What primer should I use so that Bondo does not bleed through?

Zinser or Kilz primer should do the job. Good luck!

We found the best is aroma free Kilz primer. One coat then paint over it how ever you want! Great stuff!

Spraying the spots with Shellac should also prevent bleed through. :)

Zinnzer with Bin, I used this on my cherry cabinets. It has shellac in it, and prevents bleeding!!!

Nice job! Primer works by sealing the surface to prevent bleed. I do like Kilz because it doesn't allow spores to develop between the wood and primer. Works great for outside - just remember to use an exterior paint for the top coats.

Hi, would like to use Fushion Mineral Paint. Do you have any experience with this paint? Thank you!

The previous suggestions are good. Sometimes it is a texture issue rather than bleed through. I have used a couple techniques.

1) I think it is called glazing putty or spot putty, It is typically used for autobady repair. It is a very fine grained filler that comes in a tube, similar to tooth paste. Good news: it it provides an extremely smooth surface, filling in any scratches/small imperfections in the Bondo. Bad News: it take awhile (overnight) to set up before it can be sanded smooth with very fine sandpaper (220 or higher).

2 Use multiple coats of primer and sand with very fine sandpaper in between coats, before applying finish coats.

Good luck.

Kilz primer.

Kilz 2 is a bonding, stain blocking primer. I would use a rubber roller made for flat surfaces. You can get them at Home Depot of Lowes. You need to use exterior paint. I find SHerwin Williams [use a 30% off coupon] and Benjamin Moore make a great exterior paint. Expensive yes, but it lasts for years.

I think you should use a spray primer over the Bondo. You will not have a single brush stroke doing this.

Quick sanding with steel wool or very fine sandpaper might be needed if you were too heavy handed with the paint, otherwise you can literally spray and go (once it's dry of course). I honestly have not had the best results with Kilz or BIN 1-2-3. If it were me, I think I'd go with an exterior Rustoleum spray product. The have primers made to go over Bondo but you'll need to read the label or perhaps call them about your wood door. I really can't imagine it would be an issue though.

Since this is an exterior door, I would highly recommend Kilz original (oil based). Especially if it is exposed to the elements. Then use a good door paint. Sherwin Williams would be your best product in my opinion. If you can get there before end of day July 22, they have 40% off. But you can usually get 30% most of the time. It's worth the extra $ IMHO.

Kilz is made to hide stains. Check at the paint store counter for the best primer for under the type of paint you plan to use. It can make a difference to the topcoat.