leading is only real choice, for one specific reason , It Seals , if properly applied , its a simple old school procedure that relatively easy just a few simple rules too follow.
1. keep every thing clean thru every stage
2. use a lead file not a grinder
3. only use 70/30 body solder (lead )
4. use a good cleaning agent recommended for lead work. I make my own its simple and by far way cheaper and better than what you can buy. #3 equal parts of Alcohol , Ammonia and water put in 1 gal container skake it up pour in to a spray bottle .
5. sand all paint or coatings off of area to be leaded, be sure to take coatings off way further than you think you need, clean the bare metal with home made solution or metal prep of your choice, scrub with scotch bite pad and solution ,rinse with solution wipe off with Bounty paper towels ( bounty wont leave any fuzzies when wiping)
6. buy tinning paste is the easiest way to tin your metal before leading. Eastwood sells the tinning paste also buy a lot of acid brushes to apply paste. after coating the are to leaded with paste take your torch (nap gas will work fine) apply heat to tinning paste until it changes from grey color to brite silver like solder. be careful not get to close or stay in one area to long , just spread heat evenly over the entire tinned area, once it turns silver let cool for a few minutes , break out cleaning solution scotch brite pads (red ) and a good stainless steel wire brush , always use stainless steel brushes as they will not contaminate the surface , scrub surface with wire brush and solution until clean , then scrub again with solution and scotch brite pad then rinse with solution and wipe clean . be sure to get all black spots out as they are acid that cause problems later. (clean ,clean , and clean again between all stages)
7. you are now ready to apply your lead.
8. you will need a maple paddle and paravane wax ,you can purchase threw eastwood be sure to order enough wax (probably 2 small containers from eastwood) heat the wax until liquid and coat the paddle so that you can spread the lead push to wear needed.
9. with torch in one hand and lead stick in the other( keep paddle and wax with in reach) warm the body metal to be leaded , then heat the lead stick or warm it till soft approximately 2 inch's above the end of the lead stick and press on to the metal.put lead aside temporarily warm the lead and push around to where desired ,repeat leading process if more is needed. by this time you will probably need to apply more wax on your paddle . if you think you have enough lead , then gently warm the lead until it "STARTS" to turn color from grey to silver ,take your paddle with plenty of wax on it (crucial) run the paddle across the lead while applying warm heart as needed to smooth out the lead . once you think you achieved the level you needed let cool for a few minutes ,then clean with solution and wire brush and scotch brite pad , once clean take your lead file and file down to desired level, gently warm the lean again to see if any of the acid from the lead comes to surface, repeat cleaning process. if more lead is need repeat the process ,remember when adding additional lead to heat 2 or 3 inches above the end of the stick and gently warm the lead as you push it with the paddle and remember to use plenty of wax . repeat filing and cleaning process as needed. your last stage should be warming to draw acid to surface ,filing to finish then cleaning process . to prep surface for paint or thin coat of body filler the leaded surface must be paint with 3 coats of epoxy primer. hope this helps
