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Old 23-08-2015, 05:11   #1
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I've got the gelcoat blues...

Or greens... literally...

SO I'm no bumbling gelcoat repair newb, but I ain't no minaret either by any means... But I'm having one heck of a time with a gel match issue on a "cute as hell" boat I'm trying to flip... (insert cute as hell boat here)



Long story short is that she was hit by scary big sparks of electricity from the sky... and had some hull damage that was repaired in spectacular fashion by yours truly...

Gel Repair Timeline
1. Check supplies, too old, not enough tints... Order from US Composites
2. Out of 12 tint jars, no "true yellow" was included... two named yellows yes
3. Try and match using one of the yellow tints... FAIL... One is too light to tint down, other has too much red... Neither could bring out enough yellow base…
4. Throw up hands, order an Instint color fan deck (720 colors) from "not named to not shame crappy composites supplier"
5. Pick color that matches and order gel...
6. Receive completely wrong color, not even the same card, FINALLY convinced "not named to not shame crappy composites supplier" that the color wasn't even close... (insert shameless color match here)


7. Receive replacement quart that is close but still does not match… Tried to force the color with too much tint and end up with unusable quart of gel… (won’t cure correctly)
8. Order pure yellow tint, and color match neutral gel myself… obtain SPECTACULAR match… (insert spectacular color match here)

And cropped and zoomed in...

9. Spray gel onto repair area with 6 coats, ½ hr between to flash…
10. Experience extreme disappointment with sprayed color match… (insert disappointing sprayed pictures here)




The finality of it all is that the actual sprayed material exhibited more blue/grey and green when none of these tints went in the mix….

???QUESTIONzzzzz!???
I had to thin about 20% styrene to spray… Can this much change the color??? I definitely waited long enough to flash, the coats were dry enough to touch without material transfer, but still tacky… Did I still have trapped solvents?

What is your preferred thinning agent?
Duratec?
Patch Aid?
Other?

SadSailor…
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Old 23-08-2015, 07:35   #2
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Re: I've got the gelcoat blues...

Patch Aid. Or, it's a small area... just roll it on and deal with the slight extra orange peel. Don't use styrene.
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Old 23-08-2015, 08:01   #3
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Re: I've got the gelcoat blues...

Quote:
Originally Posted by Azul View Post
Patch Aid. Or, it's a small area... just roll it on and deal with the slight extra orange peel. Don't use styrene.
Thanks for the post Azul !

I had a test strip with a brush after do the same thing, mixed 10%... All of those tinting experiments thickened the gel in the container, so I need to definitely thin it with something regardless of brush, roller, spray... I don't mind the extra texture of any method...

Patch Aid from Seahawk?
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Old 23-08-2015, 08:09   #4
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Re: I've got the gelcoat blues...

Styrene change the final color tone, it happen to me so many times with a simple White , Patch booster work well for me, but what the hell drop a pm to Minaret and my 2 cents you get a genuine answer...
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Old 23-08-2015, 17:11   #5
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Re: I've got the gelcoat blues...

Tough color to match. Everything you've done so far is very familiar territory! Nice match BTW. You are now running into the problems involved in more high end color matching, ie colors other than white. Reds and yellows are generally the most difficult to match.

Long story short, I don't generally go the neutral (clear) route anymore for exactly the reasons you are experiencing. You were on the right track with your second attempt, IMO. Get a factory color which is as close as possible to your repair, then adjust it. The tint you need is Chromium Yellow for this one. Throw out the cheap US Composites crap and order from Fiberlay. You only need 6-8 tints to match all colors.


Lots of problems with neutral. Sometimes it's actually required, but not often. You can get a perfect match, and not have enough pigment in it, which results in semi transparent gel. Or, you can get a perfect match and have too much pigment, which results in strong color changes during cure cycle or failure to cure. Starting with a color which is already close and has the correct pigment ratio helps a lot. Using the right catalyst is also important.

Stay right away from Patch Aid. Don't reduce more than 10-15% with anything. Only add surface seal to your last coat, which will be sanded off. Or use PVA. Pre waxed gel is a big no-no. I reduce with styrene monomer or MEK, and a scoche of acetone, the former to promote flow and prevent too rapid a solvent flash, the latter strictly to reduce viscosity for ease of spray. Good luck!
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Old 23-08-2015, 17:22   #6
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Re: I've got the gelcoat blues...

