Gel-coat layup

[52FordF2]

To the Gel-coat Guru's,

Is it feasible to do a layup for three consecutive days?

Like wash down with Acetone then first Gel-coat, next day do you need to wash down again or can you just lay the gel-coat down.

Then on the third day do the same but with Waxed Gel-coat.

Getting ready to lay some Gel.

Can't seem to find a day til late October or early Nov to do a full day of Gel and I want to do it while its still warm

 

[DeepBlue2010]

First of, I am no gelcoat guru. Our expert on the subject is ondarvr; whatever he tells you, follow it and you will be fine.

Is this for the outside of the boat (hull) or for the inside sections shown in your picture?

 

[52FordF2]

Inside for now.

I'll need to sand that area at the walk thru and tape off what I don't want to cover.
It has a brown stain that I would like covered also.

Was going to do ski locker later. That way I can work from back to front and climb out of the front area

 

[DeepBlue2010]

This makes it so much easier. You don't have to spray, you can roll. It is actually better to roll with a heavy textured roll to get the anti skid pattern rather than smooth surface which will be slippery. Rolling also doesn't take much time since you can just insert a new roller as opposed to spend time cleaning your spray gun/equipment.

All you need to wait is about 20 or so minutes between sessions until the gel "gels" and becomes hard to touch then you go with the second coat. On large surfaces + 70F temperature, this can be the time you will go from one end to the other and you can go back to the first area you coated to find it ready for the second coat.

If you wait until next day, you might not be able to get chemical bond between the successive coats.
Again, if Ondarvr tells you otherwise, just follow what he tells you.

 

[52FordF2]

Yep, planning on rolling and unless anything changes, planning on finish sanding walk through area, then washing out hull this evening.

Then letting it dry overnight and into tomorrow, Bow up. 80 degree tomorrow.

Then tomorrow afternoon start Acetone wash, Gel-coat.

May be working late into the night. If it tacks up within twenty to thirty minutes?

 

[DeepBlue2010]

I would wash with water. After sanding, I would vacuum and then clean with Acetone. I would want to take the risk of having trapped moisture. If you will be working in 80F, canalize at the lowest percentage recommended by your specific gelcoat manufacturing otherwise it will gel in 5 minutes or less

 

[Scott Danforth]

FYI...... ondarvr is currently at IBEX setting up a booth, so forgive him if he is slow to respond.

 

[ondarvr]

Like already said, it should start to get hard in about 30 minutes, so you may be able to start right back at the beginning and do the next coat. Waiting until the next day should be fine too, just don't do it in direct sunlight.

 

[52FordF2]

No Title

Got it washed out

Missed about four hinkies. :facepalm:

There one in the photo at the bottom of photo.
Right above the port engine mount area. Still don't know how I missed it.

Tonight Acetone wash down then hopefully Gel-coating.

I may want the MODs to probably move this to my 76 Hammond later. To keep it together

Thanks, I appreciate the advise.

Sometime I do things, then I find out I messed up :facepalm: .

 

[52FordF2]

No Title

First coat down, will have to wait for this evening to put down second and third.

Don't know if I didn't use enough MEKp? I was using 500ml of Gel and 5ml of MEKp.

The last section, it took about 45 minutes to tack up. that was about at 9 pm. Decided to call it.

Ok, what I had was two different manufacturer's of Gel-Coat. I had about a little over a half gallon left that was a year old. It tacked up right away.

The second batch which was just a couple months old (US Composite) took longer to tack up. Both we're stored at or around 70 to 75 degree. Temp yesterday evening was around 70 degree low humidity.

I'm going to increase the MEKp to 10ml and see how it goes.

 

[DeepBlue2010]

A year old could be too old for poly resin. Did you have any crystals in the gel?
1% isn't bad for the 70F. If you want increase it by 0.25 or 0.5 but I wouldn't double it. If you read the USComposites catalyst mixing ratio sheet, you will find them recommending 0.7%



Too much MEKP can lead to brittle cured resin. Not a good scenario.

 

[ondarvr]

Go with a minimum of 1.5%, 1.5 to 2% is recommended. US Composites doesn't make gel coat, they by it from a manufacture and repackage it, 1% is at the very bottom end and can give unreliable results when using it in this way. If you can't use it up before it starts to get hard, mix less at one time, don't reduce the catalyst %

 

[52FordF2]

No Title

Well I went to 7.5ml MEKp 500ml Gel-coat, it kicked off with about 100 ml left in the tray. Temps was at around 78 degrees, 72 Humidity.
Went back to 5ml MEKp worked fine the rest of the evening.

Used first coat (4) 500ml Gel-coat at 5ml MEKp
Second coat (4) 500ml Gelcoat 1st batch at 7.5ml, The rest at 5ml MEKp
Final coat (3) 500ml Gel-coat at 5ml MEKp and 10ml WAX. I covered the exact same area but it seemed to cover more.

After the second coat tacked off I waited about an hour before doing final coat.

While doing the final coat, my white socks were sticking but also leaving a faint black imprint. Was wondering could my laundry detergent be causing the chemical reaction. It covered over fine with the final coat.

The only things left on the inside are the Ski locker and two Aft lockers. I'll need to order more Gel-coat I only have about a half to a cup left.

Guess I'll be moving back to my Hammond thread now. Thanks for stopping by an helping me out.

r/ Dale J.

 

[ondarvr]

I should have explained it in more detail.

500 ml should take about 2 minutes to apply, you don't use a tray, mix it in a cup/tub and pour onto the floor, then use the roller to move it around, most of the first batch would be used up wetting out the roller. You could do 1000 ml in no more than 5 minutes.