Body work help...

saudivette

Clueless In Sandland
Joined
Mar 24, 2008
Messages
2,633
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Aussie expat in Saudi Arabia
The script insert from a C5 rear bumper that Gene kindly sent me, has arrived and I'd like to get started grafting it into my rear bumper. I have a new fiberglass rear bumper from Vanacor.

If I cut the script piece to size and shape and cut a corresponding size hole in the bumper, can I lay the script in the hole and glass it in from the rear using fiberglass mat and 3M 8115?

If so, once it's cured, what can I fill the front (or outside) of the bumper with? I have no idea what the C5 script piece is made from so don't know what sort of body filler to use there? Something flexible and poly based?

I'll also need a filler that I can use once I graft some early Vette (GRP) repair pieces into my 82. I'll be using the 3M 8115 to actually graft the pieces into the car but need to know what filler I can use to take care of the joins/seams from the ourside.

Not much good telling me actual product names as more than likely, they're not available here. A product type and/or description would be more beneficial please...
 
HEY, I din't think it get there for another 6 months via slo boat around africa from across the pacific.....

is the warp ok on it, I was afraid it was bent, but then thought of the convex on it, and thought again that one day in the sun there would straighten ANYTHING....

as for what you want to DO.....I would use it as a mold and forget those compounds....but I certainly not good at body/paint/chemistry....

:surrender:
 
HEY, I din't think it get there for another 6 months via slo boat around africa from across the pacific.....

is the warp ok on it, I was afraid it was bent, but then thought of the convex on it, and thought again that one day in the sun there would straighten ANYTHING....

as for what you want to DO.....I would use it as a mold and forget those compounds....but I certainly not good at body/paint/chemistry....

:surrender:

I was confident it would arrive Gene. I've had a couple of things go astray but they always turn up. And, it's pretty flat but even so, if I use that piece, I'll be trimming it down a lot closer to the letters.

However, I DO like your idea of making a mold of it. It might be difficult getting in the letters properly though :crap:
 
HEY, I din't think it get there for another 6 months via slo boat around africa from across the pacific.....

is the warp ok on it, I was afraid it was bent, but then thought of the convex on it, and thought again that one day in the sun there would straighten ANYTHING....

as for what you want to DO.....I would use it as a mold and forget those compounds....but I certainly not good at body/paint/chemistry....

:surrender:

I was confident it would arrive Gene. I've had a couple of things go astray but they always turn up. And, it's pretty flat but even so, if I use that piece, I'll be trimming it down a lot closer to the letters.

However, I DO like your idea of making a mold of it. It might be difficult getting in the letters properly though :crap:

I just don't get along with chemistry very well, can't even build a bomb that works well....

but a old HSchool buddy from another school actually LAUNCHED a TREE about 2' diameter way out behind his father's house, shattering windows and busting foundations/walls in the surrounding hood....

Bladensburg Maryland about 45 years ago.....:D today he is a retired professor of Physics from some California U......look up Alexander Sawchuck....aka Sandy Sawchuck.....

lucky he never revealed the formula.....about a coffee can size charge....

:D
 
I didn't know you wanted to bond it to a fiberglass bumper - that C5 bumper is urethane, it will never bond properly and it will crack some time in the future... probably won't take long....
I thought you were going to glue it to a stock urethane bumper...

Make a mold.... you'll need a good release agent, the PAM spray that I used might not work for this... this requires some accuracy....great opportunity to improve your fiberglass skills :thumbs:
 
I didn't know you wanted to bond it to a fiberglass bumper - that C5 bumper is urethane, it will never bond properly and it will crack some time in the future... probably won't take long....
I thought you were going to glue it to a stock urethane bumper...

Make a mold.... you'll need a good release agent, the PAM spray that I used might not work for this... this requires some accuracy....great opportunity to improve your fiberglass skills :thumbs:
Yeah, I was thinking about if for a few hours last night. Gonna finish my coffee and head into town to see if I can find someone who sells fiberglass supplies.

I don't think it'll be too hard to make a mold though as the letters aren't very high and there's no sharp edges at all. I thought I might be able to use the reverse of the bumper piece as the plug and just have to do the glassing once to get a final piece. But it's all rough and the letters aren't stamped as clear from the rear, do I'll have to make a mold off thr front then make the piece I want, from that mold.

Who's dumb idea was this anyway...


What about what body filler to use over SMC and GRP?
 
I am not following what you are trying to do here,are you trying to put this script on the rear bumper?? how about a pic of the script,to much over spray on the brain :twitch:
 
I am not following what you are trying to do here,are you trying to put this script on the rear bumper?? how about a pic of the script,to much over spray on the brain :twitch:
I can take some pics later, but what I'm trying to do is put the CORVETTE script in a C5 rear bumper, into my C3 fiberglass rear bumper.

Gene went to a wrecking yard and hacked out a lump of C5 rear bumper with the script on it and sent it to me. Before it arrived, I thought I could graft that piece directly into my rear bumper. But, when it arrived, I saw that it was made out of plastic/urethane. So, I am now going to (attempt to) use the piece that Gene sent me as a plug so I can make a mold from it and then use that mold to make a fiberglass piece with the C5 script in it that I can graft into my fiberglass rear bumper.

Is that any clearer?

Secone question:
What's the mixing ratio of hardener to resin? I found a boat maker this morning who sold me some stuff but of course, no one speaks much english and couldn't tell me the mixing ratio...
 
