My roof on my car had some pits through the original paint. I stripped the paint to bare metatl. I wire wheeled it earlier today, now I'm sanding the bare steel getting ready to prime tomorrow.

There are some spots that were rusted, they are the pits I spoke of previously. After wire wheeling and sanding with 80 grit there are still black spots like rust I assume still in those pits. What should I do before I shoot the primer tomorrow.

I have some Metal Ready from POR15. Should I use something like that. To use that I would have to wet the metal and I didn't want to do that.

I dont want to paint the car and in 6 months have rust bubbling up through the paint.

I will use DX1791, then DPLF, then K38.

I would use an ice pick or small screw driver and push in on the spot if i goes through you have some hidden rust probably at a cross brace. If it seems solid except for a small area i would braze or lead it and you won't have a problem later.

I went thru the same problem with my car which was origionally a vinyl top car, whatever method you use, make 100% sure ever spec of rust comes off or it will come back, believe me i know.
You have a couple choices here, acid wash it, or sandblast/ etch prime. I chose the blast/etch route and worked out great.

I just noticed in your question you list the dx1791 which is a self etching primer. FYI double etching is a big no-no, so scratch the acid wash if you plan on using that primer.

I'm done with the sanding, I now plan on cleaning and spraying the DX1791. Since it is transparent I intend on rolling it out and sand blasting the bad spots in the next couple of days, sand the 1791 and shoot with another light coat before going onto DPLF.

I am to bare metal on the whole body with doors, hood, trunk and fenders removed and through the primer stage. I will go this route to protect what I've done so far.

Any concerns with this method?

Originally posted by ccarney69:
I'm done with the sanding, I now plan on cleaning and spraying the DX1791. Since it is transparent I intend on rolling it out and sand blasting the bad spots in the next couple of days, sand the 1791 and shoot with another light coat before going onto DPLF.


Any concerns with this method? What does "rolling it on" mean??

Rolling it out. I just meant that after I sprayed the 1791 that I would take the car outside and sandblast the pitted areas since I'll still be able to see them through the 1791. I'm just trying to make sure that no rust was left in the pitted areas that will cause me trouble later. I'll have to sand the 1791 since more than 24 hours are going to pass before I can get the car cleaned and ready to spray again. I plan on spraying a second light coat of 1791 then right to the DPLF.

Hopefully that will keep rust from coming back through the paint where these pits are. Theres a couple of areas on the roof that have quite a few of these pits and then theres several scattered around individually on other body panels.

Right now the car is cleaned and masked, I used an ice pick and picked most of the rust out of the pitted areas. I'm thinking about the lead or brasing before I spray anything to try to eliminate that extra sand blasting and cleaning. I havent leaded before, whats the right method to do it right?

The sand blast method would be the easiest
( except for the mess ) most effective method for killing the rust. If you use some discretion when blasting you can avoid a huge mess. Also, you can vary your air pressure / angle of blasting to keep heat to a minimum. I would NOT & I cannot stress that enough to stay away from brazing / leading. They both require a torch & skill to do. The other thing here is warpage. If you go putting a torch to your roof skin w/o really knowing what you are doing........ a whole other world of headaches awaits you! You can fill the pits w/ filler after blasting to fill them. You have many choices such as Duraglass or a good filler if they are not too bad. Also, prime car once and then blast & reprime w/ same primer?? It sounds like a extra step w/ a waste of materials. I NEVER prime until the vehicle is ready. I have had exceptional luck w/ DP over bare metal that is clean. You cannot ask for a cleaner metal then after being sand blasted. Also, I use the finest grade sand I can get as it will not tear up the metal. Good luck. JOHN

If it were up to me, I would lead the pits after I removed the rust.

Body filler does not stick as good to the steel body as does lead.

Here is a method I used to fill in some areas on a trunk lid once.

1- Clean area as best possible.
2- Wipe down with a solvent.
3- When you go to lead the holes, hold the lead about 3" from the roof, heat it up with the torch until it starts to liquify, position the lead so that the drips to fall into the pit.
4- Once the hole is filled and the lead has cooled, take a file or rasp and file it down flush with the body.

Which ever way you choose to do it, Good luck!

-Todd

I don't know about lead a buddy of mine is getting his willy's painted and the painter would not gaurantee the paint job if the lead was still in there

Lead is the best. You just need to replace any "old" material like on the Willys. There could be rust or corrosion under it. The very HIGH end restoration houses use lead.

If it were up to me, I would lead the pits after I removed the rust. Body filler does not stick as good to the steel body as does lead.

Here is a method I used to fill in some areas on a trunk lid once.

1- Clean area as best possible.
2- Wipe down with a solvent.
3- When you go to lead the holes, hold the lead about 3" from the roof, heat it up with the torch until it starts to liquify, position the lead so that the drips to fall into the pit.
4- Once the hole is filled and the lead has cooled, take a file or rasp and file it down flush with the body.

Which ever way you choose to do it, Good luck!

-Todd To properly apply body solder the area must be cleaned with a flux first followed by a tining operation and then the solder can be applied. After the cool down period the solder must be washed with laquer thinner to remove any acid flux and rosin before shaping with files or abrasives. Some people use a vinegar solution as well. With the amount of heat involved filling holes or pits in the middle of a horizontal panel like a roof or hood will lead to major problems with warpage. Dropping melted solder from above the pits without the proper tining and heat will cause the solder to not adhere to the steel.

I think your best bet would be to remove all the rust, apply two - three coats of good epoxy primer and let dry to a full cure. Then scuff with a red scotchbrite and fill the pits with Everglass filler.

