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60s Corvette question

8.3K views 27 replies 11 participants last post by  unimog1300  
#1 ·
HI,
I have a customer who has a 60's corvette on a rotisserie he wants blasted. I only use crushed glass never blasted fiberglass before. Can you crushed glass on fiberglass or will I need to use Soda, walnut? I'm going to talk to my supplier this week see what he thinks.
 
#2 · (Edited)
Kelly I blast boats all the time with soda and crushed glass .... Last year I did a 70's vet and wondered if the 30/60 crushed would work, the guy that owned the car new me well and let me try a area to compare, In my option the soda was the best choice leaving it fairly smooth, fibers showing The glass did work ok, but left the surface a little pitted, but not to bad at all. I tried to pit the pictures on but it's hard to see the difference, first picture is soda, second glass and the last one is soda Just a note: low low psi - around 50-60 psi Like painting start blasting away from the surface and then move into it. If you start dead on you will get creators I'm the fiberglass . The fiberglass does not have a gel coat like a boat and can burn up fast Try a area under the car first to see what it looks like then move to the body

So I guess you can't see much of a difference in the picture and like a said it's not bad with the glass it's just that the glass cuts quick and you have to be really carful not to hit a area to much
The painter will have a little more work to do but he will be fine lol
 

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#5 ·
MTN REMODEL LLC said:
Kell... Pardon my ignorence.... what is a "rotisserie"... just curious... have no knowledge about sandblasting. TIA
It's what the car is on in these picture
 

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#7 ·
I have blasted many vetts. The 30/60 is a little big. I like a 70/100 or in that range. It should be about the size of table salt.

Next is that the year matters. The older ones have a fiberglass shell with a true gel coat which is actually harder than the boats. On these the gel will remain smooth to the touch.

70's will be made of a product called SMC. It is a composit and does not have a hard gel coat on top. These will have a rough texture after about the same as what the surface of 80 grit sand paper looks like. It will look the same with glass or with soda.

I do both of these with a #5 and I have the psi cranked all the way up. I shoot from about 1.5 to 3 feet away.

Smc comes out of a mold and will tend to appear smooth on the back side. The older ones will show the fiber more on the back sides.
Repair products like bondo must all be smc compatible or they will lift from the body. This is why some of the vettes I worked on had to be re done.
 
#8 ·
58 Corvette

Glen,
I would really prefer the glass my pot is full of med/fine newage I hate to remove it. If I have to use soda I'm concerned with paint lifting issues if they don't wash the body down well get the soda off. If the older ones like this one it's a 58 are gel-coated it should work with the glass but should get the fine stuff.
 
#9 · (Edited)
Kell490
Hey just a nice fact, I live in Maine and in the town next to me There was a corvette that was in-tombed right after it was bought.
had only a few 100 miles on it.
I believe it made headlines when they took it out Few years back, might of been in the early 90's.
It was a 1952 -53 ? One of the first ones made

I remember when I was a kid, you could go into the Western Auto Store and ask to see it, they would take you down to the basement and look through a small window, (it was cool till the light bulb burned out and there was no way in to change it) lol
 
#10 ·
I have done a bunch too. I have used soda and glass. vettes are actually very crappy cars underneath the paint and the older it is the more shocked you will be with the construction. I have used 100-200 glass with good results as well as natrium soda.

my advice is razor blade the paint off first and be very careful with blasting, don't stop. warn the owner of the risks of glass so thin you can see right through it (later 60's are better constructed)

charge accordingly so you can take your time.
 
#12 · (Edited)
My dad had a early one 50's or early 60's I think have to ask my mother he passed 20 years ago I remember he said it had an early type of fuel injection. We used to talk about cars a lot and go to car shows. Blasting will be this morning the pot is full of glass I had put in there before the summer to keep it out of the rain I'm going to try it at 40psi to start with a test spot. If the glass is too abrasive ill have to suck it out with a shop vac and put soda in the pot. This is why having 2 pots is nice.

UPDATE
I blasted the 58 vett yesterday with crushed glass med/fine newage worked great. The thing had so much primer and old paint jobs on it I'm sure glad I used the glass. My customer is a body shop the owner said it looked great. He actually wanted me to blow though any weak parts so he could see where all the cracks needed to be repaired. The car is being restored he is going to put a C4 engine and drive train in it says the total cost at the end will be $120k when he is done it will be worth $200k.
 
