Noticed after i bought the car which generally looks great. Bottom of passenger door bubbling paintwork. Can't see any scratches or holes. Will it get worse? How can i cure it, or at least stop it getting worse.

 

Most likely, if it is rust and not just a bad paint job.

The only way is to get the bubbling paint off and see what is underneath. If it is rust you will need to get as much off as possible using a coarse grade sandpaperthen treat the bare metal with an anti-rust liquid. The next step is to 'feather' the existing paint using a medium to fine grade wet and dry paper with plenty of water. Dry the area completely with heat, not just a leather or towel. I use a hot air gun but a hair dryer works just as well. If it is rust and the metal is pitted put a thin coat of cellulose putty on the affected area. When it is dry rub it down lightly with a fine grade of wet and dry paper so that you only leave the putty in the piited areas. Again dry with heat.

Now the fun part. Mask off all the parts, near to the area,you don't want to spray eg sill, other door on the passenger side, wing. Using a high build primer, spray the bare metal and just onto the existing paintwork. Use at least four light coats allowing each to dry for about 20 minutes before applying the next. Next step is the colour coat. Again at least four coats and 20 minutes between. When you are happy with the result remove the masking paper and just leave it to harden. Do NOT use a car wash, nor a jet wash,for at least 6 weeks as the paint may peel off.

If this is too much for you, you could check with a body shop to see what it would cost to have it done professionally.

 

Thanks Bill
Think I might check with a body shop. Sounds too easy to make a right mess of.
Strange though as the car is perfect in every other way. And i can't think why it has a problem there.