sandblasting, good move??

[tomcat]

well I have gotten to that point where i can begin to get some work done on one of my GT's. some opinion is that sandblasting would leave 9 million little dents, or they cannot be trusted to clean it properly before primer. Personally I would much rather go with a non-original color and want to blast it. another opinion is it ought to stay the original yellow. so being inexperienced i need to get some expert opinions from some of you. this one i intend to use as a dailly driver but also do a quality restore on it.

[Johnvan]

I prefer sandblasting to remove rust where needed. A sandblaster that is too strong will warp flat body panels and can create damage but is great for frame blasting.I use a smaller preasure pot sandblaster(a cheaper siphon feed will also do) with powdered glass as it gets all the rust out and doesn't warp the sheet metal.Soda blasting tends to not remove all the rust from the pores and granite is heavy, dusty and can cause warping.Then it should be coated immediately with epoxy primer as surface rust begins very quickly and is not always visible by eye. Filler work can be done on top of the epoxy which further prevents rust.Epoxy is the best for rust prevention and adhesion both underneath and on top but can be expensive.It also is a good sealer on top of fillers. Self etching primer may also be used instead of epoxy on bare metal but is not a good base for fillers and epoxy is better for adhesion.
Good paint does not have to be removed and can be sanded ,chemically washed and painted or sealed with epoxy to prevent any reaction with the top coat.Paint can be removed by sanding or chemically stripping if required.
A colour change is not a problem but involves more work depending on the quality you are looking for. Generally a quality colour change requires shelling the car so all edges showing the old paint won't show or a lot of expert masking. Colour change can look cheap if not done correctly and can therefore depreciate value.
I hope this helpsJohn

[kwilford]

I totally agree with John. I had some panels soda blasted (hood and headlight buckets) and they turned out terrific, but after I had essentially sanded the paint off, I had the rest removed with sand blasting. There's some photos at
http://www.opelgt.com/forums/139612-post6.html
And yes, be VERY careful of excessive pressure. When it was blasted, I thought he had been very careful, and perhaps he had, but I did have to do some panel beating to undo some warping and "oil canning" caused by the blasting. But the sand DEFINITELY did a better job of removing rust than the soda blast

[saxybiker]

When we started our project, we stripped the car down to a rolling shell and took it to a sandblaster. He did the outside and underneath of the car. It was well worth it. No problems with the metal from the blasting.

Vickie & Allen

[opelspyder]

Its all in the approach if they will warp the panels or not while sandblasting. Ever thought of having it dipped? The only problem I have with sandblasting is the fact you NEVER get all the sand out unless you can put it on a rotisserie and keep rotaing it...even then it is tough
Keith

[markandson]

Originally Posted by opelspyder Its all in the approach if they will warp the panels or not while sandblasting. Ever thought of having it dipped? The only problem I have with sandblasting is the fact you NEVER get all the sand out unless you can put it on a rotisserie and keep rotaing it...even then it is tough Keith

Yup, mine was done on a rotisserie and I am still finding sand in the nooks and crannies when I work on it, but overall sandblasting is the way to go if you have it done by and experienced shop, or if you know what you are doing and do it yourself. I have a different opinion about the first paint to go on after blasting, I would go with a good self etching primer. Since rust begins immediately after blasting a self etching primer will go right through the rust that you can't see and bond to the metal, then do your fillers, guide coat, sanding, priming and finish painting with products of your choice.

[tomking]

Originally Posted by opelspyder Its all in the approach if they will warp the panels or not while sandblasting. Ever thought of having it dipped? The only problem I have with sandblasting is the fact you NEVER get all the sand out unless you can put it on a rotisserie and keep rotaing it...even then it is tough Keith

I had my kadett body dipped and it is expensive. $1400 two years ago and I had to take it to Indiannapolis In. No warping for sure, but have to take great pains to get primer back everywhere it once was before painting. Need a rotisserie for that, which I made.

