Complete Gel Coat Resoration Question and Help

[ondarvr]

Re: Complete Gel Coat Resoration Question and Help

There is one other issue, you need very large tips to spray metal flake.

 

[opmope]

Re: Complete Gel Coat Resoration Question and Help

While spraying some latex house paint will let you get used to how the gun works and what the adjustments do, it doesn't give you any experience with the actual gel coat you're going to use, which can be significantly different. It takes from 2 to 4 oz to dial in a gravity feed gun, this needs to be done instead of catalyzing larger amounts and spraying that much or more trying to dial it in under the stress of it being your first attempt at a job like this and the clock rapidly ticking until gel time. Whatever gel coat you don't use in the test spray can used as normal. If that first test spray with gel coat turns out terrible it gives you time to ask questions and get it right without wasting a full pot and/or screwing up the job.

Great tips. Thank you. Here is what still confuses me. I am not shooting into a mold. I am resurfacing my boat with about 30 mils of gel over existing gel after sanding with 80 grit paper. Now the manufacture of the gel and other posts I have read state I should put one coat on and let cure a min. of 4 hours. They recommend over night cure which is exactly how I would like to do it. As long as no wax or air dry is used the gel will remain tacky with no prep needed between coats??? The final coat, (3rd coat), on the 3rd day will have air dry add to cure tack free for sanding?? They say that the only time you need to resand is if you want to add another coat over the all ready waxed coat.
Why is the Yacht Dr. saying Ihave to apply all three coat at the same time?? Can I or can I not shoot over a three day period as long as I only add the wax on myfinal coat?

 

[oops!]

Re: Complete Gel Coat Resoration Question and Help

it can be done that way.....

remember that wax is a release agent....so if you shoot over a waxed gellcoat....the last layer wont stick. that is why no wax added till the last layer. and why you need to sand if you are shooting over wax.

you can wait 3 days and do it in that fasihon....but remember...this is not paint.....it comes out really thick.....and it needs to cure. if you shoot as ondarvr directed to get the hang of it....and learn what you are doing.....then shoot the other layer all at once, it is best for you...... we shoot all at once....
(you mentioned the manufacturer suggests.....lol...there is a good chance that ondarvr IS the manufacturer)

i dont want to get into curing ....cross linking, and chemical vs mechanical bonding... but the more you can dump on at once the better.

 

[oops!]

Re: Complete Gel Coat Resoration Question and Help

this boat was shot at 55 thou all at once

the boat was walked around three times....this is still the first pass

second pass

and after the third

it took us three hours to shoot this......each pass at one hour......

 

[opmope]

Re: Complete Gel Coat Resoration Question and Help

Thanks oops. That is exactly what I wanted to hear. Ill just remember to remove my taped lines from my stripes I'll be adding after my base is down.

 

[ondarvr]

Re: Complete Gel Coat Resoration Question and Help

A gravity feed gun will be very slow, so you may have problems with your tape lines because the gel coat will be curing before you can spray enough surface to be ready to pull the tape.

Like the others have said, this type of spray job is normally done all at one time, there's no need to drag it out over three days.

 

[opmope]

Re: Complete Gel Coat Resoration Question and Help

A gravity feed gun will be very slow, so you may have problems with your tape lines because the gel coat will be curing before you can spray enough surface to be ready to pull the tape.

Like the others have said, this type of spray job is normally done all at one time, there's no need to drag it out over three days.

I appreciate the heads up. Im hoping my gun will work for me. I actually just got it today, shipped from California. They say it will work fine for me. Lets hope so. Kind of nervous now that you say it will be to slow?? It has a 2.5 mm tip so they say the gel will just dump out of that gun. The tip size is large enough to spray my metal flake too. My boat is only 14' with a 6" X 10' stripan each side. I'll just spray over the taped strip area at the very end of my shoot on each side. While spraying one side I'll get my helper to remove the tape on the other. Next day Ill just re tape the stripes and spray again.
I don't have the luxury to spray all at once. I have to work and my helper has school. So we are getting up early and have to be done by noon each day. With any luck I should be spraying next week.
Thanks again for all replies.
Dave.

 

[oops!]

