A lot of mystique has grown up about application of inorganic coatings such as Ipcote, Ipseal and Sermetal W. Although it has been rumoured that temperature and humidity controlled spray booths are required, in the UK. Ipcote and Sermetal W have both been successfully applied in wet back and dry back non-humidity controlled booths. Normal spray considerations should apply, that is, humidity 30 to 70% and temperature preferably above about 60ºF.
Ipcote and Ipseal both need significant agitation before spraying. It is more stable and less prone to settling than competitive products, but ideally it should be spatullaed up and then rolled on paint rollers for a minimum of 24 hours before application.
Ipcote has been successfully applied by Binks Bullows 630 guns, DeVilbiss JVB and HVLP. Each has their own technique, but a pressure of about 40 psi on the 630 gun is about right, although the pressure is dictated by the sprayers finger on the trigger. The same pressure or more needs to be used for Ipseal, 40-50 psi, unlike Sermaseal, which needs only about 20 psi.
Recently, Ipcote has been successfully applied by electrostatic gun. This resulted in a significantly smoother coating than with other types, and also meant that parts could be coated all round - eg on shafts etc.
Ipcote needs to be sprayed onto a perfectly clean, preferably lightly blasted surface. If the material appears to go into globules, either surface treatment is not good enough, or the sprayer is trying to apply too much. A first mist coat often helps and 2, 3 or 4 coats can be applied wet on wet. A typical coat of IP9183 Ipcote will be 25 microns thick, (1 thou). A thin film of material is sometimes required, for example on edges, flanges, and to allow part marking. Rolls Royce specify Sermetal 709 (762 or 962)or IP9356 as a dedicated product to give film thicknesses of about 12-20 microns. However, this can also be achieved by careful thin application of Ipcote. This is the process we think is used by Pratt & Whitney Canada. Ipcote when applied will appear a wet yellowy grey colour, which dries to matt grey. Normal processing them is flash off 15 minutes, or to matt grey, for best smoothness of coating, 30 minutes at 190ºC, then the final cure.
This is the process that ensures sacrificial protection.
1)It is essential that the material is well agitated.
2)If the process goes straight to 190oC, the "peaks" may be preserved. This should result in surface finish of 40 – 60 micro inches with Process A and good application.
If smoother coatings still are required, with a similar finish to 5375, of 20-35 micro inches, then either Vibrapolishing, use of Hudson, similar processing, (even get the Brasso out!!), after preferably Process A, will result in the required surface.
Air dry for a minimum of 15 mins to a matt grey finish. Stove 1 hour @ 190ºC.
The component shall then be loaded into an oven not exceeding 350ºC, temperature raised to 560ºC and maintained at this temperature for 1 hour minimum.
Alternatively :- 2 hrs @ 540ºC
4 hrs @ 515ºC
Find cure should produce a conductive coating.
Air dry for a minimum of 15 minutes to a matt grey finish. Stove 1 hour @ 190ºC.
The temperature then raised to 350ºC and maintained for 1 hour.
Alternatively: - 2 hours @ 300ºC.
Other alternatives used for example when used as a cadmium replacement, on aircraft undercarriages, include 16 hours at 275oC, or 20 hours at 200oC
When cool, the finish is bead peened to produce a conductive coating.
Normally, bead peening is done with 120 / 220 alumina grit or similar. This will achieve a specific surface finish, of perhaps 25 – 40 micro inch at 30 thou cut off (cut off used by Rolls), or 15 – 20 micro inch at 10 thou cut off (often the cut off used in the US). If you are looking at a lower surface finish, similar to Sermatech’s 5380, of maybe 10 – 23 micro inch (Rolls), and 8 –13 micro inch(US style), then use IP9183R1, and burnish using 0 – 40 grade soda lime beads to CSS 8. This should then be sealed with Smoothseal IP9444, or our new LR1365 chrome free seal coat
PROCESSING IPSEAL IP9184 SEALCOAT ; IP9444 Smoothseal and LR1365
Refer to Rolls Process Spec (RPS) 666 & 666/4 and 666/5, or apply for our copy. This is a one part, easy to apply, seal coat. It is an alternative to Sermaseal 570, which is a 2-part product. Ipseal sprays easily, like a normal paint, at about 40-50 psi, preferably over a lightly peened surface. If you have experience of 570, you may be surprised at its ease of application and appearance. It is a solid, bright green, glossy when wet and dries to a matt green, not unlike a pool table beige. Alternatively, request IP9184 - Khaki for a match to Sermaseal 570. After spraying, Ipseal should be left for 15 minutes to flash off, then stoved at 80ºC, then raise temperature to 350oC and hold at temperature for 30 minutes. On no account should Ipseal be left after the 80ºC process, as it can "green back". This means that it takes up moisture from air, and becomes wet again, but re stoving gives an unsatisfactory finish.
Before application, ensure Ipseal is well dispersed eg. shake or roll.
Apply to suitably cured, conductive Ipcoat IP9183, IP9356, 0r LR 848
Apply successive light mist coats, until a deep, uniform gloss coating is attained ideal gun pressure approximately 40 psi.
Flash off in a warm, dry atmosphere for a minimum of 15 minutes the sealcoat will give a dry, matt appearance when ready to be stoved.
Raise temperature to 350ºC and stove for a minimum of 30 minutes. If oven incapable of temperature transfer to a suitable oven the components shall then be removed form the oven and allowed to cool to room temperature.
Care should be taken with the Ipseal process as it can "green back". This means it takes up moisture from the air and becomes wet again, re-stoving gives an unsatisfactory finish.
Guidance notes are contained in RPS 619, care should be taken over media is used in the vibratory machine and also the polishing compound. In addition, if there is chipping care should be taken not to continuously feed the items into the mill and that they should not chip against each other. If there is a gold finish, it is likely there is not enough soap. PI media from Walter Trowel appears very reasonable.
IP ALTERNATIVES TO SERMATECH PRODUCTS IP9183Ipcote | Sermetal W and WFX |
LR 848Low chromeLess than 1% chrome VI variant of Ipcote/W | Sermetal 1129 |
IP9184Ipseal (Green) Ipseal (Khaki) | Sermetal 570A |
IP9183 + IP9184 | Sermetal 725 system |
PL177 | Sermetal 196 touch up |
PL270Sermaseal touch up | Sermetal 270 touch up |
IP9356Ipthin | Sermetal 709, 762, 962. |
IP9183Polish Ipcote IP9183 or 9183R1 | Sermetal 5375 |
IP9444Smooth Seal IP9444 | Sermetal 5380 |
IP1041 IPAL Aluminium silica ceramic sulphidation high temp | Sermalloy J coating |
Rockhard Ask for the report by US Navy Lab Command Sikorsky and McDonnell Douglas re: Rockhard | Sermetal 1083/1089 |
Low cure thin film Cadmium replacement coating | Sermetal 962 |
Please contact our technical office for more information.
Please contact our technical office for more information.