Your gonna have to make 2 molds, 1 for your script part you have in hand and then a second one from the new mold that will produce the part you want. You need to use s mold relesase, Pam might work, make a trial piece to see. Once you have new mold 1 done carefully clean and smooth it out because any errors will get multiplied to the new parts.
I'll look at my can and see what the ratios are..
 
Your gonna have to make 2 molds, 1 for your script part you have in hand and then a second one from the new mold that will produce the part you want. You need to use s mold relesase, Pam might work, make a trial piece to see. Once you have new mold 1 done carefully clean and smooth it out because any errors will get multiplied to the new parts.
I'll look at my can and see what the ratios are..
Yeah, got all that. I've trimmed the piece Gene sent me and stapled it to a piece of board so it's rigid and flat. I ran the buffer over it and removed a few scratches and now I'm waxing the hell out of it. I couldn't find any release agent so am going to go with pure Carnauba wax and will do it loads of times before I start glassing.

If I get to it tomorrow, I'll coat it with a couple of layers of gel coat, then resin and glass tissue then a few layers of glass mat. If that all cures and releases ok, I'll rub out any imperfections I can see in the mold then start waxing that before I lay it up with gel coat, tissue and mat. If that turns out ok, then it'll be time to cut & shut on the rear bumper. I'll post some pics when it's all done...

Thanks for the mixing ratio too. I have enough resin there that I can afford to experiment a bit before I try applying it. Is gel coat mixed with roughly the same ratio?
 
I am not following what you are trying to do here,are you trying to put this script on the rear bumper?? how about a pic of the script,to much over spray on the brain :twitch:
I can take some pics later, but what I'm trying to do is put the CORVETTE script in a C5 rear bumper, into my C3 fiberglass rear bumper.

Gene went to a wrecking yard and hacked out a lump of C5 rear bumper with the script on it and sent it to me. Before it arrived, I thought I could graft that piece directly into my rear bumper. But, when it arrived, I saw that it was made out of plastic/urethane. So, I am now going to (attempt to) use the piece that Gene sent me as a plug so I can make a mold from it and then use that mold to make a fiberglass piece with the C5 script in it that I can graft into my fiberglass rear bumper.

Is that any clearer?

Secone question:
What's the mixing ratio of hardener to resin? I found a boat maker this morning who sold me some stuff but of course, no one speaks much english and couldn't tell me the mixing ratio...

It would be good to know what you have, it could be polyester, vinylester or even epoxy.

Polyester will have about an ounce of hardner (MEKP) / Gal of resin.
Vinylester uses the same as Polyester
Epoxy will have much greater amounts of hardener in ratios of 1:1, 2:1, 3:1 etc.

With poly or vinyl, ambient temp will require adjusting the amount of hardner for the desired set time. Just mix a very little and time it for test.
Rule of thumb:
1oz resin :10 drops hardner
1 pint:7cc
1qt (32oz):1/4 oz
Gelcoat 2x the normal hardner.

Buff and wax the existing logo piece you are using as a plug very well. Using a gelcoat first is best, but not absolutely necessary.
Once you start, don't stop. From gelcoat to as many layers of glass as you feel necessary, including some wood/ metal glassed in for reinforcement.

The original bumper logo is fairly flexible and was originally made from a mold too, so separating your new plug should be pretty easy.
 
I have no idea what sort of resin I have :confused:

The guys who gave me the stuff said that I needed to put 1 x Coke bottle cap of the MEKP into a litre of resin - seriously! Does that narrow it done any?

Multiple coats of pure Carnauba wax should be ok as a release agent, shouldn't it?

Thanks for all the info though, it's all good stuff. I don't want to bugger this piece of bumper that Gene sent me as then I'd have to pester one of you Americi's to get me another one :lol:
 
Carnuba wax is goodgood enough.
You do not have epoxy, that is all that matters. Other 2 are the same except for strength.
An eyedropper is good for measuring the hardner.

Make sure you re-inforce the plug with wood strips or something so it won't warp.

You won't screw up the part if buffed and waxed. You can glass in a water or air fitting to pop it loose if desired. (where it won't show)
Polish with a glazing compound before waxing.
 
I buffed the piece with a mild polish first and then used AutoGlym Super resin Polish with the buffer. It was pretty slick before I started on it with the wax. I've given it quite a few coats of wax already but I'll do a few more yet.

I don't think I'll bother glassing in an air or water fitting as the letters are only about 1.5mm deep and there's no sharp corners anywhere - I'd reckon it should pop out pretty easily (fingers crossed). I'll glass in some strips of wood or something though for strength :thumbs:
 
Clear as a bell now Wayne :nuts: although i still do not have any suggestions or help for you :tomato:
 
Righto, I popped the mold apart this afternoon and the plug came away real easy. I'm damn happy with the result too, although I would have to be a complete cluster to mess up something like this!

Anyway, opinions needed here please. You can see where I stapled the original piece of bumper to the wood. This was to obviously hold it in place and to also hold it flat as it had a slight curve/twist to it.
35497b1b0f75e9d.jpg


The staples have been molded perfectly too. I'd like to fill them before I try and cast from this so will ordinary body filler be ok, then rub that down and polish it like the rest of the mold. Or would I be better of degreasing the mold and putting a dab of gel coat into each staple?
35497b1b10d0410.jpg
 
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