Pinhole repair, What product is best?
03-11-2007, 09:29 AM
#1
Melting Slicks
Thread Starter
Pinhole repair, What product is best?
Car in primer, several nagging pinholes. What method is best to fill then and leave no air underneath?
Resin with a toothpick
Bondo on a tiny knife
Some other product..?
Resin with a toothpick
Bondo on a tiny knife
Some other product..?
03-12-2007, 12:05 AM
#2
Advanced
Blue,
If I understand, after you had it stripped, you put 2 coats of resin on the bare glass sanding with 220 in between coats. Big no no, resin is very brittle, its the glass that gives it strength. You will probably end up with a lot of "stress cracks" down the road.
Then you poly primed, then epoxy seal & prime, then after sitting you epoxy primed again. The poly prime should have taken care of any pin holes. Epoxy is usually thinned to make it flow better as a sealer. Most epoxies doesn't fill much. At any rate, you shouldn't have had any pinholes after blocking the poly. If you had very many, then I would have applied more poly or a 2K urethane primer. Once everything was straight and no pinholes, then seal with epoxy.. If you still are having pinholes with all this material on it, either they were really big to begin with, or there is something funky going on with the materials you've put on since stripping.
To answer your question about what to fill the pinholes with, I'd use something like Metal Glaze or Easy Sand ( they are finishing putties- very thin and will work into the pinholes). If your last coat of epoxy has sat over 7 days, you will have to sand before applying anything else, putty included.
Hope this helps
Dan
If I understand, after you had it stripped, you put 2 coats of resin on the bare glass sanding with 220 in between coats. Big no no, resin is very brittle, its the glass that gives it strength. You will probably end up with a lot of "stress cracks" down the road.
Then you poly primed, then epoxy seal & prime, then after sitting you epoxy primed again. The poly prime should have taken care of any pin holes. Epoxy is usually thinned to make it flow better as a sealer. Most epoxies doesn't fill much. At any rate, you shouldn't have had any pinholes after blocking the poly. If you had very many, then I would have applied more poly or a 2K urethane primer. Once everything was straight and no pinholes, then seal with epoxy.. If you still are having pinholes with all this material on it, either they were really big to begin with, or there is something funky going on with the materials you've put on since stripping.
To answer your question about what to fill the pinholes with, I'd use something like Metal Glaze or Easy Sand ( they are finishing putties- very thin and will work into the pinholes). If your last coat of epoxy has sat over 7 days, you will have to sand before applying anything else, putty included.
Hope this helps
Dan
03-12-2007, 10:39 AM
#3
Melting Slicks
Thread Starter
Thanks for the info Dan, I wish the paint and forum stuff would have been up a year ago. The polyprimer was not something I would have wanted to go with, but I was looking to replace the gelcoat with something. I was going to try and get a really smooth finish and yet preserve the original body of the car as best I could. In any case the paint store here was absolutly awful and made terrible recomendations as well as poor product information. I now order PPG direct. I am pretty happy with the way thing look, but I don't like how it got there. The resin coat on the car is pretty thin. If it gets bad I will switch back to Camaros I think.
03-12-2007, 10:51 AM
#4
Burning Brakes
Blue,
If I understand, after you had it stripped, you put 2 coats of resin on the bare glass sanding with 220 in between coats. Big no no, resin is very brittle, its the glass that gives it strength. You will probably end up with a lot of "stress cracks" down the road.
Then you poly primed, then epoxy seal & prime, then after sitting you epoxy primed again. The poly prime should have taken care of any pin holes. Epoxy is usually thinned to make it flow better as a sealer. Most epoxies doesn't fill much. At any rate, you shouldn't have had any pinholes after blocking the poly. If you had very many, then I would have applied more poly or a 2K urethane primer. Once everything was straight and no pinholes, then seal with epoxy.. If you still are having pinholes with all this material on it, either they were really big to begin with, or there is something funky going on with the materials you've put on since stripping.
To answer your question about what to fill the pinholes with, I'd use something like Metal Glaze or Easy Sand ( they are finishing putties- very thin and will work into the pinholes). If your last coat of epoxy has sat over 7 days, you will have to sand before applying anything else, putty included.
