1977 Ventura build

Same stuff I think. Cabosil is fumed silica powder iirc. As for the hole prep there is no easy way to prep the inside of the holes for filling so I just filled them. I also preferred to block the duratec first not final finish but very close. The pinholes tend to ball up with primer around the opening leaving the orfice smaller than the valley if that makes sense. So cutting it down first, removing all the orange peel from the primer opens up the pinhole shape a bit and allows a really clean and smooth application of the duratec putty. I applied the putty the way I was taught for body work which is to cram the hole as full as possible coming at it from different angles too ensure good contact of the putty around the entire pin hole. Then using the spreader to flatten the surface out. Always flipping directions if you have to take multiple swipes so it doesn’t make ramps of the putty. I mixed up the duratec to a stable putty but not at all thick it was very light and creamy. It worked really slick and easy for me I can’t think of anything else to add but it’s not hard. As for long term adhesion in the pinholes I guess time will tell.

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Originally Posted by LakeFever

Same stuff I think. Cabosil is fumed silica powder iirc. As for the hole prep there is no easy way to prep the inside of the holes for filling so I just filled them. I also preferred to block the duratec first not final finish but very close. The pinholes tend to ball up with primer around the opening leaving the orfice smaller than the valley if that makes sense. So cutting it down first, removing all the orange peel from the primer opens up the pinhole shape a bit and allows a really clean and smooth application of the duratec putty. I applied the putty the way I was taught for body work which is to cram the hole as full as possible coming at it from different angles too ensure good contact of the putty around the entire pin hole. Then using the spreader to flatten the surface out. Always flipping directions if you have to take multiple swipes so it doesn’t make ramps of the putty. I mixed up the duratec to a stable putty but not at all thick it was very light and creamy. It worked really slick and easy for me I can’t think of anything else to add but it’s not hard. As for long term adhesion in the pinholes I guess time will tell.

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Do I need to mix it with a catalyst or just duratec and silica?

Yes catalyst as normal for the duratec just add the silica to suit after. Just add bit by bit until you get a consistency you like. I mixed mine sort of like toothpaste if I had to pick a comparison. A little goes a long way too so don’t waste the duratec $$$

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Originally Posted by LakeFever

Yes catalyst as normal for the duratec just add the silica to suit after. Just add bit by bit until you get a consistency you like. I mixed mine sort of like toothpaste if I had to pick a comparison. A little goes a long way too so don’t waste the duratec $$$

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The pinhole trick worked excellent. Took me about an hour to go over the whole primed area. Lots of pinholes in the gator glide base coat also, I figured I’d try the duratec paste there also, it filled it in really well. I only did a sample area, the base coat is very slippery and I want to make sure it will stick to it. I went out and checked it a little while ago and I can’t scrape it off with my fingernail so it looks promising.

That’s precisely what I thought too when I used it the first time. I was desperate for an easy and good solution that wouldn’t make me have to sand off most of the duratec and this trick worked great for me. Glad it worked out well for you too

Attachment 532728Just finished spraying gel on the bottom. Everything went pretty good, no equipment malfunctions Attachment 532729or anything like that. I definitely have some work to do tho, there’s lots of areas that look like the moon surface, like small craters in the gel. Not sure what causes this but hopefully my gel is thick enough that I can sand down to them and still be fine. Otherwise I have the orange peel effect but I expected that. The duratec additive definitely gives it a good shine right out of the gun. Time to let it cure which it already is getting there then on to sanding and sanding.

Well after sanding on the little craters in my new gel coat I’m not having much luck, most of them go to deep, bummer. Going to sand the whole works until there all gone and try again. Maybe My air pressure wasn’t quite right. I don’t think I’m going to try and do the hole bottom in one shot this time, split it in half and maybe my results will be better not being in such a rush. I might not add as much duratec to my next batches either, the 50/50 mix sprays like water. I don’t mind the orange peel but the craters are crap. Sanding the orange peel was a piece of cake, now if my second attempt will only give me orange peel I’ll be stoked.

Bummer. What’s your spray set up like?

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Originally Posted by LakeFever

Bummer. What’s your spray set up like?

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Purple hvlp gun from harbor freight it has a regulator on it, I drilled the tip out with 5/64 bit which should be around 2.4mm, 30 gallon northstar compressor. I tested each batch on cardboard right before I sprayed and I looked good. I sprayed at 40 psi. I might have went over the first coat before it kicked, the first pass looked good. The craters didn’t happen till the 2nd and 3rd pass, I think I was to confident and rushed the 2nd and 3rd pass.

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Originally Posted by Jmr1974

Purple hvlp gun from harbor freight it has a regulator on it, I drilled the tip out with 5/64 bit which should be around 2.4mm, 30 gallon northstar compressor. I tested each batch on cardboard right before I sprayed and I looked good. I sprayed at 40 psi. I might have went over the first coat before it kicked, the first pass looked good. The craters didn’t happen till the 2nd and 3rd pass, I think I was to confident and rushed the 2nd and 3rd pass.

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Got any close up pics of the craters? It could be fisheye which is an issue with the surface not the spray technique. Also 2.4 seems really big for duratec is that what the tds recommends for tip size?

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Originally Posted by LakeFever

Got any close up pics of the craters? It could be fisheye which is an issue with the surface not the spray technique. Also 2.4 seems really big for duratec is that what the tds recommends for tip size?

