Safety first!!! Comments and advice further down the page.
Lead in its powderd or fuumed form can be extremely hazerdus to your health, life, and reproductive ability.
This is from a material safety data sheet for lead dioxide please read this carefully.
More information is avalable from http://www.jtbaker.com/msds/englishhtml/L2956.htm
Potential Health Effects
Lead can be absorbed through the respiratory system. Local irritation of bronchia and lungs can occur and, in cases of acute exposure, symptoms such as metallic taste, chest and abdominal pain, and increased lead blood levels may follow. See also Ingestion.
POISON! The symptoms of lead poisoning include abdominal pain and spasms, nausea, vomiting, headache. Acute poisoning can lead to muscle weakness, "lead line" on the gums, metallic taste, definite loss of appetite, insomnia, dizziness, high lead levels in blood and urine with shock, coma and death in extreme cases.
Lead and lead compounds may be absorbed through the skin on prolonged exposure; the symptoms of lead poisoning described for ingestion exposure may occur. Contact over short periods may cause local irritation, redness and pain.
Absorption can occur through eye tissues but the more common hazards are local irritation or abrasion.
Lead is a cumulative poison and exposure even to small amounts can raise the body's content to toxic levels. The symptoms of chronic exposure are like those of ingestion poisoning; restlessness, irritability, visual disturbances, hypertension and gray facial color may also be noted.
Aggravation of Pre-existing Conditions:
Persons with pre-existing kidney, nerve or circulatory disorders or with skin or eye problems may be more susceptible to the effects of this substance.
4. First Aid Measures
Remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical attention.
Induce vomiting immediately as directed by medical personnel. Never give anything by mouth to an unconscious person. Get medical attention.
Immediately flush skin with plenty of soap and water for at least 15 minutes. Remove contaminated clothing and shoes. Get medical attention. Wash clothing before reuse. Thoroughly clean shoes before reuse.
Immediately flush eyes with plenty of water for at least 15 minutes, lifting lower and upper eyelids occasionally. Get medical attention immediately.
Now to the advice.
The mesh(commonly refered to as the grid) from the negative and positive plate were likely originaly the same aloy of lead and antimony, witch is much stiffer than pure lead. Over time the grid in the positive plate may have coroded into lead oxide(Red in color) giveing it the redish tint when you cut into it. This coroding process may also be why there is litel of the positive plate grid left.
I think pasting the lead dioxide(Black or brown in color) back onto a grid with sulferic acid may work for the positive plate, maybe. As for the negative plate I would recomend cleaning the girds first with a fluxing agent(posibly rosin, it is known to clean lead verry well) to get them really clean and then pouring liquid lead over them in a mold. Aloying the entire negative plat with upto 4% antimony can help to extend the expected life span of your battery, but also increases the self discharge rate and gassing during charging. I do not think you will have a solid enough electical connection if you just bend the lead around the grid. The electrical conductivity of the plates is verry inportant to current output,and heat production.
The plastic bag that the positive plates were in was likely micro-porous polyethylene, witch is very permeable to the acid,yet impasable to coroded pieces of lead dioxide. It surves two purposes, 1 to insulate the positive plate from the negative plate, and 2 to keep sulfated pieces of positive plate from breaking off and shorting the paltes with a conductive pile of rubble at the bottom of the cell.
On the first charge of the new cells(the forming charge) use a soulution of weeker sulferic acid. Only after the cells are fully charge do you bring the specific gravity of the acid up to something around 1.265. If you use standard acid (1.265) on the first charge, sulfer from the pasting process will be liberated into the acid greatly increasing the specific gravity, making it highly corsive to you negative plate and you will end up with a destroyed battery again in a verry short amount of time.
I have had plans for making my own verry large lead acid cells with 25 plates each using a 4 gallon pollyproplyne bucket for the cell container. I already have, or have acess to all the suplies that I need for the project and have made plans, but money and the health cocerns have been holding me back...
Please be very careful about cross comanation form colthing or the work area. You can be exposing others, posibly children witch are more suceptable to lead poising than adults. Whenever around the particulate you should wear a disposable plastic jumpsuit , a resprator(that can handel lead particles),a disposable hat, saferty goggels, and take a good shower imeadetly after exposer as a minimum... as for decontamanting the work area??? Be careful you want to get rid of ALL! of the lead dust before you use it under normal circumstances again.
If you plan to go on with this project, the best of luck to you. All of this information I have gleaned from the internet in the past year for my own project,mentiond above. I am not a profesional in the battery field, some of my information may be skewed or flat out falce with out me knowing the wiser of it. Pleas use at your own risk.
If you are suffering from the symptoms of lead poisoning seek medical attention imeadeatly. If you have been breathing in the particulate with out a gooood sealed reseprator go and see your doctor and tell him all, get tests.
Above all be safe, for you and others. Lead is dangerous.