Finish it assembled, doors and drawer fronts can be off.

 

Trying to spray the interior will be a pain on a piece this size, hence why I want to prefinish it.

 

Are the center dividers the issue? If so, make them removable and assembly the rest.

This piece really isn't that big. If your worried about one side setting up and overspray, use a retardant to slow it down.

 

Ive heard about people running into pieces warping if you only finish the inside as opposed to both sides, which is why im leaning towards finishing both sides at once.

The issue is im afraid of damaging the finish on the outside when I glue on the sacrificial blocks to help clamp the miters, even though the blocks will be glued on using the blue tape/CA glue trick.

 

I'm fairly certain you will damage the finish doing as you described, besides with the finish applied that trick might not even work. You will depending on the finish to hold the glue blocks. I would probably gamble on finishing the interior pieces, assembling, then finish the exterior. That is, if I was certain I couldn't do the interior after assembly.

 

I doubt you will have problems with warping if you pre-finish the interior before assembly, unless you leave the pieces sitting around for months or have big climate changes in your shop.

I prefinish my big projects and haven't had any issues. My approach is to get sealer on all of the pieces (that helps with glue squeeze out issues). After the sealer is dry and sanded, apply 2-3 coats of finish (Arm-R-Seal) to the interior pieces and a single coat to the exterior. The glue surfaces don't generally get any finish on them (mortise/tenons, edges). Glue up sub assemblies, complete finishing on them if finishing will be more difficult later on, then then glue up the final assembly and finish the exterior.

You might also consider using biscuits on the mitered corners to hold them in place so you don't have to resort to temporary glue blocks.

 

Post a pic of your design. I doubt you have to worry about warping. Thousands pieces that sizes are built without issue.

 

See the attached picture of the design. I was thinking of spraying the inside of both sides and top/bottoms, as well both sides of the center dividers. Then spraying the rest of the piece after glue up.

Thoughts?

 

Well, I don't see a picture…but I still think you're good to go with your plan.

 

I think for each piece of furniture, a debate could be had as to prefinish or finish after assembly. I almost always finish after assembly. I've never prefinished a large cabinet. I always finish those after the fact.

If the case has a removable back panel, I keep that off and finish it separately.
Doors and drawers can be finished separately as well.

If you get stain and finish on joint surfaces, they won't have much strength.
Overall, I feel the benefits of prefinishing are overstated, and it's not usually worth it.

Finishing part of the case now / and part later is a recipe for disaster in my opinion.

Best of luck with whatever you decide.