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I can’t get pics to load, my internet has been screwed up lately. I talked to Jody at us composites about the gun and that I was drilling the tip bigger, he said he used to do the same thing. Yeah I don’t know you would think with it being the consistency of water that a smaller tip would be better. As far as surface prep went, I sanded the duratec primer down with 180 and used acetone to clean it a lot of acetone. Like I said I wonder if I’m better with a 25/75 mix of gel to the clear additive with my setup. Jody told me to wait about 1 hour between coats for a total of 3 coats. Then when I ordered the material over the phone I talked to another older guy there that walked me thru the spraying, he told me 3 coats don’t stop, wet on wet. He said “ you’ll spend 10 minutes laying down the gel and 2 days sanding. Then I called him again a few days later just to refresh what he told me. I’m sure it’s something I did, I’ve never dine this before. Probably something so simple but without experience I’m just gambling. I started sanding it down with 220, I’d like to salvage some of this gel and not sand into the primer, 180 gets pretty aggressive and burns right thru it quick. I’d like to. Then spray again after the 220 instead of the 180. Also I sprayed yesterday morning, temp was 65, it actually probably took me a total of 30 minutes to complete with cleaning and all. I’ll try again to post pics.

Good news and bad news. The good news is your spray technique looks solid your good there keep up the same method. The bad news is those are fisheyes which is caused by something that has contaminated the boat surface, or more likely you have oil from your compressor coming out in your air line as you spray. The real bummer is those fisheyes are not easy to do a quick fix on your going to have to sand those down and go at it again. You might be able to use the duratec putty trick again but now that you know there is something waxy or oily or possibly water from compressor condensation in those spots. If its oil or wax nothing is going to adhere in those areas unless its cleaned out. Acetone with a new tooth brush might do it although tread lightly I have no idea how well acetone plays with Duratec clear additive. A tiny burr on a die grinder and some very careful grinding would also work so you dont have to cut all the gel back off the duratec putty.

Some of this may be redundant but I'll walk through what works for me. Once your prepped you have to put some effort into cleaning up your air supply and making absolutely sure the hull is properly degreased before spraying again. I use brand new white terry cloths and wiping in one direction you keep going over the hull until the rag discolors and repeat until your last rag stays perfectly white not discoloration at all. With acetone you have to move quick it evaporates so fast. Once the hull is ready to go you want to add an air separator to your spray system and use these especially right on the base of the gun because your air line is likely oily as well. I use one of these for every spray job I do then bin it. I have bought expensive ones and cheap harbor freight ones and they all seem to work for me. I do have a Devilbiss air filtration system for painting though so it could be mostly that. Regardless you defeinitely want one of these on the gun itself just take the quick connect off thread this on then the quick connect and your good to go. That will likely solve any further fisheye problems and if you could repeat that quality of finish I think you could buff that up great.

Attachment 532779


On the compressor side you want a filter drier if you dont have so it captures any moisture coming out. Those gun filters do a good job but its still something your likely going to want to add. I like Devilbiss product its been great to me but there are some no namers at Harbor freight too if you wont be using it much. This should get ya sorted out for next time

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Originally Posted by LakeFever

Good news and bad news. The good news is your spray technique looks solid your good there keep up the same method. The bad news is those are fisheyes which is caused by something that has contaminated the boat surface, or more likely you have oil from your compressor coming out in your air line as you spray. The real bummer is those fisheyes are not easy to do a quick fix on your going to have to sand those down and go at it again. You might be able to use the duratec putty trick again but now that you know there is something waxy or oily or possibly water from compressor condensation in those spots. If its oil or wax nothing is going to adhere in those areas unless its cleaned out. Acetone with a new tooth brush might do it although tread lightly I have no idea how well acetone plays with Duratec clear additive. A tiny burr on a die grinder and some very careful grinding would also work so you dont have to cut all the gel back off the duratec putty.

Some of this may be redundant but I'll walk through what works for me. Once your prepped you have to put some effort into cleaning up your air supply and making absolutely sure the hull is properly degreased before spraying again. I use brand new white terry cloths and wiping in one direction you keep going over the hull until the rag discolors and repeat until your last rag stays perfectly white not discoloration at all. With acetone you have to move quick it evaporates so fast. Once the hull is ready to go you want to add an air separator to your spray system and use these especially right on the base of the gun because your air line is likely oily as well. I use one of these for every spray job I do then bin it. I have bought expensive ones and cheap harbor freight ones and they all seem to work for me. I do have a Devilbiss air filtration system for painting though so it could be mostly that. Regardless you defeinitely want one of these on the gun itself just take the quick connect off thread this on then the quick connect and your good to go. That will likely solve any further fisheye problems and if you could repeat that quality of finish I think you could buff that up great.

Attachment 532779


On the compressor side you want a filter drier if you dont have so it captures any moisture coming out. Those gun filters do a good job but its still something your likely going to want to add. I like Devilbiss product its been great to me but there are some no namers at Harbor freight too if you wont be using it much. This should get ya sorted out for next time

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I figured I’d have to sand out the fish eye completely, there’s just to much to do the putty trick. As far as the acetone cleaning I use the white rags and keep using new rags until the come up white. I’m going to harbor freight when they open to get those filters and more sanding disc’s . Before I started spraying yesterday I told myself I should drain the tank but didn’t, live and learn. Instead of sanding gel coat off today I should be buffing.

We’ve all been there. I’ve done much worse. Just a small blip in the middle of an awesome project

Attachment 532787Attachment 532788Attachment 532789Attachment 532790Attachment 532791So I had enough gel left to do my transom. Sanded gel (fish eye) till it was gone, cleaned with acetone. Went to harbor freight to get filter for spray gun. Taped off boat so when I get more gel I can sand and blend. Fish eye shows back up but not as much. In the one photo you can see the original spec of red gel. I’m guessing my spraying system was messed up (contaminated) when I sprayed the primer and is going to continue to screw me. I even washed the boat with Dawn dish soap before I sprayed the primer. Is there a chemical I can use to wash the bottom with to get rid of this problem? A lot of the fish eyeing didn’t show back up so I must’ve sanded out th