Fin Panel Layup Question

I’ve been laying up a few panels with 6oz and Poly resin, both by UV and with MEKP. I am not using a roller, just a squeegee and trying to use as little resin as possible just to wet out the cloth. I’ve had some of the panels start to warp a bit in the center when I release them from the glass.

Any ideas why I’m getting this warping? I have been laying up about 6 layers at a time and letting it cure, sometimes leaving it overnight, before continuing to add more layers to reach the final thickness. Is this the problem? Do I need to wet out the layers in small catalyzed batches continuously all in one sitting? Is it even possible to do this or would this cause a problem?

Any help would be greatly appreciated. Thanks.

…hello, not so much information to decipher where exactly is the problem.
I make all types of panels due to I build lots of boards with glass on s. I laminate all the layers with the same batch of resin if the panel is not so big. Now I do not have enough space so I downsized my fin table to the wide of a fiberglass roll.
Other point is if you do the way you are doing the possibility to have gobs of tiny bubbles augment a lot. This is not good if you want a nice tinted fin.

I do all at one sitting with two batches. Whenever you add on to one side of a cured panel you’ll get warping. Waiting 24hours before popping it is a good idea.
You can also get a tighter panel if you use a combo of roller and squeegee. It takes a few more layers to yield the same thickness which is ok with me for a good result.
I’d stay away from suncure because the top cures faster than the under layers and probably adds to the problem.

Historically fin panels were laid up with 30 layers of 8 ounce cloth. Lam resin, with cat, 10 layers at a time. Typical fin had two colors. The center layer was usually white, outside panels were matching colors. Lots of variations are possible. As Gene suggests, stay away from the sun cure resins. Don’t get sucked into over thinking a process as simple as making a fin.

I really appreciate your input and have learned from you and some others that my problem originated in not laying up the panel all in one sitting. And yes, the way I was doing it caused me to have to fight tons of miniscule little air bubbles. I’ll pick up a roller and try the next one in one sitting. Thanks for your help.

Gene, your advice is greatly appreciated. My main mistake has been not completing the panel in one sitting. I don’t know why, I had thought that this was not possible as it would heat up too much or something. Anyway, I will implement your suggestions for the next one. Thank you very much for taking the time to help me out.

Thanks for sharing about the history of fin making and for the layup advice. I will definitely stay away from the UV cure for my next panel. I appreciate the help you and the others have given me. I am relatively new to shaping and glassing and the help from everyone here is so very much appreciated.

One other thing. Are you putting a dead weight on top of the layup before it cures? I’ve found I got better results by replicating the working surface under and on top of the layup. I used smooth plywood as a base, then window glass and wax paper. After laying up the glass cloth I placed a sheet of wax paper on top, then glass, plywood, and a 4" cinder block.

been using a roller since day one.
initial spread with squeege then roll a back and forth
in an diagonally to bring bublles out.
I wet two layers of glass at a time because I don’t want
any bubbles. I don’t think I could get a bubble free panel
without rolling. I do the entire panel and then brush a
hot coat over it. Because the bottom is on a polished
tile surface it sands nicely and is perfectly flat.
FYI. Polypropolene also works for panel layups.
a little wax before you start and the panel pops right off.

Stay Stoked, Rich
P.S. The fins attached are the ones Anthony Toshnick is running on his Mavs Gun.

As stated; unequivocally truthful.

Thanks for this suggestion. I have heard the same technique from some others as well. Someone said that using the wax paper and the glass helps the resin to cure hard like a sanding resin, helping with the foiling. I appreciate you taking the time to give me this help.

Thanks for the tips and for explaining your technique. I will definitely be picking up a roller before I lay up my next panel. The final hit with a hot coat makes a lot of sense too. I am new to all of this and I really appreciate you, and the rest of the people, who have taken the time to help me out. Thanks.