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  1. tnatale

    Encapsulation of PCB with Epoxy

    This is fairly straightforward. The are two possibilities, primarily depending on the board quantities. If larger volume, have a tray made that holds the board. Place the board in the tray and then fill the tray with epoxy. Tray, board and epoxy make the final assembly. For lower volume...
  2. tnatale

    Corrosion

    Yes, you have crevice corrosion. The crevice is formed between the band and the pipeline. If you do a Google search on pipeline crevice corrosion support you'll see a lot of examples. The more typical example would be carbon steel on both sides, (you have CS and SS combo). While the SS is...
  3. tnatale

    DEMIN WATER used for Hydrotest in carbon steel tank

    You're going to need corrosion inhibitor(s) in combination with a low level of biocide. The oxygen scavenger will not work in this situation as there is too much air present. For a hydrotest or lay-up situation, an oxygen scavenger is used when there is basically no air present, like for a...
  4. tnatale

    How to increase the coefficient of friction for flexible PVC

    To modify the formulation, I'd look at adding a filler that has a "sharp" profile, perhaps some kind of silica or perhaps look at the paint anti-skid additives. My first choice would be to leave the formulation as is and add an abrasion step after molding.
  5. tnatale

    Brown spots on powder coated brass substrate

    It looks like typical contamination. Any residue on the part surface runs the risk eventually sucking up water and then corroding. Just because it looks clean doesn't mean that there isn't any residue. Take a serious look at your cleaning and rinsing process. Also look at how the parts are...
  6. tnatale

    Vinyl covered 304 SS sheets and Clear powder coat issues

    Looking at the picture, it is clearly an issue with your pretreatment. You can clearly see the drip pattern on the surface of the part. A "typical" powder coat process means may things to many people. Are you using an alkaline cleaner or neutral?, Iron phospahte? Sealer? Talk to your...
  7. tnatale

    galvanic corrosion in automotive coolant system

    Normally the coolant in those types of systems are a mixture on inhibitors in a water/glycol vehicle. A mixture is necessary because of the wide variety of metals typically involved in the cooling system, Al, Cu, steel, cast iron. As would be expected, inhibitors that work for one metal may...
  8. tnatale

    soft pvc

    I would consider using a coextrusion. You can make the exterior layer any color that you want and look at loading it with anti-block materials to reduce the adhesion between pieces (akin to what they do for polymer films. You can also put less plasticizer in the skin, this will reduce the...
  9. tnatale

    Acid Resistant Plastic Sheet Material

    I would look at something off the shelf like welding curtains. They can handle those temperatures and should be able to handle the acid.
  10. tnatale

    Test to Determine Water Penetration Through Coating

    Can you deposit the coating on a different substrate? There are machines that can determine the moisture permeability of polymeric films. If you can deposit on something that was highly permeable to moisture like say polyester, you can then get an actual water permeation rate (weight of water...
  11. tnatale

    brown-reddish treatment

    It looks more like a conversion coating. Are you sure it is a steel substrate? I've seen those types of colors on Al.
  12. tnatale

    alternative to PVC coating plastisol

    It is very difficult to have a similar system for polyolefins as they are such a pain in the butt to get into solution. There are polyolefins used in this type of application, look for Flame Spray of polyolefins, it is used on pipes all the time. It basically take a polyolefin powder and...
  13. tnatale

    Chemical resistance of paint

    You need to get detailed info about both paints. A 2 part PU has a urethane piece (aromatic or aliphatic) and and isocyante piece (TDI, MDI, etc). So all 2 part urethanes are not the same..
  14. tnatale

    Powdercoating Failures - Blistering

    Hot rolled steel is typically more prone to this kind of problem than CRS. (You often get a scale in the HRS). It is difficult to idnetify the probelm based on the limited amount of info that you gave, but a couple of thoughts: - Examine the raw stock for signs of corrosion, this means looking...
  15. tnatale

    Paint is Fading Looking for Test

    A couple of points: As the base color is black, the most likely pigment is going to be carbon black. In general, carbon black is very UV stable and is used as a UV stabilizer. What you are describing seems more like chalking, which is typically a breakdown of the resin, which turns light...
  16. tnatale

    Amonia Gas Corrosion on Electronics

    Ammonia gas will be corrosive to copper and copper alloys. The potential for the problem will be: - amount of ammonina that gets inside the case - the amount of water that gets inside the case - the sensitivity of your equipment, ie, primarily large components, circuit boards with fine traces...
  17. tnatale

    Comparative testing

    If you can provide a good description of how the part will be used, environment, temp, etc, then I can give you a few things to try. Also what do you have available to to assist in the testing, access to ovens, chemicals, labware, etc.
  18. tnatale

    encapsulation of winding for use on salt water

    We used to do something similar for stators for windmills. We took a filled polyester and injected the mixture into a mold that held the stator. When it was removed from the mold we also added a thin silicone coating over the polyester to ensure that there as as good of seal as possible...
  19. tnatale

    measurement of amine in hydrocarbon liquid

    Good Morning, Is anyone aware of any standards/procedures that would be used for determining the level of amine present in a hydrocarbon liquid (estimated to be 100 ppm or lower). I have found numerous methods for aqueous solns and also some that are specific for ammonia only (in...
  20. tnatale

    References/background information

    Good Morning, I am looking for info/references in regards to "typical" background info in regards to liquids stored in above ground storage tanks: For example: crude oil sulfur content range 0-?, typical ? hydrogen sulfide range 0-?, typical ? water...
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