Body solder "LEAD" can be a nightmare of problems if not properly applied. Trapped acid flux can blister and rot the solder and steel very fast. Imbedded rosin can cause adhesion problems with primers. And poor quality solder often has contaminants right from the manufacturer. A good example of where I use solder is areas that are highly stressed like around door strikers, etc. Solder failures are common for the novice so if you're not familiar with the proceedure find a professional to help and teach.

60/40 ? what flux? Will muriatic acid work?

I worked at a shop and on a total resto, all lead is removed. Many customers came back in saying that we don't need to remove it and just paint it. Melt the lead out and find that it hides more rust and bad bodywork then bondo can. Now all you have to worry about doing lead work is poisioning from it.

This thread is better than the "tastes great--less filling" debate.

LEAD--Got rid of all of it in the late 70S.
Use of product is not for the inexperienced. Worked with many old time Body that couldn't properly prepare surface, tin and apply the material without having a huge mess.
Use for rust pits may be overkill.
Not a Lead fan. Remove it whenever I can.

Here are some cleaning tips that will work.
Buy a "Crud Thug"
This is a rotating, air powered wire wheel. Uses wires impregnated in a replaceable band. Different stiffness of wire bands may be used to clean surface. Will leave a coarse or fine texture, depending on wire of choice.
Have seen very few rusty surface spots that this tool will not remove. Very little heat generated, so no warpage.
Also works great for removeal of caulking and sealants.
Spot sandblasting some of the deeper areas is also appropriate.
Broken 3/8 in drill bit works well for the smaller crusty spots. Cleans them out nicely.

Use the etching, priming, surfacing procedure as recommended by Paint manufacturer.
After proper cleaning spot fill deep pits with chemical filler, or poly filler as required.
If Paint manufacturer allows filling on top of its etch primer, etch prime first.
Por 15 is good stuff, however it needs a conversion coating to have conventional refinish products applied.
If you have pinholes through panel they should be welded prior to fill.

Good Luck
Karl

Many people hate lead and many people won't use anything but lead. I prefer lead.

The way that I mentioned above worked for me. Even after 5 years. I never used flux. I just roughed up the section and cleaned it. I never knew you were supposed to use Flux. I know you do on soldering. The trunk lid is still smooth with no seperation.

Also, I use this method on flat sections only.

I covered the whole car with plastic, cut the the plastic from the roof and taped. Then sandblasted the whole roof. Now I'm going over the rest of the car and using an ice pick to clean the black spots on the side panels. Some I just scratch and spot goes away, some I can actually dig out some material. I'm getting everything that I can out and try to see clean metal. I plan on sanding one more time, cleaning with DX330 then spraying DX1791.

Question: Will that be suffiecent if I use the DX1791 etch primer then 2 coats of DPLF then K38 or should I just take the car outside and sandblast every little spec then go to etch primer. The specs or pits on the side panel are much smaller than the ones on the roof and almost microscopic in some cases.

Thanks
Chris

Sandblasting exterior panels WILL ruin them!!!
The sand streches the metal out, making darn near impossible to repair.
Its NOT the heat involved that ruins the metal, heat shrinks metal, sandblasting streches it. Each grain of sand is like a little hammer hitting and streching the metal.

Go to your local auto body supply store and buy a clean-n-strip disc. Its a black 6in sponge looking disc, it does a great job cleaning rust pits.

That sounds like what I need, thanks. I dont think I hurt the roof with the blasting. I used a siphon blaster with low air pressure. I'll know for sure when I block it.

Go to your local auto body supply store and buy a clean-n-strip disc. Its a black 6in sponge looking disc, it does a great job cleaning rust pits. Today I bought a 3M Paint and Rust Remover disc. It is a sponge like disc that attaches to a drill type tool and is very course, equivilant to about 60 grit I assume. I tried it on a small area on the rockers and it seemed to cut the rust out of the pits real well. I went back over it with 80 grit on a DA and it looked fine.

It is pretty coarse and I am reluctant to do any more until I am sure that this is the right tool.

Here's a way to make sure the pits never bother you again, and it's simple. First, use the ice pick method to be sure the pits don't go all the way through. If they don't, sand or blast the metal around the pitted area, clean it with the purple stuff or Dawn dish liquid, and then etch it with a phospate based rust remover. Finally, give it two coats of POR-15. When it dries, scuff it lightly and then coat your roof with the epoxy primer.
I have used POR-15 for the last 10 years with never a single failure. The stuff actually works.
Good success.
Andrew Offutt

ccarney69, these are the clean and strip disc sevt was referring to just to make sure you baought the right kind.

"]http://products3.3m.com/catalog/us/en001/auto_marine_aero/automotive_aftermarket/node_GSDSSYWRKPgs/root_GST1T4S9TCgv/vroot_GSLPLPKL4Xge/bgel_464Q7MK40Rbl/gvel_GS66HQKGFZgl/theme_us _aad_3_0/command_AbcPageHandler/output_html] ( [url="http://products3.3m.com/catalog/us/en001/auto_marine_aero/automotive_aftermarket/node_GSDSSYWRKPgs/root_GST1T4S9TCgv/vroot_GSLPLPKL4Xge/bgel_464Q7MK40Rbl/gvel_GS66HQKGFZgl/theme_us_aad_3_0/command_AbcPageHandler/output_html) [/URL]

You can also spot blast the pits with a hand held blaster, warpage will be minimal to none if you do it in short bursts-I've done it this way for years. Run a metal file or long block over these areas to check for warpage-high spots before you prime. If you get all the visable rust removed the job will be fine.