[Johnvan]

Heavy blasting is as good as the guy doing it. The material has to be "shaved off " at an angle. Heavier materials such as granite or steel media has replaced silica sand which has been outlawed, at least in Canada for health reasons. Heavier media creates heat which can also cause warpage. I use #60 grit light crushed glass media which will get out the rust and will also strip paint on a flat panel without warpage and can remove sealer or filler if you want while providing a fine surface for primer.I can even use it on aluminum without damage.
I have received many acid dipped parts from customers which tends to over-thin the metal and traps corrosive chemicals both on the metal surface and in between panels and usually won't remove all the rust without seriously thinning the metal. Companies generally don't neutralize the acids well.On top of that the panels have to be blasted to clean them up.
Sandblast media can be successfully be removed by blasting with high pressure air right after blasting before it gets damp from the elements and solidifies in corners etc..It should then be immediately coated with a primer and not left overnight as surface rust begins right away. A metal conditioner can be used to remove surface rust if left too long but it can have it's own problems but thats another story.Of course sanblast outfits generally don't like to clean and prime.That's why I do my own blasting even thought I hate it John

[opelenvy]

Tom, in 2004 on Overhaulin' they came to Austin and did Lance Armstrong's GTO. They did have it blasted here in Austin. Two Austin body shops revved up about Lance's 1970 Pontiac GTO - Austin Business Journal:
Custom Car Crafters Austin, Texas did the body work, I can't remember if they blasted it themselves. I'm sure they are not cheap, but if Chip Foose trusted them to do one of his...

[Johnvan]

Originally Posted by markandson Yup, mine was done on a rotisserie and I am still finding sand in the nooks and crannies when I work on it, but overall sandblasting is the way to go if you have it done by and experienced shop, or if you know what you are doing and do it yourself. I have a different opinion about the first paint to go on after blasting, I would go with a good self etching primer.......)

I used self etching primer for many years and it is certainly a good product as you describe.I found that it could react with some fillers or topcoats but not all of them ;therefore what you use is important.It does a good job for rust prevention and adhesion to the base metal as the main ingredient "zinc chromate "etches" the metal and prevents rust. Zinc chromate primer was used for many years in it's purer state to prime unsanded aluminum such as truck bodies .They are continually trying to remove zinc chromates from the market due to it's health hazards. Epoxy primer under a microscope has "tenacles"which grabs onto the metal and topcoats applied and therefore is becoming more popular due to it's adhesion and sealing ability.
I use a epoxy primer which has zinc chromates in it which I figure is the best of both worlds. But it is fast being removed from the market.Most epoxies now don't contain chromates at least in Canada. There is a big move today toward water based products due to the environment

[newman27]

Originally Posted by opelspyder ...The only problem I have with sandblasting is the fact you NEVER get all the sand out unless you can put it on a rotisserie and keep rotaing it...even then it is tough Keith

While this is a ways down the line for your car, keep this point in mind. I had small amounts of sand coming out of the hood for the first month or so each time I propped it open. These sand particles would land on the nose section and headlights under the leading edge of the hood. Each time this happened, I would take a hose and rinse the sand particles off and away from the car. If you try to just wipe them off (even with a damp microfiber towel) you run the risk of scratching your paint job. That was the only place I ever found sand coming in contact with the paint since Keith had my car on the rotisserie. Good luck with your car!

HTH

Matt

[1.9 GT]

You are the one driving the car pick a color you like, look through the member photo gallery maybe one color will catch your fancy. As far as original color the monetary difference in appraisal value is negligible. The die hard restorers will love that line. Enjoy your car and express yourself in the paint job. Yellow is a great color and the car looks fast just sitting still, however I may be biased I just painted my GT Competition Yellow in PPG Base Clear with a 21" black stripe.

[Johnvan]

I'm a die hard restorer but I would certainly paint a colour I like over an original colour I don't like. In fact cars with a lousy colour have less value.Cool sells

[tomcat]

It was suggested by someone i know that walnut blasting will take the paint off but not affect the metal. only $100 more. The place doing the work quoted me $350 for sandblasting and primer. I will be sure to check type primer they use. self etching primer sounds good although there is very little rust on the car even now. I verified they would clean it before primer but I expect there is going to be a short period betweeen primer and paint where i take a look over for a small amount of body work and sanding. Thanks for all the support I will post a pic when its painted once i buy another digital camera, as I got burglarized twice last month, oh well they didn't know how much my opel parts were worth as they didnt touchem.

