Final layer of mold plug?

There are dozens of Duratec products, some you mix with gel coat, others are stand alone.

Primers are stand alone products, Duratec clear additive is mixed with gel coat.

Duratec clear can be used at ratios where you won't need any wax for the surface to cure tack free, it will also spray, level and flow better. There are always trade offs though, it doesn't make gel coat better, just easier to use.

 

on plugs i always use duratec surface primer.

its easy to sand and polish to a good enough finish to take a mould from it.

using gel on plugs is ok but it takes a lot longer to sand and polish it up.

if i use gel on a plug i always put a layer of mat down first and then build up the gel thick enough to sand and polish.

 

Thanks for the help guys, thought I would give an update and it might help the very few who are new to polyester on this board

I really like how easy gel coat is to work with, I am getting the hang of it and no longer intimidated (usually use epoxy)...little things like knowing what wax does, knowing how gel coat cures facing the air without wax, and proper mixing ratios are most important.

Right now I am using only like 1 or 2 ozs at a time so I have been using about 10 drops of MEK-P which should be around .6 cc @ 2%...Maybe next I can work on knowing exactly what % works best depending on the weather...but it's difficult when using only small amounts and the measuring cup's lowest mark is 2.5 cc

So I put 3 layers of gel coat on the mold, the last layer had wax. What I would have done is used wax on all thre layers and lightly sanding after each layer to smooth them all out. I had to sand a lot to get the final waxed layer smooth and even. O boy is gel coat a different sanding experience than epoxy- much more solid and it's easier to sand

I then wet sanded to 1500 grit, added a few layers of the Johnsons paste wax and added a layer of Partal #10 with a brush. That stuff is pretty cool to, made sure I waited about 50 minutes for it to dry and then added a layer of tooling gel with a brush. That layer cured overnight in the HUMID garage...Then today after work I put a second layer of tooling on.

So far so good and will be epoxying several layers of fiberglass to build up the mold behind the gelcoat. Tomorrow night or Friday I will try to pull it off.

I should have paid attention in high school chemistry......

 

post a pic if you can, love to see it

 

Now you have me worried..
The epoxy sales machines have done a great job of $h1tbagging poly/styrenated resins.
What I'm concerned about is the epoxy you're proposing to use against the tooling gelcoat- unless an epoxy sounds like a bad idea to me.

Get a couple of syringes for measuring small amounts of mekp & some digital metric kitchen scales(you can borrow from the kitchen but put in a plastic bag to return unharmed)- cheap investment on exxy materials especially if purchacing small quantities

Jeff

 

I put white gel coat over the epoxy plus surface and then build the mold off the gel coat. I will post a picture sometime soon

 

where you say you are building up several layers of fiberglass behind the gellcoat to build up the mold, most people wouldn't be using epoxy.

 

O I see, should I use polyester resin?

I also need to work on getting a smooth finish on the plug and mold

 

yeah, besides epoxy is double the price, poly sticks better as I understand it.

 

Here are the pictures, you can see the gel coat didn't cover the whole piece after I block sanded it, this is the piece with Partal #10 on it ready for tooling

And the mold is kind of dull. there are some bumpy parts on it which I knew would come through. I didn't care to fill them in because that's not where I will be pulling the part from the mold

 

If you sand the moulding with superfine paper and then polish it,you should be able to get a mirror finish.

 

You think 1500 grit is fine enough?

And what polish should I use by hand and what type of towel should I use?

 

1500 will be great,but it might take a little time.I would follow with fine rubbing compound and not be too concerned about towel type-even paper kitchen roll will work.

 

id start off with 800 wet n dry paper and then use 1000 , 1200 and 1500.

to polish it i use farecla G3 advanced liquid compound or G6 advanced liquid compound.

you could use a course compound to get the wet n dry marks out and then use the G3 or G6 to polish it.

ive never had any problems using the compounds i have mentioned when polishing moulds.

 

You can even start at 400 grit IF you have to... as long as you work through the grits, it will polish up fine. These days even 3000 grit paper is available.
Mostly the polishing pastes will leave a flawless surface from 1200 grit so not too much need to go finer, though you will likely need a power polisher.