mixing with hardener?
I may attempt the gel coat repair on my 400X this weekend using the gel paint that QCC shipped me a month or so ago and would like to know what kind of consistency / viscosity to expect after I mix the hardener into the gel.
- Will it be relatively thin and pourable, or relatively thick and spreadable?
The ratio of MEKP hardener to gel that Phil had suggested to me was 10 drops per teaspoon.
- What do you prefer to use to measure out relatively precise amounts of gel? Do you use cheap plastic kitchen type measuring spoons or cups or something more specialized?
- Do you mix the hardener with the gel in the same container in which you measure out the gel?
It’s probably best to …
… use a metal tray , and after mixing catalyst and gel , spread the mixture thin in the tray … reason for this is , the pot life of a clumped mix will begin to set up much quicker than thinner spread out mix , the two part mix is thermally activated (chemical reaction heat) , a clump can become hot enough to self ignite so be careful not to dispose of waste until cooled down … pharmacy will have large plastic seringes (with out needle) to draw and measure ratio parts with … the product you have purchased should have directions for mixture with it … if in doubt , do a test mixture and adjust as required … I don’t know anything about need to cover and keep from air exposure but perhaps , never had to with any other catalyst (hardner) activation products ??
MEKP hardner …
… is the catalyst (or hardner) for polyester or vinylester resins … MEKP is added to resin to effect chemical reaction (hardening) … MEKP has very short shelf life , aprox, 2 mo. , is highly vilotile and dangerous if mishandled …
Thanks for the tips.
– Last Updated: May-17-08 12:12 AM EST –
I've never done any gel repairs, so I'm nearly completely ignorant and illiterate in this area of life.
The gel from QCC came without instructions.
Don’t mix the …
… MEKP hardner and resin (polyester or vinlyester) in a paper or styrene cup , or anything glass … use a cheap paint roller pan or simular made of tin or metal … if the resin doesn’t harden or cure in open air , it because you didn’t add the catalyst (MEKP hardner) , that’s why the two components are kept seperate until ready to mix and use … you’ll have to scuff up (#80 aluminum oxide paper will do) the area desired to repair (tape off perimeter of repair area first) , maybe even have to do some infilling with a fairing or (an epoxy with some filler in it) first (will cure a grey or brown probably) , depending on extent of damage depth in the skin … usaually after final top color coat of MEKP hardner and resin mix is applied and cured , you would wet sand out with #1200 paper and buff the remaining out with wax coat … if the color of the gel repair kit is same as original color of repair area , you won’t even be able see the repair after buff … same process is used to repair all fiberglass things I know of , minor boat repairs , auto hoods etc. , fiberglass tubs and shower stalls …
Have the surface all prepped
– Last Updated: May-17-08 10:10 AM EST –
Gelcoat for dummies like me -
Gelcoat that is runny isn't going do much of a job at sticking to the surface to rebuild the layer.
If you have overshot the hardener amount a bit, you'll be moving fairly quickly to get it down. Like 15 minutes.
If you left it a bit softer, you have more time.
Either way, it's a pretty limited amount of time per layer.
Heed to advice about plastic cups - they can become part of your gelcoat. (Not sure why not glass though.)
And if you did an unhappy job you can always sand down the excess or add more. It's not sensitive work.
If you want written instructions, you may be able to find them on the site for either West Marine or Hamilton Marine. I'd take a second look at what you have in your hands though - there may be instructions on the hardener.
Well the “no” glass …
… part is probably more appropriate for larger quanity mix , the mix can generate enough heat to burn you and the glass gets very hot , that’s all …
I did not know that. Of course, I’d hope that I wouldn’t need that much at one time…
Yanoer, you know you can always call…
You are NOT getting what you need to know from this thread at this point.
Above statement is not intended to hurt, offend or dis any of above good hearted posters.
