[TMC] Cabinet Colors

Fri Mar 4 12:31:26 EST 2011

Hi Chris,

This is indeed a very good question, and one that has been raised here previously, as well as in other collector radio forums, etc.

There really is a single correct color, the so-called TMC Blue. This color will exhibit an acceptable range of shades within the TMC Blue designation.

My GPR-90 and GSB-1 are both the earlier Mark I versions, built in the 1955-1956 time-frame, and when viewed side-by-side, there is a very slight variation in the color of the two units. My GPS-1 Speaker is actually closer to the GSB-1 in color, and as I acquired the speaker separately and much later, I have no idea as to when it was built. It could have built as late as 1962, or as early as 1955.

The color shade variations are due to the paint manufacturers variations in paint mix from one production lot to the next. This is even evident when looking at Collins 75A-4s; put two of them side-by-side, and subtle variations in the St. James Gray color and texture are frequently obvious.

Paint will also change color due to exposure to light, dirt build-up in the crackle or textured finish, or by the normal chemical changes of the paint vs. time.

The same is true of the textured finish TMC used on many of their products. For example, the texture of the finish as used on the cabinets for the GPR-90, the GSB-1, and the GPS-1 or GPS-2 is actually a fine crackle finish, similar in texture to that used by Collins on the 75A-series of receivers, etc. On the other hand, the texture of the finish used as used on the GPT-750, the SBT-1K, and other larger systems as built by TMC, was actually a much coarser or "lumpier" texture, that was commonly used in industry to cover up the imperfections in the fabricated sheet metal due to it's better hiding capability.

The variations in the fineness of the crackle texture are a function of the air pressure used when the paint was sprayed on the work, the type of catalyst additive used with the paint to provide the desired crackle finish, the baking temperature, and of course the skill of the painter. Thanks to OSHA and the EPA, the crackle catalyst additive was outlawed for use about 20 years ago, but it is still available in certain powdercoat finshes. But no powdercoat product I am personally familiar with can even come close to the TMC Blue color.

The lumpier finish used on the bigger transmitters and systems did not employ a paint catalyst additive for the texture, but rather is a function of the air pressure used to apply the paint, and again, the skill of the painter. This paint is still available as an oven-bake enamel, and any qualified spray painter can essentially accurately duplicate the texture finish used on the GPT-750 cabinet, etc. As I stated previously, this paint, although correct in color, will not duplicate the crackle finish as used on the GPR-90, etc., due to the non-availablity of the crackle catalyst additive.

Chris, W7JPG: like vintage and collectible cars, original un-repainted finishes with their so-called "patina", are very frequently much more desirable than a vehicle or other object that has been repainted. Nothing beats a well-maintained, original-finish piece of equipment, even with some flaws in the appearance due to age, etc. Consider the subtle color variations of the original TMC equipment you have as an example of the way these units came of the assembly line, warts and all. I personally would never even think of repainting the equipment just to get the colors of the three units consistent. If the cabinets are really badly beat-up, like so much of this +50 year old equipment is nowadays, refinishing them then makes a lot of sense.

I hope this information is of value to the TMC collector and restoration community.

73,

Bruce, W2XR

----- Original Message -----
From: Chris Kepus 
Date: Friday, March 4, 2011 3:01 am
Subject: [TMC] Cabinet Colors
To: tmc-bounces at mailman.qth.net
Cc: TMC at mailman.qth.net

> Hello TMC list members!
> 
> Is there a single "correct" color for GPR cabinets? My GPR-90, 
> GSB-1 and
> GSP-1 have very similar colors but slightly different tints and 
> wrinklepatterns. It does not appear that any have been 
> repainted. I have toyed
> with the thought of repainting them the same color but due to 
> the fact that
> the paint on each is in great shape and I do not know which 
> color/tint to
> use, I have not proceeded. Hi Hi. Not sure that I ever will, 
> either, but
> still would like to know if someone out there in TMC land has 
> the answer to
> my question and the formula for the paint. 
> 
> 73,
> Chris
> W7JPG
> 
> -----Original Message-----
> From: tmc-bounces at mailman.qth.net [mailto:tmc-
> bounces at mailman.qth.net] On
> Behalf Of triodes at optonline.net
> Sent: Thursday, March 03, 2011 9:42 PM
> To: tmc-bounces at mailman.qth.net
> Cc: TMC at mailman.qth.net
> Subject: [TMC] GPR-90 Matching Speaker Reproduction Grille Cloth
> 
> Hello fellow TMC enthusiasts!
> 
> I am offering a reproduction grille cloth for the relatively 
> rare matching
> speaker unit for the TMC GPR-90 Receiver.
> 
> This speaker is actually identified as TMC Model GPS-1 (General 
> PurposeSpeaker-1). Another version of this speaker, and even 
> rarer, was the model
> GPS-2. It was identical to the GPS-1, but the speaker cabinet 
> was actually
> borrowed from the GSB-1 SSB Adaptor, so the cabinet depth is 
> deeper when
> compared to the more popular and less costly GPS-1.
> 
> At any rate, the speaker grille cloth I am offering is virtually 
> identicalto the original and now unavailable grille cloth 
> materal, which was
> discontinued decades ago. It is extremely close to the original 
> used by TMC
> in terms of color, type of weave, and fabric density.
> 
> The grille cloth is easily replaced by removing the speaker 
> baffle board
> assembly (4 nuts) from the cabinet, separating the speaker from 
> the baffle
> board (4 nuts), and removing the stapled-in-place original 
> grille cloth. The
> replacement cloth is positioned in place and restapled to the 
> wood baffle
> board with standard 1/4-inch upolstery staples and a staple gun. 
> The speaker
> is remounted and the baffle is then replaced within the cabinet.
> 
> I had to purchase several yards of this material at significant 
> cost, as it
> was a special order fabric, and I searched for quite some time 
> before I was
> able to locate it.
> 
> The price for one replacement pre-cut grille cloth for one GPS-1 
> or GPS-2
> speaker is $15.00 each, plus shipping via the US Postal Service.
> 
> Replace that dirty, nicotine-stained, faded, or damaged grille 
> cloth on your
> GPR-90 speaker, and immediately transform it's appearance with a 
> minimum of
> effort.
> 
> 73,
> 
> Bruce, W2XR
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