Help stripping and sorting a HW35k

[TonyL]

When Gerald Cardew wrote in Airgunworld about filling the void in a 35 cylinder he mentioned using a vacuum chamber, Tone.
The reason for using a vacuum is that the Loctite may bridge the gap between the cylinder and breech plug and not drop down far enough into the void to fill it.
As the Loctite drops down the cylinder wall towards the void the air pressure in the void will increase slightly and hold the Loctite from fully flooding the void.
By putting the Loctite in the bottom of the cylinder and then applying a vacuum the air is drawn out of the void so when the vacuum is released the Loctite is sucked into the void to fill the gap where the air was.

You may be trying to fill the top groove or both grooves --- who knows ? :-


Attachment 315816



I've tried solder without success, mainly due to not being able to clean the void well enough coupled with the fact that there's a lot of metal breech end of the cylinder to warm up without damaging the bluing --- Loctite is by far the easiest way of filling the void.




All the best Mick

Brilliant, as ever, Mick, and I remember the reasonings for the vacuum method. Come to think of it, when I did mine, after the "compression" phase, and holding by TP bung in situ, I drew my piston back a little and held for a while. Then compressed again. Not the most comprehensive method, I'm sure, but it did seem to do the trick and it's the one I brought to the last Bash at The Hollow in October '19. 11ft.lbs in .177, so job done, methinks and achieved with that later piston that we did the exchange with. Maybe my leak wasn't as bad as some?

Great that you have tried the solder method and can report. I knew that if someone had tried it it would have been your good self. That'll save plenty of people the hassle of going down that route.

[TonyL]

Cheers Mick, nice tip !

I was perusing the net and came across a product called Permabond F201 which is designed to fill the voids in porous metal to prevent leaks ! It comes in three viscosities, F200 the lowest, F201 - medium and F202 - highest.

They suggest warming the metal with a hot air stripper or even a hairdryer and using a fine artist paintbrush to apply a small amount of the sealer, which is drawn in as the metal cools.

I guess this would work if you can get the end of the cylinder warm enough without damaging the blueing !

If it helps, the one I used was the JB Weld Perma-Lok from the House of Glues. Huge choice of product, by the way, and very quick turn-around.

[Mr.Fixit-Norm]

My 35 arrives tomorrow and I will cover this in the video, but....

The 35 has had different piston lengths over the century or so it has been made. Because of this you need to put the slip washer and top hat in the piston and measure from where the spring sits to the piston skirt in mm. This is the spring room.
Divide this number by 3.6 (the wire gauge) and it will tell you how many complete coils will fit before it gets coil bound.

Once that's done test power and report back

Hi Nick,

I’ve done as you suggested and the distance if I’ve measured it correctly is 110mm, divided by 3.6 would mean it could take 30 complete coils !
The spring in the pack has 27 coils and with the spring guide installed and the piston push right home in the cylinder, this gives 50mm of preload

Does this all sound right to you ? I’m concerned that with that much preload the cocking effort is going to be way up but I guess I’ll have to try it first before I cut anything.

Norm

[Mr.Fixit-Norm]

If it helps, the one I used was the JB Weld Perma-Lok from the House of Glues. Huge choice of product, by the way, and very quick turn-around.

Hi Tony,
I’d been thinking about redoing the Loctite but decided to try something out. I pushed the piston ( still with the old seal ) into the cylinder so that the piston head was just past the circular part of the cocking slot. I then covered the port with my finger and tried to push the piston in further. I was only able to push it in about 3/8” before the pressure was too much to push it any further by hand. I kept it there for about 30seconds and when I let the piston go it came back out again.

I’m thinking that if there were any leaks in the cylinder plug, with sustained pressure on the piston it might have very slowly started to move in ? Does my thinking make sense ? I’d rather avoid having to start all over again with the Loctite method as it seems to take ages to set ! ( the drip left in my bottle cap is still liquid after 48 hrs )

Norm

[tinbum]

Hi Nick,

I’ve done as you suggested and the distance if I’ve measured it correctly is 110mm, divided by 3.6 would mean it could take 30 complete coils !
The spring in the pack has 27 coils and with the spring guide installed and the piston push right home in the cylinder, this gives 50mm of preload

Does this all sound right to you ? I’m concerned that with that much preload the cocking effort is going to be way up but I guess I’ll have to try it first before I cut anything.