PS: I always complete my repair, color match in the prep halo, and brush apply a few coats to the repair as a primer and final fairing. Several advantages to this method. It fills all pinholes, no glazing required. It allows you to final fair with the entire repair surface in a single density, no soft and hard spots of original gel, bare glass, and fairing compound. This makes perfect final fairing much easier. And, it allows you to see if your color match has cured in the anticipated direction, ie lighter or darker, and make final adjustments before spraying. Failing this, always spray a small test patch and polish it all the way out before assuming a match is good.
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Old 24-08-2015, 09:03   #7
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Re: I've got the gelcoat blues...

Quote:
Originally Posted by neilpride View Post
Styrene change the final color tone, it happen to me so many times with a simple White , Patch booster work well for me, but what the hell drop a pm to Minaret and my 2 cents you get a genuine answer...
Hey Neil,

Thanks for the help confirmation wise! I knew minaret would be along soon as well... I needed a mental break from the frustration anyway!

PS Got an extrusion to finish my stick... I appreciate all the help there too... Picture story to come along shortly... It's a hoot...

Quote:
Originally Posted by minaret View Post
Tough color to match. Everything you've done so far is very familiar territory! Nice match BTW. You are now running into the problems involved in more high end color matching, ie colors other than white. Reds and yellows are generally the most difficult to match.

Thanks a ton, I've done it successfully quite a few times, but never had so much practice as with this dang yellow! I knew it was going to be tough though...

Long story short, I don't generally go the neutral (clear) route anymore for exactly the reasons you are experiencing. You were on the right track with your second attempt, IMO. Get a factory color which is as close as possible to your repair, then adjust it. The tint you need is Chromium Yellow for this one. Throw out the cheap US Composites crap and order from Fiberlay. You only need 6-8 tints to match all colors.

I was definitely having more difficulty than I thought would happen getting the "neutral color of of the neutral color" if you know what I mean... using way more base pigment than I thought should be necessary... I definitely erred with US Composites.... When attempting the difficult, don't make it harder by using crap... Lesson learned...
I was thinking of giving another company a shot at matching the Instint deck... and then adjusting if need be... Do you think Michigan, or Fiberglast ave decent product?

Or would you simply go the route you suggested, Chromium from Fiberlay, and know that I'm going to have to adjust??? The color BTW is straight yellow with a red, white to get close enough...


Lots of problems with neutral. Sometimes it's actually required, but not often. You can get a perfect match, and not have enough pigment in it, which results in semi transparent gel. Roger... Done this already... Or, you can get a perfect match and have too much pigment, which results in strong color changes during cure cycle or failure to cure. Oh, I went to both places here too... Starting with a color which is already close and has the correct pigment ratio helps a lot. Using the right catalyst is also important. Plan as above... Chr yell, or fan deck as you suggest... MEK-P, 10 drops/oz of gel

Stay right away from Patch Aid. Don't reduce more than 10-15% with anything. Only add surface seal to your last coat, which will be sanded off. Have been using wax on the last coat, preferred over PVA...Have both... Or use PVA. Pre waxed gel is a big no-no. NO WAY!!! ICKY!!! ***spits taste out of mouth having to say it*** I reduce with styrene monomer or MEK, and a scoche of acetone, the former to promote flow and prevent too rapid a solvent flash, the latter strictly to reduce viscosity for ease of spray. Good luck! Makes sense for MEK to help with solvent flash... Sister to the P... Acetone's OK huh? Skosh is 2-3%ish???
Quote:
Originally Posted by minaret View Post
PS: I always complete my repair, color match in the prep halo, and brush apply a few coats to the repair as a primer and final fairing. Several advantages to this method. It fills all pinholes, no glazing required. It allows you to final fair with the entire repair surface in a single density, no soft and hard spots of original gel, bare glass, and fairing compound. This makes perfect final fairing much easier. And, it allows you to see if your color match has cured in the anticipated direction, ie lighter or darker, and make final adjustments before spraying. Failing this, always spray a small test patch and polish it all the way out before assuming a match is good.
Makes a ton of sense, and will follow to the letter... or at the very least... loosely conform to the ideas...

I almost forgot... To make matters even more difficult... There's a base layer of gel... "or final layer of the gel before layup I suppose" that is BLUE/GREY... So... your suggestions right above are generally what I'm trying to... or attempting to do in spirit...

i.e. all blending will have to be done from the top layer down... Sheesh... Tanks for nuttin' ya dang yeller boat!

