Miguel del Rio

  • Content Count

  • Joined

  • Last visited

Everything posted by Miguel del Rio

  1. These are photos of the Chile 1968So coins that were purchased in their PVC flips 50 years later, now holdered: The damage done to the 5 Peso coin is typical of the packing from the mint and not due to any interaction with the PVC flip.
  2. PVC flips were popular decades ago before anyone knew any better. However, overtime, the damage to coins became apparent. These Chile 1968So coins were shipped from Santiago and some coins are still sold in their original holders. I was fortune to purchase a set that did not have any signs of damage, however, this set currently for sale on Ebay is not so fortunate. Notice how the 5 Peso coin is discolored where it made contact with the flip: Photo below shows the upper half of the PVC flip used to ship the Ecuador 2006 coin, now in the square hard plastic capsule, that shows th
  3. The photos were obviously the seller's and not taken by The Coinhouse Auctions. I had similar experience with a merchant who claimed his picture of a nearly flawless proof was taken years before the coin was damaged by the PVC flip in storage. These are photos of the actual coin received: These are the promotional photos: On the reverse side, notice the toning between the words "25.000" and "SUCRES" and extending to "ECUADOR" matches toning to be found also on the damaged coin's reverse. The damage is almost entirely due to pitting, the remainder due to fo
  4. Yes. Some auction houses supply their own photos when the seller's can not be used. This HA auction delayed the photo of this coin while they made suitable reproduction: https://coins.ha.com/itm/brazil/brazil-republic-gold-proof-discovery-anniversary-20-reais-2000-/a/61181-97118.s
  5. Greetings! Bought a coin not so recently at Auction No 16 from The Coinhouse Auctions in Belgium on Sept. 30th which Peter Eyckmans so kindly posted on Nov. 4th, and subsequently received the coin Nov. 16th. Expected a coin resembling this photo posted for lot 574: Wouldn’t have bid for the coin given its visible imperfections except that this coin is difficult to obtain in higher grades and, at 50 Euros, what could go wrong? These are photos of the coin actually received: Notice that some identifying features of the idealized coin are also present in the a
  6. A CoinTalk member asks, "Could it be residue from whatever organic was dissolved and then redeposited if the acetone evaporated without being thoroughly rinsed?" This is true. Acetone is such a good organic solvent that pure acetone is only theoretically available in the lab where it's distilled. It takes additional solvents to remove acetone impurities using a probe sonicator. Tub style ultrasound is not sufficient since the only solvent that may be used in the tub is distilled water. Use of other solvents present a fire hazard. Also, differences in acoustics could burnout the a
  7. Acetone always leaves an ugly residue, regardless of purity. Such acetone residue can not be conventionally removed from a coin surface by distilled water or by isopropanol because these solvents bead, while acetone covers the coin surface completely. For example, an acetone dip may be used in conjunction with other solvents to provide a substrate free from residue. One would need a ventilator hood, a probe sonication device, a temperature controlled nitrogen evaporator, supply of glass beakers, metal clips to fasten the substrate, etc Don't know if a coin could be mounted
  8. The following 23 coins are for sale on Ebay as authentic coins from Peru, however, the Krause-Mishler catalog numbers for these coins indicate that they are exonumia, and as such, were neither solicited nor authorized by Peru: 1) PERU 20 SOLES 1996 PATTERN SILVER PROOF #alb38 361 (Ebay# 273914690286) Reverse: https://i.imgur.com/GJvUM8h.jpg Obverse: https://i.imgur.com/uuAtTvU.jpg Reference: Exonumia Peru KM# X-14.1 Listing: https://www.ebay.com/itm/PERU-20-SOLES-1996-PATTERN-SILVER-PROOF-alb38-361/273914690286 2) PERU 20 SOLES 1996 PATTERN SILVER PR
  9. With an over-abundance of beautiful, "rare" coins, how do you find the time?
  10. I have a number of unused 99+ isopropyl alcohol bottles which leave residue on coins. Walmart's Equate first-aid brand is 91% isopropyl alcohol and 9% distilled water. It's inexpensive and leaves no residue. Not my first test of this brand, though you can never be too sure. Tested this coin using only the Equate alcohol and no distilled water rinse to see if evaporating the alcohol would leave a residue: Splashed both sides of the coin with alcohol. Dried the coin. No detectable difference from these images taken afterward: Used a manual drying bulb rather than the pre
  11. Further investigation reveals that residue is an issue regardless of the grade of acetone. Maximum non-dissolved solids after evaporation for the highest grade is 5 ppm. The next lower grade, an ACS grade reagent, is 0.001%, or 10 ppm: Clearly, a procedure involving a successive series of diluting solvents and powerful mixing is required if acetone is to be used. Such a procedure is outlined in the response below: (In the example above, substrates are suspended in racks on metal clips.) To accommodate acetone, one would need a ventilator hood, a probe sonication
