Scratches on swim platform

[paulga]

I can't argue with your logic. Seems sound to me.

Is suggest hopping on Hull Truth or anywhere else you see a thread about it, even a dead one, and asking about single coat coverage.

The two things I wonder about are...

1) whether, if the gel is heavily diluted, it'll still be able to provide good enough 1-coar coverage, and

2) whether it kicks as quickly as a normal gel mix, allowing multiple coats quickly after each other, or if each coat requires more time.

But, again, I'm just wondering. I've never used it.

I look forward to your full report, whatever you use! Can't wait for the pics!

I have tried twice to apply gelcoat. It has to be a weekend with warm good weather while I also have time, so the timing is important.

The first time I used the paste form gelcoat in the Evercoat repair kit. I thought the paste could be thinned like kids watercolor paint which I could apply using a brush to have a smooth layer, but as it turned out, the gelcoat paste remained to be a paste even after being thinned a lot. When brushed on, it looked rough. I had to sand it down later. One thing to note was the white tint tube in that kit was less than 1/5 of its capacity. The brushed paste was not runny.

The second time, I ordered Totalboat laminate white gelcoat, added some black tint from the Evercoat repair kit, 10% styrene, and applied using a preval sprayer. It sprayed easily, but the tint did not fully mix with the gelcoat even though I mixed a long time. The tint clumps were sprayed out and ruined the efforts. So I wiped it clean with a lot of acetone.

The sprayed gelcoat was runny and flowing. Is this expected?

I will try again next time. Does the Evercoat tint not mix well with Totalboat gelcoat? Or did I miss anything?

 

[STB]

Hi PaulGA,

Can you post links to the kit you got the tints from and the gel coat you used? I'll take a look and see if I can sort why they didn't play well together. But, that probably won't fix them not playing well together!

The sprayed gel cost gets runny like that when it is sprayed to thickly for the viscosity. It might also be spraying from too close.

The dimensions you can optimize across are the viscosity of the gelcoat, the distance from the sprayed to the work, and the speed of the stroke.

I always practice on cardboard first and tune my mix until it goes nicely for me.

 

[STB]

BTW, you are doing the right thing to try and try again. It may be tuition, but the education will be lasting and empowering.

 

[paulga]

Hi PaulGA,

Can you post links to the kit you got the tints from and the gel coat you used? I'll take a look and see if I can sort why they didn't play well together. But, that probably won't fix them not playing well together!

The sprayed gel cost gets runny like that when it is sprayed to thickly for the viscosity. It might also be spraying from too close.

The dimensions you can optimize across are the viscosity of the gelcoat, the distance from the sprayed to the work, and the speed of the stroke.

I always practice on cardboard first and tune my mix until it goes nicely for me.

evercoat gelcoat repair kit

TotalBoat marine gelcoat white quart no wax

it liquid tint easier to blend with gelcoat?

https://www.amazon.com/Colors-Colorant-Liquid-Pigment-Translucent/dp/B07NQ4Y85H

It's probably spraying too close. spraying the edge while squatting down on the swim platform is awkward and difficult.

 

[lwarden]

You will either have to add wax to the laminating gelcoat or spray PVA over it or it won't cure properly. The Evercoat gelcoat tint should mix in just fine, that's an odd result. Any chance it's gone bad and setup?

 

[paulga]

You will either have to add wax to the laminating gelcoat or spray PVA over it or it won't cure properly. The Evercoat gelcoat tint should mix in just fine, that's an odd result. Any chance it's gone bad and setup?

I have PVA. Preval sprayer is able to make a mist of PVA easily.

It was said the min temp to gelcoat is 60F, it may not cure properly if the temp is lower. the temperature over the coming weekend is 60/40F, is temp too low during the night for the gelcoat to cure?

 

[lwarden]

PVA and the Preval should be fine to seal it. Can you get a heat lamp on the area? 60F should be ok, but lower than than isn't ideal. Also, you can use a heat gun on a warm setting to help the gelcoat flash off between coats, this works well. If you lay it on when it's cold it will take a long time to flash off between coats. You should let it get to the point where you can just put a fingerprint in it before adding another coat or it will run/sag.

 

[paulga]

PVA and the Preval should be fine to seal it. Can you get a heat lamp on the area? 60F should be ok, but lower than than isn't ideal. Also, you can use a heat gun on a warm setting to help the gelcoat flash off between coats, this works well. If you lay it on when it's cold it will take a long time to flash off between coats. You should let it get to the point where you can just put a fingerprint in it before adding another coat or it will run/sag.

below paragraph is from www.fibreglast.com

1. Ensure that your mold surface is properly prepared and has a Class 'A' finish. For more information on this, please see our Learning Center article- Plug Surface Preparation and Mold Surface Maintenance.
2. Thin gel coat to your preferred viscosity using #70 Styrene Thinner or #1039/1040 Duratec Clear Hi-Gloss Gel Coat Additive.
3. You can catalyze gel coat with #69 MEKP at 1.5-2.5%. Due to the lower monomer content for low emissions, we suggest catalyzing the LE gel coat at 2% depending on ambient temperatures. Mix thoroughly to ensure that all gel coat is properly catalyzed.
4. Apply gel coat to mold surface. Spraying gel coat is recommended for more accurate and consistent coverage. Apply gel coat in 4-5 layers at approximately 5 mils each, allowing 15-20 minutes between layers for a total thickness of 20-25 mils. Use #122-A Gel Coat Thickness Gauge to ensure proper thickness is achieved.
5. Once gel coat has tacked up, about 20 minutes after final layer has been applied, lay-up of the part can begin.

here are my questions:

Using long sweeping strokes, left to right, right to left, then to right: is this considered one coat?

Is 15-20 minutes wait time between coats a bit too long? I remember the final layer should not wait too long before PVA, otherwise it may not cure

What is the "lay-up of the part" in step 5 above?

 

[lwarden]

One coat is just enough material to create a glossy surface, so depending on how far your spray tip is away and how fast you move the gun it might be a couple passes. The instructions above are for making a part off a mold, so you can ignore the lay-up part which would be laying glass and resin over the partially cured gelcoat. You will want to spray the PVA after the last coat has tacked up just like the other layers.

If you are looking for some better guidance, Andy at Boatworks Today on YouTube has some great videos on patching gelcoat.