No offense taken …
– Last Updated: May-19-08 12:30 PM EST –
......... onnopaddle ....... although I am fully capable of gelcoat finishing and or structural repairs in fiberglass hulls or products , there are questions about the nature /extent of repair required for Yanoer that I haven't answers to without getting into a step by step specific work order process ......... my preferable choice for gelcoat only repairs is multiple layered spray on applications ......... the tacky surface that Eric_Nyre speaks of which make him think he has to cover with wax paper or something , is standard fare with air -inhibbited gelcoats (nowax in resin) , the tacky (which is a surface film only) is instantly removed with first stroke of finish sanding , if Eric_Nyre found that his gelcoat would not set up (harden) , it was because he didn't use or use correct proceedure when adding MEKP hardner ........ in any case , I agree with you Onnopaddle , if Yanoer can call you for assist , and if you know what you are doing without doubt , then he should call and work with you or another with lots of experience so as to not get all this complicated confussion ..
some good advice
– Last Updated: May-19-08 1:02 PM EST –
The mixing ratio between gel coat and hardener (MEPK) is usually 12 drops per oz.
You want this to be between 1% and 2% of the gel coat, so whatever info you have sounds way off, so you may want to check that.
One ounce covers quite a bit of area.
Prep the area. I used a dremel tool, but do whatever works to take down the damaged area to the fiberglass.
Clean it with boat cleaner solvent or acetone, be careful with the acetone not to discolor other good gel coat.
You can use a plastic or paper mixing cup, (plastic to be safe) as this is what is sold at boat shops.
You will use more than one applications and more than one mixing cup.
Use a small throw away brush. Try and clean it and pull free any loose bristles.
Mix first batch, 12 drops per ounce, thoroughly stir. If it is hot, then 10 drops of hardener.
You don’t want too much hardener or the gel coat will be brittle, too little and it will not cure properly.
Apply the first coat with as much gel on the brush as it can hold without dripping off. It is kind of thin but it’s best not to try and touch over it, as the first application is the thickest.
When the first batch is setting up, wait until you can touch it with your finger and it leaves a finger print, but doesn’t pull any gel coat away, and apply the second coat. Then do a third coat is the same way. (you will need to mix another ounce for each coat)
On your final coat, apply a Mold Release gel with a throw away brush. Try not to deform the soft gel coat. You will need to be very delicate, then let the excess mold release drip off. It washes off with water.
The plastic covering is a nightmare and you end up with air pockets and all kinds of problems.
You will be left with a built up area then sand this down. Start with heavy grit with a block, (folded cardboard words well) then work you way down, to 150, 220, 320 wet, 400 wet, 600 wet, 1200 wet.
You don’t need every grade of sandpaper. The 600 and 1200 are more of a polish that shines your boat.
Be careful not to over sand.
Then polish with a compound polish.
Edit: with the gel release, dip thick on the brush then one swipe, redip, as long as it touches the gel you will be fine. Try to apply just before it starts to set up.
If it is hotter then use slightly less NEPK. 10 or 11 drops if it is over 80. Don't spread it out in a pan. (sorry, but it is a chemical reaction) Let it sit in the cup for about a minute or so with mixing. You should have plenty of time for one coat, say 15 minutes, unless it is too hot or you used too much hardener.
You can clean brush and cup with acitone, use latex gloves.
Well , the spreading of …
… the mix out into a pan , is to make the mixed gelcoat thinner (as in thinner depth wise) so that it does not build any more heat than nessasary … a thinner layer will cure much much slower than a clump or thicker layer because it is a chemical reaction taking place causing the heat which deternines cure rate , the thicker layer or clump heats up to a higher temp. thus excellerating curing temp. and pot life usable time …
Yeah, that’s a good idea if you need to extend the pot life for epoxy or gel goat. But keep in mind that it also must be mixed first and sit up so the chemicals can react.
However you should have plenty of time in a cup, so the pan isn’t necessary, for this small application.
I had no problems with a cup repairing over 10 spots with one ounce each batch.
Follow my directions for DIY and you will be golden.
I just did this, so I wanted to pass this on.
I also keep the other tips in mind.