Paraset: Lettering with Decals ~ Pt. 2

Here are the results using the water-slide method:

As you can see the masking tape is still in place and the holes still need to be cleared.  The SERIAL NUMBER tag is also a slide decal on a scrap of metal and is only temporarily in place with some un-set eyelets.

On an angle you still may see some of the plastic carrier materials.  Placement is a little tricky as there can be no pencil guidelines or any marks, and the material is extremely prone to stick to itself as well.   Glad I made plenty of duplicate labels!

Continuing clear coats and sanding downs, with extreme care not to sand off the decals. 

The method is:
1) to only cut as much carrier as needed, (see my last post) the irregular shapes and ones cut as close as possible to the letters seem to be the best.  

2) For sanding; the trick is, use ultra fine sand paper on a block, and rub just enough to just knock off some of the clear coat on top of the decals. You want to only see the carriers as dull white and not areas surrounding to start and eventually the whole surface is matching as the clear coat builds up in between the decals.

3) Multiple light coats between sanding.  The idea is to build up the clear material surrounding the labels until they are at the same level

4) **Keep the area clean as possible! Dust and dirt will collect and stick on the coat. Try not to touch the surface to see if it is dry, just give it time.  (**Yes, this means all cats were banned from the workroom!)

Just keep building up the low areas and the decals carriers will disappear!  (no magic, just a light touch and plenty of coats ~ I lost count but at least 4 t0 6 )



Tools:

I used a fine Iris scissors, tweezers, a small bowl of lukewarm distilled water (Hot water does not work! ~ the decals will shrivel up, tap water may leave a mineral film) and a dabbing tool ( Looks like a paint brush with a little sponge attached.) and Krylon Clear Gloss ( No. 7110) and 3M 9084 Ultra Fine Sandpaper  on a sanding block.

~ ~ ~

Again, as with the painting, it seems like a lot of work. But you can do a coat and sand cycle over a couple of hours in between other things ~ makes it a little less tedious.

Note: The decals came with a clear coat as well that was sponged on. I only used this on the sheet as directed. I suppose the enamel on the sheet would be just fine.

Paraset~ Panel Finish - With Paint!

Instead of the nickel plate;  I elected to use simple enamel spray paint.

I am no painter, but I have painted on metals before, surface preparation is the key to a good outcome. The one thing I have learned is painting steel is by far easier than aluminum, which is like, in fact, painting on glass.  It will peel off and look terrible in no time if it is not prepared properly.  The chemicals you need to prep the surface are pretty nasty and toxic as you actually need to etch and de-glaze the surface.

Prep:
Steel on the other hand is far simpler, since most auto body repairs are steel, lots of material is readily available.   I start preparing the surface by a fine sanding, followed by de-greasing the surfaces.  I use carburetor cleaner, which is really just strong solvents in a spray can,  to remove any oil:

Item #08796 3M™ Carburetor Cleaner

Make sure to handle the panels very carefully only with gloves after cleaning, not to get any oil, even by simply by touching the surfaces.

I put then carefully put some blue masking tape discs on bottom around screws and connections with tweezers.  I wanted these holes to be electrically grounded.   I suppose I could have skipped this and simply removed the paint later with a small rotary brush.  

Next, two coats of:  Item #249415, Rust-Oleum® Sandable Primer  - Gray 
Sanded between coats, with fine sandpaper on a sanding block, not just with sandpaper.  The idea is to make a smooth surface to fill in the scratches, low spots, and tool marks. 

I then let it bake in sun for an hour or so.  This helps let the VOC solvents in the paint evaporate. The bottom side had only one coat, no sanding just to stop any rust since it had been sanded and de-greased

With primer the idea is to make a smooth surface for the color coats: 

Second PRIMER:  


I only sprayed one coat of primer with no sanding  which is why it is dull compared to the front surface:

 Note:  Masking tape on back side is covering some holes.

Followed by Three light coats of Industrial Spray enamel:
Item # 37487, Krylon® Industrial Grey Tough Coat® Acrylic Enamel Paint

Let dry for an hour or so in the sun, with a ery light sanding between the coats.   

Then baked it on -  after the final coat in a small toaster oven at its lowest setting for about 30 - 45 mins.  I read the max surface temp was about 145°F  with an IR thermometer.

Coat #2:

Final coat!   I know, it sounds like a lot of work, but really not too bad, I did it in only one day.

Next, I will  apply decals and use a clear coat to protect the decals, and then finally remove the paint on the counter sink holes with the same bit used for making them for even more electrical contact area.

Note: The hole for the crystal holder is back?  Yes, as suspected, drilling through two hardness's of materials was an interesting challenge, which is why the hole is not countersunk.  I ended up using some epoxy putty to fix it. I had to grind the hole out and enlarge it bit to effect the repair.   

 Also there are four more "hidden" holes!  Yes, I pre-drilled the 4-way mounting holes for the choke transformer and filled in for future used if needed, since I had the locations marked.