As always Min... you're savin' my butt, a big chunk of money that I don't have the luxury of not feeling the loss... AND... A trip to the padded room in the white coat... My appreciation cannot be expressed!!! Thanks for your valuable time...
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Old 24-08-2015, 09:55   #8
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Re: I've got the gelcoat blues...

Quote:
Originally Posted by HappyMdRSailor View Post
Hey Neil,

Thanks for the help confirmation wise! I knew minaret would be along soon as well... I needed a mental break from the frustration anyway!

PS Got an extrusion to finish my stick... I appreciate all the help there too... Picture story to come along shortly... It's a hoot...





Makes a ton of sense, and will follow to the letter... or at the very least... loosely conform to the ideas...

I almost forgot... To make matters even more difficult... There's a base layer of gel... "or final layer of the gel before layup I suppose" that is BLUE/GREY... So... your suggestions right above are generally what I'm trying to... or attempting to do in spirit...

i.e. all blending will have to be done from the top layer down... Sheesh... Tanks for nuttin' ya dang yeller boat!

As always Min... you're savin' my butt, a big chunk of money that I don't have the luxury of not feeling the loss... AND... A trip to the padded room in the white coat... My appreciation cannot be expressed!!! Thanks for your valuable time...

If you want someone to get you close, deal with GCP, here in Seattle. They'll do a pretty good match from a chip or part, using spectrometry to get close and a girl with a good eye to lock it in. They also have good tints and gel. Wish I knew more industrial grade sources in your neck of the woods, but I don't. This stuff is pretty rare anyway, and a whole lot of it is based here.

Reducing: reduce 10-15%, using about 50-50 acetone and MEK. Don't catalyze with Hi-Point 90 or any other very hot laminating catalyst. I'd suggest ordering one of the small (qt?) bottles of catalyst from Fiberlay. Catalyst these days is not just 35% methyl ethyl ketone peroxide, there are all sorts of accelerants and promoters in use. If you use a catalyst accelerated with cobalt, for instance, it often leads to blue shift, whereas MDA leads to red shift. Many of these products will also lead to color change over time, ie aging differently than surrounding gel. This is why I don't use patch aid, it's a melange of accelerants. And please, never measure by drops, it's not precise enough. Use a proper catalyst beaker or a syringe for very small batches. If you exceed 2%, this will likely lead to a darker cure.


Have you discovered 3M flexible abrasive sheets yet? The bees knees. Go straight to 800 on the wet sand, no other grit required. Then finish with 3M microfine sponge, then ultra fine sponge (1000 & 1500 respectively), Polish with 3M Gelcoat polishing compound. Most people can stop right there, but if you really want that top end depth and glow, do Farecla glaze followed by Fleetwax.

Always happy to help out. As always, feel free to ask away!
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Old 25-08-2015, 14:12   #9
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Re: I've got the gelcoat blues...

Quote:
Originally Posted by minaret View Post
If you want someone to get you close, deal with GCP, here in Seattle. They'll do a pretty good match from a chip or part, using spectrometry to get close and a girl with a good eye to lock it in. They also have good tints and gel. Wish I knew more industrial grade sources in your neck of the woods, but I don't. This stuff is pretty rare anyway, and a whole lot of it is based here.

Reducing: reduce 10-15%, using about 50-50 acetone and MEK. Don't catalyze with Hi-Point 90 or any other very hot laminating catalyst. I'd suggest ordering one of the small (qt?) bottles of catalyst from Fiberlay. Catalyst these days is not just 35% methyl ethyl ketone peroxide, there are all sorts of accelerants and promoters in use. If you use a catalyst accelerated with cobalt, for instance, it often leads to blue shift, whereas MDA leads to red shift. Many of these products will also lead to color change over time, ie aging differently than surrounding gel. This is why I don't use patch aid, it's a melange of accelerants. And please, never measure by drops, it's not precise enough. Use a proper catalyst beaker or a syringe for very small batches. If you exceed 2%, this will likely lead to a darker cure.


Have you discovered 3M flexible abrasive sheets yet? The bees knees. Go straight to 800 on the wet sand, no other grit required. Then finish with 3M microfine sponge, then ultra fine sponge (1000 & 1500 respectively), Polish with 3M Gelcoat polishing compound. Most people can stop right there, but if you really want that top end depth and glow, do Farecla glaze followed by Fleetwax.

Always happy to help out. As always, feel free to ask away!
Oh man.... I just new I made a mistake the day after hitting the boat with the big grinder and gettin' busy..... I probably had 2-3 square feet of hull I COULD HAVE taken a generous couple square inch gel match sample... Now I get to yell at myself while taking a hole saw to a perfectly sound hull...

I'll hit CGP for a match and a quart... Fiberlay for some MEKP and maybe an extra quart of your chrome yellow if it ain't in the $50 range...

It really doesn't matter where I buy from... There's nothing around here... It's all 3-5 days away via the fedex dood...

50-50 MEK/acetone at 10-15% sounds really good to me... Here's today's $64k question... Am I ok with MEK and acetone from Lowes??? Seems like lab grade stuff might be the way to go with all my issues??? Am pretty careful about avoiding solvent contamination

Taking my public thrashing punishment in stride... No more drops... Even with 1oz test batches... Already had new syringes, cups, nifty MEKP squeeze bottle/volume dispenser on the way...

NOOOOOoooo !!!! I have not seen the 3M flexible shiznit! Looks great! Already in my shoppin' cart! I've sprayed my fair share of cars and don't mind the process to gloss... But anything to make a job easier is game on...

BTW... Shootin' this stuff with an old primer gun I've had for years, laying down fairly well... but obviously a PITA to clean... Never used a cheap gravity cup... Thinking about one for this... I have 3 main patches about 3 sq ft each... However.... If I do get this dang color down, I can shoot em all for each pass!!! (pinch me I'm dreaming)

Thanks Min!

E
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Old 25-08-2015, 18:23   #10
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Re: I've got the gelcoat blues...

Quote:
Originally Posted by HappyMdRSailor View Post
Oh man.... I just new I made a mistake the day after hitting the boat with the big grinder and gettin' busy..... I probably had 2-3 square feet of hull I COULD HAVE taken a generous couple square inch gel match sample... Now I get to yell at myself while taking a hole saw to a perfectly sound hull...

I'll hit CGP for a match and a quart... Fiberlay for some MEKP and maybe an extra quart of your chrome yellow if it ain't in the $50 range...

It really doesn't matter where I buy from... There's nothing around here... It's all 3-5 days away via the fedex dood...

50-50 MEK/acetone at 10-15% sounds really good to me... Here's today's $64k question... Am I ok with MEK and acetone from Lowes??? Seems like lab grade stuff might be the way to go with all my issues??? Am pretty careful about avoiding solvent contamination

Taking my public thrashing punishment in stride... No more drops... Even with 1oz test batches... Already had new syringes, cups, nifty MEKP squeeze bottle/volume dispenser on the way...

NOOOOOoooo !!!! I have not seen the 3M flexible shiznit! Looks great! Already in my shoppin' cart! I've sprayed my fair share of cars and don't mind the process to gloss... But anything to make a job easier is game on...

BTW... Shootin' this stuff with an old primer gun I've had for years, laying down fairly well... but obviously a PITA to clean... Never used a cheap gravity cup... Thinking about one for this... I have 3 main patches about 3 sq ft each... However.... If I do get this dang color down, I can shoot em all for each pass!!! (pinch me I'm dreaming)

Thanks Min!

E
Chromium yellow is a tint, not a gel. Start with the closest yellow you can find and tint with chromium yellow, red, and then anything else you need to dial it in.

A cheap cup gun is great for gel. Just make sure to use the medium cone filters.


No thrashing. You're miles further along this path than most. For many, I'd suggest they just paint the boat instead, given the color.

Solvent from Lowes should be fine.
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Old 26-08-2015, 07:43   #11
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Re: I've got the gelcoat blues...

Quote:
Originally Posted by HappyMdRSailor View Post
maybe an extra quart of your chrome yellow if it ain't in the $50 range...
A quart? How many 300' boats are you gelcoating?

BTW, be very careful with chromium yellow. That stuff is like 5200 - the smallest little bit of it let loose will track everywhere and color everything within 3 miles.

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Old 26-08-2015, 08:04   #12
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Re: I've got the gelcoat blues...

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Chromium yellow is a tint, not a gel. Start with the closest yellow you can find and tint with chromium yellow, red, and then anything else you need to dial it in.
TINT! Roger!
Too bad the "not even in the same family shameless Instint color match by the shall not be named composites supplier" is so light... I'd never get it yellow enough...

A cheap cup gun is great for gel. Just make sure to use the medium cone filters.

Aye Aye Sir!

No thrashing. You're miles further along this path than most. For many, I'd suggest they just paint the boat instead, given the color.

