Catalyzing Polyester Resin question

General Discussion
1

Ok - I have only worked with epoxy resin with slow hardeners.  I only make about a board a year, so for me waiting 3 or 4 hours for the resin to gel doesn’t really matter.  But, on my latest board, I have decided to put a polyester gloss coat for UV stabalization and for the nice finish.  This particular board is Western Red Cedar and is gorgeous with the epoxy…  With a really nice finish, it is going to be unreal…

With the epoxy, I mix the hardener for like 5 minutes or more to get a good mix.  With polyester, how much do you have to mix the catalyst?  Is there any good technique? 

This is the board after laminating / hot coat…

2

This is what it looks like from the tail:

3

To green to offer you knowledge on the gloss coat, but I can say that is a nice looking board.

4

poly is wayyyy easier to mix.. i dont know what the specific ratio is for your resin, but on glosses we usually use 4-7 parts to 100. that is with whatever resin we use. usually on lams and hot coats we use 2 to 100, but we want the gloss to gel quicker so it doesnt slide around.

 

if you have been working with epoxy you will have no trouble mixing poly. instead of adding the resin to the hardener and stirring for a while, add the catalyst to the resin and give it a couple moderate stirs and get going cause it is going to kick really fast

also, you dont need fancy paint sticks and all that stuff, a bent coathanger or a stick work well. although the paint sticks are nice and they are free at home depot

dont overthink it.

5

 

Cool.  I know laminating with epoxy takes me a little time - maybe 20 - 30 minutes to get the cloth all soaked in and all the excess pulled out.  But the hot coats, they have never taken more than about 5 minutes to spread / even out.   

So, what I gather, I need to stir up the catalist in quickly and make sure to flow everything out in a couple mintues.

Anyway, I have pictures through most of the process, I will post it up when I am finished.

6

Just set it off at 2-3 % thn stir real good for 30 sec, good to go.

7

The tricky part is to brush on your gloss coat: from nose to tail then from rail to rail then back to nose to tail very lightly. Do it fast.

8

    Howzit balsa, A little trick I found is when brushing from center to rail angle the brush just a little so it forces the resin towards the rail, works great for keeping an even amount of resin on the board. Aloha,Kokua

9

by the way, that is a great looking board. its compsand right?

10

girvin, balsa, and kokua give good advice. One thing to avoid is brushing too much. As the resin ‘kicks’ the wax rises to the top. If you brush too much you will disturb that top layer and the resin will remain tacky forever and not be easy to sand.

11

It is actually a hollow cedar board.  The skin is 1/4" western red cedar and the frame is 6 mm marine plywood.  The rails are bead and cove.   

I took pictures through most of the process and I will post up a thread when the board is finished.

Thanks!