Home made P weight?

[ferris213]

Does anyone have any experience casting their own P weight? I have a DSS SS back plate with no STA and currently dive with about 2 or 3lb on a belt. I'm thinking of casting a small P weight to fit into the bottom of the channel in the plate.

What is the normal way of attaching the weight to the plate? Any tips on making a mould or casting it? I have searched a bit but only found a thread from about 10 years ago, all the links were dead...

A friend of mine has been smelting and casting different metals for a few years now so I'm aware and respectful of the safety issues involved in dealing with hot metal.

Any advice, tips or photos would be greatly appreciated!

 

[HenrikBP]

I've seen threads where some people line the channel in their backplate with heavy duty aluminum foil and use that as a mold. No personal experience with that solution though.

As for attaching it, you may be able to use short bolts through the plate?

Henrik

 

[Rich Keller]

Using the backplate itself as a mold would work if it was a steel plate, I am not sure it is a good idea with an aluminum plate or foil for that matter. Coating the plate with solder flux then foil would be safer. Then when it cools just drill holes in the weight and bolt it to the plate.

 

[richard_severn]

I made a 6kg one a few weeks ago i didnt line the bp with foil as it melts if you get it hot enough and messes up the lead.
sadly i didnt take any pics but shall try to explain it best i can.
I cut some 1 by1 wood to the profile of the backplate and then screwed them onto the plate with a big a spacing as possible
i then folded up some heavy duty aluminium foil a fair few layers and layed it over the bp on the cylinder side to cover up all the holes in the plate then pushed my sta through the foil flipped the lot over and using normal hex nuts bolted the sta down nice and tight (this gives you a perfect 11 inch spacing and when removed no holes to mark or guess) then i was ready to melt the lead i used a camping stove under a milk pan and a gas blowtorch from the top to speed things along i did all this in a green house with the door and window open to get rid of the chance for wind or rain upsetting me. i added the lead 2kg at a time untill i had all 6kg in the pan, dont rest the pan on the camping stove it most probably will fall over and spill lead everwhere and thats bad i used some bricks out of a heater and stacked them up with a wire metal oven tray ontop with the pan over that to giver it the stability. i then scraped all the crud off the top of the lead and added a bit of beeswax to get some more out then i was ready to pour. I checked the bp was level and ran the blow torch over it to compleetly dry it off and get rid of any water as it can explode and also to warm the plate up a bit to gove a better finish. then i poured the lead into the plate slowly wearing welding gloves and thick jeans as to not get burnt then i went arround the whole weight with the torch to even off the edges and level it out as muc as i could. After i went inside and waited for a few hours for it to cool then i brought the plate inside and tried to remove the lead that was a pita i ended up with a big hammer a chisel and a screwdriver but eventualky it was free then i got 2 sex bolts and markesd the spacing out on the back of the weight coountersinking them so the female part will be flush once seated under the lead. I then went back out to the green house melted a bit more lead and covered the sexbolt in flux heated up the sex bolt a bit and then poured the lead into the hole making sire i avoided getting any down the threaded part (you can fill it with greese if you want to stop it) then i took the torch and heated it up again to level it off and make sure it was properly stuck.

Now down the cellar with a hole saw and a bench dril. As the lead is in the way of the wing nute and everything else i put theweight into a clamp and drilled a 32mm hole through the lead centering it on the holes left from the sta so i have a 11 inch spacing and rookm to tighten the wing nuts up after a lot of the hole saw getting caught i gave up and drilled a lot of little holes 2mm all around the hole that should of been cut out and once i had drilled all the way arround i smashed the plug out with a hammer J then filed it down and ran the hole saw through to level it all off and this is what i ended up with

On removing from my plate one of the sex bolts had come out so i sudgest you wrap tape over them aswell so if the lead come off the weight is still held in by the tape and sex bolt but it shouldent fall off as it cant slide past the bolts J

Sorry for the spelling etc hope it makes sense

 

[ferris213]

Thanks for the replies, Richard thanks for the very detailed post and photos. Did pouring the lead directly onto the plate damage it's finish in any way? I like the idea of setting the sex bolts into the casting.

