gel coat repairs

[Todd Pearce]

HI,I`ve,read capt Pat`s re-gelcoating article,My question is, can you spray '' touch up" gel coat in small to medium size patch repairs. I have a previous paint repair about 18 inches long 8 inches deep,done by the previuos owner,Its a bad repair and has all but been worn off by a fender,I would like to remove the last of it and spray it, in gel coat, and at the same time fill,fair and spray some unsightly holes in my dash. Is this a good choice ? or am i reinventing the wheel so to speak, I read somewhere " the wheel reinvented often ends up square'' I have purchased some gel coat from Danny at High Tide who assures me its a very close match,It arrives this week and whilst I am a bit intimidated after reading captains article, I`am keen to have a go, was thinking to have a trial first, any and all,expriences,advice,opinions,etc welcomed Thanks for reading
Regartds Todd

[bob lico]

Todd I am in the same predictament I am doing a hurricane sandy repair for a good friend.this boat has a 6" hole right thru just below rub rail.i was able to built up from inside rope locker and make nice and flat out side but now face the gel- cote task. Many people with many methods really not sure some spray with thinners in special gel- cote HVLP gun some use the same nozzle size in there regular paint priming gun.similar to you I have small area to match and would like to hear with the pro's do..

[CaptPatrick]

Spray gelcoating small patches or repairs isn't worth the time and effort. Everything has to be sanded anyway...

To prepare the area for gelcoat, make sure that the substrate is dished out to 1/8" below and feathered into the surrounding surface, clean thoroughly with acetone and build up a new gelcoat base using a paint brush. Several coats may be needed to build the new gelcoat to be 1/8" above the surrounding surface.

When applying the first coat, first rub the gelcoat into the raw surface good to fill any pin holes. A finger or clean rag will work fine. Successive coats should be applied as soon as the previous coat tacks up. Use surfacing wax mixed in for the final coat so that you have a sandable surface after the cure takes place. Remove the surface wax residue with naphtha.

Allow to the gelcoat to cure for at least 3 days, a week is better, after which time begin sanding it down to close to the final surface. The last dry sanding will be with 360 grit paper, (don't start corser than 100 grit). At that point begin wet sanding, starting with 400 grit wet through 1,000 grit wet. Buff out with 3M Heavy Duty Rubbing Compound followed with 3M Finesse-It and then 3M Perfect-It.

Provided that color match was good, the result should only be noticable to a trained eye. Old gelcoat has already bleached out and new gelcoat will start bleaching, so there really is no such thing as a true color match except maybe pure white or pure black...

[Todd Pearce]

Sounds very do-able even for me,will have a go in a spot thats not easly seen and let you know the out come,thanks for the help

[bob lico]

Well I'll be damned gel- cote applied with a brush instead of a specialize spray gun. That one hell of a tip considering I don't have to haul a air compressor to a remote dock area! Thank you as usual your at the top of the "game".

[Bruce]

I've used a preval disposable for gel coat up to 10" diameter. Cleaning my spray guns is too much of a pain.

Scratches and nicks I use the paint brush method.

[bob lico]

I like that idea Bruce I use that preval disposable all the time for small paint repairs I did not imagine I could use it for something as thick as gel- cote. I imagine you must thin it considerably .

[Todd Pearce]

Hi Bruce can you tell us more about the preval you use,is it any different?like Bob i didnt think of this becuase i thought the gel cote would be to thick
Regards Todd, and Bob your so right, capt Pat always seems to have the right answer,i`d have never thought you could brush it on!

[Skipper Dick]

I've been using Preval for years with gel coat. Assuming you can get a good match, I usually do my own tinting and overspray some because it usually orange peels to some degree. With over spraying it, you can easily use a wet/dry sand paper to smooth it out after it sets for a few days or longer. I've done large and small projects including my bow pulpit and to the areas that needed repair. You have to thin the gel coat some after adding the catalyst. Add the thinner in small quantities and test it on a piece of cardboard or something until you get a good spray. I've always used acetone. Spray on a good coat and let it flash and then put on another one after that. You can add several other coats after that to get it thick enough. The bottle cleans up good and so does the co2 cartridge if it has any co2 left. I've used the brush method too on small projects, especially in areas that are flat and not vertical and the need is for a good thick coat.

I've found that the new gel coat will blend in after exposure to this hot Florida sun and no one can find the repair.