Norm

That's fine, it's the older, leather washered pistons that were shorter and require the spring cutting to fit.
Bare in mind this is an export power spring, it may be harsh and/or too powerful with it all in there

[Mr.Fixit-Norm]

That's fine, it's the older, leather washered pistons that were shorter and require the spring cutting to fit.
Bare in mind this is an export power spring, it may be harsh and/or too powerful with it all in there

Cheers Nick, I’ll give it a try and see what happens ( if I can cock it )

Norm

[TonyL]

Hi Tony,
I’d been thinking about redoing the Loctite but decided to try something out. I pushed the piston ( still with the old seal ) into the cylinder so that the piston head was just past the circular part of the cocking slot. I then covered the port with my finger and tried to push the piston in further. I was only able to push it in about 3/8” before the pressure was too much to push it any further by hand. I kept it there for about 30seconds and when I let the piston go it came back out again.

I’m thinking that if there were any leaks in the cylinder plug, with sustained pressure on the piston it might have very slowly started to move in ? Does my thinking make sense ? I’d rather avoid having to start all over again with the Loctite method as it seems to take ages to set ! ( the drip left in my bottle cap is still liquid after 48 hrs )

Norm

Hi Norm,

By the sounds of it, the porous breech issue would not actually lead to losing air out of the system altogether on most guns, it's just that the void would reduce the compression ratio, if that makes sense. From the power output readings already stated, you might not have the issue. So, to my mind, it might not be that bad an idea to proceed with the build anyway. Especially once you try it with the Hobby, you may well find the muzzle energy sufficiently healthy. If, for any reason, you have to strip again anyway, you'll be a dab hand at it now with all the practice.. Hope all goes well and the results are pleasing.

[coburn]

Hi Nick,

I’ve done as you suggested and the distance if I’ve measured it correctly is 110mm, divided by 3.6 would mean it could take 30 complete coils !
The spring in the pack has 27 coils and with the spring guide installed and the piston push right home in the cylinder, this gives 50mm of preload

Does this all sound right to you ? I’m concerned that with that much preload the cocking effort is going to be way up but I guess I’ll have to try it first before I cut anything.

Norm

That pistol seal looks seriously old and the old style, have you got one of the new HW ones to fit?

That will make a lot of difference.

[Mr.Fixit-Norm]

That pistol seal looks seriously old and the old style, have you got one of the new HW ones to fit?

That will make a lot of difference.

Yes I have, I ordered it from Nick when I ordered the tuning kit I haven’t fitted it yet, that’s going to be the last thing once I’ve sorted the rest out

The old one is actually a very good fit in the cylinder, doesn’t have any cuts or nicks out of it but just looks old. It’s also quite supple.

[Mr.Fixit-Norm]

That's fine, it's the older, leather washered pistons that were shorter and require the spring cutting to fit.
Bare in mind this is an export power spring, it may be harsh and/or too powerful with it all in there

Hi Nick, well it’s been assembled and tested, and my left elbow is suitably plastered in deep heat

The cocking effort is only marginally less than when I had the Ox spring in with your guides, but as you so rightly said the twang has all but gone completely with the supplied spring in but just faint enough to remind you you’re shooting a springer

These are the figures I got when tested. I think other than fitting the new piston seal and trying out the alternative pellets my only option now is to cut the spring down to an acceptable cocking effort and live with whatever the power figures are. With a bit of luck it’ll stay above 9ftlbs

Norm

549 - 10.65
547 - 10.57
557 - 10.97
543 - 10.42
537 - 10.19
548 - 10.63
547 - 10.58
533 - 10.02
540 - 10.31
535 - 10.11
544 - 10.45
537 - 10.19

Average 543 / 10.4 spread 533 - 557

[tinbum]

Hi Nick, well it’s been assembled and tested, and my left elbow is suitably plastered in deep heat

The cocking effort is only marginally less than when I had the Ox spring in with your guides, but as you so rightly said the twang has all but gone completely with the supplied spring in but just faint enough to remind you you’re shooting a springer

