OK, a little secret about heat shrink and guides

[CharlieDaTuna]

that I have never shared with anybody else including Gene.

First, I consider heat shrink as a band aide fix that does in fact work if done properly but will never take the place of fitted guides. It usually causes a loss in power because of the drag and more importantly, usually increases torque and that you don't want. Yes, you can use it on both the spring and the guide.....but....here is the problem and the solution.

Usually when you use heat shrink, depending on the gun and spring, it will be very tight fitting. The same with the tophat. That will indeed eliminate the vibration and twang. But at the same time, it will not let the spring wind up and unwind on the guide and somewhat on the tophat without turning freely and will want to twist both the tophat and the spring guide. If the spring guide is fixed and part of the spring block (one piece) it will not let it turn freely and can cause an even greater increase in torque. In fact, I have seen them that have the cheaper synthetic guides actually get twisted off. If there is no tophat then all of the abuse is on the spring end opposite the spring guide.

Depending on the spring, spring guide design, and top hat, the solution is to use a thrust washer (not a thrust bearing) between the tophat if used or the bottom coil face of the spring and the bottom of the piston. It should be a thin washer, either a grade #8 steel washer polished on both sides or a stainless steel washer with an O.D. just a bit smaller than the piston I.D. with free movement. You should use a moly paste on both sides of the washer and face of the spring as well as on the spring side end if applicable. You should do this even if you do not use heat shrink on the tophad. Be sure that the bottom surface of the piston is as clean as possible and that the spring end has been smoothed out with no sharp edges and maybe even polished. Room permitting and the spring guide design, you should do the same thing on the spring guide end.

How to install the heat shrink. By the way, be sure that your heats shrink is Polyolefin Heat Shrink

Prep the spring guide prior to putting it on? Clean the guides carefully with acetone or lacquer thinner. Roughen the surface 120 grit sand paper and clean again and be sure there is no trace of oil on it. Then slide the heat shrink onto the spring guide and top hat. Cut off the excess letting it extend just a over the end just a bit. If available, spray some adhesive on the guides prior to installing the heat shrink. Kodak photo-mount is a good adhesive to use.

For Steel guides only. Without mama looking, preheat the kitchen oven to 275 to 300 degrees F.

It’s important that the guide gets good and hot. Heat it for about 20 or 30 minutes. Don't just a heat gun as it does not heat the metal enough to do the job effectively. The heat shrink will shrink but the metal itself will not and when used for this purpose, it should get pretty warm. This is very important with the tophat as its solid steel and very slow warming.

You can apply a light coating of silicone on the guides or clear tar even. Just a light coat. The heat shrink is pretty much self-lubricating.

When installing the spring on to the guide and top hat it will be pretty tight. but just screw the spring guide and tophat into the spring.

Use very little heavy tar or lube on the spring itself and only apply it about half way up the spring.

Ok…so now you know but please.... please keep this to yourself.... cuz it will hurt my business if it gets out.

Thanks guys 

[Rixtrix]

Wow, Bob.

Ric G

[shadow]

Thank's Bob, and on my B3 I also installed the washer and both end's of the spring were debured and polished as was the washer. A dab of moly paste applied to the vital's. I even went as far as heat shrinking the little section of wire that extend's from the end of the guide. Guy's, the B3 is not a highend airgun as you can tell by the price hehe and they don't make a assortment of part's for them. Any improvement's made to them are a plus. As Bob said,it doesn't take the place of well fitted part's or a CDT tune and care is required when doing this. It worked wonder's on my $20 varment getter along with a lovin tune. Ed

[shadow]

P.S. guy's THE SPRING GUIDE ON THE B3 is plastic so I don't think that you would want to stick it in the oven. What's that burning plastic smell hehe. Just a thought. Ed

[Gene_SC]

Thanks Bob for sharing this poor mans tune...:) But like Ed said.. It is probably the cheapest way to tune a B3 which only cost $20.00 to begin with.. hehe

I think knowing myself, I probably wound not do that mod on any of my guns but the B3 maybe:) The B3 seems to be a tinkerers dream though... hehe.

My question is what if I ony have a wood buring stove? Will the flames mess up the heat shrink...:)

Gene

[CharlieDaTuna]

Yes, you don't want to put a plastic guide in an oven cuz it does get smelly. You can use a hair dryer on it and get it as warm as possible without damaging it. It's important to scuff up the plastic guide pretty good and don't use acetone or lacquer thinner on it as they may damage it or cause the plastic to become brittle. Just plenty of soap and water and rinsed real well. Polyolefin Heat Shrink, because of it's self lubricating properties will need a good gripping surface because if it doesn't it will eventually slide off the guide which also has lube properties.