[Todd Pearce]

Thanks Dick, I brought enough gel to have a bit of a play so Iam going to have a play with the preval and see how it goes,seems like it could be a good place to start
thanks again for you input

[Raybo Marine NY]

used to thin gelcoat with acetone, spray with my eyes closed- never had to think about it. Talking hundreds if not thousands of gelcoat repairs.
Now they have LVOC and HE gelcoats, armorcote, buff back, etc

thin new gelcoats with acetone and watch the repairs turn pink in a year.
I like to think I have tried every method I can, wax, acetone, pVA, styrene, etc..
Keeping the gelcoat as PURE as possible is the key to longevity. Its easy to look good when your done you want it to look good years later.
For the last few years we have been using different patchaids according to what gelcoat you purchase.
I buy 5 gallon pails and tint to match my own whites, have repeat customers where I can keep my eyes on the old repairs- you cant use those old methods anymore they wont last.

Bad thing about Preval on a larger repair is it lumps the gel on thick with a very narrow spray pattern, so all the blocking after still wont get the repair straight again it will look lumpy.

[Todd Pearce]

so, Raybo, if you were me how would you go about it?

[Raybo Marine NY]

I would use a quality reducing/patching product like CCP patchaid, in the appropriate temp rating for your environment. It is sold in different "speeds" for this purpose. Practice on one or two before going all out because the last thing you want is insufficient cure which turns into a paper clogging mess. I would also caution you may end up sanding the original gelcoat through around the perimeter of the repair depending on the age and condition of your original gelcoat.

Ideally if you have the gelcoat a bit on the warmer side it will naturally reduce its viscosity, but this will also make it cure much faster so have a spare preval or two on hand if this happens and throw it in a bucket of water if it starts to go off on you. Dont skimp too much on the MEKP or else it can also not cure properly you have to stick to the 2% rule you can sometimes push 1.5% but again this will affect its longevity.

Thin just enough to spray then spray the final 2 coats with a 50-50 reduction of your patchaid to act as a surface cure, practice and try to get your methods right.

Its one of those things thats practice practice practice. Imagine trying to repair the middle of a 20 year old car hood and have it come out undetectable? Cant be done but people think its possibly with gelcoat. In a certain lighting conditions a trained eye can always pick them up.

[Todd Pearce]

So ,today i went and spoke with our local F/glass supplier,and much like Raybo, he warned of problems with thinnig,his answer was not to thin,but use a HPLV gun with a 2.5-3 mm tip,his agument,You have to sand anyway and its a small repair,similar in some ways to capt Pats brush on approach,but as capt points out , a brush just goes in the bin! Bob, he also said that just about all companies sell both spray and brushable gel,I didn`t know that ,so being a keen kiwi I brought a gun,a preval ,some brushes ,and surficing wax and Iam giong to have a practice with them all,and see how good/hopeless i am ,cant wait!
just checked capts re-gel coat article and it suggests 10% surficing wax,Ross at nz f/glass said no more than 2%, this is somthing that sounds like a trap for young players,any thoughts???

[Bruce]

Never had a repair turn pink or discolor, but I haven't done a repair in 5 years or so and products may have changed to reactions of thinners.
Prevail does have its size limits. I always sprayed multiple coats.

What one has to remember is repairs tend to shrink anyways with time. Thats what a repair is, a repair, a patch is a patch. Everyone's eye sight is different. Some see imperfections, some don't.

I've seen expensive show quality paint jobs look amazing in sun light. Put that same car under different light waves such as a street light at night and not so much.

Do your best and remember your eyes are always going to go right to the repair and see any imperfections. You could ask 10 people to point out the fix and unless it looks like a mustache on a woman, most won't be able to tell.

[mike ohlstein]

I used to thin gelcoat with MEK. Not MEKP, MEK. That was 35 years ago, but I don't know why it wouldn't work today. You're going to add the same stuff with some peroxide in it as a hardener anyway.....

[Todd Pearce]

well I did my first gel repairs this week, some on the boat and some down in the shed, the ones on the boat I took capt pats advice and did by brush, all worked out really really well, infact I`am stoked with the result, most of the repairs, you would have to know where to look to find them, the gel coat from high tide was a great match, the other big repair was on the helm foot rest well, It had about 37 holes in it where it had been fitted and refitted over the years,truly a mess, This, I decided to spray, as first attempts go, it didn`t go so well, to much gel, not enough air pressure, etc etc,,after some practice and some more advice from a painter I know ,thinks got better and despite having a first coat with a lot of orange peel, I continued to spray ,put three good coats on and crossed my fingers that it would all work out, So tonight I wend down to the shed and began to sand, It all went very well ,its quite easy to work with and within the hour I had it all sanded and ready to buff,15mins on the buff and its was fantastic, what a great result, What I love about it is, that you don't have to be a expert to get a great result, the foot well looks like it just came out of the mould, I`am hooked now,I cant wait to fix all the other little chips and nicks, its such a rewarding job
Thanks to all for your help and support
regards Todd