Paraset~ Lettering with Decals

The problem with lettering the paraset panel ~ Solved?  Well, I think so.  I now intend to use a method called water slide decal. 

Decal Paper.COM

I chose the ink jet version, so I could use color for other projects.  The process is simple you make a decal pattern, print it off on this special paper, cut out the decal, soak in warm water, apply to the panel and blot.  The next phase involves using a clear enamel to protect the carrier which is a real thin plastic material. 

Decal Patterns:

Power supply Patterns:

Dial Close up:

Note the dial pointer.  I made this from one of the #4 M-F  0.25 round stand off I used in making the friction dial parts.  I found these are really plated brass and chucked up in the drill press touched up the cut side with some sand paper.  I intend to cut a thin line with a razor saw and fill with some black enamel.  I think it looks more finished than just a screw head.

Paraset ~ Rivets

One of the "controversies" in Paraset replica making are the rivets used. On close study of the original photos it can be seen that on all the known samples, the tube sockets are fixed in place with rivets.  Simple?  Well, I venture to guess the hardware used definitely not modern “Pop rivets”. 



Ser No. 2357  Photo by SM7UCZ

Ser No 7629  Photo By F6EJU

Studies of these photos show the center of these are open, not solid.  The initial plan I had was to use pop rivet tool and make a tool that uses the ⅛-inch shaft that only presses (swage) the rivets in place and does not break off the little ball inside.  This tool gets a little complicated to make as it has to be shaped to roll the edges.

I suppose you could also drill out the rivet after it is set to simulate the original.

But I think these are more precisely “eyelets”  Here is a link to some electronic riveting hardware:  Keystone

No need to special order any.  I found some kits which are actually readily available at craft and sewing stores! The Tandy #3632-00 consist of a little tool that folds the edges neatly and an anvil to hammer against, and a little dimple in the anvil to roll both sides:

 

Tandy Leather Supply  #3632-00



  I also bought bought both a snap kit  #3630-00:

Tandy Leather  #3630-00

The problem is the eyelets in the kit are 3/16" not the correct size.  The snap kit has a smaller tool.

This should fit the ⅛" eyelets I have, the combinations of the two tools, the smaller one for bottom and the larger one for the top  as the anvil.

Why? The issue I see with the supplied anvil is; there is no clearance from the tube socket on the bottom, it must be centered as it is actually concave, and I fear the tool will leave a mark in  the finished surface from the top since this has to be done after the decals and the finish are complete.  

I will clamp or hold one tool as the anvil in the vice, on the top side of the chassis, and tap the other with a small hammer to set the rivet from the bottom of the chassis.  It will be a balancing act but this gives the reach needed to set them.

Now I have an eyelet and snap tool to repair the eyelet on my favorite hiking boots and fix the snap on Wax Coat I got in Scotland as well!

~ ~ ~

I saw that one builder, Jean Claude (F6EJU) in France, was looking for assistance on finding proper rivets for the “cash box”; he likes to make exact replicas.    I remembered that I had found some of these exact rivets to use as contacts for the key!

These are most likely aircraft rivets:

I sent some to him after he confirmed they looked OK.

There is a volcano in Iceland, no air travel in EU so I have no idea when he will get them ~ Mailed him a pound or so this week so he could complete his authentic cash box!

** There is really no controversy, build with what we have and "this is no beauties contest" is our motto.

Paraset ~ Friction Dial

The friction wheel is now in place. Made the plate from brass and standoffs with washers. 

Needs some adjustments, but works!

‎Sunday, ‎March ‎21, ‎2010, ‏‎1:28:12 PM

Linerizing the Dial

The "REC TUNING" dial was the most difficult part to find.  I saw a number of these on e-bay some for a quite a lot of $$.  There are similar dials with 3" and 4" plates to be found.  I could not locate a 0-100 scale dial.

One day while poking around the Junk in California Electronics Supply in El Cajon, CA I spotted two likely candidates. If only could I re-engrave the numbers? 

Oh well, I will figure out that later.  The price was right @ $4 for the pair plus some other junk as well.

So how to separate the parts?  Looks like they were swaged and stamped in with a chisel?

Chucked a grinding stone in the drill press and...

Original machinist markings? Cool!

The 120° holes were under there as well.  How convenient!

Flipped the dial ~ real clean.

Ready to renumber!

Paraset Panel ~ Mechanical Parts

 Paraset now has  all the panel mechanical parts!

Front View

The major parts are all now fitted in place.  The changes in the upper left hand corner for the "EXT KEY" jack required moving the tie point to above the crystal socket.  The repair of the off-center hole between the crystal sockets is visible as well, more on that later. 

