Gelcoat over semi-perm release

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#1

Got some cleaner, sealer and WOLO for experimentation. Used it on the plug, first. I know it may be considered a waste of resources, but with 300+ hours in the pattern (27 sq/ft) to get it straight and true, and a few tricky details to complicate matters, I was not going to take ANY chances on not getting a clean release (I laid up a partial, thin trial mold last week, which DID release trouble-free… slid right off). Anyway, using tooling gel (w/ MEKP @ 2%) and a cup gun (@ 55-60 PSI), the first pass looked as if it almost wanted to fisheye. It DID eventually cover, but it startled me at first. Anybody else have this experience? Did you do/try anything that eased this for you? Would Duratec Hi-Gloss Additive help?

Thanks.

#2

Most everytime you lay any gelcoat down on a waxed surface youll get mad fisheyes and streaking. Its just how it goes and why we use multiple passes after each layer is cured.

Ive recently discovered that you should never try to add another layer of gel to what you think is “B” staged. It will alligator on you so you may as well let it get a bit harder before the next layer. Most all gelcoat will not cure(FULLY) without sealing it from air anyways so you have time

#3

It always happens to me. Its normal.

Have you tried spraying at different pressures to see if you can get it to atomize a little better?

Ive been spraying at 70 to 80 psi with a 50’ hose. That would be about a 20psi pressure drop at the gun. So we probably spray at the same pressure.

I spray gel just thick enough to wear the fisheyes disapear. Let the gel sit for a minute and a half (which helps eliminate surface porosity). Then continue spraying before the rest of it kicks in the cup.

Havent had a problem yet.

#4

I use WOLO religiously and the fish eyeing always happens after the first application. I found that if you don’t let it air dry, it won’t be as bad. I always wait until it starts evaporating, then lightly wipe the excess off with some Bounty paper towels. I’ve got some small molds that I have gotten 25 pulls from with one application. Kinda scared to go any farther than that though. ;o)

#5

Just wasn’t sure with this new stuff. We’re OK on this end, though. Shot gelcoat over the same plug for a partial mold, today… thinned about 15% with Duratec additive, catalyzed just under 2% and at 50PSI (regulator at the gun) w/ a #5 tip… down from the standard #6. Just ignored the fisheyes as best I could on the first pass and they covered right up on the second pass. Fact is, thinned, with the smaller tip and tad lower pressure, it went down pretty smoothly. Got about 15 mils from the first cupful (24 ounces) over 12 sq/ft. Didn’t think it was EVER gonna run out! Got the second cupful on it and called it quits.

Thanks guys.

#6

I have the same problem when I gelcoated another layer in the “B” stage. The alligator view is happened and after the gelcoat is cured and you pass another new layer.

#7

Just to confirm.

So I should just lay it on as thick as possible the first time? To get the fisheyes to disappear.

Or wait til it is past the B stage before doing another coat?

#8

No as long as its still wet you should be fine.

The problems come around when you let it start to cure and then add some more wet gelcoat to it too soon and the styrene from the second layer attacks the partially cured first layer.

So if you put it down, dont sweat some fisheyes…infact just ignore it and on small parts like I make…you just wait about 30 seconds for it to settle down a bit and go back over it.

I had serious problems with tooling gel because of the earlier mentioned problem not surface gel coats. I just dump that crap on.

#9

Is WOLO a Frekote product?

#10

If you have a lot of time into making the plug, then why not wax properly, brush on 2 coats of gel, leaving plenty of time for the first coat to harden?

There are no problems with fish eyes if you brush gel coat, and if you are making a mould and want things to be trouble free, then its worth looking at this method.

#11

If you have a lot of time invested in a plug, brushing on gel coat would be a great way to ruin it!
Spray it for proper coverage and thickness.

#12

Laminator that makes parts for me, who seems to really know his stuff, doesnt have a spray gun of any kind, and appears to do very well when it comes to making top class moulds.

#13

So he’d still use a brush if making a boat mold?

The OP states his plug has 27sq ft of area. That’s rather large, and brushing will take a long time.

#14

For something this size, I’m partial to spraying. Not that it would make a difference (till I can get past this semi-perm/pre-release issue), I wish I had an HVLP gun with the reservoir capacity to shoot this thing, though. Just seems a little more natural to me than the cup gun. I have a gun with a 2.2mm tip that I shoot surfacer with, but it only has a 20 ounce cup, and it’d be just my luck that I’d lock it up trying to get two cups of gel through it. If you include the flanges, this mold will be about 35 sq/ft so it would take “a cup or two”. Ah, well…

It’s not a boat,… but close! :smiley: