paint prep help needed

[ToddK]

I have a car that is currently in a bare metal and bare fiberglass state. What's next? Is there a nice primer that will etch and show up the imperfections. The last car that I painted was about three years ago. I used a high fill grey primer and I was sure that the car was as smooth as glass. After I applied the paint, some waves appeared on the flat panels. I want to avoid that this time. Besides being more dilligent with the board sander, what else can I do to highlite any imperfections before painting?

[philv]

there is a spray on primer that you apply and then block sand. All

of the low spots will show up. It goes on in black so it showes up against

a light colored primer. I can't remember where I saw this. You might

want to check the Eastwood Co. web site.

[dubois]

the experts can "feel" the imperfections, waves or lack of straightness with the palm of their hands. It takes a lot of touch (no pun intended) to master it. The second way is to spray some slow vaporizing solvent, like prepsol, wax and grease remover, etc. (use a water bottle spray). The idea is to have the panel "shine" for at least a couple seconds. You can quickly peek, especially from the sides (not perpendicular) and see all the irregulaties in the panel much easier.

By the way, filling imperfections with primer is not an accepted practice, like we say: you shouldn't have the prepper do the work of the bodyman. There are limitations as to the thickness of the filler primer you should apply to a panel, that's is why they invented bondo too.

I know Sikkens had an sprayable bondo that worked pretty good, but most good bodyman never used it in the shop.

Good luck

Michael

[ToddK]

What should I do next? I know I have to use an etching primer on the bare metal. Can I put filler over the etching primer? I don't have much body work to do. I have taken alot of time blending the fiberglass into the metal. I will just need to spread a little filler and block sand before final primer and paint. On tv, I have seen them spray on a yellow primer before they start filling and sanding. What is that stuff and is there another step they are not showing? Someone give me an A to Z list of steps from bare metal to final buff. Thanks.

[winstontj]

Todd,

With Polyester based fiberglass start by taking organic peroxide (the hardener) and cut it 50/50 with acetone. Spray it on with a spray bottle or Preval sprayer generously. This will take care of any tacky spots on the surface. Let dry overnight or at least for a few hours. Wipe down with denatured/acetone and for both metal and fiberglass sand to 120grit. Wipe down with denatured AND second, wipe down with acetone. It's important to follow up with the acetone because it will really clean out all the skin oil as well as machine oil that comes out the exhaust of pneumatic tools.

Use a "High Build" type primer. Look at www.ppgcarpaint.com and type in "mp181" in the search. Any two part epoxy-based high build will do and this is a good example. Apply exactly as the MSDS sheets say - meaning no "capping" or "hot pots". You want this stuff to dry slowly because it dries like CONCRETE. Here comes the fun part....

Ever hear stories of how the Italians used to hand build aluminum race cars? They would come out with buckets of Bondo and pour it on then about 10 guys would block sand till it was smooth...

You want to sand the high build before it's dry. It’s just right when you can scratch/dent the paint with your thumbnail but not your fingernails. You're going to burn through A LOT of sandpaper because the high build isn't dry and it will gum up the paper quickly! We used to spray at about 6pm and then come in the next morning around 8am for the sanding party. Buy a gallon of DYKEM staining fluid and cut it 50/50 with denatured, this is the best stuff on the market. Rub on with a rag and some good gloves - this stuff will stain anything and everything including skin. You can buy DYKEM at MSC Industrial Supply www1.mscdirect.com its item #02598902 or just type DYKEM. (I'll split it with you if you want because it goes a long way and they kill you on shipping) The high build comes in yellow, white or grey, the DYKEM is best in dark blue. Take an old rag and wipe it on and start sanding. Wet sanding is usually easiest but if you are at risk of break-thrus to bare metal then it’s best to dry sand with a block. Buy a 3M # 05520 8” sanding block and have at it. Take some 3/16” foam and some spray adhesive and stick the foam to the pad under the sand paper. This will give you a better, smoother finish. Sand until the DYKEM dye is all gone. Start sanding with 80grit and then go down to 120grit when the orange peel is gone. At this point you can mix up a small “hot batch” cup full of high build and fill pinholes with a popsicle stick DO NOT use Acrylic pin-hole-filler as it shrinks over time and will turn all of your efforts to crap in a few years. Once your surface is prepped to 120grit let it sit overnight and then wipe down with prep solution supplied by the paint manufacturer, use a tack cloth for final wipe-down and prime. Sand, spot prime and paint.

Buy the 3M Imperial brand (gold back) sand paper. It will be worth it as it cuts better and lasts longer. My brother works at a distributor and has access to all this stuff really cheap. Email me when you’re ready to do this and for the cost of lunch/beer I’ll be happy give it all I’ve got for a weekend. (With the good arm)

Hope that helps.

TJW

[DukeRimmer]

When you are looking for straightness of a panel using high gloss reflection, look for a florescent light. They provide both brightness and straight edges.

[esty]

from bare metal....top with,

1. epoxy primer

2. do any body work needed [bondo, etc]

3. 2k filler primer

4. block flat

5. paint

there are no epoxy "hi-build" primers..epoxy isn't meant to fill, but seal and protect against rust

[ToddK]

Thank you esty, I knew you would make it short, sweet and easy to understand. Off to buy some epoxy primer. Can I leave the car primed that way for a long time in the garage? This project is not a priority, and sometimes it will sit for months on end without any work being done to it.

[winstontj]

Do a google search for: "high build Primer" without quotes or: http://www.google.com/search?hl=en&q=high+build+primer

and you will see Results 1 - 10 of about 7,750,000 for high build primer. (0.43 seconds) many, many, many high build primers in epoxy, polyester and acrylic. Epoxy based high build primers are very standard in the marine, aviation and automotive paint industries. They are just regular primers with colloidal silica as a thickening agent.

I'll be happy to forward you a bunch of information on paints and applications if you are interested. Let me know!

TJW

[Tiger75]

I would add one step. after bondo( i would use all metal) sand , and then put a layer of epoxy primer on the repaired areas. This is called sandwiching the repaired areas with epoxy primer. Then go with 2 k primer. The last coat of primer could be tinted with 5 % of your base coat color.

[Tiger75]

(nt)

[esty]

Thank you esty, I knew you would make it short, sweet and easy to understand. Off to buy some epoxy primer. Can I leave the car primed that way for a long time in the garage? This project is not a priority, and sometimes it will sit for months on end without any work being done to it.

yes...you can leave it in epoxy indefinately...however, if left that long, you'll have to scuff it with something like 600 or a red scuff pad before moving on to the next step...

....you gonna do it yourself? if so be sure to look at smartshopper.com for the primers...best price anywhere

good luck

[esty]

I'll be happy to forward you a bunch of information on paints and applications if you are interested. Let me know!

TJW

i don't doubt your search results at all, however "hi-build, sanding" primer commonly available in auto finish products is either urethane or polyester....

it makes no sense to send someone on a wild goose chase for something he doesn't need, would cause more work and cost a small fortune to boot

[canadamatt]

there are no epoxy "hi-build" primers..epoxy isn't meant to fill, but seal and protect against rust

Kirker makes a nice sandable epoxy. Not really called a full high build, but from what I read fairly close. I used it once and it seems pretty good. Its pretty popular on autobodystore.com.

Matt

[esty]

Kirker makes a nice sandable epoxy. Not really called a full high build, but from what I read fairly close. I used it once and it seems pretty good. Its pretty popular on autobodystore.com.

Matt

it is a very good product...it's what i used...but again, it's not intended as a filler and would not do the job...you'd need the perfect prime 2K urethane primer for final blocking, b4 paint

if you ever need objective info from the pro's go HERE

len stewart at autobody has one agenda...sell, sell, sell, sell ...what's needed is what he can sell you or what you want to buy