Jump to content
I Forge Iron

Casting dies for battery grids and internal posts


Recommended Posts

Hi I currently own a battery Restoration business named JWR Battery Restoration that specializes in reviving sulfated lead acid batteries. However, I'd like to expand into rebuilding depleted batteries as well as constructing my own brand of see through AGM batteries using acrylic as the body.

The purpose of making these batteries translucent is so my customers can easily monitor the health of their batteries and be more informed about how lead acid batteries work. In doing this, I'm hoping to arm my customers with the knowledge they need to properly maintain their batteries. 

I was inspired by this idea because most of the customers that come by to get their batteries fixed end up handing me fairly young batteries that have severely low electrolyte levels, rotted internal posts, bloated and/or cracked casings, severe sulfation, all things that can be avoided if they could just keep their batteries maintained properly.

I can source all of the materials I need, however the one thing that escapes me are the dies needed to cast all of the lead components.

I need dies to cast the battery grids, internal posts that connect the grids, and external posts. Does anyone know where I can find these dies?

I'd make them myself, but I don't have a CNC machine and the dies have to be made of steel so they can be reused and also so the lead doesn't stick. 

If possible, for the grid dies, I would like to have a bunch in an array that bolt together with long bolts so I can cast a bunch at the same time. 

 

Link to comment
Share on other sites

I have no clue to what sizes and shapes you are wanting to cast. I have experience casting detailed lead and lead alloy items. Some are pretty big,, lol, big is relative. I make my own molds from RTV rubber, a two part mix. They last a long time, are cheap to make and with simple equipment, no centrifuge. You might look into it. 

Link to comment
Share on other sites

Lead CAN "solder" to steel, aluminum is typical for sinker and bullet molds or was. Ganging molds isn't a "thing", it's more a matter of prepping the molds pre casting. Thin and detailed molds need to be hot enough the pour doesn't solidify before they're full but nt soo hot they take an excessive length of time solidifying.  

I've never taken a lead acid battery apart so I don't know what the plates look like. Do they have a lot of surface feature, say fluted to increase surface area maybe? If you make your molds from al you can cast them individually or in small groups until you have a basic number to take care of your needs. Then cast more as or if you need more. You'd have a couple sets of master plate forms to make al molds as needed. 

Without knowing details there's no way I can suggest "how tos" but I can think of a couple basics. Connecting plates determines "series" or "parallel" Yes?  When stacking plate mold segments place the connections mirror to each other one parallel the other series and reverse the molds as necessary to develop the battery you need from the same molds. You could easily make, 6v, 12v, 24v, 480v and amp hour ratings in the same way. Which way which plates get cast would be a matter of how you stack the molds. The posts on lead acid batteries are built in sprues and risers. 

Frosty The Lucky.

Link to comment
Share on other sites

This is a battery plate grid. They come in different grid shapes depending on the manufacturer, but just a standard vertical-horizontal grid works just fine. The grid size is generally 5.75x5.25" and about 1/16" thick. 

PXL_20220716_221447852.thumb.jpg.486800933439a3e3412e3890b7587ce3.jpg

PXL_20220716_221457701.thumb.jpg.11a5c6464b18649c9eb84fd794ab824e.jpg

 

This is what connects an array of plates. each array forms the positive/negative halves of a cell. 

PXL_20220716_221641545.thumb.jpg.742a2e14349cdf66e31526744a92366e.jpg

PXL_20220716_221653010.thumb.jpg.47f39c78bdcbdc237e70adf1573799cd.jpg

 

This is what it looks like inside a lead acid battery. The plates are arranged negative to positive with 10 positive and 11 negative plates per cell. Each Positive plates is always encased in a porous separator pouch to prevent the positive and negative plates from touching and shorting out.

PXL_20220716_221541623_MP.thumb.jpg.fd9d01ffba0212bfa60b66c332d2be01.jpg

Link to comment
Share on other sites

Have you done any sand casting? Investment casting would work I suppose. A grid rather than a "plate" is a different casting problem. The melt has to stay liquid enough to flow into the whole mold and shrinkage as it cools will be exaggerated. Happily lead has a decently low COE (Coefficient Of Expansion)

I'd start by modeling master forms to be cast in aluminum. Thin plates, flat on one side with your grid on the other. They'd be matched front to back so you could stack as many as you wish per pour. Either clamp or screw them together. Each mold segment would need to have a pour cup/ reservoir to supply enough weight of lead to force the pour to the whole mold. These would be part of the tab you're holding in pic #1 and form a long cylinder when the mold is screwed together to pour. It'd look something like a battery with a piece of pipe connecting the poles.