 

[lucca brassi]

I made once P weight , but honestly next time if i need it i'll buy it ;-).

poison vapours , risk of injury burns .. for saving few euros ;-/ ?

I make mould like described by adding thin stainless stell foil into my backplate ( foil for industrial quenching of the coke ) and close mould with lateral plate on bot sides. I made perforated stainless steel plate as anchor inside lead for screwing M8 screws and as additional support to whole P weight.

Problem is that must be mould ( in my case backplate ) all time equaly heated to prevent local premature solidification of lead. Lead mus be heated from upper and lower side . And after cooling comes to some ''collapse lead ''. On previous nice surface starts come cracks and roughness.

So IMO in first palce MOULD SHOULD BE MADE COSTUM (not backplate ) and VERTICAL (if wanted really nice work ;-)). I have also seen some moulds from hard wood or clay what is interesting because it made fine surface because they are both heat isolators and in that case lead is cooling down very equally and slowly .

Workshops / Blei selber gießen - dir-austria

some other wariants http://www.seveke.de/tauchen/technik/1edelstahl.htm

 

[cmburch]

Plumbers, gutter installers, electronic workers, etc. soldered with lead. Poison vapors. How hot does lead have to be for the lead and antimony to vaporize. There should be a lot of heavy metal poisoned people that use to use lead solder if this was true.

Looks great for DIY!

 

[richard_severn]

No problem with the backplate after. I once filled 2 cans with petrol and put a bp ontop of them and just chucked the lead onto the plate and let it melt but that plate took forever too clean ended up with wire wool to get the carbon off the weight was ok though only weighed 2 and a half kg though.

You can line your pb with tin foil but its a pita to remove from the lead and half the time it melts or rips so why not use your bp on its own your not getting it too hot only pouring the lead into it.

on lead poisioning first time i melted lead in the open air i had a bad throat ffor the next week when i did it in the green house i had no problems and was sat next to the lead for over a hour i would imagine as i made a couple of others as trials. And lead solder is the easiest to solder with imho the lead free stuff never melts or flows properly

---------- Post added April 22nd, 2012 at 12:03 PM ----------

I made once P weight , but honestly next time if i need it i'll buy it ;-).

poison vapours , risk of injury burns .. for saving few euros ;-/ ?

I make mould like described by adding thin stainless stell foil into my backplate ( foil for industrial quenching of the coke ) and close mould with lateral plate on bot sides. I made perforated stainless steel plate as anchor inside lead for screwing M8 screws and as additional support to whole P weight.

Problem is that must be mould ( in my case backplate ) all time equaly heated to prevent local premature solidification of lead. Lead mus be heated from upper and lower side . And after cooling comes to some ''collapse lead ''. On previous nice surface starts come cracks and roughness.

So IMO in first palce MOULD SHOULD BE MADE COSTUM (not backplate ) and VERTICAL (if wanted really nice work ;-)). I have also seen some moulds from hard wood or clay what is interesting because it made fine surface because they are both heat isolators and in that case lead is cooling down very equally and slowly .

Workshops / Blei selber gießen - dir-austria

some other wariants Edelstahl

few dollars/euros/pounds it cost me about a tenner(£) or less to make a 6kg weight the lead was £2.50 for 2kg i can get a nicely made one from on the internet for arround £40 for a 2.6 kg one going buy that mine is worth around 85 quid......

 

[cmburch]

I was looking for a weight. I am using a TransPac with a weighted STA and looking to add an additional 7lb. I like this idea of making your own.

I had already ordered a nylon bag that fits in the channel for $12 though. I am going to use recycled lead shot from a shooting range. While not environmentally friendly, lead shot (Pb/Sb powder from rubbing) versus a solid piece of lead, it is easy. I collect lead from tire weights, fishing weights, car batteries, etc. also. And will think of other projects such as yours. Thanks!

 

[PeterNBiddle]

Mix N pounds lead shot with enough two-part epoxy to form a fairly stiff dough where all lead shot is wetted.
Liberally spray Pam coking spray into your backplate cavity.
Pack the dough into cavity.
Let set.
Drill holes through weight to attach to BP.
If you wanna be super slick cover with a custom fit bit of ABS.