Hope this helps
Dan
If I understand, after you had it stripped, you put 2 coats of resin on the bare glass sanding with 220 in between coats. Big no no, resin is very brittle, its the glass that gives it strength. You will probably end up with a lot of "stress cracks" down the road.
Then you poly primed, then epoxy seal & prime, then after sitting you epoxy primed again. The poly prime should have taken care of any pin holes. Epoxy is usually thinned to make it flow better as a sealer. Most epoxies doesn't fill much. At any rate, you shouldn't have had any pinholes after blocking the poly. If you had very many, then I would have applied more poly or a 2K urethane primer. Once everything was straight and no pinholes, then seal with epoxy.. If you still are having pinholes with all this material on it, either they were really big to begin with, or there is something funky going on with the materials you've put on since stripping.
To answer your question about what to fill the pinholes with, I'd use something like Metal Glaze or Easy Sand ( they are finishing putties- very thin and will work into the pinholes). If your last coat of epoxy has sat over 7 days, you will have to sand before applying anything else, putty included.
Hope this helps
Dan
I would recommend starting from scratch and sand the primer and resin back off. You are not that far along to start over and I think if you don't, you will be dealing with headaches forever on your car.
I have never heard of getting pinholes with polyester primer. it sounds like "solvent pop" and I have never seen polyester primer do that. I have always used Evercoat's polyesters. Both Featherfill and Slick Sand and both are excellent products.
Roger
03-12-2007, 02:43 PM
#5
Melting Slicks
Thread Starter
Understood. I'm not that far away from the beginning, and I really think that its better to run the other way for a few days. Thanks again. This sucks...
03-12-2007, 04:06 PM
#6
Le Mans Master
I think I would be blocking that car with 40 grit to remove that resin before it starts cracking. Then either seal it with Ecklers Gel Coat spray or a good epoxy primer like Southern Poly Inc or PPG DP.
03-12-2007, 05:29 PM
#7
Melting Slicks
Thread Starter
I had read on another corvette forum that the ecklers gelcoat was to be avoided. The calif products I have in PPG available are DPLF, but these are not specific gelcoat replacements. Are you suggesting to go down to 40 grit then sand 80 to 220 or so then coat with ...?
03-12-2007, 05:57 PM
#8
Le Mans Master
Not sure where you read that because many a person and resto shop uses the old school Ecklers gel coat where one has had to do a lot of body work. I blocked my very rough '67 with 40 grit and then scuffed it down with 80 grit. Then I shot it with 4 wet coats of Ecklers gel coat. Next I blocked out the orange peel with 80 grit and shot it with several coats of Slicksand.
03-12-2007, 07:52 PM
#9
Burning Brakes
I used Eckler's spray Gel Coat one time. It worked fine and does what is supposed to do but it is kind of a PITA to work with. Besides having to sand it, you have to wipe it down with solvent first.
I think where people might say to avoid it, it's probably because it's a lot of work versus epoxy primer not because it's not good.
If I have a Vette that is stripped and the glass looks a little worse for wear, I would use the epoxy. With the epoxy, you just spray it on, let it dry overnight and then spray on the polyester primer (no sanding). Easy and gets the job done.
Roger
I think where people might say to avoid it, it's probably because it's a lot of work versus epoxy primer not because it's not good.
If I have a Vette that is stripped and the glass looks a little worse for wear, I would use the epoxy. With the epoxy, you just spray it on, let it dry overnight and then spray on the polyester primer (no sanding). Easy and gets the job done.
Roger
03-12-2007, 07:55 PM
#10
3rd Gear
Member Since: Sep 2006
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first of all find out where those pinholes are coming from.find a spot thats out of the way and sand it down till you see what the pinholes are in.if its coming from the resin you applied, then you can fill them in with a little polyester putty and prime.you say you put on two coats of resin on the body,I don;t think that was needed.if you don't have any cracks under the resin you should be fine as long as you sanded it good before ,like with 80 grit.
03-12-2007, 10:23 PM
#11
Burning Brakes
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If the pinholes are in the fiberglass or body filler, spraying primer over them doesn't always work. The primer will not want to cover the holes. Sand the area then apply some polyester putty to fill the holes.
