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What material is recommended for creating a new transfer port?

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ajshoots

ajshoots

Member
Apr 1, 2015
2,054
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Uniopolis, Ohio, United States
I had to make a transfer port(TP) for my .30 marauder. The tubing I was using wasn't working. I had a stick of PTFE and used it to turn out a TP. .250 OD X .185 ID. It sealed great and is working perfect. Curious as to what other types of plastic you guys use to machine TP's and other parts that might need to seal against HPA? Thanks for your input!!

MOD EDIT: Changed wording of title to be less vague.
 
I've not yet made one, but I would probably use either brass, steel, or 7075 T-6 aluminum and o-rings. It would be similar in design to what Crosman uses.

When I put a full 16mm diameter Lothar Walther barrel on one of my Marauders, I used the same transfer port. To accommodate the length, I just counterbored the barrel deeper. However, I was not changing to a larger caliber which would require a larger inside diameter. 

 
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With the high power .25's and .30 I have been playing with, there is not enough meat on a stock port to open it up to .185-.190. I was using a softer clear fuel line type tubing but it was collapsing. The solid PTFE allowed me to get a consitant .185 port with the rigidity to hold shape and size as well as a perfect seal. I was just curious what types of plastics others might be using. Using brass, aluminum, steel, is not an option as there would not be a good way to seal both ends unless you alter the OD of both the airtube and breech to accomodate seals to fit. The reason for using such plastics as PTFE is due to the fact that you can compress it to make a seal instead of alloys with rubber seals at both ends.

 
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ztirffritzPTFE has to be too soft. It's like wax. UHMW or Delrin would be better I'd think. I've never done any of the work that you're doing but I do know plastics.
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I have uhmw, delrin, nylon, etc. The reason I went with ptfe is the fact that it is soft enough to seal with a little bit of compression. Wasn't sure if the other plastics would seal properly? Ptfe works perfect, just curious if others are able to seal other types of plastics for this kind of application? Compared to what I was using prior, ptfe is much harder, so in response, it is far from too soft. It is actually a near perfect material for a marauder TP. Though it is not the most machinable plastic, it does work very well as it holds shape and seals.

Has anyone used any other plastics for a similar or the same application?? That is what I am looking for. I am aware of the typical uses for different plastics, but I am only interested in airgun applications for plastics and those that have experience with these plastics for airgun uses.
 
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3bi5I'm using clear PVC tubing in my .25 synrod for .190-.195 sized transfer port. I can't remember the outside dimension but it is a tight fit, seals good and no signs of collapsing so far. The same piece of tubing has been there atleast 10 months now.
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I have 3 guns using similar pvc tubing. 2 have been sealed and working great for about a year. The 3rd gun using the same tubing has been fine for 5 months or so. Though it did seal in my .30, it kind of collapsed in from .185 down to .155 which choked air flow and that was the reason I wasn't getting the velocity I had hoped for. I made another out of the same tubing and it did the same. It sealed, but wouldn't hold the .185 id. The ptfe worked great but sucked trying to turn down the od as all I had was 1/2" and had to turn it down to 1/4". That stuff doesn't machine the greatest. I ordered a couple rods of 1/4" od so all I will have to do is pick Id size and cut to length.
 
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NMshooterI may have to make a new transfer port on one of my Falcons. Van recommended that I contact Alan Zasadney as he makes transfer ports. He may be able to answer your question. I have heard nothing but good things about him. His contact information has been on one of these forum.
Hope this helps,

Doc
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Doc,
I spoke with Mike Reames last night. He uses everything from brass to different plastics for TP's. Sounds like it is all personal preference and what might work on one gun, might not work as well for another. I kind of assumed that would be the case.
None the less, I am just curious what others are using as I am just getting my feet wet machining different plastics.
 
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