These are the figures I got when tested. I think other than fitting the new piston seal and trying out the alternative pellets my only option now is to cut the spring down to an acceptable cocking effort and live with whatever the power figures are. With a bit of luck it’ll stay above 9ftlbs

Norm

549 - 10.65
547 - 10.57
557 - 10.97
543 - 10.42
537 - 10.19
548 - 10.63
547 - 10.58
533 - 10.02
540 - 10.31
535 - 10.11
544 - 10.45
537 - 10.19

Average 543 / 10.4 spread 533 - 557

Change the seal and retest, if higher then remove a coil and fire a couple of hundred through before retesting and reducing the spring again if necessary.

[TonyL]

What Nick said and don't forget that the output will be higher with the Hobby (and maybe others, like the JSB Jumbo RS).

[Mr.Fixit-Norm]

Right, hopefully no ones bored with my dally into the wonderful world of tuning a Weihrauch, so here goes

Today I fitted a new piston seal ( easy when dropped in a cup of very hot water-thanks again Nick ), and I decided as the cocking effort was still quite a bit beyond my comfort level, I’d remove 2 coils from the new spring

Having done that and spent a good half hour straightening and polishing the spring end I cleaned it and then relubed it with the slippery bottom stuff - I must say it’s very paste like, and thicker than the almost empty tub of Ox lube I have used over the past few years

Having carefully reassembled it making sure there was lube in all the correct places, the first thing I found was the cocking effort to still be quite strong but much better than previous efforts

I fired off a couple of shots and with no discernible dieseling I started recording figures using the JSB’s first, then moved on to the FTT’s in 5.53 flavour and the Hobby’s last.

All the results were pretty good but for me the FIeld Target Trophy’s stood out the most with very consistent results although the Hobby’s weren’t far behind - good call on those two as potential pellets of choice Tony

The results are below if anyone’s interested, I know it’s only 12 of each but with the combro attached, the loss of 4” of leverage makes the cocking effort quite hard. Given the results I’m seriously thinking of taking one more coil off the spring, although I’d welcome any comments on whether or not this would reduce the consistency. I know the power would possibly go down a bit as well but as a somewhat weaker oldie I’d appreciate a lower cocking effort ( or at least my left elbow would )

I noticed that with the JSB’s and FTT’s there was one high result out of 12 that increased the overall spread and in the Hobby’s, one low one, the last set of figures on each line have the high or low one removed.

I must say I’m very impressed with the consistency of both the FTT’s and the Hobby’s and even the JSB’s aren’t that bad. But I think the FTT’s in 5.53 will be the ammo of choice with this gun from now on

Results.


JSB. Mean - 544 (10.5) Range 537-555 (10.2-10.9) or 537-550 (10.2-10.7)

FTT. Mean - 580 (11.0) Range 577-587 (10.9-11.3) or 577-584 (10.9-11.1)

Hobby. Mean - 655 (11.3) Range 646-663 (11.0-11.6) or 649-663 (11.1-11.6)

Norm

[Shed tuner]

good result, so a new seal, two coils off, and still 11 FP.

Now just shoot it. If you decide it's still too much hassle to cock, knock another coil off. Worst case it'll be 10, but more than likely still over 10.5 If you want to squeeze it back up, adding a slip washer in is a good idea anyways.

[Mr.Fixit-Norm]

good result, so a new seal, two coils off, and still 11 FP.

Now just shoot it. If you decide it's still too much hassle to cock, knock another coil off. Worst case it'll be 10, but more than likely still over 10.5 If you want to squeeze it back up, adding a slip washer in is a good idea anyways.

I’ve had a play in the back garden this afternoon, only 15yrds but with the 3-9x50 Nikki sterling mount master that came with it put back on and me doing my bit I reckon it’ll one hole at that range, as it was I was getting a cloverleaf hole, which will do me for the time being.

I’m in two minds about putting a muzzle break on to increase the leverage as sitting down it’s about the right length to pull down on when cocking. I may well pull it apart for the last time tomorrow and take just one more coil off

As you say if I decided it was too much there’s a couple of slip washers in Nicks kit

Hopefully that’ll be it then

A bit of a rest and I might be tempted to strip that Remington……..

Norm