I like to think I know what I'm doing on most of this... As I've done it plenty before over the years... BUT... When it comes to head scratching problems... You just gotta say uncle and get some help sometimes... (compliment not unnoticed... TY)

Solvent from Lowes should be fine.
Thank god for small things...
Quote:
Originally Posted by colemj View Post
A quart? How many 300' boats are you gelcoating?

RIGHT???? Oh Mark... I mix n test-mix-n-test-mix-n-test.......... couple ounces at a time makes the bottom of the can appear way faster than I would like... I should have enough left over to spray the dog no?

BTW, be very careful with chromium yellow. That stuff is like 5200 - the smallest little bit of it let loose will track everywhere and color everything within 3 miles.

Boy can I see that for sure!

Mark
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Old 26-08-2015, 15:56   #13
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Re: I've got the gelcoat blues...

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A quart? How many 300' boats are you gelcoating?

BTW, be very careful with chromium yellow. That stuff is like 5200 - the smallest little bit of it let loose will track everywhere and color everything within 3 miles.

Mark

I find black to be the worst for this. I always tape down some Wypall for my matching area, triple glove, lay out all my tints, not just some, and split tongue depressors into tiny slivers for tiny drops of pigment. Pull top layer and reglove every time you get the slightest bit of tint on your hand. Pigment can be impossible to clean up if it gets on porous gel, and it stains fabrics permanently. I'm very cautious with it and never get any anywhere but inside my tint kit. Have done matches in some very high end interiors.
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Old 26-08-2015, 16:30   #14
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Re: I've got the gelcoat blues...

I don't know gelcoats, I do know colors. That's generically called a "chrome yellow", i.e. yellow based on chromium. Also called "taxi yellow" "schoolbus yellow" and, from the folks at Kodak who were supposed to know about colors, "Eastman Orange" the color of their film packages. Orange--not yellow--they say.


The yellow and red pigments of ALL kinds are the ones that are most actively degraded by UV in sunlight, and paint shops all say they are the hardest colors to match, because once they've had a few years in the sun, nothing "factory" will match them any more.


The advice to send a chip into someone with a spectro-photometry machine is the best way to go. These machines are cheap and common these days (rare and expensive 25 years ago!) and with a competent operator, they will get you closer to the matching color than anything else. You may still have to work a wide area and feather the color into the old one, rather than working in small spots on the hull.


And then if course, even if it is a perfect match in daylight, when seen at night under sodium lights or other lamp sources dockside? It may not match. That's a whole other world of pain, hopefully not a big concern for you.
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Old 26-08-2015, 16:52   #15
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Re: I've got the gelcoat blues...

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I don't know gelcoats, I do know colors. That's generically called a "chrome yellow", i.e. yellow based on chromium. Also called "taxi yellow" "schoolbus yellow" and, from the folks at Kodak who were supposed to know about colors, "Eastman Orange" the color of their film packages. Orange--not yellow--they say.


The yellow and red pigments of ALL kinds are the ones that are most actively degraded by UV in sunlight, and paint shops all say they are the hardest colors to match, because once they've had a few years in the sun, nothing "factory" will match them any more.


The advice to send a chip into someone with a spectro-photometry machine is the best way to go. These machines are cheap and common these days (rare and expensive 25 years ago!) and with a competent operator, they will get you closer to the matching color than anything else. You may still have to work a wide area and feather the color into the old one, rather than working in small spots on the hull.



And then if course, even if it is a perfect match in daylight, when seen at night under sodium lights or other lamp sources dockside? It may not match. That's a whole other world of pain, hopefully not a big concern for you.


Ideally when doing a gel repair, the surrounding area will have had all oxidation/discoloration removed by wet sanding, bringing back the original color. Sometimes the whole hull might need to be wet sanded to restore original color.

Here's a Plan B method:

If you can't quite match the color absolutely perfectly, but only say 95%, try a duratec blend. Spray first three coats as normal, then dry sand flat 400. Then mix 20% duratec clear into your match, and spray out past your repair 4". Then do 40% duratec and a further 4", of course being sure you have prepped far enough. Work up to 80% duratec, which will put you out about 16". Blend as usual. The color will slowly fade from original to your match. I usually only do this on extremely tricky reds and yellows, they are already translucent enough for this to really work. Have done a number of repairs only I could find this way, including Donzi Red, the hardest color in the whole world to match.


There is also such a thing as a color matching light. They are pricey, and most people have never seen one.

http://www.amazon.com/3M-Sun-Color-M.../dp/B0013HFX56
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