Weight a minute!

Gary Chilling­worth is now work­ing on his spring gun’s bal­ance

Air Gunner - - Airgun Wisdom -

As I am writ­ing this, there is good news; I sur­vived and I still have most of my fingers and thumbs. Last month, we fin­ished the TX200 stock – or as my friends have started to call it, the Franken­stock. We put on an ad­justable cheek piece made from Ky­dex, a ham­ster made from an old um­brella shaft and some 2x1 scrap tim­ber at­tached with some M6 bolts and rub­ber tap wash­ers, and fi­nally, a very nice ad­justable 3D-printed butt plate from Brian Sam­son.

The thing is though, the stock needed a bit more weight at the back, so in­stead of go­ing to my old re­li­able, self-ad­he­sive wheel weights, I thought that I would cast a spe­cific weight to fit between the top of the cheek comb and the top of the ad­justable cheek piece.

Be­fore we start, I promised that I would tell you how I got on with the stock at the Es­sex Open. Well, the stock worked very well. The ad­justable cheek piece helped me to make sure that my eye was al­ways cen­tral to the scope, and con­sid­er­ing we were shoot­ing out to 55 yards, this was very im­por­tant; the ham­ster en­abled me to rest my hand on the ground and then the ri­fle on my hand so this helped to max­imise sta­bil­ity, and the Brian Sam­son Butt pad was a rev­e­la­tion. It helped the gun to lock into my shoul­der and I am con­sid­er­ing at­tach­ing one to my CS1000.

TWO POINTS IN IT

There were 70 peo­ple at the shoot and 20 of those were HFT shoot­ers. In the Spring class, I man­aged to take the win, but more im­por­tantly, I was only two points be­hind the over­all win­ner, An­war Ghazi, who was us­ing a top- of-the line PCP. This showed that a fairly stan­dard TX200HC with a bog­stan­dard stock and £ 50 worth of ex­tras can take on a £ 3000 Steyr and scope set.

Enough of that, it’s time to start forg­ing, but be­fore we go any fur­ther I have to give some ad­vice and words of warn­ing. Molten metal is dan­ger­ous, very dan­ger­ous. When I told my friend, Alex, what I was go­ing to do, he did that thing where he sucked air in through his teeth and said to me, “Are you sure you want to do that?”

Alex is a fire­man and he also knows that I am not great with tools. My wife also told me, “Do it some­where that you won’t burn the house down.” The faith th­ese peo­ple have in me is amaz­ing.

The thing is, what I am go­ing to do is quite dan­ger­ous and I have to take some pre­cau­tions. The ad­vice I got was; wear safety gog­gles, thick gloves and cot­ton or leather cloth­ing – no polyester or plas­tic be­cause this will melt if hit by molten lead – and a hat or prefer­ably a full face mask. Also, molten lead does gives off toxic fumes, so DO NOT do this in­side! It must be done in

a well-ven­ti­lated area. The fi­nal thing is, a big bucket of wa­ter. If you do get burned, the NHS rec­om­mend that you keep the area sub­merged for at least 20 min­utes and as lead melts at 327°C, if it burns you, it will hurt. I would also rec­om­mend a per­son to help, and check out where the lo­cal A& E depart­ment is. Well, that’s enough caveats and warn­ings, so I hope that, Phill, the ed­i­tor is now happy that we won’t get sued.

SUP­PLIES

To cast a lead weight, we will need a few things – firstly, some lead! I pur­chased 100 8g olive shaped fish­ing sinkers from eBay for £11. Next, some mask­ing tape, a clay flow­er­pot or bucket, and some kids’ play sand. We will also need a heat source that can be used out­side. I am us­ing a gas cook­ing stove and fi­nally, a saucepan that you are happy to de­stroy.

The first thing that we need to do is make a mould. As I look at the back of the stock, there is a nice gap between the top of the in­side of the riser and the top of the comb. This is per­fect be­cause the weight will be al­most in line with the spring.

