Big Al Posted January 24, 2015 Report Share Posted January 24, 2015 Dulite is the trade name for a form of bluing. The proper term for bluing is black oxide. Recon Bob has explained it the best, since he actually builds Thompson guns. Link to comment Share on other sites More sharing options...
buzz Posted January 24, 2015 Report Share Posted January 24, 2015 (edited) AFAIK, Dulite is the trade name for the company making type 3 black oxide in 1939. Are you saying that Thompsons were not finished with Dulite? You'd have to show me an original document indicating that before I'd believe it. Also, "Parkerizing" is a trade name, the proper term is electrochemical phosphate conversion coating. There are a lot of trade names used interchangeably with the product or process out there. Edited January 25, 2015 by buzz Link to comment Share on other sites More sharing options...
Big Al Posted January 24, 2015 Report Share Posted January 24, 2015 Are you saying that Thompsons were not finished with Dulite?No. It just looked like there was some confusion here. Link to comment Share on other sites More sharing options...
Paladin601 Posted January 24, 2015 Report Share Posted January 24, 2015 (edited) I made my conclusion from 2 pic on the GB posting the last pic the has a close up of the the receiver and trigger frame meeting. It looks chipped, instead of worn, phosphate/Parkerizing does not chip, it wears, there is a difference in the pattern. The engraving seems to have been filled on certain letters, like excessive paint is at the bottom. Could be worn roll dies. The Finned barrel appears to have shiny spots between the fins, with Phosphate you don't have this, but painting you do since it is hard to cover those areas, due to fin depth. And lastly, the parts are very uniform in color, very hard to do this with aZinc Phosphate, if all the parts are separated for the process. All these conclusions are based on photographs which in it self is a bad this to do. Lighting and Camera angle can add to poor conclusions and judgments. One way to solve this argument would be photographs of the inside components. Areas like the feed ramp and bolt channel. Edited January 24, 2015 by Paladin601 Link to comment Share on other sites More sharing options...
mnshooter Posted January 24, 2015 Report Share Posted January 24, 2015 Just relisted; no takers at $18,500. Tells something. Link to comment Share on other sites More sharing options...
Mike Hammer Posted January 24, 2015 Report Share Posted January 24, 2015 How is the mfg. listed on the paperwork. Is this a fully-transferable or is the kitchen sink parkerizing job trying to hide a reweld? No telling what is underneath that thick awful coating. Mike Hammer Link to comment Share on other sites More sharing options...
reconbob Posted January 24, 2015 Report Share Posted January 24, 2015 It can be very difficult to determine the actual finish or process used when all you can see is photos.I had never seen that Wikipedia article and it has some interesting info such as patent holders and dates,etc. However, the author or authors (anyone can post anything on Wikipedia, right?) seem to have noactual hands-on experience "Parkerizing" guns. I have mentioned this before but for those who may have missed it - there are basic finishes we aredealing with with Thompsons which can be divided into "bluing" which is really black oxide, and "Parkerizing"which is some type of phosphate finish. I do not understand the use of the term "electrochemical" as applied to Parkerizing. No electric current,anode, cathode, etc. is used with the phosphating process, unlike electroplating - nickel, chrome, etc. Phosphating is often referred to as a "conversion" coating. Phosphating/Parkerizing is a chemical process which grows (on a molecular level) phosphate crystals onthe surface of the steel. The Wikepedia article is wrong. the Iron-manganese process (I have never known manganese phosphateto be used on firearms but it does have other industrial uses) provides the thinnest and smoothest finish. Thecoating process is completed when the gassing (bubbles in Wikipedia) stops and keeping the parts in the tanklonger does not improve the finish. If you keep the parts in the tank too long the acidic properties of the solutionwill start to eat away at the parts. The iron-manganese finish is that found on WW2 Garands, early Springfields, and some but not all Carbines.The Military Specification for this finish specifies that the color be "grey to black" with no mention of the color green. To be able to phosphate you must sandblast the surface first or else the crystals will not grow. So, a shiny spoton an otherwise parkerized surface could be due to a gap in the sandblasting. Also, if a drop of oil gets on the surfaceit will mask that spot from the effects of the phosphate chemicals and that spot would also be lighter in color. The current zinc phosphates will grow coarser and coarser crystals the longer the parts are left in the bath and the parts will aquire a rougher finish. Thereis no black phosphate. To achieve a flat black finish a prepared part is dipped in a bath that reacts with the steel insuch a way that a flat black soot-like coating adheres to the surface. This coating is very fragile and falls away iftouched. However, when the part is them immersed in the standard zinc or iron-manganese bath the soot becomes integratedwith the crystals and you get a true flat black finish. It can be confusing because if a part is sandblasted, then blued/black oxided you get a flat black finish virtuallyidentical in appearance to a black phosphate. Bob Link to comment Share on other sites More sharing options...
Kilroy Posted January 24, 2015 Report Share Posted January 24, 2015 I have heard that 'green' parkerizing comes from a parkerized item sitting for years in cosmoline and that is absorbed into the finish and changes the color some. Yes, anyone with an account can edit Wikipedia. Link to comment Share on other sites More sharing options...