Lead is a darned low temp melt, 621f +/- a bit depending on purity or alloy. A large stack of mold plates will chill it quickly so preheating it to a working temperature would probably be a must. Then with that much 621F lead it will take time to cool enough to solidify enough to break out of the mold. 

When anvil mentioned centrifugal casting I rolled my eyes but darned if ganging several mold stacks off a large central reservoir isn't a good idea. The molds would spin around a large reservoir forcing lead to the bottom of the lattices and you'd be casting 2 maybe 3 stacks at a time. 

Please, bear in mid I am NOT caster and the only gang molding I've done was in high school metal shop to get an A on the casting. You need to talk to a caster and get an expert opinion. Heck, when I first saw the pic my first thought was stamp them from lead sheet, one those things would be coming out of the press about every half second.

There might be a way to continuous cast them too. I know battery companies cast them by the millions probably daily and they sure don't do something as cumbersome as I described above. Then again I can imagine such a mold being automatically assembled, poured, cooled and opened by machine, so maybe. 

You really need to get professional advice, I'm just some guy on the internet.

Frosty The Lucky.

Link to comment
Share on other sites

I have seen an old battery manual that subjected casting the plates in wooden molds. I have myself cast lead in the rabbit on hard wood flooring for radiator repair. 

as aluminum can be cut with woodworking tools, carving intel of casting would be best. A trick with lead is you can heat it enough to melt the metal next to it, so repaired can be made with simple molds and either a melting spoon or a torch and stick filler.

gloves, respirator etc are recommended. Lead poisoning sucks

Link to comment
Share on other sites

A wooden mold is an interesting idea, but I'm pretty garbage at hand carving and the plates have to be perfectly flat. And I don't have the money to buy a router unfortunately. Also yea I get what you mean about lead poisoning. I got a nasty case of that back in the day when I used to use leaded solder.

On 7/16/2022 at 7:09 PM, Frosty said:

Have you done any sand casting? 

Yea I was thinking the exact same thing with the design of the mold array. However I put a lot of thought into the material that the molds should be made of and I don't really like the idea of aluminium because of how thermally conductive it is. However if there's some kind of mold coating that is thermally resistive and doesn't stick to lead, that may solve my problem with that. I saw a video of a dude from India that used a steel mold that hinges open and closed. He just holds the mold closed, pours the lead in, waits a few seconds, and then opens the mold again and pulls the plate out. I couldn't get the video link by itself, but you can find the video on this page:

https://m.made-in-china.com/product/mold-for-hand-lead-plate-One-out-1913356952.html

 

That said, I do really appreciate the advice and will continue to figure this stuff out.

Edited by Mod30
Excessive quoting
Link to comment
Share on other sites

Silicon rtv rubber and done in a centrifuge would work very well foe everything you show in your pics. It would be the cheapest and the only product that would not break your pocketbook for mold making. Undercuts are very difficult to get with metal molds. Especially your third pic. Rtv rubber is a high temp silicone that flows into the voids when poured and holds up very well.  

molds using lead need a release agent. Pam for spray on, vaseline  for wipe on works too. Plane ole talcum/baby powder works too.

Frosty, you are a hoot. 

For your education,,,   Oops, I removed the link. forgot about the no advertising deal. google "low melt metals casting with rtv rubber" and see a whole new industry.

Best of all, its made in the USA.

Link to comment
Share on other sites

You aren't saying I get carried away are you anvil!?:o PM the link to me please anvil. I'm aware there is more I don't know than I do and I'm always looking to shift the ratio.

I was under the impression the question was in regards to making production castings, not one offs or small runs. 

I have zero experience using RTV rubber for casting lead though know it's done routinely. How do you break the lead grid out of the mold without bending it up? 

Lead doesn't stick to aluminum, I've cast I don't know how many hundreds, maybe thousands lead of sinkers in aluminum molds. Dad bought the molds and electric lead pot to save money and I discovered there was always a good market to other fishermen so I started cranking them out for spending money. I don't know if you can MAKE lead stick to aluminum other than mechanically. Aluminum solder doesn't contain any lead, last I looked.

JWR: I watched both links. You ARE wanting to do this in a more 1st world way I hope, those are both 3rd. world tech how to videos. The fellow hand pouring plates in the hinged steel mold is about as modern as I saw. Did you notice his plates were all getting warped from the little handling he did removing them from the mold and laying them down?

