Eta-to-M50: Build thread

[dirtysix]

On sanding, get yourself a flexible sanding block for the rounded surfaces, I use 60 grit for the first shaping sand and then use 100 for the second and finally 180 for finishing the filler.

If you get it right and avoid mixing air bubbles into the filler you wont need to use glazes or anything but a primer surfacer.

[ck_taft325is]

I always ended up putting 220 on the final sand before a guide coat of high fill primer.

180 is probably far easier.

[Jand3rson]

Ok, here's a question. The spot on the wheel well, below the shock tower on the passenger side, has been taken back down to bare metal, no JBW was used there. The area on the bottom of the wheel well (lower washer bottle bracket), as well as the area of the wheel well on the driver side (AFM/airbox bracket), are the 2 areas where I skimmed them with JBW to fill the pinholes/cracks. The JBW in those spots dried rock-hard, I'm talking "hard to mar them with the putty knife" hard.

If I take a sander to those 2 JBW'd areas, can I just take those flat, and do my prep on top of the JBW? Taking those spots back down to bare will be REALLY difficult. I know that JBW isn't supposed to be used as a filler, but I was only using it to fill the tiny pinholes/cracks left by the welds, and it worked for that purpose.

[dirtysix]

Without knowing much about JB weld, I think you would probably be fine as long as it's roughened.
If if it doesn't stick you'll soon know when you're sanding the filler as the edges of it wont feather nicely.

[Big Willy]

Without knowing much about JB weld, I think you would probably be fine as long as it's roughened.
If if it doesn't stick you'll soon know when you're sanding the filler as the edges of it wont feather nicely.

Basically you just need to create a rough enough texture for the body filler to stick to, with bondo I would suggest 60 grit, with evercoat or an equivalent product use 180 grit to create the need texture.

[e46s54dr]

So, if I take those areas down to bare metal, in a few of the spots where the welding was done, I'm going to be left with several tiny pinholes and tiny cracks. What do I do about those? The welding we've done to this point is as good as it's going to get, because the welder just keeps burning through the sheet metal because it's so thin.

What kind of welding machine are you using? Is it mig or flux core? If you are welding sheet metal, I suggest you use anywhere between a 0.020 to 0.025 wire so you don't burn through.

[Jand3rson]

Awesome, thanks for all the help, everyone. I've got the 2 areas on the pass. side taken back down to bare metal and/or JBW, and tomorrow I'll do the driver side, and get back at it.

[gmyers395]

IMO use the evercoat metal glaze oem. Its used to fill scratches and pinholes on bare metal that has not been prepped like yours. Finish all body work with 320, the reason for this is so you do not have to use filler primer to get rid of any sanding scratches. The reason you don't want to use filler primer is because you would have to sand all of it and this is the engine bay, it hardly needs to be perfectly straight, you just don't want a bunch of scratches. After the metal glaze use etching primer on all areas that are bare metal, otherwise no paint or regular primer will stick for any length of time. After the etching primer use sealer and paint and that's it. Also the entire engine bay should be etched, sealed, and painted at the same time. You don't want a bunch of different spots painted at different times. And finally, all of the etching, sealing, and priming need to be done in one night, otherwise you will have to prep the entire bay after something dries to get the next coat of product to stick.

List of things to do:
1. Finish all body work that needs to be done.
2. Prep the entire engine bay, this means scuffing all surfaces, nooks, and crannies that are going to be painted. Don't half ass this portion because it is probably the most important. One good rule of thumb is that if it is shiny, paint wont stick. It doesn't have to be absolutely perfect but should definitely be the most time consuming step.
3. Once everything is prepped, clean it. There is a product called wax and grease remover that you should use. It does exactly what it's title says. I'm not talking about grease from an engine either because that should already be cleaned off. This removes oils from hand prints and all other contaminates. It's important.
4. Tack everything. With a tack rag.
5. Now your ready to start spraying in this order. Etching primer, sealer, paint. Use single stage paint so you don't have to spray clear. This step should probably take an entire Saturday especially if you have never done extensive refinishing. All products will have instructions like mixing ratios, flash times, the window for spraying another product over the top and having it stick, how many coats, etc.
6. Drink lots of beer because you have earned it. Let the paint completely dry for about a week before you mess with it again. It takes a while for all of the solvents to evaporate and even longer because it probably wont be baked in a paint booth.

So that's my advice. Take it or leave it. My dad painted for fifteen years and now manages one of the top body shops in Colorado so I have been around the process all of my life and have done lots of work myself including a color change on my e30 two years ago.

[yberther]

Pro Tip: Use an OV mask if you use polyester based primers :up:

[FredK]

What kind of welding machine are you using? Is it mig or flux core? If you are welding sheet metal, I suggest you use anywhere between a 0.020 to 0.025 wire so you don't burn through.

The wheelhouses in the front are paper thin and are pretty hard to weld!

Most pinholes shouldn't be too difficult to plug, but some areas are very difficult to access, especially if you want to back them up with a copper spoon.

I shaved the brackets off my car, but now it's too cold to paint! :neutral:

[nando]

anyone manage to shave off extra brackets without welding?

[ck_taft325is]

I've seen it done but it takes an ungodly amount of grinding very, very gently.

[jackbenny]

You should use "evercoat z-grip" and when your done with that you should use "evercoat metal glaze". Then when your done you should use a high build filler primer. More than likely going to be a polyester base primer. Then rub a guide coat on it and sand all the panels. Then when your done sanding, you use the metal glaze again in spots missed and spray another coat of the filler primer and wet sand it. By this time you should of got everything and be ready for paint. I would use an epoxy sealer. You should get black of course. Then spray your color and clear.

tada. Thats what I did with my black car and the same thing with the sepang e30.

This as well. I used both products on my build including my engine bay and was pleased with the results. I do of course look forward to seeing your results as well. :)

[FredK]

anyone manage to shave off extra brackets without welding?

Yes. I used a spot weld cutter to remove the M20 coil bracket, the AFM bracket, and the M42 coil brackets, then used a die grinder with a 2" flap wheel to gently remove the nubs left from the spot weld cutter. The AFM bracket was kind of tricky because IIRC it has a seam weld at a few spots but I just used tin snips to gain more accessibility.

I plug welded a late model expansion tank bracket to my wheelhouse on my 318is. This was fairly difficult because of the thin metal in that area.

[Jand3rson]

Alright, I got the Bondo today, along with a pack of spreaders and some primer. I'm going to strip the driver's side area back down tomorrow, and then get back at it. It's going to be beautiful.