Paladin601 Posted January 24, 2015 Report Share Posted January 24, 2015 (edited) Some say they can mimic the green color "phosphate", so careful that original finish may not be original. (I believe it is with a copper chore ball) (Flat Black park or Greek Black park, is accomplished by blue oxide over the park, was done on Greek Garands and 03's) Edited January 24, 2015 by Paladin601 Link to comment Share on other sites More sharing options...
mgvince Posted January 24, 2015 Author Report Share Posted January 24, 2015 In my e-mails with the seller. I asked who is listed as the maker. It is on a form 3, and seller says Auto Ord. is the manufacturer. He had sent me additional photos I had requested.And there is a very suspect shot that I had requested of the right side behind the mag well. There is a line of some deep irregular holes that are clearly visible. That to me look like a bad reweld job. I asked for a more detailed inspection of the inside. He said he was not that familiar with Thompsons and would have his guys look at it. I have not gotten anything back yet. He said that it does not look like a paint type of coating. Link to comment Share on other sites More sharing options...
buzz Posted January 25, 2015 Report Share Posted January 25, 2015 (edited) you're right, "electrochemical" would apply to anodizing, not a chemical conversion wikipedia is wikipedia Edited January 25, 2015 by buzz Link to comment Share on other sites More sharing options...
buzz Posted January 25, 2015 Report Share Posted January 25, 2015 I wonder how many re-weld guns out there would be within the dimensional tolerances on the original drawings given the skill set of the average "gunsmith" out there and the difficulty involved in welding metal, I'd be willing to bet on none being within spec especially since this work was done back when these guns were not worth all that much Link to comment Share on other sites More sharing options...
DLansky Posted January 28, 2015 Report Share Posted January 28, 2015 the seller sent me a video of the receiver. there are a number of close up shots. he says the "bubbles" at the nose of the receiver are pitting and not weld marks. here is a link: https://www.dropbox.com/s/zolgqbeea5k9lq7/20150127_141313.mp4?dl=0 would parkerizing take to a weld? does the inside of the receiver look like it has been welded? if this receiver had been cut, would it have only been cut in one place? Link to comment Share on other sites More sharing options...
Uncle Dudley Posted January 28, 2015 Report Share Posted January 28, 2015 It sure looks like it's welded to me. I think it is a good candidate for a restoration. Link to comment Share on other sites More sharing options...
Paladin601 Posted January 28, 2015 Report Share Posted January 28, 2015 (edited) welded and not parkerized, look at the inside Can a weld be parked, depends on the filler material. Yes. Will it look the same? depends on the filler material. Also the heat marks would have to be removed or the park will be darker in that area. Edited January 28, 2015 by Paladin601 Link to comment Share on other sites More sharing options...
laurencen Posted January 28, 2015 Report Share Posted January 28, 2015 my money says its welded, the area by the lock slot blow holes also at the back below patent numbers and inside face opposit the auto stamp, that would make 3 cuts or 4 pieces, not sure how the numbers were salvaged but I think its a weld job, seems nice work not sure why they did not fill the blow holes, finish still looks gritty Link to comment Share on other sites More sharing options...
Speeddemon02 Posted January 28, 2015 Report Share Posted January 28, 2015 Is it just me or do the slots for the blishlock look different? It looks like the corner is chipped, but one side still looks wider than the other. Link to comment Share on other sites More sharing options...
mnshooter Posted January 28, 2015 Report Share Posted January 28, 2015 (edited) From the video, it's obvious the Blish slots don't have the small reverse bevel at the top (bottom, actually), as found on all originals. They were welded and recut without this feature. Also visible are some more pits or voids in the slots themselves. The drum slot divots have been recut, probably with a ball end mill, leaving a ridge. Very honest of the seller to present this video, warts and all. Edited January 28, 2015 by mnshooter Link to comment Share on other sites More sharing options...
darrylta Posted January 28, 2015 Report Share Posted January 28, 2015 (edited) The finish may be from a DuraCoat like product. I had some Crosby L drums black duracoated sincethey were originally painted black anyways. The finish turned out great, if you didn't know it, you'd swear itwas black oxide.Darryl Edited January 28, 2015 by darrylta Link to comment Share on other sites More sharing options...
shadycon Posted January 28, 2015 Report Share Posted January 28, 2015 I tryed Duracoat on an AK build and it came out thick and flaked. I redid it with Gun kote and it is holding up great.GK Link to comment Share on other sites More sharing options...
Paladin601 Posted January 28, 2015 Report Share Posted January 28, 2015 I have had great luck with Duracoat and a airbrush, nothing wrong with it. Also, have had good luck with the BBQ paints. Link to comment Share on other sites More sharing options...
reconbob Posted January 28, 2015 Report Share Posted January 28, 2015 I just looked at the video, without question this is a welded receiver. The row of pits behind theejection port are the weld. Bob Link to comment Share on other sites More sharing options...
hntrdarren Posted January 28, 2015 Report Share Posted January 28, 2015 From review of the video, I would absolutely agree with reconbob"s assessement of the receiver being welded behind the ejection port. Darren Link to comment Share on other sites More sharing options...
shadycon Posted January 28, 2015 Report Share Posted January 28, 2015 I have had great luck with Duracoat and a airbrush, nothing wrong with it. Also, have had good luck with the BBQ paint Header paint works good too. Throw parts in oven, about 200 degrees, heat, paint and heat again. Good for shooters. GK Link to comment Share on other sites More sharing options...
buzz Posted January 28, 2015 Report Share Posted January 28, 2015 (edited) That "rust pitting" looks exactly like weld porosity. The weld will get full of air bubbles because the gas shielding wasn't effective, and when the weld surface is machined it shows up as a line of little round holes Look how uneven the surface is on the bottom of the receiver, right in line with the weld Also, the top of the gun has a wrinkle, which is also right in line with the weld and the port is unevenly shaped Edited January 28, 2015 by buzz Link to comment Share on other sites More sharing options...
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