Re: Complete Gel Coat Resoration Question and Help

gell is really thick......it is actually pigmented polyester resin......the grav feed will be slow......its not the tip size that feeds the gun.....but the ease of the load of gell to the tip......

thats why it will be slow.....even blotchy as the tip gets some...spits it out.....and the hopper wont be able to supply fast enough.

that is also why pressure pots are commonly used in gellcoat applications.

the sellers of the gun will say that it will spray out fast.....but remember.....you are talking to a guy that sprayed gell out every kind of gun for 30 years before he became a rep for the company your gell most likely came form.

i shoot a 3.5 tip and the gravety hopper wont keep up.....the gell just takes too long to pour from the hopper to the thorat of the gun.
pressureize the hopper....and it will work. but that is a pressure pot

 

[Woodonglass]

Re: Complete Gel Coat Resoration Question and Help

opmope,

You really need to pay attention to these two guys. You will not find ANYWHERE two guys with more experience in the application of Gelcoat. Regardless of what the Gun's mfg says, if these guys say it won't work, then IMHO, you can take it to the Bank, It won't work. I've been surfing around this forum for two years and have yet to find anyone find them to be wrong when they give out specific advice. You would do well to heed their advice.

 

[ondarvr]

Re: Complete Gel Coat Resoration Question and Help

Every gun will be slightly different and each brand of gel coat will be a little different, with the right combination it "may" be OK, so give it try and report back.

 

[opmope]

Re: Complete Gel Coat Resoration Question and Help

Every gun will be slightly different and each brand of gel coat will be a little different, with the right combination it "may" be OK, so give it try and report back.[/QUOTE

Well I'm all finished. Worked out well. The gun worked great but my compressor could not keep up. Crazy, 2.25hp 20gal. and I would have to stop to let the pressure build up. I could only mix 16oz at a time and took 5 cleanings just to apply the first coat. I applied 4 coats, one per day and the last one I added the air dry. Very happy. I have pictures but do not know how to add to post. If I can email them and someone can post them for me would be great. Or guide me throught the process.
Many thanks again to all of your imput. Now time to sand sand sand.

 

[Outback Jack]

Re: Complete Gel Coat Resoration Question and Help

Hey opmope, good to see you got it done. I would love to see your pictures as I will be doing this in the next couple months. I use to spray gelcoat 4 hrs a day and the other 4 run the cop gun. I have been doing lot's of reading etc because I have not done it in over 20 years. Can't remember what we used for equipment but I use to curse it alot because there was always something needed to be tweaked. We use to run pressure pot's for different colours, worked good. Never had to worry about the quality of the finish as it was getting chopped over with glass. Just worried about thickness . You always had to be watching your gun as we had external mixture of catalyst on the chop gun and the gelcoat gun. I don't know how many times I would be spraying and take my eye off the gun for 20 seconds then to see the catalyst was not spraying right. The love of being in the fiberglass trade. I hope the equipment today is better then what I use to run.

Anyhow you can post your pictures by going into advanced reply and you can upload them from your own computer. You go to advanced in the reply to thread, then look for the insert image link (6 from left in the middle row , when you scroll over it it says insert image) just click on that and you will see a window pop up and you can just upload the images from your computer. Wait until the upload is finished and you have attached your photos. Then click submit reply.

another way is uploading them to say a photo place . Then copy the link from the photo place and paste it in the link through the insert image link .

But uploading them from your computer you must go into advanced reply or the pictures will not post


Hope I explained it for you

Jack

 

[opmope]

Re: Complete Gel Coat Resoration Question and Help

Hey opmope, good to see you got it done. I would love to see your pictures as I will be doing this in the next couple months. I use to spray gelcoat 4 hrs a day and the other 4 run the cop gun. I have been doing lot's of reading etc because I have not done it in over 20 years. Can't remember what we used for equipment but I use to curse it alot because there was always something needed to be tweaked. We use to run pressure pot's for different colours, worked good. Never had to worry about the quality of the finish as it was getting chopped over with glass. Just worried about thickness . You always had to be watching your gun as we had external mixture of catalyst on the chop gun and the gelcoat gun. I don't know how many times I would be spraying and take my eye off the gun for 20 seconds then to see the catalyst was not spraying right. The love of being in the fiberglass trade. I hope the equipment today is better then what I use to run.

Anyhow you can post your pictures by going into advanced reply and you can upload them from your own computer. You go to advanced in the reply to thread, then look for the insert image link (6 from left in the middle row , when you scroll over it it says insert image) just click on that and you will see a window pop up and you can just upload the images from your computer. Wait until the upload is finished and you have attached your photos. Then click submit reply.

another way is uploading them to say a photo place . Then copy the link from the photo place and paste it in the link through the insert image link .

But uploading them from your computer you must go into advanced reply or the pictures will not post


Hope I explained it for you

Jack

Here is the completed project. Link below
I think you can even see my Photo Bucket pictures of the second boat I did. It's a yellow 15' Fibertron
opmope's Library | Photobucket