gunner1 Posted March 9, 2022 Share Posted March 9, 2022 I was thinking about making my own single shot preloaded mortars. I'd be using six inch tubes that are 1 1/4" I.D. for the mortars and tubes that are 2 1/2" long with an I.D. of 1" with 1/8" walls. The inserts are an amazing fit inside the mortar tubes with virtually no space in between the two. My question is this: do I need to put a disk in between the lift charge and the insert with a hole for the fuse or should I just slide it on top of the lift? Link to comment Share on other sites More sharing options...
pyrokid Posted March 9, 2022 Share Posted March 9, 2022 What is the purpose of the disk? I have seen Chinese products done both ways. Frequently there is also a disk glued or pressed on top of the insert, presumably for handling stability. I think the risk of lift powder migration is minimal when the shelf life of the product is short. I have concerns about the integrity of the end plugs when the insert fits too tightly in the launch tube. The better seal it makes with the tube, the greater pressure the end plug is subjected to. I've had failures that I attributed to end plug failure under these circumstances. Link to comment Share on other sites More sharing options...
gunner1 Posted March 9, 2022 Author Share Posted March 9, 2022 What is the purpose of the disk? I have seen Chinese products done both ways. Frequently there is also a disk glued or pressed on top of the insert, presumably for handling stability. I think the risk of lift powder migration is minimal when the shelf life of the product is short. I have concerns about the integrity of the end plugs when the insert fits too tightly in the launch tube. The better seal it makes with the tube, the greater pressure the end plug is subjected to. I've had failures that I attributed to end plug failure under these circumstances. Link to comment Share on other sites More sharing options...
gunner1 Posted March 9, 2022 Author Share Posted March 9, 2022 What is the purpose of the disk? I have seen Chinese products done both ways. Frequently there is also a disk glued or pressed on top of the insert, presumably for handling stability. I think the risk of lift powder migration is minimal when the shelf life of the product is short. I have concerns about the integrity of the end plugs when the insert fits too tightly in the launch tube. The better seal it makes with the tube, the greater pressure the end plug is subjected to. I've had failures that I attributed to end plug failure under these circumstances. Link to comment Share on other sites More sharing options...
gunner1 Posted March 9, 2022 Author Share Posted March 9, 2022 What is the purpose of the disk? I have seen Chinese products done both ways. Frequently there is also a disk glued or pressed on top of the insert, presumably for handling stability. I think the risk of lift powder migration is minimal when the shelf life of the product is short. I have concerns about the integrity of the end plugs when the insert fits too tightly in the launch tube. The better seal it makes with the tube, the greater pressure the end plug is subjected to. I've had failures that I attributed to end plug failure under these circumstances.Are you using hot glue for the endless or Elmer's glue? The article I read recommended regular Elmer's glue to avoid end plug failure. Link to comment Share on other sites More sharing options...
Carbon796 Posted March 9, 2022 Share Posted March 9, 2022 Techniquely those mortars tubes are shorter than ideal. But, if you're getting the height you like/want out of them. It doesn't really matter. The insert tubes, sound like the one's frequently used for comet to report shells. As popularized by DWC. Typically the end disks for those. Should use an outer and inner 1/8" chipboard disk, for each end. A 1" and 1-1/4" which are glued to each other then glued to the tube. Typically with a yellow pva wood glue. Once dry, a two layer over wrap, of pasted 30# or gummed tape is recommended. Smooth on the sides, pleated over the end disks. If your using TF, it should be hide glued into the two end disks. With hide glue fillets on both sides of the disks. Once dry/assembled, the pleated paper should just touch the TF. Where another fillet of hide glue is applied. Yellow pva will probably also work. But, I tend to use hide glue. If the insert keeps the lift in place. Without any migration, you shouldn't need the extra disk between them. Link to comment Share on other sites More sharing options...
countryboy7978 Posted April 11, 2022 Share Posted April 11, 2022 (edited) How did your preloads turn out? I have used the same set up. If you still want to discuss them let me know. Edited April 11, 2022 by countryboy7978 Link to comment Share on other sites More sharing options...
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