PDA

View Full Version : Prepping for paint - Harder than it looks



Basil
01-18-2005, 01:09 PM
Over the past couple of weekends, I have been wet-sanding my 90 Nissan Pickup to prep it for painting. The truck is metalic maroon with clear coat. As happens with many metallic red paint jobs, the clear coat has been deteriorating over the years and now the truck has huge ugly blotches all over it.

SO, I have decided to take this opportunity to try my hand at painting since my local Air Force base auto shop has a paint booth I can rent. I can tell you, prepping a 14 year old truck for paint is no small task! I have been sanding until my arms feel like they are going to fall off! But I must perservere!

If this paint job comes out well, I want to take a stab at re-painting my new Daimler SS. The paint on that looks good at a distance, but when you get up close its obviously done in a hurry and very poorly.

If I do paint the Daimler, I want to strip it to bare metal and have any and all body work done properly. What's the best method for stripping to bare metal without removing the body and dipping it? Remember the body of this car is aluminum (the wings (fenders) are steel).

Basil

waltesefalcon
01-18-2005, 01:29 PM
You mean other than sanding? I think blasting might be too abrasive on aluminum, but it would work well on the fenders, or as you high brow Daimler owners say, wings.

PC
01-18-2005, 03:12 PM
[ QUOTE ]
Prepping for paint - Harder than it looks

[/ QUOTE ] Yup. That's why a good paint job costs so much. Prep is the most time consuming and least entertaining part or a profession paint job (and the most important). The actual shoot is the fun part.


[ QUOTE ]
...I have been sanding until my arms feel like they are going to fall off! But I must perservere!...

[/ QUOTE ]Are you using power tools?


PC.

Keoke
01-18-2005, 05:46 PM
Yo Basil, very messy but "Aircraft Stripper" will do the job and you can do it a panel at the time. You will need rubber gloves,Safety glasses and a long sleeved shirt.If it gets on your skin it will -"Bugger" burn.---Keoke /ubbthreads/images/graemlins/laugh.gif

Basil
01-18-2005, 10:10 PM
[ QUOTE ]
Yo Basil, very messy but "Aircraft Stripper" will do the job and you can do it a panel at the time. You will need rubber gloves,Safety glasses and a long sleeved shirt.If it gets on your skin it will -"Bugger" burn.---Keoke /ubbthreads/images/graemlins/laugh.gif

[/ QUOTE ]

I actually used that stuff once - what a mess! And you also need an air breater as the fumes will make you higher than a kite! That might be an option though. But I thought you could do bead blasting without hurting the metal if you used the right media?

Basil

01-18-2005, 10:36 PM
If any of you use Naval jelly, or as someone called it "aircraft stripper", please do use breathing and skin protection. The active ingredient in these products is methylene chloride, aka dichloromethane, which is on the federal governements list of known carcinogens. I'm a chemist, and I used straight methylene chloride as a solvent extensively for the extraction and concentration of environmental samples for the first 4 years of my career. I have intimate knowledge of what that stuff can do to your skin, eyes and other sensitive parts of your body, not to mention the cancer risk. Also, do not use rubber gloves, as methylene chloride will go right through it. Nitrile is slightly better, they last a little longer, but it will work it's way through that eventually as well. Use polyvinyl gloves, they offer the best protection. Don't bother with those surgical type masks, they are only for particulates, you need a full face sealing mask with chemical cartridges to be fully protected against fumes. If you don't have that just work in an extremely well ventilated area and take lots of breaks. These products do work well though. I used to take my car parts into my lab on weekends and strip and degrease them in our fume hoods using the straight stuff. Talk about making quick work, I could strip 3 coats of thick paint in 5 minutes. It is probably also the best degreaser known to man, that and freon. You name the solvent, chances are I've used it more than I care to think about.

Here's some data on this compound if anyone is interested:

https://www.atsdr.cdc.gov/MHMI/mmg14.html

https://www.denison.edu/sec-safe/safety/msds/methylen.html

Eric
01-19-2005, 12:57 PM
Basil - two words: air sander! Power tools were invented for a reason - so you don't end up with arms that can steer an 8L Bentley at rest!

Are you sanding to make the surface nice and smooth or to strip paint? If you're stripping, there's a 3M abrasive disk/wheel that looks like a congealed mass of thin plastic spaghetti (forget what its called)that does an excellent job and is gentle on metal. Your local auto supply probably has a bunch lying around - much faster than sandpaper.

Edit: Scotch Brite Roloc is the stuff

trrdster2000
01-19-2005, 02:13 PM
Basil, I have not been long through with my Roadster on the painting and as you know it was aluminum body and steel wings. I used Kutzit from Lowes and it did the best. It did take a couple of coats on some items, like the wheels and it struggled with the original primer, (the dark brown stuff), not a bad smell. You will need to scarp it off with a razor blade or puddy knife and a good wire brusch. I cleaned each area with lacquer thinner as I went along then did the whole car in Barcoat before painting. I found this was also preferred by all those around, no dust. Wayne

PC
01-19-2005, 06:54 PM
[ QUOTE ]
If any of you use Naval jelly, or as someone called it "aircraft stripper"...

[/ QUOTE ]Naval Jelly and Aircraft Stripper are not the same thing.

