60s Corvette question

7130 Views 27 Replies 11 Participants Last post by unimog1300, Sep 10, 2014

kell490

Discussion Starter · Dec 10, 2013

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.

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Dyer

· #2 · Dec 10, 2013 (Edited)

3

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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Live_oak

· #3 · Dec 10, 2013

Walnut shells is what my husband recommends. He's restored probably 15 different ones from C2's- C4's. Glass bead would be fine for the frame though.

MTN REMODEL LLC

· #4 · Dec 10, 2013

kell490 said:
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.

Kell... Pardon my ignorence.... what is a "rotisserie"... just curious... have no knowledge about sandblasting.

TIA

Dyer

· #5 · Dec 10, 2013

2

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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kell490

Discussion Starter · #6 · Dec 11, 2013

As seen in the picture they make it a lot easier to work on but they aren't cheap. I guess ill have to use soda Walnut is just too expensive don't want to chance glass pitting it.

Betterblast

· #7 · Dec 18, 2013

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.

kell490

Discussion Starter · #8 · Dec 19, 2013

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.

Dyer

· #9 · Dec 20, 2013 (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

ratherberacin

· #10 · Dec 20, 2013

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.

ratherberacin

· #11 · Dec 20, 2013

Kell

no factory gel coat on early vettes they were made from a process called "press moulding" that's why you have two halves of the car. top mold and bottom mold.

kell490

Discussion Starter · #12 · Dec 21, 2013 (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.

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kell490

Discussion Starter · #13 · Dec 22, 2013

2

Some pictures of the job nice having that rotisserie

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Betterblast

· #14 · Dec 22, 2013

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

ratherberacin

· #15 · Dec 24, 2013

Glen

I am not comparing smc to fiberglass I am saying the early vettes were not gelcoated they were press moulded. the very first vettes (54) were hand laid matte. 55-up were press moulded. later ones were smc.

hope that clears it up for you.

SD DMB

· #16 · Dec 26, 2013

I've used 70-100 crushed glass and crushed light bulbs on several vettes. Love doing fiberglass with it. Takes the junk off and leaves the bare glass in a real nice workable profile.

Bob Moore

· #17 · Aug 23, 2014

Been reading as much about fiberglass that I can get my hands on. I have a quote for a 67 vette pending and thought I'd ask if anybody used a Geo Blaster on fiberglass? I thought I'd blast at 50-60 PSI and use 120 Garnet. I realize it's been a long time since anyone has been on this topic. Thanks

Sand Pot

· #18 · Aug 24, 2014

Several of us strip bottom paint off of fiberglass boats all the time with farrow/geo machines. 40-60 psi depending on grit size and gel hardness (it varies). I use 70 VitroGrit crushed glass.

unimog1300

· #19 · Aug 29, 2014

3

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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Dyer

· #20 · Aug 30, 2014 (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...

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