100% N00b Preparing for First Filler Job - VW Ute

[Lex4TDI4Life]

I am getting ready for my first attempt at doing any body work. This is not a repair job, rather it is finalizing my 2001 VW Golf TDI --> Smyth Ute Conversion. My build thread is here, but long story short:

This:
IMG_20191109_110125_exported_7115301637130700516.jpg

Is now currently this:
IMG_20191220_125629.jpg

It is time to permanently affix the fiberglass body panels to the frame and, therefore, my first adventure with using body fillers. There are several places I will be using filler:

• Window surround to the roof
• Quarter panels to back edge of door frames
• Bumper to quarter panels
• Side skirts to quarter panels and frame under front door

Essentially, I am hoping y'all can check my plan and see if I have any blind spots. I do not plan on this being a professional-quality job. This will not be a show car. I just want to get it decent shape for, most likely, a wrap job.


After much reading, I have decided on using two different fillers, depending on the location. For the window-roof and quarter panel-door frame jobs, I will be using Rage Xtreme because those areas are more cosmetic than structural and will not see much flex. For the bumper-quarter panel and side skirt jobs, I will be using short strand fiberglass filler.

I started my prep on the window-roof piece by sanding down the back edge of the roof with a 36 wheel grit on an angle grinder. I then reinstalled (friction fit) the window surround. These pics shows the sanded edge with the fiberglass window surround in place:

PXL_20201108_215226236.jpg

PXL_20201108_215226236.jpg

I am using Rage Xtreme on this section and will sand using 36, 80, 120, and 180 to finish, using guide coat along the way. I will use polyester putty as my skim coat. I have a couple questions:

1. Do I need to sand the fiberglass as well? I would assume so, but would rather not if I do not have to.
2. Did I sand enough of the roof down to the bare metal? It's about 2" at the moment.
3. How long can I leave this untreated/unprimed?
4. Am I missing anything?

Thanks in advance!
-Lex

[Len]

Hi Lex welcome aboard.
I have a couple of questions before I start answering yours.
1. Are the metal panels welded in place?
2. Is there a chance that moisture can get to your filler from the back side of the seams?

Answering some of your questions....
1. The fiberglass should be sanded so that it has the ability to bond with the filler.
2. The 2" that the metal is sanded may be enough if it doesn't need filler to go any further back.
3. Depending on the storage conditions you may be able to leave the metal unprotected for a while but moisture can cause rust very quickly.
4. My guess is that you're probably missing something if this is your first attempt at this type of modification so take your time with each step.

[Lex4TDI4Life]

Hi Lex welcome aboard.
I have a couple of questions before I start answering yours.
1. Are the metal panels welded in place?
2. Is there a chance that moisture can get to your filler from the back side of the seams?

Answering some of your questions....
1. The fiberglass should be sanded so that it has the ability to bond with the filler.
2. The 2" that the metal is sanded may be enough if it doesn't need filler to go any further back.
3. Depending on the storage conditions you may be able to leave the metal unprotected for a while but moisture can cause rust very quickly.
4. My guess is that you're probably missing something if this is your first attempt at this type of modification so take your time with each step.

Thanks for the warm welcome. The roof and frame are all stock and welded in place. For at least the bumper, there is a chance for water to get into the back of the seams. The others should be shielded from water.

Is there anything I could apply to remaining bare metal temporarily until I can get this thing wrapped?

[Len]

Thanks for the warm welcome. The roof and frame are all stock and welded in place. For at least the bumper, there is a chance for water to get into the back of the seams. The others should be shielded from water.

Is there anything I could apply to remaining bare metal temporarily until I can get this thing wrapped?

To protect the metal you can apply epoxy primer now then sand or grind it off before continuing your repair.

[Lex4TDI4Life]

To protect the metal you can apply epoxy primer now then sand or grind it off before continuing your repair.

Excellent. Thanks for the quick and knowledgeable reply!

[Henry]

Excellent. Thanks for the quick and knowledgeable reply!

Been following what you've posted and I have a concern for you. When any vehicle drives over certain ground such as a raised APRON of a driveway or parking lot (where ever) the body TWISTS. Concern is your patch of fiberglass to metal will twist and help to create cracking in that area. Hate to see your project completed, looking so sweet and have this happen going forward.

Just a thought before you get too far along. I do like what you're doing. We certainly don't see those everyday and I wish you well with it and glad you're onboard to share it!

Henry