On the guides that are like a four corner/edge pillar, put tiny little notches down each leg before installing the shrink. Some will hold and others will not.  On the tapered ones, don't even bother. It wll be a waste of time.

[fnash]

So, then should the spring be snug on the guide or loose, that is to slide and turn freely when still out of the rifle. Before re-assembly.... ?? FN

[Big_Bill]

From what I have just Frank, the spring should be "just" freely moving on the guide.

The guide should not interfere with the spring, very close but not interfering.

Bill

[shadow]

You want the main spring to do it's thing without interference from the guide. Ed

[fnash]

Ok, understand then.. as some springs are binding on the guide until I smooth them out I just wonder about the shrink tubing making them kind of tight again.  I have not tried the shrink tube but will next time and see how the fit is after the oven treatment. Thanks for the information..... FN

[Big_Bill]

Hay Frank,

I do not know what air rifle you have, but as Charlie has noted, Don't place plastic spring guides in the oven, they will melt and smoke up uour house.

The oven is for metal spring guides.

Let us know how U have made out, I'd like to know.

Bill

[fnash]

Thanks for that but I was referring to metal guides,,, didn't even think of the plastic type.  But good advise non the less... Thanks....   FN

[CharlieDaTuna]

There is a bit of a misconception about how the spring should fit the guide when heat shrink is used in my opinion. Those that suggest that they fit a bit  loose are in my opinion incorrect. In fact a couple of the old timers liked them real tight. Most of them liked them tight enough that you had to more or less screw them on to get it all the way up on the guide. I liked the latter and it worked. In fact, I did a few that way myself on the old B-19 years ago by request and always wondered how long it would last.  Some customers reported that they  lasted several thousand shots but of course, they don't last like a custom fitted Delrin guide, that's for sure.

Anyhow, the spring should fit at least a bit snug on the guide. Most of the time, especially on the Gamo's, the spring will be pretty tight on the guide and that's ok. What most people don't realize is that as the spring is being compressed during the cocking stage, it also expands and that tightness will decrease. The only time, if using heat shrink, tightness is a problem is if it is not correctly installed, it will slide off and wad up in the bottom. Even that isn't serious and doesn't really hurt anything. And even if the spring is free on the guide with heat shrink and not properly installed, it will still eventually come off and wad up.

Also, by the same token, if it is correctly applied, it, the Polyolefin will wear down to a point where it is "self-fitting".

 One of the secrets (as Gene could tell you but would cost him his life) is in the making of spring guides and how they are fitted to the spring. One of the reasons my tunes are so successful and so highly regarded and why I don't sell "tune kits". They are never set to be able have a "loose" clearance on the spring but neither are they overly tight. Every one of my guides are fitted to that particular spring and spring block or seats for the gun in front of me. That's the difference in a so called "off the shelf guide" and a true "custom fitted" guide.

 As Gene pointed out in a prior post somewhere, if the spring guide is not perfect, I throw it out and start over. It just drives him nuts when I'm running around with a digital micrometer in my hands and scribbling numbers all over the place...lol... But I'm a bit of a perfectionist I guess and it is virtually impossible to make and sell a true so called custom spring guide off the shelf to someone when you don't even have the parts to customize it to or without the action to fit it into. A generic "one fits all" off the shelf if properly designed and the right material used may improve the gun but it's a long way from perfection.

[Gene_SC]

Amen Bob....:) And that is why I have over 13 air rifles that shoot like $1000.00 springers...hehe Also I contribute it to many other factors that make up the final outcome of each and every one of my air rifles.. They all shoot with a close variable.... Smooth shooting, with a nice feel to them... Most all people who have had a CDT Turbo Tune will attest to what I am saying.. But you don't really understand untill you see the before and after results... I know some of you wonder why I buy so many Gamo Air Rifles....:) For the price of most of then and a Turbo Tune, you end up with a winning combination... And it does not cost you  $500.00 to $1000.00 for a high end springer... hehehe

Gene

[CharlieDaTuna]

I know you can't read this far. And I know that your arms aren't long enough to reach your keyboard from there and there ain't no letricity where your at. Howd' you do that?