fiberglassing procedure

It looks like your rings for  your speakers aren't even 3D. If the whole entire speaker box is made of MDF and you just want to paint it then you dont even need to glass the box to paint it. I usually just rough up the MDF  with some 120gritt to take the shine off so it will hold the primer, sand, primer, sand, priner, paint.  Sometimes i will use a little bondo or glazing putty to hide inperfections.

The whole point to stretching fleece is to create 3D designs. You can stretch the fleece to make any design you want. Once the fleece is glassed and you have the shape that you want. You add more layers of chopped matt either to the front or from behind in order to strengthen the form.

If every side on your box is MDF and you just stretched cloth over it with a coat of resin. I would just rough up the entire box, use a thin layer of bondo or glazing putty and start primer and paint. The resin and matt are only used to add strength.

Is that the answer you were looking for?

Correct on the procedure.

I can't see the wood in the pic very well but it looks like the wood that you are using is not MDF. With MDF you can't actually see little particals of wood that are glued together which you can in "project board". MDF is more or less just glue and sawdust; but it sure is great to work with! I believe thats why you are having the problem with the other wood soaking up all your primer. MDF wont hog up your primer but it does have a smoother surface that the primer wont even stick to unless you rough it up. Thats why I "take the shine off.

Whether you start over or not. Make sure you get MDF next time. Let us know if you have more questions.

Curious, what are you putting this in? It looks like a big box.

Wow... where to begin... I am sorry to say, but this one is going to have to start over. First I would start with making sure you have the right materials. MDF and fleece (or cheesecloth) would be the materials to get. It looks like you are using elastic-polyester or spandex material for this. Big no-no. unless you are mounting 5" speakers or smaller this won't hold up at all. If you are mounting subs, even 6.5" or larger definitely look for fleece. if doing 8" sub or larger expect to start layering F/G on its interior at LEAST 3/8" thick. From what I can see in the picture it does look like you have MDF. Just make sure it is at least 3/8" thick too. I prefer to go 1/2" to be honest.

Now it is a matter of construction of the box. Unless you are planning to do a bottom mount on the speakers, the holes for your box don't look like they will mount speakers. (if you are planning on doing the standard top mount installation read on, otherwise ignore the rest of this paragraph) Since you are mounting the speakers 6" deep in the front of the box, you need to make a ring sandwich that are the size of the speaker mounts.  Secure the inner ring to the position that you want to mount the speaker. Staple in the fleece and stretch it into place. before you begin glassing, mask the outer ring with masking tape. I recommend the green masking tape (I think 3m calls it their 355 tape) or if you can't find it, use the 14+day blue tape you can find at Lowes. (paint dept) mix and apply your resin to the fleece. While it is still fresh, put the outer ring in place and secure it with clamps. This will create a flat sturdy base for your speakers to mount.

I know I said some rather confusing things in here. I'll draw up some diagrams and hopefully can get it uploaded within 48 hours to better explain what I am talking about. I hope this helps. PM me if you have ?'s