
Here are several articles on the topic:
MR 11/78 p80 Resistance soldering ( RESISTANCE, SOLDER, SOLDERING, TECHNIQUE )
NGSL 9/81 p70 Building your own carbon-rod resistance soldering unit ( RESISTANCE, SOLDER, TOOL )
MR 4/92 p112 Introduction to resistance soldering ( RESISTANCE, SOLDER )
jeff.scherb@turner.com
: >In article <3c7uucINNsp7@duncan.cs.utk.edu> bass@cs.utk.edu (Vance Bass)
writes:
: > I have heard that it is possible to build a resistance soldering rig
: >>using, among other things, an automobile battery charger and carbon rods from
: >>flashlight batteries.
The following is from the FAQ on CONSTRUCTION TECHNIQUES:
Date: 20 Mar 94 01:00:00 GMT
From: urf@icl.se (Urban Fredriksson)
Subject: FAQ CONSTRUCTION TECHNIQUES, 14/14: Soldering, resistance
SOLDERING, RESISTANCE
Any recommendations for a resistance soldering unit?
Go to your local friendly electronics supply house and buy a
transformer with 110v primary, 6.2v (? or there about) secondary and a
4 to 6 amp output on the secondary.
Go to your local Radio Shack and get an insulated box big enough to
hold the transformer.
Wire a 110v plug to the primary of the transformer. (Do I need to
remind you to use a grounding plug and take care not to electrocute
yourself???)
Run the secondary to two wires, one with something like an alligator
clip, and the other to a clamp making a good connection to a carbon
rod.
Where do you get a carbon rod? one might ask. Go somewhere where you
can wash some chemicals away, and cut up an old flashlight battery or
two. I have had good luck with both C cells and AA cells. The center
contains a carbon rod. Make a point on the rod with some sandpaper, or
a pencil sharpener, or something, and clamp the second wire from the
transformer's secondary to it. Radio Shack will have conenctors that
will do the job.
Now, when you plug in the transformer to the wall, and you connect the
alligator clip to something metal connected to what you want to
solder, and touch the sharp tip of the carbon rod to where you want to
solder, the metal right around the tip of the carbon rod gets REALLY
hot. Sounds kind of like one of those $250 dollar units to me. If you
really make it fancy, you might spend $25 or $30 building the thing.
How to make it fancy??
First, I like to put a control on the 110v side of the transformer. A
normal light dimmer works well, although I have also had good luck
with a sewing-machine foot control. These do not really have the
current rating, but are ok for light duty work. I like having both
hands to set up the work (the rod holds stuff in place) and then Zap
with the foot.
Second, I use large stereo-type plugs to connect to the secondary side
with the clips and rods. This lets me have several different rod-size
and clip configurations that are easy to switch.
Third, Fancy handles for the carbon rods...
Fourth, whatever else comes to mind. For the price, and ease of
construction, you can afford to experiment.
------------------------------
good luck
wunder@convex.com
In article <3c7uucINNsp7@duncan.cs.utk.edu>,
bass@cs.utk.edu (Vance Bass) wrote:
> I have heard that it is possible to build a resistance soldering rig
>using, among other things, an automobile battery charger and carbon rods from
>flashlight batteries.
>
> Has anyone ever done this? Do you have or know of plans which detail
>how to accomplish this? (I have more money than time, but the amount which
>is allocated to my hobby prevents me from spending $300 on a resistance
>solderer.)
>
Its not possible. The transformer has to be a special type with a high
current output secondaries. These things are expensive, hence the price
of the comercial units. There are safety considerations.
The units in the UK sell for about #100 ie $150 so you should be able to
shop around for a better deal.
----------------------------------------------------------------------
--
Bill Bedford Designer of Photo-Etches
billb@mousa.demon.co.uk
+44 9505 327
Living on a island gives the world a different perspective
----------------------------------------------------------------------
--
In article <3c7uucINNsp7@duncan.cs.utk.edu>, bass@cs.utk.edu (Vance Bass)
writes:
> I have heard that it is possible to build a resistance soldering rig
>using, among other things, an automobile battery charger and carbon rods from
>flashlight batteries.
I helped a friend build one for use in model car construction. The
system that we used is very robust and I would much rather have it
than a lamp-dimmer based unit.
The components are:
1 VARIAC variable auto-transformer, a small one is OK.
A hefty 120V pri / 24V sec transformer
AC voltmeter (across secondary of 24V xformer)
ON/OFF foot switch (wired into primary of VARIAC)
Carbon rods available from welding supply for carbon arc torch.
All the electrical parts were obtained from various surplus houses
(cheap). We put a fuse in the secondary of the 24V xformer for the
rated output current of the transformer. I am told that the thing
works very nicely!
-BK
I just completed my home built resistance soldering rig, based on the plans and info provided by some members a few months ago. And it works great!!
I did deviate from the parts lists, though. I found that the Radio Shack transformer is no longer available. Besides, using only a 4 amp trans. bothered me. After some brief head-scratching, it dawned on me to use the guts from an automotive battery charger. Those things are available in all kinds of big amperage ratings.
The one I chose was a 6-12 volt 10 Amp manual model made by Exide. I bought mine from K-mart for $40. The bonus was that I now also had a fancy case, wiring, and a power cord. The only extras needed were a few stake-ons, a fuse holder, two binding posts, and a $5 lite dimmer (*).
Basically, I removed the existing circuit breaker, diodes and meter, installed the fuse holder in the line, installed the dimmer in the case where the meter used to be, and rewired the whole thing using most of the wires salvaged. I used the existing wires as much as possible since they were large enough to handle the amperage and already had connectors that matched the other components.
The tool was made according to the plans, from an old Radio Shack soldering pencil I had laying around. I did end up getting a box of carbon rods from a welding supply shop. I had to by a box of 50 for $18. This is enough for about 10 lifetimes, I think. At least I'll have plenty of spare tips!
The other modification I made was to increase the output. The transformer is a center tapped type, which is like having two transformers side by side electrically. I cut the common lead, and rewired the now two secondary windings in parallel. This boosted the capacity to about 20 amps. I measured all the good stuff, and it turns out, it comes to about 150 watts. So for about $75, I have a $300 unit that, thanks to the original case, doesn't even look home made!!
If anyone is interested in the specific details, please feel free to contact me. Even if you don't know very much about electrical stuff, I can talk you through it.
And not to forget, my many thanks to those who provided bits of information!!
Ben Y.
[* Editor's note: take care when testing out the dimmer, as most of them are
not originally designed for using a transformer as a load...]
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