  12. Please enlighten us as to the proper use acetone on coins without using a final rinse of distilled water. Include photos of this procedure, if possible.
  13. Acetone will completely cover the coin surfaces. Much more acetone must be evaporated than water or alcohol, which bead and slide-off the coin. Residue is also an issue, whether the residue is in solution with the acetone as an impurity or the additional residue dissolves from organic debris on the coin as the solution evaporates. Distilled water leaves no residue.
  14. I can see that you have never tried mixing these solvents on the surface of a coin. Low surface tension of acetone prevents the mixing with water on the coin surface. Acetone forms an even layer covering the coin surfaces, while water beads, rendering water effectively immiscible with acetone on the surface of the coin for human life spans. See http://ptfaculty.gordonstate.edu/lgoodroad/SUMMER 2011/Chem 1212/chem 1212 chapter 11 solutions[1].pdf Isopropyl alcohol and distilled water bead and slide off the coin surfaces, leaving far less of these solvents to evaporate as com
  15. I got a thumb print on this coin as it fell from my fingers on to the linoleum floor: I quickly doused the coin in acetone. I knew the evaporation rate of acetone was far less than isopropyl alcohol, but I still waited for a few moments anyway. Finally, I splashed the coin with isopropyl alcohol, then, using Butyl II gloves to protect by hands while manipulating the coin, I placed the coin into another glass bowl having distilled water. I saw that the coin still had a slick acetone residue, so I repeated a couple of times more, first dousing and soaking the coin in fresh isopropyl al
  16. That may be, however, I haven't had the time to waist for acetone to slowly evaporate and to see how much residue the acetone solution leaves on a coin. (In the time it takes for the acetone to evaporate, more surface residue may be dissolved into the acetone solution.)
  17. Hi Total Newbie, No, you have acetone confused with alcohol. Acetone is volatile, however, it evaporates very slowly. Isopropyl alcohol, which evaporates very quickly and is used as a drying agent, is miscible in both acetone and distilled water. Acetone and water don't mix well, similar to gasoline and water. Yes, if you were to leave the ultrasonic cleaner unattended, you could do damage that may appear only on a high resolution photograph. Ultrasonic cleaners are commonly used to clean jewelry, though for proof coins, I use the cleaner for only a few seconds initially depending on t
  18. One of the global publications' weaknesses it that it is impossible to contact a specific contributor to correct a catalog coin specification, to report a coin variety, to report a fantasy issue, or to add a coin. The online publications are better with corrections, though they are more incomplete than the traditional guides. In many instances, the traditional guides are the only source for the online publications.
  19. Acetone does not evaporate very quickly. Acetone and distilled water don't mix. You could use isopropyl alcohol to rinse the acetone, and then use distilled water to rinse the isopropyl alcohol. Care must be taken to use an isopropyl alcohol that does not leave a residue. I use Walmart's 91% solution with 9% distilled water, then place the coin in an ultrasonic cleaner. Replace the distilled water solution immediately if you notice debris in the solution as solid debris or suspended dust may scratch the coin while the ultrasonic cleaner agitates. You will find an ultrasonic cleaner at Ho
  20. The same variation can be found in the Paraguay 150 Guaranies KM# 37 1973 Proof. This is a photo of the large purity: This is a photo showing a half size purity typeface: This is a photo of the official obverse of the 1973 150 Guaranies coins: This is a photo of the Paraguay 150 Guaranies KM# 37 1973 Proof from the web page portalguarani.com/detalles_museos_otras_obras.php?id=17&id_obras=937&id_otras=155:
  21. Bought this Mixteca Culture coin recently from MA-SHOPs: It has the same large 1000 fineness stamped between the denomination characters as does the Paraguay 150 Guaranies KM# 36 1972 Proof.However, another example from NumisMaster shows a much smaller fineness between the denomination characters for the coin: Other than paying the variant fee, is there an actual advantage to creating a slab which documents the variant when the variant is so plainly visible and the normal coin so well documented? Thanks.
  22. I count 146 dots around the legends of either side on either coin. Each irregularity in the placement of dots on one coin duplicates the irregularity in placement on the other coin. Just the typeface of the legend appears narrower to me than that of the graded coin. Can't distinguish any differences in the design of image features.