Which abrasive cloth?
ARH says you can fit their Tesla piston seals by hand using 180 – 220 grit abrasive cloth. Anyone tried this? What brand of abrasive did you use?
I use wet paper backed up with something flat to keep everything square. My preference is always Norton but about any quality brand will work well. Spin it mounted to the piston in a drill press or lathe. If the seal slips on the piston I clamp it down with a flat nose live center. Use a little oil to float the debris. Cuts better and keeps nasty grit off my lovely machines. Don't over do it. You'll have to do it over! I just did my FWB 124 seal a few weeks ago.
This home made leather seal is being shaved down first before I finish sand for final fitment.
Fitting a synthetic seal is, shall we, an art. But not unobtainable on a first try.
First question: are you replacing a leather seal? If so, much more needs to be discussed. If not, see below.
When I buy seals from ARH, I usually buy 3, knowing one of them will be right, but not knowing which one it will be.
I size my seals without a lathe, because, well I don't have one. I chuck the piston into a cordless drill, and spin it against a piece of 120# wet/dry emory paper. I aim to size the seal where the piston will not move by hand without some force on my part. Too much force required, need to spin it down a bit. Too little force, I've gone too far and that seal is toast for that gun. It's a feel thing, and hard to explain, even harder to quantify.
The biggest obstacle is usually mounting the seal to the piston. My technique involves digging into my socket set, and finding one that is very close to the max OD of the mounting flange on the piston head. I then push the seal onto the socket, stretching the lesser diameter to meet the larger diameter. I then put the socket/seal assembly over the piston head and slide it into place.
Here is the piston, don't know how I'll spin it
A male threaded hole that is.
I wish I could help. 🙄 If you were local I'd invite you over. Perhaps someone local to you can assist?
Thanks Karl. I'll get it figured out.
From the ARH web site concerning the tesla seal
The seal can be sized on a lathe or in a electric
hand drill or using a dremel tool if super
careful. (Or just by rotating it in your hand
against the abrasive-best if fitted to the piston.
Keep the natural seal contours as they are)You
should get a semi gloss edge on your newly sized
seal. This material sizes super well and very
little effort is required
It might take a little longer but less chance of over doing it. Wrap the paper around the end of the piston an turn the piston. Thats how I sized the delrin buttons on my piston.
I expect he is talking about emery cloth. Probably something like 100 to 120 grit.
so how do you spin a piston with an over size seal and have no way to spin it other then by hand
in this case you need a piece of tubing, pipe as a sleeve and then a Phillips screw driver for the drive side
is it perfect, hell no but you bought that over size seal and had no idea what is was going to take
try a Giss System front piston and an over size seal
i buy factory seals just because i'm lazy
oh by the why if you make it too small or damage it in all your screwing around, you guessed it, you get to start over, what fun