#14 ·
Rather, I'm afraid to say it was the early vettes that were fiber glass. Then in the 70s, no one agrees on exactly when, they began to introduce the SMC "press moulded" panels. Press moulding is of course a quicker cheaper way to build and so it's logical that it came around after. The best way to guess which you have in front of you is to look at the back side. SMC is smooth while fiber glass is quite rough because it has no coating on the back side. It does have a gel coat to make it smooth on the face. This can be varified in any vette forum if you search SMC. It started in 71-73
 
#19 ·
Bob,
I have a Geoblaster and just did a hood on a 1974 Corvette for a friend of mine that oversees 3 body shops. One coat of silver paint with primer underneath. I used Newage 40/70 and ran 50 psi. It went slower than I had anticipated but I was a little apprehensive since it was my first Corvette part. The hood was off the car and I had it on my stand so I started on a corner by the windshield to test it out. Called the body shop guy back out to show him and he said to proceed. He was a little unsure that it should look like it did but they usually use stripper to remove the paint. I had no idea what it should look like other than the pictures and comments on here. Anyhow, finished it up and washed it off and went home. Got a call from my friend and he said it took off too much of the gel coat. They were just going to remove the paint with stripper on the rest of the car. So I lost out on doing the whole thing. I was advised to use 40/70 so I'm not sure if I needed something finer.
 

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#20 · (Edited)
First off, I don't think there's a gel coat on cars.
The cars are either laid in or sprayed molded.
The fibers are smother on the out side due to the mold.
The glass is filled with a sealer that keeps the mold release from Coming out.

Now with that said, soda will leave it a little bit smoother,
and glass Will etch in a little more depending on how long you blast in one spot.

Either way you will " raise the hair fibers on the fiberglass on cars and will need to be resealed.

Just for reference, gel coat is a spray on paint to seal boats...
 
#21 ·
Thank you guys, I appreciate all the input. Dyer, you mentioned that the "Gel Coat" is a sprayed on coating that act's like a sealer. Is that the gray finish that I see and seems to be harder than the paint. In some cases, it comes off very easily and others, it's like a thin coat of steel. I did a canoe before and the "gray" finish was really tough to remove. The customer wanted it off so that's what I did. I did wonder if that was what was called the GEL COAT?
 
#23 ·
On boats (and I grew up working on the back of a lobster boat and building boats for a long time) the gel coat is put direct to the laid fiberglass, can be any color, and is a supper tough paint. that is why most do not want to remove it from boats, very costly to be redone, but can be touched up if removed.

on vets, there is no gel coat from the factory, usually its a black or dark gray coating that looks like primer, but is a little hard to get off.
it seals the fibers and keeps the mold release agents from coming back out. (the new vets 1970"s? and up have it mixed right into the fiberglass so it can be sprayed on a production line. if blasted or sanded it will keep coming out no mater how much you take off.
on the older vet pre 70"s? the cars were hand molded and a release agent was sprayed on to the mold, then the fiberglass laid in. (like boats are made.)

if there is a gel coat on a car then it was put on buy a previous owner.

most times, boats are painted over the gel coat with a paint call Awl Grip. anther tough to get off paint, usually the top sides of boats are done with this, but not the underside were the bottom paint goes. the bottom usually gets a barrio coat (like a rubber) then its painted over.

when blasting vets, if you can get the paint off down to the black or gray "last Coat" then its usually good, they don't need to be bare like metal.

if you go to far, and see the fibers of the fiberglass, the body shops just has to apply the first coat of sealer (not primer) to build the paint up.
if they give you hell about going to far, then they are just Bitching because they have to do more work.

I to work for over 10 HIGH end body shops that do $100,000+ street rods, and rebuild for customers....
and a lot of other body shops that do regular normal stuff.
 
#22 ·
I'm well aware of gel coat for boats. I actually had 2 guys tell me that I removed too much of the gel coat on the hood. The first is my friend who oversees the 3 body shops. He has been doing body work since his teens. He was district rep for PPG Paint in the autobody end of their business for years. He also has national award winning street rods he has painted. The guy who told me to continue blasting the hood works in one of the body shops he oversees. The other is friend who restored his 1965 Corvette to Bloomington Gold status himself. He also has done award winning paint work for people. I'm just passing along what both told me at separate times, not together in one conversation. HTH
 
#24 ·
So by the pictures I posted do you think I went too far? It was silver paint then brown primer and then clean down to the fiberglass as I see it.

I just don't want to take on another Corvette and have this happen without knowing I didn't hurt it.

I don't really want to stock a super sack of 70/100 for the occasional Corvette.
 
#25 · (Edited)
So if you look at post 2 of this thread, I put some pictures.
It looks like you went to deep into the fiberglass,
when doing the vets, I try to take off the top layer of paint and try to leave the last coat of paint on.
The body shops what it as smooth as you can, and they are going to sand it any how.

The more you can find out- learn the prosses about painting and prep they do, the better blaster you will become!
The best blasters are x painters.
 
#27 ·
Unimog, the vett you did was an S.M.C. body It is a composite fiberglass and has no actual gel coat as some of the first vetts do. You may want to stop at the grey as Jim was suggesting, however what you did is acceptable and normal for this type. They will always have a rough finish to some degree. The older vetts will be smooth and you can use a medium grit on any of them if you keep moving. If you find an area of thicker paint just move on and let them sand that little bit out so you don't go through the exposed areas. Always inform the customer of your intentions and ask what they prefer