Naval Jelly (https://www.henkelcamsds.com/pdf/01-80276.pdf) is a rust remover whose primary active ingredient is Phosphoric acid.

Like Dotanukie said, traditional Aircraft Stripper (https://www.uschem.com/msds/495-Aircraft_Paint_Stripper.pdf) is awfully nasty stuff. I would encourage anyone to avoid it if at all possible.

Bas, the need to cut back on the use of nasty chemicals has led to the development of a lot of new products. Check with the local aviation crowd, they might be able to lead you to a painter who can give you the lowdown on stripping aluminum.

I would be very wary of media blasting unless the blaster had extensive experience with delicate aluminum panels (i.e. does aircraft).

Here are a couple of manufacturers' websites who make environmentally friendly paint strippers:

https://www.eldoradochem.com/environmentally-compliant-strippers.htm
https://www.m-tc.com/efs2500_home.htm
https://www.biowash.com/products/product.php?pid=5

Here's an article from Eldorado Chemical (https://system.netsuite.com/core/media/media.nl?id=1122&c=ACCT67767&h=d75e36690059c2137b1 4&_xt=.pdf) on using their chemical strippers for aircraft.


PC.
/ubbthreads/images/graemlins/hammer.gif /ubbthreads/images/graemlins/hammer.gif /ubbthreads/images/graemlins/hammer.gif

01-19-2005, 08:20 PM
[ QUOTE ]
Naval Jelly is a rust remover whose primary active ingredient is Phosphoric acid.


[/ QUOTE ]

Oops, thanks PC for the correction, Naval Jelly does indeed use both phosphoric and sulfuric acid. It's been a long time since I've used that stuff. I distinctly remember using it to remove rust from a pair of chromed motorcycle wheels, back when I was 16. It's been a long time...

Anyway, unfortunately in my experience, the safer, more environmentally friendly strippers and solvents just don't have quite the same effect. Or, more accurately, you need to use more of them for a longer period of time. This is based only on the off the shelf stuff you can buy at Home Cheapo and the like. I haven't used any of the industrial grade stuff like what PC has listed from Eldorado Chemical. However, if you read their info they admit that their product is not quite as potent, but it will stay on the part longer and thus let you apply and walk away while it does it's thing, even overnight. If that potentially adds a few more years onto the end of my life then it's well worth having to let it sit overnight to eat away the paint.

Keoke
01-19-2005, 09:25 PM
Thank you very much PC!---Keoke /ubbthreads/images/graemlins/thumbsup.gif

Bugeye58
01-19-2005, 09:37 PM
Basil, I used to be able to get some stripper, that when you applied it, you could actually <u>hear</u> it work! It sounded like frying bacon. Alas, those days are gone.
But, a few tips to make things go easier using the available, "over the counter" type chem strippers today.
Break the surface of the existing paint with sandpaper. Cheap, Home Depot style 80 grit garnet paper will work fine. This allows the stripper to get to the softer, non oxidized paint, and will help a bunch.
Only work about 1 square foot at a time, and after applying the stripper, cover it with a piece of Saran wrap. This slows the evaporation, and concentrates the stripping action.
When brushing the stripper on, only brush in one direction. Don't go back and forth as if you were painting. I know it sounds strange, but it helps.
Jeff

Keoke
01-19-2005, 09:52 PM
No Jeff, That is "Aircraft Stripper" available at most Auto Paint Suppliers. What is sold at the home stores and discount auto places is a watered down version but better than the environmentally friendly stuff. On the otherhand, grinding paint off is about as mesy as sand blasting in the back yard.FWIW---Keoke

Bugeye58
01-19-2005, 10:25 PM
Keoke, I use "Tremco Aircraft Stripper" that I buy at the airport. Not the watered down stuff that you get at home stores. It is nowhere near as potent as the stuff I was using 10 years ago. The stripper I used to get had a plastic inner liner in the can. It <u>would</u> eat through the metal of the can if the liner wasn't there.
As you know, the primary active ingredient is Methylene Chloride, and I think the EPA forced a reduction in the concentration.
The all time best stripper I ever used was "Turco", used by the Navy to strip the paint on board ship. That stuff was awesome, but almost violent in it's reaction.
Jeff

Keoke
01-19-2005, 10:50 PM
Wot Jeff, /ubbthreads/images/graemlins/shocked.gif no body gave me anything but a scraper and a chipping hammer what Navy was You in. /ubbthreads/images/graemlins/laugh.gif--- OH! I almost forgot they did give me a bucket full of Zinc Chromate.---Keoke /ubbthreads/images/graemlins/devilgrin.gif-PS "Aircraft Stripper" now comes with an evaporation retardant built in.

Bugeye58
01-20-2005, 07:22 AM
Keoke, I was in the Air Force, but we "liberated" some of the stripper from the Navy.
The built in evap retardant is behind the rationale for only brushing the stipper on in one direction.
Jeff

Basil
01-20-2005, 02:55 PM
AFter reading all these suggestions, I got to thinking. I could take the bonnett, doors and boot all off and have them dipped, then I'd only have the main body (aluminum) left to contend with.

Basil

Keoke
01-20-2005, 06:20 PM
Well Basil, That sounds ok,but since the car will be almost to bits why not take the Wings along too? Then all is left is the Aluminum bits---Keoke