The Stovebolt Site Forums The Shop Area Paint and Body Shop I'm puzzled about something???

Greetings folks,

OK…so here is my dilemma: I’ve read lots of posts regarding media blasting versus sanding versus chemical stripping. This list is not all-encompassing, however, below are some of the key points that I gathered from reading all the posts and my own past experience:

Media blasting:
Time consuming process
Can be expensive if you pay a shop do it for you
Requires large volumes of air…and you must have all the equipment
Excellent choice for thick metals such as frames, axles, brake drums, etc.
Be careful with flat panels that could warp due to heat build-up

Sanding:
Time consuming process
Lots of sanding disks for the DA sander
Good for flat surfaces
Tedious on curved and raised areas of the body
Not the greatest approach of sanding multiple layers of paint to bare metal

Chemical:
Good technique that removes everything to bare metal (rust, old bondo, etc.)
Gets in all the nooks and crannies (inside doors, etc.)
Complete process as the whole part is dipped into a caustic bath.
Vendor will often coat with a phosphoric etch post dipping to retard flash rusting
Overall can be very expensive
May be hard to find a shop local to where you live
Chemical can leach out of seams and ruin a paint job (or so I’ve read)

So, let’s take, for example, a door on my 1964 C60. After I remove the windows and “guts” from the door I’ll be left with a bare door shell. So, I can media blast the outer surfaces and given the thicker sheet metal coupled with a cautious approach can easily obtain the desired results. But what about the inside of the door? How do I get the internal surfaces clean to bare metal? Or perhaps most folks merely do the outside surfaces only? In this instance, the chemical dipping technique seems to be the method of choice. However, do I really need to be that concerned about chemical leaching out of seams and metal folds? Or is that a very infrequent occurrence? True, I like the idea of dropping the doors off at a chemical stripper and later in the week picking them up…all down to fresh metal and ready for work; however, if chemical WILL leach out over time it would ruin the paint.

What have other folks done? Any past experiences using the chemical stripping technique versus the media blasting? If so, have you ever notices and chemical leaching that caused a problem later on in the process?

Any info would be appreciated. Thanks much…

The last place that performed this told me that there would be no checmical leaching. I would have gone to them as their work looked great"BUT"
darn was that expensive.

Unless you have a severe surface rust problem why not just sand the current coating down, reprime and paint. Nothing says you have to strip it down to bare metal. As for the internal surfaces, why worry about it? If you dipped it then it would just start rusting again since it would be trouble to coat those surfaces.

I've been media blasting the areas that I will be painting such as outer skins of doors, etc. In the nooks and crannies that won't ever see paint like the inside of a door I have been using Eastwoods Rust encapsulator. It can be brushed or sprayed if you reduce it.

My doors, for example, were blasted carefully on the inside and out, blown clean, and vacuumed. I made an attachment for my shop vac that plugs up the main big hose with an off shoot for a 1/2 hose that I can get up inside the doors to vacuum the remaining media out. I then coated the inside of the door with rust encapsulator. Came out pretty well. Other surfaces were treated in prep for paint. So far its been the best go at your own pace method I could find.

Matt

My local sandblaster guy has a heavy hand, he is used to tractors etc. & will warp up thin sheetmetal. Dipping too far away. Also I am poor/cheap/frugal/got two kids. On mine I stripped the outside/inside wDA 80grit(lock the sander,w/the door on sawhorses, it can be done fairly quickly), pressure washed the interior, after drying, do any metal patching; then I used Rust Bullet(encapsulator) brushed into the pinchweld, followed by brushable seam sealer Mine were coated well inside w/sound proofing, what didn't come off was allowed to stay. Epoxy primer both sides. I did this to my '79 in 2000(driver,sits outside), so far so good. It had had a door skin replaced(brazed on in 1980)once, & started rusting all around the pinchweld where they all seem to start rusting. Brian

Hi fellas...

Thanks for all the great inputs. The doors (that I used as an example) are in remarkably great shape. Yes, I have the "V" below the mirror from opening past the stop, but I'll pull that easily.

The point of my thread was to merely question which technique is the best to use...but it appears that it depends entirely on the shape of the piece you are working on, cost, time...the usual factors. I guess that perhaps I'm being too anal about the need to restore the "insides" of assemblies such as the doors.

Thanks for all the feedback fellas!!!