03-12-2007, 10:49 PM
#12
Advanced
Blue,
As stated, I think the initial application of the resin is the source of your problems. If it's not now, it will be in the future with the resulting stress cracks.
First things first. Let me state for the record, Corvettes have never had gel coat on them from the factory, NEVER.. Second, putting gel coat on a stripped Vette is a major PIA. If you put it on too thick and don't sand most of it off, guess what. It's brittle, prone to cracking, especially on corners and character lines. Ask me how I know this.
What Roger has suggested is a lot like my suggestions. Sand off everything down to the resin you put on with 40 grit. Once you have it there remove the resin with 80 grit. Now complete any bodywork that may need to be done. When you are fine with your bodywork, sand the entire car with 120 grit. If you don't get any contamination (silicon, wax, grease) on the car, just blow it off with air. I usually use 150 lbs. with a blow off nozzle about an inch away from the surface. The idea is to blow any sanding dust out of any scratches. Mask the car and tac it off and you're ready for epoxy. If you feel that the fiberglass might be contaminated, you can use a solvent based wax & grease, but I prefer a waterborne W&G remover. If you use one of these cleaners, let the car sit until the next day before priming with the epoxy. Remember, fiberglass is porous.
You can use DPLF if you want. I prefer black SPI epoxy. Whichever you use, spray one coat unreduced in the morning. Wait at least 4 hours before you apply the 2nd coat unreduced. For best results, it's important that you do this. It's also imperative that you keep the surface (as measured with an ir gun) temp at a minimum of 65* (72*-75* preferred) for 24 hours.
Wait 3 days and then spray your poly primer of choice (SlickSand, FeatherFill, etc). Follow their directions for application. Before sanding this poly, guide coat it so you'll be able to see any flaws. If all imperfections are not gone by the time you sand down to the epoxy, STOP. You don't want to sand any of the epoxy as it's job is to seal the fiberglass. You may have to reapply more poly or you could switch over to a 2K urethane primer to remove any flaws.
This should give you a good start, If you need any other help, don't hesitate to ask.
Dan
As stated, I think the initial application of the resin is the source of your problems. If it's not now, it will be in the future with the resulting stress cracks.
First things first. Let me state for the record, Corvettes have never had gel coat on them from the factory, NEVER.. Second, putting gel coat on a stripped Vette is a major PIA. If you put it on too thick and don't sand most of it off, guess what. It's brittle, prone to cracking, especially on corners and character lines. Ask me how I know this.
What Roger has suggested is a lot like my suggestions. Sand off everything down to the resin you put on with 40 grit. Once you have it there remove the resin with 80 grit. Now complete any bodywork that may need to be done. When you are fine with your bodywork, sand the entire car with 120 grit. If you don't get any contamination (silicon, wax, grease) on the car, just blow it off with air. I usually use 150 lbs. with a blow off nozzle about an inch away from the surface. The idea is to blow any sanding dust out of any scratches. Mask the car and tac it off and you're ready for epoxy. If you feel that the fiberglass might be contaminated, you can use a solvent based wax & grease, but I prefer a waterborne W&G remover. If you use one of these cleaners, let the car sit until the next day before priming with the epoxy. Remember, fiberglass is porous.
You can use DPLF if you want. I prefer black SPI epoxy. Whichever you use, spray one coat unreduced in the morning. Wait at least 4 hours before you apply the 2nd coat unreduced. For best results, it's important that you do this. It's also imperative that you keep the surface (as measured with an ir gun) temp at a minimum of 65* (72*-75* preferred) for 24 hours.
Wait 3 days and then spray your poly primer of choice (SlickSand, FeatherFill, etc). Follow their directions for application. Before sanding this poly, guide coat it so you'll be able to see any flaws. If all imperfections are not gone by the time you sand down to the epoxy, STOP. You don't want to sand any of the epoxy as it's job is to seal the fiberglass. You may have to reapply more poly or you could switch over to a 2K urethane primer to remove any flaws.
This should give you a good start, If you need any other help, don't hesitate to ask.
Dan
