acid dip?

Post by **les** » Wed Nov 12, 2008 10:16 pm

I've got 3 doors that I need to clean up to decide the best one, I'm thinking of acid but wondered if this is too expensive to get all 3 done. Has any one used this method before that can advise?

Post by **jonathon** » Wed Nov 12, 2008 11:08 pm

Acid dipping is probably the best route to take to fully strip a car/door etc to bare metal. It will remove everything including the rust. However this can be just the start of a process of refurbishment, ie it will show every possible fault with the steelwork.
We normally dip cars/panels, have them back ,weld them up ,then have them re dipped and E coated. Do not have the parts you have dipped etch primed, as this will only reach the parts that the gun can reach, the E coat is an electrphoretic process and will cover every surface that has been acid stripped.
This process is perfect for all bodywork but cannot penetrate where two parts are spotwelded together, so any rust in these areas will stay there and probably develop further. We view it as kinder that shot or media blasting and probably the only real way to secure longevity of the steel. The downside is cost, and the small number of companies providing this service. We use SPL in the Midlands, but they currently have a 6 month waiting list.

Post by **MartinB** » Wed Nov 12, 2008 11:17 pm

Les,

I have had a Hillman Imp shell acid dipped, what looked to be a tidy shell came back with a lot more holes in it than I thought it had!

You may well find you have three doors which are no good.

Acid dipping certainly finds any rust but repairing them afterwards may prove more difficult depending upon thickness of metal left.

On a cautionary note, if anyone is thinking of getting a shell dipped, beware how the shell is lifted in and out of the tank. Some places lift the shell by the roof (strop through door/window openings) which will result in a bent roof due to the weight of the water within the floorpan and sills when lifting out.

Jonathon is spot on about the etch priming, you end up having rust developing again in the seams within months.

Wouldn't it be better if you fitted a new door skin and repaired a door so you definately know you have a good one? Probably much cheaper to use paint stripper to investigate the condition of the doors first.

Regards

Martin

Post by **les** » Thu Nov 13, 2008 7:40 pm

Thanks for both your replies, which deserve a further explaination. The doors in question, well two of them at least are virtually rust free, which as you know is pretty rare! The downside is they have many dents. I noticed one dent in each door, although extensive I kidded myself that was ok, so I bought them.
Each door had a weird protective paint on them that turned out to be an effective disguise for many more dents! So thought the best thing to do was get them stripped to see clearly whether to scrap them.
They are lcv doors and I don't think skins are available, but I think you may be right about paint stripper as I feel they may be scrappers in the end, so acid may turn out to be an expensive option.

Post by **bmcecosse** » Thu Nov 13, 2008 7:52 pm

I would strip them off with paint remover and/or heat gun/blow torch - backed up with angle grinder/wire brush where necessary. Then survey the doors very very carefully before worrying about acid dip.

Post by **alex_holden** » Thu Nov 13, 2008 10:45 pm

les wrote:They are lcv doors and I don't think skins are available, but I think you may be right about paint stripper as I feel they may be scrappers in the end, so acid may turn out to be an expensive option.

Don't scrap them! I'm sure somebody would be happy to take a couple of battered but rust-free doors.

Post by **minor_hickup** » Thu Nov 13, 2008 10:55 pm

Jonathon, do you remove the e-coat on surfaces that are to be repainted? I've been told by a couple of sprayers that a lot of paint manufacturers reccomend doing this as the e-coat is so hard you cannot etch it properly and it can cause problems in the future!

Post by **jonathon** » Thu Nov 13, 2008 11:08 pm

No, the ecoat stays on but is just keyed to accept primer. You should not etch prime e-coat this is probably what is causing the problems as they react against each other.It would be wise to roughen the steel surface ( remove the e-coat if you are going to apply filler.
E-coat is used by most car manufacturers, our are coated on the Aston Martin line, so there shouldn't really be a known issue with paint if its applied correctly.