Wiring Side View

The Internal Key:

The little internal key was a weekend project itself.  I used acrylic plastic sheet (the stuff in hardware stores is too thin I wanted at least 1/4")  a technique called solvent welding.  It actually melts a small layer of the material, just like metal welding, and bonds the parts together.  It is very effective when joining the polished faces together, not so much the ends. I got my supplies from TAP Plastics:

Qty	SKU	Product	Price	Total
1	10774	IPS Weld-On 3 Cement (4 oz.)	5.95	5.95
1	25658	Small BD-25/2 Hypo Applicator	3.25	3.25
1	30738	Polypropylene Funnel	0.75	0.75
2	00010	Acrylic Sheets Clear Sample 1/4" (.236) Sample 4" x 4"	2.00	4.00

The material is easy to cut and drill, a little trickier to do well.  I simply cut a strip slightly wider that the final key and laminated the three pieces together.  The center was simply offset and the excess was cut and sanded off when the bond was done. This saved from dealing with two cuts or machining out the center.  The trick to drilling was to use the slowest setting on the drill press and remove a small amount at a time.  If not, the plastic would build up and/or melt causing the hole to crack out.   Probably should have ordered the special plastic bits they sell?

The bottom was not absolutely flat at 90° when I  drilled the mounting holes, this caused a slight angle to the long mounting holes. This would have been unnoticed in shorter holes!  It would have also been real hard to compensate for on the panel if I had drilled those counter sunk holes first.  I ended up enlarging the holes on the key slightly to make up for the difference and drilling where they lined up on the panel. 

The arm and contacts are made up of the 18ga. panel metal.  For the little bend in the arm; I pressed it in a vice which just happened to have “V” shaped groves for holding work and a bit slightly smaller than the  ⅛” axle.    I made the axle from a broken  ⅛” drill bit shank.  Chucked it up rounded and smoothed the ends with a file.  Drilled and tapped the holes on a smaller piece to hold the axle and attached using some shortened #2-56 x  ¼ ”  (3A) pan head screws.   I used some of the small semi-tubular rivets for contacts; the small spacers were made from 1/16" aluminum washers filed down on the drill press  by placing these in a stack on as screw and milling to size with a file.  Electrically, the arm was grounded to the chassis by a short length of fine braid copper wire soldered to the tags.  The Key line tag is connected to one of the screws on the "T" shaped tab on the key's base.

The spring was a bit of a surprise how short it needed to be.  I cut the spring in half using some wire cutters and bent a hook.  It hooks into a small 1/16" hole on the arm and is now temporarily held by a length of paperclip wire.  I tried to machine a step but the smaller wire insisted on falling out or getting pulled down the hole.  Maybe a flat bottom bit would be better but I think I will cut this wire down and simply heat the small wire with a soldering iron to melt it in place  to fasten it permanently. 


A little bit ironic I guess;  building a 70 year-old radio that the “quiet key” bumper used on the key was a small rubber plug found on the back of an old cell phone!  Simply pressed it into a small hole drilled on the arm.   The adjustment screw was a #4-40 brass round head screw with a brass locking nut, the hole was located above the bumper and drilled and tapped. 

The knob is much larger than the original, but it was a 1930’s vintage parts drawer Bakelite knob I thought it was appropriate to use.   The only issue is the hole was tapped for a ¼-20 screw!  I fixed that by using a piece of threaded rod, an old bolt I think, and screwed it in and filed it flat to the bottom of the knob.  Then drilled and tapped a #4-40 threaded hole through the center!  It was attached to the arm with a #4-40 "cheese head" screw and lock washer.

Another "KEY" part in place!

BTW ~ I have  tested the key on the air already!  By attaching it to the external jack and using a ¼” to ¼” patch cord to my Kenwood TS-440.  The action was nice and worked OK.  It was a little “bendy” but all-in-all OK to use.  I first used my added that jack and the key at the same time!


The Hole issue:

This steel is easy to work in some ways but harder in others...literally!  Drill bits will wander and miss the required locations if you are not careful.  This problem was NOT caused by drilling error.  I drilled exactly where the drawing has the mark.  The problem was the center hole moved 0.1” from the other holes by accident. I think it happened when I was putting objects in the drawing “on-grid” to line up with the other holes on the drawing. I did not select this as a group of three objects.  I did not notice this until I mounted the jacks.



Key and Crystal Jack Details


To patch it I used a counter sink to create a surface to attach solder to.  And yes, I soldered it closed and sanded it flat!  This may become an issue when I drop the jacks  behind the panel; closer to the original design and I need the mounting hole here. We will see how drilling through this patch works out.

De-construction:

Now the hard part: Back on the workbench for tear down!  I needed to remove all the parts for counter sinking holes, final finish and rivets.   Yes - those modern S/S Philips head screws will be all gone as well.



Mk-VII is Ready for Final Finishing

 I think I sat there and played with the controls and admired for about an hour before I Took it all apart!

By the way -  Sorry for the blurry pics... but if you notice the light bulbs have different color beads? One of the original glass bulbs was slightly off center and got scored by the sharp metal edge and sheared off cleanly, like a little cap.  I think I will keep the parts in case I want to do a LED replica bulb or something.