Even if you bought one of those hinged steel molds you'd be sitting there for how long per 12v 100amp hour battery? Less than a couple hours but you need to trim the flashing and do more fiddly hand work before you can assemble cells.

A lead grid like that is silly soft and malleable you could crumple it like cheap paper in your hand, flatten it between two boards if necessary. The guy assembling the repaired battery was flattening plates between the insulating wrap. Unless you actually stretched or crushed them, flat isn't an issue, that happens during assembly of cells. 

At this tech level it might work for folks living off the grid and say making a solar power system without having to pack batteries in through the woods. This just isn't how a manufacturer makes lead acid battery plates.

Frosty The Lucky.

 

 

Link to comment
Share on other sites

This is very true. Maybe I should instead invest in sourcing premade plates instead. Then all I would have to worry about is cell assembly. That said, shipping costs would probably be high since I'd have to source from a factory or supplier. I'd probably have to buy in huge bulks too.

 

Designing and manufacturing my own battery was a nice pipe dream, but I may just have to stick to reviving dead batteries. It sure would be a lot of fun to build a prototype though! Maybe one day.

Edited by Mod30
Remove excessive quote.
Link to comment
Share on other sites

Checking into ALL the alternatives before starting a company is what we were talking about in another thread. Plans take a lot of research, thought ad a pretty cold sense of the practical. I can't imagine finding a manufacturer for most anything near to Pa. would be a deal breaker, I'd at least look. 

There used to be two battery manufacturers in Anchorage, Alaska Husky Battery is the only name I remember but I used Husky batteries until they closed. They made everything, plates, separators cases, everything on site. I used to live about 6 blocks from the shop. One trick I remember, they used the first ultrasonic bath I'd ever seen to clean the crud off reclaimed lead before it went into the melter. They had another process to remove the lead from the crud.

I'm not trying to discourage you from making your see through battery, I'd just like to see you take it on with a chance of success. By all means hand make a couple few as proof of concept while you investigate what it'd take to manufacture them profitably. 

What might be your real money maker is selling the rights to a major battery company for a % of the take. That takes all the hassle, legalities, etc. off your doorstep, your worst will be filing taxes on your take. Hmmmm? 

HEY WAIT! :o The real change you're proposing is a transparent battery case, not some revolutionary new battery design. Injection molding plastic is pretty EZ PZ. Sell Delco transparent cases or the rights to the patent. You know, seeing as you're talking about it here and now you might want to file for your patent soonest or someone will steal it even if they have no intention of using it. 

Frosty The Lucky.

Link to comment
Share on other sites

All the rtv molds I've made are two part molds and the rubber is flexible enough to slip out of voids yet strong enough to not tear. And multi-part molds beyond 2 is pretty easy to do for really detailed and undercut pieces. A common use for these molds is for casting jewelry, Gold, silver and lead are all low melt metals. 

 sent.

Link to comment
Share on other sites

  I've been following along with this thread and have to ask what major manufacturer want's to add a feature that allows the consumer to prolong the life of their product?  If that were the case, wouldn't fluid level indicators and alarms on batteries have been installed long ago?  I'm suprised they put caps on the cells to add liquid in the first place.   Now aren't they sealed gel products?  This may be the dumbest comment ever but I am curious.  I can see breaking new ground so the do it yourselfer can do more and starting a new thing but it would be a long hard slog, I would think.

Link to comment
Share on other sites

No sweat, I do the same all the time and some things are hard to catch. It looks like not much is left and there's no directory except file addresses. I guess I'll download a few and see what I want to save.

Thanks, Frosty The Lucky.

Link to comment
Share on other sites

It's amusing as transparent battery cases were the norm 60+ years ago.  My Mother has told me many a time about the bank of glass case lead acid batteries that a windmill charged on their farm in rural OK that was used only to run the radio...they used kerosene lamps for light.

I've also seen transparent 55 gallon drum lead acid batteries used, at least in the 1990's, for telephone central office back up power.  AT&T Bell Labs did quite a bit of research on batteries for that purpose.

Link to comment
Share on other sites

Ran out of high speed Data and there is so much hidden bloatware on the net these days that I couldn't  effectively run at low speeds; everything times out before loading finishes; no matter that I don't buy ANYTHING advertised on the net, ever!   So lets see how far I get this month! 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...