[heimue]

Originally Posted by 1.9 GT ... Enjoy your car and express yourself in the paint job. Yellow is a great color and the car looks fast just sitting still, ...

I personally don't like yellow or white on cars, but... a bright yellow on a GT, if it is done right, is an AWFUL GREAT choice for a paint job!
BTW - just for the record, I have two white Opels...

Dieter

[opelspyder]

Dieter, don't you own a "white" Kadett??????????? Anyways, remeber that plastic/soda/and walnut will not affect the body, and it will not affect rust either!!!! Meaning it does not remove rust, only a media sand or product that etches will remove it like acid tank. Evaluate how much rust you have and then deside to do both, maybe only part of the underneath actually needs sand blasted. I do have mine primed after sandblasting...reason, it might be a month before I can actually get any bodywork done on it, and it will surface rust quickly
Keith

[Bill Hoffmann]

Originally Posted by tomcat another opinion is it ought to stay the original yellow. so being inexperienced i need to get some expert opinions from some of you. this one i intend to use as a dailly driver but also do a quality restore on it.

Whomever is saying you ought to stay with the original yellow should be considered a very wise and knowledgeable, trusted person.

Whether or not to media blast depends on the condition of the original paint. If it isn't cracked or otherwise distressed, I would just repair any bad areas and paint over it. Of course you have to clean, scuff it, etc. as well as seal it if the top coat is incompatible. I don't think you can apply a more durable base than the original paint already is. I am not an expert, but that is my opinion.

Bill

[jordan]

Also because of how much of the top coat is sprayed over and inside of the car one may never be able to remove it all unless it is fully blasted or acid dipped. Or else you are very liable to find the original top coat color in places here and there once the car is sprayed.

[BQS4]

Originally Posted by jordan unless it is fully blasted or acid dipped.

Jordan;
Acid dipping is almost non-existiing, except for like radiator shops. The EPA hit those shops HARD. Atlanta used to have several shops you could get a whole body acid dipped, but, they are ALL gone. We still have Sims Radiator, and they have tanks in their Lawrenceville shop that can handle smaller assemblies. They don't advertize this service, but, a slipped $20 or a few beers can get a few parts cleaned

[Johnvan]

Walnut blasting will strip paint but not rust as opelspyder recommends and I wouln't spend the money on it. I would not remove a good factory paint if it was not needed and expose bare metal . A primer or sealer coat over a good quality paint would ensure a good job but it is not necessary if sanded correctly,chemically washed (prepsol,wax and silicone remover etc.),and compatable with the topcoats applied. John

[namba209]

Just to give you and idea how good the factory paint bonds to the body. I used 3 different paint strippers on the headlight buckets and they barely removed the paint. I ended up using a wire wheel to finally get them to bare metal. So, I would suggest if the structure is sound under the factory paint, don't mess with trying to get it off, just sand it and paint over it. That's what I did to the interior on Willit? and also what the body shop did in areas that didn't need any structual repair, albeit there wasn't too much of that. Unrepaird areas, that is.

[tomcat]

The paint that is on the car is actually very good. so I will skip the blaster and go with the sanding and priming on the old paint job. probably costs about the same but as ya'll mentioned I dont want it to rust, and the old paint job will protect the car. I suppose the yellow will not show through if I have the new paint, painted with 2 coats at least. have ya'll got any suggestions for a rust issue in the rocker right where the screw holes are for the plate below the door?

[tomking]

If its thru rust cut out and weld in new metal. If its surface rust then spray with rust converter and coat with POR15 or Rust Bullet.

[Johnvan]

It depends on the extent of rust. If it is surface rust I would grind the rust off with a #24 or #50 grit flexible grinding disc and prime it. John