My ri­fle riser was formed over a cylin­dri­cal tube that was used to hold vi­ta­min C tablets. This tube slides into the gap between the top of the riser and the top of the comb, so I can use the same tube to make my mould. The tube is what is known as ‘a pos­i­tive’. You could fill the void with chil­dren’s plas­ticine or air-dry­ing clay and use this to make a per­fect cast of the top of the comb, but this is quite ad­vanced and for now, I will use the cylin­der and keep it sim­ple.

THE SCI­ENCE BIT

So, how much lead you will need? Take a large glass and fill it to the very top, then gen­tly push the pos­i­tive into the glass un­til it has just sub­merged. You will no­tice that a large amount of the wa­ter will have spilt over the edge. Re­move the pos­i­tive and start to fill the glass with your lead. When the wa­ter level has reached the top of the glass again, you have the ex­act 75% of lead that you will need. There will al­ways be some lead and slag left in your pan, so add 25%. You can then raise a glass to Mr Archimedes, his bath­tub, and his the­ory on dis­place­ment.

The next step is to take a large clay, or ter­ra­cotta, flow­er­pot and fill it with play sand; this type of sand is finer then sharp sand and will give a bet­ter fin­ish – it’s also only £ 5 a bag from B& Q. Half fill the pot and place the pos­i­tive into it. Start to fill the pot with more sand and keep tap­ing it down. You want it to be as com­pact as pos­si­ble. When the pot is full and the

sand is at the same level as the top of the pos­i­tive, you will need to re­move the pos­i­tive from the sand. Pull the pos­i­tive out slowly and what should be left is a void in the sand that looks ex­actly like the pos­i­tive, but in re­verse. This is called ‘a neg­a­tive’.

If the sand col­lapses, you can try wet­ting the sand a lit­tle, but not too much be­cause molten metal and wa­ter cre­ates steam, and steam will burn. If you have a good neg­a­tive, it’s time to melt the lead.

Place the lead in a pan and start to heat it – use a long stick to stir it every now and then – and af­ter about 10 min­utes, the lead will start to turn into a liq­uid. When­ever you are near this stuff, you must wear the full safety gear be­cause a spit of lead in the eye will blind you.

Take the lead and pour it very slowly into the mould, and when all of it is in, let it cool for a few hours. You will now have a weight that will fit per­fectly to the top of your comb and also the in­side of your riser.

As you can see from the pic­ture, the lead weight fits between the top of the comb and the top of the riser. To keep it in place, I placed some epoxy on the in­side of the riser and stuck the weight there. There is also a piece of tape on the comb and some ma­te­rial to cush­ion any move­ment, al­though I’m go­ing to re­place this with foam.

BET­TER BAL­ANCE

This weight makes the ri­fle feel well bal­anced, and it cer­tainly helps to deaden the re­coil. If you have a stock like the CS1000, you could cast a weight that sits just be­low the cheek piece, or you could drill a hole into the riser and fill it with lead, but I’m not even go­ing to at­tempt this be­cause I will break my stock.

Cast­ing a lead weight was a lot of fun and I know that it looks a bit rough, but this was my first at­tempt and I want you to see my suc­cesses and my mis­takes. With more prac­tice I will im­prove, but part of the fun of th­ese ar­ti­cles is the fact that I am am­bi­tious, but rub­bish. The in­for­ma­tion that I have passed on to you is all cor­rect; it’s just the ap­pli­ca­tion that’s a bit lack­ing. Please be care­ful. If you want to have a go and let me know how you got on, you can con­tact me at garychilling­worth36@ gmail. com and good luck. Next month, we will be mak­ing pel­lets from depleted ura­nium. That is if my North Korean con­tact, Kim, comes through with the goods.

You now have a lead core

Re­move the pos­i­tive and you will have a per­fect neg­a­tive into which to pour the lead

The wa­ter level is now back at the top of the glass, this is 75% of the lead you need

A per­fect void to hold a weight

Heat the lead in a pan you are happy to ruin

Play- pit sand is cheap and ef­fec­tive for cast­ing

“I man­aged to take the win, but more im­por­tantly, I was only two points be­hind the over­all win­ner”

Pour the lead very slowly

A per­fect fit and the rough ex­te­rior will help the epoxy to stick

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